四家中国企业进入前十名，比亚迪排第三 May 5th, 2015 by James Ayre Republish Reprint Those interested in tracking the state of the electric vehicle (EV) battery manufacturing market will likely be interested in taking a look at the chart and table below — which provide a fair amount of data on the market as pertaining to consumer electric car batteries (not pertaining to “heavy duty” vehicles such as buses, or to energy storage systems). And a big thanks to José Pontes for the numbers. Battery Manufacturer 1st Quarter 2015 (MWh) 2014 (MWh) % of 1Q 2015 % of 2014 Panasonic 888 2726 45% 41% AESC 361 1620 18% 24% BYD 196 461 10% 7% Mitsubishi/GS Yuasa 135 451 7% 7% LG Chem 114 886 6% 13% Samsung 105 314 5% 5% Wanxiang 62 0 3% 0% Beijing Pride Power (BPP) 47 121 2% 2% Tianneng 38 77 2% 1% SB LiMotive 37 0 2% 0% Total 1983 6656 100% 100% As you can see, Panasonic continues to dominate the market — with Tesla’s strong showing being a major factor. The company supplies Volkswagen as well, though, it should be remembered — giving it some growth potential beyond the Tesla association. The joint venture between Nissan Motors and NEC, AESC, is continuing on its long dive (down nearly 20% of top 10 market share in just 3 years). Considering that Nissan will be sourcing batteries from LG Chem in the future, this dive is set to continue. BYD is continuing to do well — and it should be noted here that these figures don’t even factor in the company’s electric buses or its energy storage solutions (which are considerable). BYD’s market share is especially thanks to the top-selling Qin EV , but also its many other market offerings. The rest of the list (again, coming to us via the EV Sales blog ) is about what you’d expect — a slow loss of top 10 market share mostly, with the exception of LG Chem and Samsung, which are providing the batteries for the Chevy Volt and some of BMW’s electric offerings, respectively. Some of the small companies further down the list have managed to gain some market share as well, though. Wanxiang managed to climb to number 7 (up from number 11 in 2014) with a top 10 market share increase of 2% thanks to the success of the Zotye E20, etc.
Hydrothermal synthesis and potential applicability of rhombohedral siderite as a high-capacity anode material for lithium ion batteries Shiqiang Zhao, Yue Yu, Shanshan Wei, Yuxi Wang, Chenhao Zhao, Rui Liu, Qiang Shen* Journal of Power Sources 253 (2014) 251-255 2014.5.1-赵世强-journal of power sources .pdf http://www.sciencedirect.com/science/article/pii/S0378775313020338 DOI: 10.1016/j.jpowsour.2013.12.055 a b s t r a c t Natural siderite is a valuable iron mineral composed of ferrous carbonate (FeCO 3 ), which is commonly found in hydrothermal veins and contains no sulfur or phosphorus. In this paper, micro-sized FeCO 3 crystallites are synthesized via a facile hydrothermal route, and almost all of them possess a rhombohedral shape similar to that of natural products. When applied as an anode material for lithium ion batteries, the synthetic siderite can deliver an initial specific discharge capacity ofw1587 mAh g -1 with a coulombic efficiency of 68% at 200 mA g -1 , remaining a reversible value of 1018 mAh g -1 over 120 cycles. Even at a high current density of 1000 mA g -1 , after 120 cycles the residual specific capacity (812 mAh g -1 ) is still higher than the theoretical capacity of FeCO3 (463 mAh g -1 ). Moreover, a novel reversible conversion mechanism accounts for the excellent electrochemical performances of rhombohedral FeCO3 to a great extent, implying the potential applicability of synthetic siderite as lithium ion battery anodes. 2013 Elsevier B.V. All rights reserved. Keywords: Lithium ion battery Anode material Hydrothermal synthesis Ferrous carbonate Rhombohedral crystallite 4. Conclusions Rhombohedral FeCO 3 (or synthetic siderite) has been facilely synthesized by a hydrothermal method, possessing an average size of 1.4±0.2 mm. Tentatively applied as LIB anodes, the excellent durability and high-rate performance of these micro-rhombohedra can be reproducibly observed. Even at 1000 mA g -1 , the reversible capacity (w800 mAh g -1 ) is still higher than the theoretical capacity of FeCO 3 (463 mAh g -1 ). As for the novel electrochemical activity of FeCO 3 towards metal lithium, the simultaneous formation of unknown Fe 3 + -containing derivatives and possible C - 1 -containing Li 2 C 2 incompletely answers the high-capacity characteristics of FeCO 3 (e.g., the 120th reversible value w1000 mAh g -1 at 200 mA g -1 ). Therefore, the lithium storage mechanism of FeCO 3 needs to be further conducted in future.
For the first time, I didn't have any questions for my trainer. But, I went anyway, to learn anything new. First, I asked my trainer to walk me through the rest under System Preferences. He was knowledgeable. When it's done, I still had five minutes left. So, I asked him to show me a trick. He thought about it, and told me this: You pay 30% more for your MacBook (than a desk top), because of the battery. So, use it. I said I know this, from my son's experience. If one plugs in his MacBook all the time, the battery loses its capacity. So, my Mac friends, go ahead and use your battery. You don't need to drain it completely all the time; just once a month will do. Happy Mac-around!
http://www.technologyreview.com/news/514266/battery-could-provide-a-cheap-way-to-store-solar-power/ Battery Could Provide a Cheap Way to Store Solar Power Combining aspects of high-energy lithium-sulfur batteries with flow battery technology can lower costs. By Kevin Bullis on April 26, 2013 Flask battery: A new kind of flow battery lights up a small LED. The battery stores energy in a sheet of lithium metal and materials dissolved in a liquid electrolyte. There’s a promising new entry in the race to build cheap batteries for storing energy from solar panels and wind turbines. Stanford researchers led by Yi Cui, a professor of materials science and engineering, have demonstrated a partially liquid battery made of inexpensive lithium and sulfur. Cui says the battery will be easy to make and will last for thousands of charging cycles. Cui believes that the material and manufacturing costs of the battery might be low enough to meet the Department of Energy’s goal of $100 per kilowatt-hour of storage capacity, which the DOE estimates will make the technology economically attractive to utilities. Existing batteries can cost hundreds of dollars per kilowatt-hour of capacity, although several companies are working to commercialize cheaper ones (see “ Ambri’s Better Battery ” and “ Battery to Take On Diesel and Natural Gas ”). The technology is a cross between a flow battery and an experimental type called a lithium-sulfur battery. In a flow battery, positive and negative liquid electrolytes are stored in swimming-pool-size tanks. The batteries are attractive because the amount of energy they store can be increased simply by expanding these tanks, without increasing the size of the electronic connections and other battery parts needed to extract the energy. But they require expensive ion membranes and large amounts of material. Lithium-sulfur batteries, meanwhile, consist of two solid electrodes connected by a liquid electrolyte. They have the potential to store large amounts of energy, but they’ve been hard to commercialize because they can’t be recharged often enough. The problem is that compounds called lithium polysulfides, which form during the charging and discharging process, tend to dissolve in the electrolyte, leaving the lithium and sulfur inaccessible for future charging cycles. With each recharge, more energy capacity is lost, limiting the life of these batteries. But Cui saw that this phenomenon could be useful in a flow battery, where energy is stored in the electrolyte and not in a solid electrode. Indeed, the dissolved lithium polysulfide stores more energy than the materials usually used in flow batteries, such as vanadium, so less material is needed. That, and the fact that lithium and sulfur cost less than vanadium, could help lower the cost of flow batteries. What’s more, Cui says, his modified flow battery needs no ion membrane. Only one of the electrodes is a liquid; the other is metallic lithium. An inexpensive coating on the lithium serves the purpose of the membrane, allowing ions but not electrons to move between the lithium metal and the polysulfides. That is key to both protecting the lithium and creating an electrical current. Challenges remain before the battery can be commercialized. For example, the number of times it can be recharged, while currently impressive for a lithium-sulfur battery, still needs to be improved for the technology to be economically competitive. Cui’s battery has been charged 2,000 times, but the DOE target is 5,000 recharges. Even to reach 2,000 cycles, he needed to include extra lithium in the battery to accommodate the fact that the metal degrades a bit with each charging cycle. The extra lithium adds to the cost, which could make it harder to meet the target of $100 per kilowatt-hour.
http://www.nature.com/nnano/journal/v3/n1/full/nnano.2007.411.html Letter Nature Nanotechnology 3 , 31 - 35 (2008) Published online: 16 December 2007 | doi:10.1038/nnano.2007.411 Subject term: Electronic properties and devices High-performance lithium battery anodes using silicon nanowires Candace K. Chan 1 , Hailin Peng 2 , Gao Liu 3 , Kevin McIlwrath 4 , Xiao Feng Zhang 4 , Robert A. Huggins 2 Yi Cui 2 Abstract There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices 1 . Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g −1 ; ref. 2 ). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials 3, 4 , silicon anodes have limited applications 5 because silicon's volume changes by 400 % upon insertion and extraction of lithium which results in pulverization and capacity fading 2 . Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75 % of this maximum, with little fading during cycling. Introduction Previous studies in which Si bulk films and micrometre-sized particles were used as electrodes in lithium batteries have shown capacity fading and short battery lifetime due to pulverization and loss of electrical contact between the active material and the current collector ( Fig. 1 a). The use of sub-micrometre pillars 6 and micro- and nanocomposite anodes 5, 7, 8, 9 led to only limited improvement. Electrodes made of amorphous Si thin films have a stable capacity over many cycles 5, 8 , but have insufficient material for a viable battery. The concept of using one-dimensional (1D) nanomaterials has been demonstrated with carbon 10 , Co 3 O 4 (refs 11 , 12 ), SnO 2 (ref. 13 ) and TiO 2 (ref. 14 ) anodes, and has shown improvements compared to bulk materials. A schematic of our Si nanowire (NW) anode configuration is shown in Fig. 1 b. Nanowires are grown directly on the metallic current collector substrate. This geometry has several advantages and has led to improvements in rate capabilities in metal oxide cathode materials 15 . First, the small NW diameter allows for better accommodation of the large volume changes without the initiation of fracture that can occur in bulk or micron-sized materials ( Fig. 1 a). This is consistent with previous studies that have suggested a materials-dependent terminal particle size below which particles do not fracture further 16, 17 . Second, each Si NW is electrically connected to the metallic current collector so that all the nanowires contribute to the capacity. Third, the Si NWs have direct 1D electronic pathways allowing for efficient charge transport. In electrode microstructures based on particles, electronic charge carriers must move through small interparticle contact areas. In addition, as every NW is connected to the current-carrying electrode, the need for binders or conducting additives, which add extra weight, is eliminated. Furthermore, our Si NW battery electrode can be easily realized using the vapour–liquid–solid (VLS) or vapour–solid (VS) template-free growth methods 18, 19, 20, 21, 22, 23 to produce NWs directly onto stainless steel current collectors (see Methods). Figure 1: Schematic of morphological changes that occur in Si during electrochemical cycling. a , The volume of silicon anodes changes by about 400 % during cycling. As a result, Si films and particles tend to pulverize during cycling. Much of the material loses contact with the current collector, resulting in poor transport of electrons, as indicated by the arrow. b , NWs grown directly on the current collector do not pulverize or break into smaller particles after cycling. Rather, facile strain relaxation in the NWs allows them to increase in diameter and length without breaking. This NW anode design has each NW connecting with the current collector, allowing for efficient 1D electron transport down the length of every NW. Full size image (35 KB) A cyclic voltammogram of the Si NW electrode is shown in Fig. 2 a. The charge current associated with the formation of the Li–Si alloy began at a potential of ~330 mV and became quite large below 100 mV. Upon discharge, current peaks appeared at about 370 and 620 mV. The current–potential characteristics were consistent with previous experiments on microstructured Si anodes 6 . The magnitude of the current peaks increased with cycling due to activation of more material to react with Li in each scan 6 . The small peak at 150–180 mV may have been due to reaction of the Li with the gold catalyst, which makes a negligible contribution to the charge capacity (see Supplementary Information, Figs S1 and S2 ). Figure 2: Electrochemical data for Si NW electrodes. a , Cyclic voltammogram for Si NWs from 2.0 V to 0.01 V versus Li / Li + at 1 mV s −1 scan rate. The first seven cycles are shown. b , Voltage profiles for the first and second galvanostatic cycles of the Si NWs at the C / 20 rate. The first charge achieved the theoretical capacity of 4,200 mAh g −1 for Li 4.4 Si. c , The voltage profiles for the Si NWs cycled at different power rates. The C / 20 profile is from the second cycle. d , Capacity versus cycle number for the Si NWs at the C / 20 rate showing the charge (squares) and discharge capacity (circles). The charge data for Si nanocrystals (triangles) from ref. 8 and the theoretical capacity for lithiated graphite (dashed line) are shown as a comparison to show the improvement when using Si NWs. Full size image (47 KB) Si NWs were found to exhibit a higher capacity than other forms of Si (ref. 5 ). Figure 2 b shows the first and second cycles at the C / 20 rate (20 h per half cycle). The voltage profile observed was consistent with previous Si studies, with a long flat plateau during the first charge, during which crystalline Si reacted with Li to form amorphous Li x Si. Subsequent discharge and charge cycles had different voltage profiles characteristic of amorphous Si (refs 24 – 27 ). Significantly, the observed capacity during this first charging operation was 4,277 mAh g −1 , which is essentially equivalent to the theoretical capacity within experimental error. The first discharge capacity was 3,124 mAh g −1 , indicating a coulombic efficiency of 73 % . The second charge capacity decreased by 17 % to 3,541 mAh g −1 , although the second discharge capacity increased slightly to 3,193 mAh g −1 , giving a coulombic efficiency of 90 % . Both charge and discharge capacities remained nearly constant for subsequent cycles, with little fading up to 10 cycles ( Fig. 2 d), which is considerably better than previously reported results 8, 9 . As a comparison, our charge and discharge data are shown along with the theoretical capacity (372 mAh g −1 ) for the graphite currently used in lithium battery anodes, and the charge data reported for thin films containing 12-nm Si nanocrystals 8 (NCs) in Fig. 2 d. This improved capacity and cycle life in the Si NWs demonstrates the advantages of our Si NW anode design. The Si NWs also displayed high capacities at higher currents. Figure 2 c shows the charge and discharge curves observed at the C / 20, C / 10, C / 5, C / 2 and 1C rates. Even at the 1C rate, the capacities remained 2,100 mAh g −1 , which is still five times larger than that of graphite. The cyclability of the Si NWs at the faster rates was also excellent. Using the C / 5 rate, the capacity was stable at ~3,500 mAh g −1 for 20 cycles in another device (see Supplementary Information, Fig. S3 ). Despite the improved performance, the Si NW anode showed an irreversible capacity loss in the first cycle, which has been observed in other work 5 . Although solid electrolyte interphase (SEI) formation has been observed in Si (ref. 28 ), we do not believe this is the cause of our initial irreversible capacity loss, because there is no appreciable capacity in the voltage range of the SEI layer formation (0.5–0.7 V) during the first charge ( Fig. 2 b) 8 . Although SEI formation may be occurring, the capacity involved in SEI formation would be very small compared to the high charge capacity we observed. The mechanism of the initial irreversible capacity is not yet understood and requires further investigation. The structural morphology changes during Li insertion were studied to understand the high capacity and good cyclability of our Si NW electrodes. Pristine, unreacted Si NWs were crystalline with smooth sidewalls ( Fig. 3 a) and had an average diameter of ~89 nm (s.d., 45 nm) ( Fig. 3 e). Cross-sectional scanning electron microscopy (SEM) showed that the Si NWs grew off the substrate and had good contact with the stainless steel current collector ( Fig. 3 a, inset). After charging with Li, the Si NWs had roughly textured sidewalls ( Fig. 3 b), and the average diameter increased to ~141 nm (s.d., 64 nm). Despite the large volume change, the Si NWs remained intact and did not break into smaller particles. They also appeared to remain in contact with the current collector, suggesting minimal capacity fade due to electrically disconnected material during cycling. Figure 3: Morphology and electronic changes in Si NWs from reaction with Li. a , b , SEM image of pristine Si NWs before ( a ) and after ( b ) electrochemical cycling (same magnification). The inset in a is a cross-sectional image showing that the NWs are directly contacting the stainless steel current collector. c , d , TEM image of a pristine Si NW with a partial Ni coating before ( c ) and after ( d ) Li cycling. e , Size distribution of NWs before and after charging to 10 mV (bin width 10 nm). The average diameter of the NWs increased from 89 to 141 nm after lithiation. f , I – V curve for a single NW device (SEM image, inset) constructed from a pristine Si NW. g , I – V curve for a single NW device (SEM image, inset), constructed from a NW that had been charged and discharged once at the C / 20 rate. Full size image (56 KB) The Si NWs may also change their length during the change in volume. To evaluate this, 25-nm Ni was evaporated onto as-grown Si NWs using electron beam evaporation. Because of the shadow effect of the Si NWs, the Ni only covered part of the NW surface ( Fig. 3 c), as confirmed by energy dispersed X-ray spectroscopy (EDS) mapping (see Supplementary Information, Fig. S4 ). The Ni is inert to Li and acts as a rigid backbone on the Si NWs. After lithiation ( Fig. 3 d), the Si NWs changed shape and wrapped around the Ni backbone in a three-dimensionally helical manner. This appeared to be due to an expansion in the length of the NW, which caused strain because the NW was attached to the Ni and could not freely expand but rather buckled into a helical shape. Although the NW length increased after lithiation, the NWs remained continuous and without fractures, maintaining a pathway for electrons all the way from the collector to the NW tips. With both a diameter and length increase, the Si NW volume change after Li insertion appears to be about 400 % , consistent with the literature 5 . Efficient electron transport from the current collector to the Si NWs is necessary for good battery cycling. To evaluate this, we conducted electron transport measurements on single Si NWs before and after lithiation (see Methods). The current versus voltage curve on a pristine Si NW was linear, with a 25 k Ω resistance (resistivity of 0.02 Ω -cm) ( Fig. 3 f). After one cycle, the NWs became amorphous, but still exhibited a current that was linear with voltage with an 8 M Ω resistance (resistivity of 3 Ω -cm) ( Fig. 3 g). The good conductivity of pristine and cycled NWs ensures efficient electron transport for charge and discharge. The large volume increase in the Si NWs is driven by the dramatic atomic structure change during lithiation. To understand the structural evolution of NWs, we characterized the NW electrodes at different charging potentials. The X-ray diffraction (XRD) patterns were taken for initial pristine Si NWs, Si NWs charged to 150 mV, 100 mV, 50 mV and 10 mV, as well as after 5 cycles ( Fig. 4 a). XRD patterns of the as-grown Si NWs showed diffraction peaks associated with Si, α -FeSi 2 , Au (the Si NW catalyst) and stainless steel (SS). The α -FeSi 2 forms at the interface between the SS and the Si wires during the high temperature (530 °C) NW growth process. The α -FeSi 2 was not found to appreciably react with Li during electrochemical cycling, although a small amount of reaction has been reported 24 . After Si NWs were charged to 150 mV, the higher angle Si peaks disappeared. Only the Si(111) peak was still visible, but its intensity was greatly decreased. This is consistent with the disappearance of the initial crystalline Si and the start of the formation of amorphous Li x Si. The four broad peaks that appeared in the lower angles are due to the formation of Li 15 Au 4 (see Supplementary Information, Fig. S5 ). At 100 mV, the pure Au peaks disappeared, indicating that the Au had completely reacted with Li. The Si(111) peak was very weak at 100 mV, and disappeared completely at 50 mV. It appears that Si NWs remain amorphous after the first charge, consistent with the non-flat voltage charging / discharging curve in Fig. 2 b. This contrasts, however, with other studies on Si electrodes 25, 26 , which have reported the formation of crystalline, Li 3.75 Si at potentials less than 30–60 mV. In situ XRD studies have determined that this crystalline phase only forms at 50 mV for films thicker than ~2 m (ref. 27 ). We did not observe this to be the case in our Si NWs, most likely because of their shape and small dimensions. Figure 4: Structural evolution of Si NWs during lithiation. a , XRD patterns of Si NWs before electrochemical cycling (initial), at different potentials during the first charge, and after five cycles. b – e , TEM data for Si NWs at different stages of the first charge. b , A single-crystalline, pristine Si NW before electrochemical cycling. The SAED spots (inset) and HRTEM lattice fringes (bottom) are from the Si 1 / 3(224) planes. c , NW charged to 100 mV showing a Si crystalline core and the beginning of the formation of a Li x Si amorphous shell. The HREM (bottom) shows an enlarged view of the region inside the box. d , Dark-field image of a NW charged to 50 mV showing an amorphous Li x Si wire with crystalline Si grains (bright regions) in the core. The spotty rings in the SAED (inset) are from crystalline Si. The HRTEM (bottom) shows some Si crystal grains embedded in the amorphous wire. e , A NW charged to 10 mV is completely amorphous Li 4.4 Si. The SAED (top) shows diffuse rings characteristic of an amorphous material. Full size image (30 KB) The local structural features of Si NWs during the first Li insertion were studied with transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The as-grown Si NWs were found to be single-crystalline. Figure 4 b shows an example of a typical Si NW with a 112 growth direction 29 . Figure 4 c shows a Si NW with a 112 growth direction that was charged to 100 mV. In this case there were two phases present, as expected from the voltage profile. Both crystalline and amorphous phases were clearly seen. The distribution of the two phases was observed both across the diameter (a crystalline core and an amorphous shell) and along the length. The SAED showed the spot pattern for the crystalline phase (Si), but weak diffuse rings from the amorphous phase (Li x Si alloy) were also observed. Li ions must diffuse radially into the NW from the electrolyte, resulting in the core–shell phase distribution. The reason for phase distribution along the length is not yet understood. At 50 mV, the Si NW became mostly amorphous with some crystalline Si regions embedded inside the core, as seen from the dark-field image and HRTEM ( Fig. 4 d). The SAED showed spotty rings representative of a polycrystalline sample and diffuse rings for the amorphous phase. At 10 mV ( Fig. 4 e), all of the Si had changed to amorphous Li 4.4 Si, as indicated by the amorphous rings in the SAED. These TEM observations were consistent with the XRD results ( Fig. 4 a) and voltage charging curves ( Fig. 2 b). Top of page Methods Si NWs were synthesized using the VLS process on stainless steel substrates using Au catalyst. The electrochemical properties were evaluated under an argon atmosphere by both cyclic voltammetry and galvanostatic cycling in a three-electrode configuration, with the Si NWs on the stainless steel substrate as the working electrode and Li foil as both reference and counter-electrodes. No binders or conducting carbon were used. The charge capacity referred to here is the total charge inserted into the Si NW, per mass unit, during Li insertion, whereas the discharge capacity is the total charge removed during Li extraction. For electrical characterization, single Si NW devices were contacted with metal electrodes by electron-beam lithography or focused-ion beam deposition. For more detailed descriptions of NW synthesis, TEM and XRD characterization, electrochemical testing, and device fabrication, see the Supplementary Information .
http://phys.org/news/2010-10-graphite-anode-silicon-anode-li-ion.html Who killed the graphite anode? Researchers move silicon anode li-ion battery technology forward October 11, 2010 High-resolution transmission electron microscopic (TEM) images of silicon anode morphologies: a) original porous silicon and b) porous silicon coated with nano layer of carbon. (PhysOrg.com) -- Scientists at Pacific Northwest National Laboratory developed a lithium-ion (Li-ion) battery technology with reversible capacity of more than 1,600 milliamp hours per gram (mAh/g) after 40 charging/discharging cycles. This silicon-based anode technology doubles the capacity of conventional graphite anode technology used in Li-ion batteries, and may lead to Li-ion batteries with much higher energy density and capacity. google_protectAndRun("render_ads.js::google_render_ad", google_handleError, google_render_ad);Ads by GoogleBuy 18650 li-ion battery - Buy 18650 Rechargeable batteries Fast Deliver and Free Shipping - www.ledsupermall.com A future with millions of fossil-fuel powered cars displaced from American roadways by plug-in electric vehicles presents significant economic and environmental benefits. It also poses a challenge to develop a next-generation battery technology that offers far greater energy density. Silicon anodes for Li-ion batteries present a promising solution. Today's electric vehicles rely on nickel-metal hydride batteries. They are heavy, bulky and have a specific energy that is too low, about 80 watt hours per kilogram (Wh/kg), for long-distance travel. Li-ion batteries, commonly used in handheld electronics, offer greater capacity. Composed of three main components—a graphite anode, a cathode and electrolyte (lithium salt dissolved in organic solvent)—the graphite anode has specific capacity of about 350 mAh/g. Li-ion batteries using graphite anodes exhibit a specific energy of more than 160 Wh/kg, double that of nickel-metal hydride batteries. "If we want to increase driving distance of electric vehicles, we need to have much better capacity -- at least double the capacity of graphite anodes and cathodes used in the Li-ion battery," said Dr. Jason Zhang, a PNNL scientist. One of the limiting factors of the Li-ion battery is its anode—the graphite. Lithium is added to graphite when charging and removed as the battery is used. Graphite anodes are used in nearly all Li-ion batteries, but recent research has sought to capitalize on a better anode solution—silicon. With a theoretical capacity of more than 10 times that of graphite, silicon anodes can at least double the capacity of graphite-anode batteries. However, it is this very ability to absorb lithium and expand during charging that is the problem: The silicon breaks down quickly. The challenge for PNNL researchers: Take advantage of silicon's high capacity while finding a way to keep it from deteriorating through repeated charging/discharging cycles. Zhang and the PNNL research team addressed the challenge by designing a silicon particle architecture that would maintain structural integrity. Nanostructured porous silicon was used to maintain stability through repeated expansion and contraction. Next, chemical vapor deposition (CVD) of carbon coatings and highly elastic Ketjen Black (KB) carbon were used to improve the electrical conductivity throughout all cycling stages. The team placed these anodes between graphene -- planar sheets of bonded carbon atoms—to maintain strong electrical contact between silicon particles. They tested these anodes in the laboratory and found they had a reversible capacity of more than 1,600 mAh/g after 40 charging/discharging cycles. This technology more than doubles the capacity of conventional graphite anodes used in Li-ion batteries. The PNNL research team continues to improve the performance and long-term stability of the silicon anodes from 40 to 50 charging/discharging cycles today to a goal of about 500 cycles in the future. One solution may be the development of a better binder that can maintain improved mechanical and electrical contact. This method has potential for much greater cyclability while maintaining high energy density. More information: Xiao J, W Xu, D Wang, D Choi, W Wang, X Li, GL Graff, J Liu, and J Zhang. 2010. "Stabilization of Silicon Anode for Li-Ion Batteries." Journal of The Electrochemical Society, August 2, 2010, doi:10.1149/1.3464767 Read more at: http://phys.org/news/2010-10-graphite-anode-silicon-anode-li-ion.html#jCp
http://www.gizmag.com/crushed-silicon-lithium-ion-battery/24885/ How to boost lithium battery performance – just add crushed silicon By Jason Falconer November 6, 2012 5 Comments 2 Pictures Tweet Rice University researchers Madhuri Thakur, left, and Sibani Lisa Biswal with their crushed silicon anode material (Photo: Jeff Fitlow) Image Gallery (2 images) Gold Nanoparticles - www.nanopartz.com Research Gold Nanoparticles Monodisperse 1.8nm - 10 microns Ads by Google Researchers at Rice University and Lockheed Martin may have developed a low-cost method of creating longer-lasting, high-capacity lithium-ion batteries. Currently graphite is used as the anode in commercial li-ion products, despite the fact that a silicon anode could potentially store ten times more lithium ions. The team says it has solved one of the problems associated with silicon, which nearly triples the energy density of current li-ion designs. Engineer Sibani Lisa Biswal and research scientist Madhuri Thakur had been working on a porous silicon film with sponge-like properties, but wanted to create something more applicable to the current battery manufacturing process. They discovered that by crushing the film, the resulting powder had a surface area 50 times that of regular crushed silicon. The result is an anode material that can hold a charge of 1,000 milliamp hours per gram compared to graphite anodes, which store 350 mAh/g – and that's only a third of its theoretical capacity. Both vials contain the same amount of crushed silicon, but the vial on the right contains the treated powder with 50 times more surface area (Photo: Jeff Fitlow) “We’re truly excited about this breakthrough and are looking forward to transitioning this technology to the commercial marketplace,” said Lockheed Martin researcher Mark Isaacson, despite questions of cost and scale that need to be addressed. The team is working on a completed battery that will test their design, and part of that will be finding the best silicon-friendly cathode material. That said, if all goes well this could be the long overdue breakthrough in battery technology that electric vehicles and mobile electronic device manufacturers have been waiting for. Source: Rice University
http://www.prweb.com/releases/2012/3/prweb9280084.htm California Lithium Battery To Commercialize Lowest Cost Lithium Battery CLBattery announced at last week's Department of Energy's ARPA-e Energy Innovation Summit in D.C. that they've entered into a Work for Others agreement with Argonne National Laboratory to commercialize the low cost "GEN3" lithium battery. Our VLF battery has a clear performance and cost advantage in providing the massive currents needed with the minimum materials and battery management components, resulting in a more affordable lithium-ion battery for wide-scale use.” Phil Roberts, CEO California (PRWEB) March 15, 2012 California Lithium Battery Inc. (CalBattery) announced at last week’s Department of Energy’s ARPA-e Energy Innovation Summit in Washington, D.C. that they have entered into a Work for Others (WFO) agreement with Argonne National Laboratory (ANL) to commercialize a breakthrough low cost “GEN3” lithium battery. This new transformational battery will offer the highest energy density and longest cycle life of any lithium battery made today. CalBattery believes that it will be able manufacture this GEN3 lithium-ion battery in the US at a comparable cost reduction up to 70%. According to Phil Roberts, CEO of CalBattery, “Billions of dollars of energy are being wasted every year because we can't store electricity affordably and practically.” Roberts continued, “Incredibly, some energy storage systems providers and independent power producers today are using hundreds of thousands, if not millions, of small cylindrical cell batteries in massive utility-scale storage systems. This approach is simply too costly and not viable. Large storage must be built from large batteries, not small batteries originally designed for powered hand tools. Our VLF battery has a clear performance and cost advantage in providing the massive currents needed with the minimum materials and battery management components, resulting in a more affordable lithium-ion battery for wide-scale use.” This novel “GEN3” lithium-ion battery will combine Argonne’s silicon-graphene battery anode process with other advanced battery materials into the lowest lifecycle cost per watt lithium-ion battery ideally suited for energy storage and EV applications. The key technology advancement is CalBattery will become the first US battery manufacturer to be able to successfully use silicon in its battery anode. Silicon which has the ability to absorb lithium by a factor of 10X has until now not yet proven to be stable enough for battery anode use. While much research today is focused on ways to improve silicon stability, ANL tests indicate this newly patented process that embeds nano-silicon into graphene through a novel chemical vapor deposition (CVD) process will dramatically improve silicon stability by protecting the silicon material as it charges and discharges, extending battery cycle life by 3X. CalBattery recently entered into an option for an exclusive license from ANL for the CVD process for Large Format battery applications. Plans are to take new ANL and other advanced battery material chemistries and apply them into a superior commercial Very Large Format (VLF) battery for energy storage and electric vehicle applications over the next two years. Dan Vogler, CTO of Ionex Energy Storage Systems said, “The CalBattery Very Large Format form factor battery is ideally suited for grid-scale 1-25MW energy storage systems and/or in heavy-duty EVs. No other lithium, lead-acid, or flow-battery we have seen today can compete with CalBattery’s superior GEN3 lithium-ion battery in terms of easy maintenance, better performance and lower overall use cost.” About California Lithium Battery Inc. California Lithium Battery (“CalBattery”) Inc . was established in 2011 as a California corporation to develop and manufacture in the US the most technologically advanced and affordable lithium battery for grid-scale energy storage, heavy-duty EV transportation, and consumer electronics. CalBattery was named a finalist in the 2012 DOE’s America’s Next Top Energy Innovator challenge. For more information contact: Phil Roberts, 562-243-1800, phil(dot)roberts(at)CLBattery(dot)com
Hierarchical mesoporous perovskite nanowires for ultrahigh-capacity Li-air battery Li-ion batteries have developed rapidly in recent years because of their low cost, long cycle life, good reversibility and no memory effect. However, the highest energy storage of Li-ion batteries is insufficient to satisfy the ever-increasing requirements for batteries with high capacities. Recently, Li-air batteries have attracted great interest because they potentially have much higher energy storage density compared with all other chemical batteries. They could theoretically offer very high specific energies (i.e. 5000 Whkg −1 ) because of the cathode reaction: 2Li + O 2 → Li 2 O 2 and 2Li + 0.5O 2 → Li 2 O in nonaqueous electrolyte. However, it also brings many problems including the precipitation of reaction products Li 2 O 2 /Li 2 O or electrolyte decomposition products on the catalyst and electrode eventually blocked the oxygen pathway and limited the capacity of the Li-air batteries. To enhance the performance, constructing a structure with continuous oxygen diffusion channels is very important. In WUT-Harvard Joint Nano Key Laboratory ， Liqiang Mai and colleagues synthesized hierarchical mesoporous perovskite structure La 0.5 Sr 0.5 CoO 2.91 (LSCO) nanowires constructed by nanorods using a facile multi-step micro-emulsion followed by a slow annealing method. The high-performance catalysts for the oxygen reduction reaction (ORR) of hierarchical mesoporous LSCO nanowires was demonstrated, with low peak-up potential and high limiting diffusion current, via rotating disk electrode (RDE) measurements in both aqueous electrolytes and nonaqueous electrolytes. Furthermore, Li-air battery based on hierarchical mesoporous LSCO nanowires and nonaqueous electrolyte was fabricated, which exhibits ultrahigh capacity, c.a., over 11000 mAh g –1 , with the improvement of one order of magnitude than LSCO nanoparticles. A large specific surface area with ~ 10 nm size pores was confirmed by BET. HRTEM demonstrated LSCO nanorods are tightly attached to each other at atomic level when they formed the hierarchical nanowire. This structure can provide continuous oxygen diffusion channels that contribute to its electrocatalytic performance. “Constructing hierarchical perovskite LSCO mesoporous nanowires in this paper is a simple and efficient route to provide continuous channels for oxygen transmission and ionic diffusion. The hierarchical perovskite mesoporous LSCO will have great potential applications in Li-air battery, fuel cells or other electrochemical devices.” saysMai. Reference 1. Y. Zhao, L. Xu, L. Mai * , C. Han, Q. An, X. Xu, X. Liu, and Q. Zhang, Hierarchical mesoporous perovskite La 0.5 Sr 0.5 CoO 2.91 nanowires with ultrahigh capacity for Li-air battery. PNAS. (2012). Author affiliation State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China *Email: mlq518@whut.edu.cn
http://goldsea.com/Text/index.php?id=10526 Yi Cui's Nano-Wire Battery Venture Raises $25 Mil. Battery startup Amprius has raised $25 million to commercialize founder Yi Cui’s breakthrough in using silicon nano-wires to boost the efficiency of lithium-ion batteries. The funding source includes Google CEO Eric Schmidt and venture capital firm Kleiner Perkins Caulfield Byers, VantagePoint Venture Partners, Stanford University, Trident Capital and Chinese funds IPV Capital and Qian Neng Fund. Stanford Associate Professor Yi Cui has developed a battery cathode (the side of the battery that stores the positive charge) that uses silicon nano-wires to store up to 10 times the density of lithium ions as the carbon cathodes commonly used in even the most advanced lithium-ion batteries. The breakthrough has improved battery energy density up to 40% on the scale used in portable electronic devices like smartphones. Yi Cui (right) visited China’s Suzhou Institute of Nano-Tech and Nano-Bionics of the Chinese Academy of Sciences in January of 2011. Cui hopes to scale up the concept to the far larger batteries used to power electric cars. Success there would give Amprius a virtually unlimited market since, for the forseeable future, batteries make up half the cost of electric cars and their cost and capacity are the limiting factors in their popularization. At the moment the battery industry coaxes out about a 2% efficiency improvement each year from lithium-ion batteries. “Our recent fundraising will enable us to deploy our first commercial product, validate our manufacturing processes, and launch a global presence,” said Amprius CEO Kang Sun, a 20-year tech venture veteran. Amprius was founded in 2008 by Yi Cui, a superstar associate professor and researcher at Stanford University. His breakthroughs in devising ways to configure functioning devices on the nano scale attracted a $10 million grant from Saudi Arabia’s King Abdullah University of Science and Technology ( KAUST ). That grant is currently funding Cui’s sizeable Stanford research group focused on nanoscale phenomena for energy conversion, electronics, and nanobiotechnolog. His group has developed nanowire and nanocrystal materials for energy storage, solar cell and memory devices. Cui was the first person to demonstrate nanowire field effect biosensors. He has published 32 research papers related to nanowires and nanocrystals. He has presented his work in over 70 invited talks at conferences, universities, and research centers around the world. Among his inventions is a process for turning clothing into a battery by dying fabric with a solutioin containing carbon nanotubes. Yi Cui graduated from China’s University of Science and Technology in 1998. He moved to the U.S. to study at Harvard and obtained his PhD in chemistry there in 2002. He completed a two-year postdoctoral research project on electronics and colloidal nanocrystals at the University of California, Berkeley from 2003 to 2005. He then joined the Stanford University faculty as an assistant professor in the department of materials science and engineering. In 2010 he was elevated to the status of an associate professor. In 2011 was was appointed to the Photon Science Faculty at the SLAC National Accelerator Laboratory. http://alumni.stanford.edu/get/page/magazine/article/?article_id=30750 Oh, to be young, smart and funded. Suddenly, sensationally and stupendously well funded. That pretty much describes Michael McGehee and Yi Cui. McGehee, associate professor of materials science and engineering, initiated the research proposal that won a $25 million grant from King Abdullah University of Science and Technology (KAUST), which is being built on the shore of the Red Sea in Saudi Arabia. Cui, an assistant professor in the same department, has a $10 million grant from KAUST. McGehee, 35, and Cui, 32, are only in the early months of work that will be supported by the five-year grants. But such an extraordinary level of funding was immediately life-changing. For McGehee, whose project involving solar cells is the impetus for the new Center for Advanced Molecular Photovoltaics at Stanford, the cachet of the KAUST grant has led to even more funding. A dozen companies are signing on—at either $30,000 or $50,000 annually—for an industry affiliates program. McGehee seems too mild-mannered and reflective to ever muster any public bravado. Nevertheless, he's keenly aware of being lifted above the typical scrambling for dollars. He's not getting the attention of a rock star, but he's a clean-tech star. “The only reason I would ever want publicity is if it helps me to get good people and funding,” he says. “Now I have good people and funding.” Cui's focus is on energy storage, and the potential results include the kind of benefit the average consumer can appreciate: better batteries for laptops, cell phones, iPods and other devices. He smiles more readily than McGehee and may be a little more animated, but he too seems to be utterly without swagger or affectation. As best Cui can recall, he reacted to the news of the KAUST grant by going for a quiet walk so he could begin mentally organizing his plans. He's sure that the first person he called was his wife, and he remembers thinking, just because of the excitement in her voice, “that it sounded like she might be jumping in the air.” McGehee's center will support research by 16 professors—12 at Stanford—and they'll have an array of new equipment at their disposal. Peter Peumans, assistant professor of electrical engineering, worked closely with McGehee in writing the KAUST proposal and is the center's deputy director. A six-person management team, which includes McGehee and Peumans, has been established as a way of sharing control and oversight. The center's goal is highly focused: to develop more efficient solar cells (photovoltaic cells) by depositing liquid solutions of semiconductors on the part of the cells that usually is made with silicon semiconductors. Think of the process, McGehee says, “as painting instead of tiling” the cells. The work involves nanoscale technology and the ultimate goal is to “generate solar cells at a price competitive with coal-fired power plants.” KAUST, scheduled for completion next year, is billed as an international, graduate-level research university accessible to men and women. It says all classes will be conducted in English, and the core disciplines will include industrial biotechnology, scientific computing, and energy and environment. The Los Angeles Times described the project as a signal of Saudi Arabia's pressing need for globalized education, but also as a political tinderbox because of its Westernized features. The funding for McGehee and Cui is just a portion of the money being spent by KAUST to establish collaborative relationships around the world. Stanford is partnering with KAUST in other areas, such as helping to select faculty and organize parts of the curriculum. “We've been assured there will be no restriction on academic or social freedom at the university,” McGehee says. McGehee's obligations to KAUST are as a resource for collaboration; Cui will spend three weeks per year at KAUST. Both bubble a bit as they look ahead. Cui, noting that his KAUST grant is “20 times a National Science Foundation grant,” says he has budgeted a large amount of money for equipment that other Stanford scientists will be able to utilize. “It's really satisfying,” McGehee says, “to watch people coming together for this.” http://www.news.harvard.edu/gazette/2002/03.21/01-nano.html Yi Cui (left), Charles Lieber (center), and Wayne Wang discuss a wire sensor they have made to detect low levels of prostate cancer. Because the wire is only about 100 atoms thick, they used the large, powerful microscope in the foreground to see and manipulate wires mounted on circuit chips. (Staff photo by Kris Snibbe) HARVARD GAZETTE ARCHIVES Nanowire is used to sense cancer marker: May be used to detect diseases and biowarfare agents By William J. Cromie Gazette Staff Last month, when Professor Charles Lieber and his students made wires whose thinness is measured in atoms instead of fractions of an inch, he boasted excitedly that "there are so many potential uses for this technology that we feel like kids in a candy shop." In the past week, Lieber's team has developed what is likely to be an important piece of scientific candy, a coated wire capable of detecting low levels of a protein that marks the presence or recurrence of prostate cancer. "The device immediately senses levels of PSA (prostate-specific antigen) four times smaller than is now possible with blood tests that often take days," says Lieber, Hyman Professor of Chemistry at Harvard University. He believes it will be possible to expand the use of such unimaginably small wires to sense the presence of malignancies, such as breast and ovarian cancers, as well as other types of diseases, and pathogens used in biological warfare. The sensor is so small it opens up the possibility of detectors implanted in the body to continuously monitor levels of insulin and other critical molecules. The nanowire, as it's known, is a scant 10-billionths of a meter (10 nanometers) in diameter, or about five times smaller than a virus. Its length stretches to approximately 1,000 nanometers. Proteins called antibodies, placed along the wire, bind to antigen proteins like PSA in a blood sample. The antigens carry an electric charge that changes the conductivity of the wire when they stick to the antibodies. That change can be measured by an ordinary voltmeter. The technology exists for making antibodies to any protein specific to a disease, or to proteins present in viruses, bacteria, or other pathogens. This capability leads Lieber to envision an inexpensive generic device that would quickly detect many different disease markers and biowarfare agents such as anthrax spores. Chips that carry such detectors could be made small and cheaply enough to equip soldiers, firefighters, and other individuals with one. Harvard has applied for a patent on the device, and a company called Nanosys, which was founded by Lieber, has licensed the technology. "Our goal is to have testable prototypes of a PSA detector within a year," Lieber says. "Depending on the necessary FDA approval, and tests with cancer patients, a couple more years of work could lead to a commercial product." This process could be accelerated if the chip can fill a unique gap, such as providing a disease or biowarfare test where none now exists. Pushing the limit Prostate cancer survivors, like myself, live with the fear that tumor cells will regrow and spread to our bones. We undergo regular checks of PSA. A rise in blood levels of that protein signals recurrence may have begun. In such cases, you want to detect any rise in PSA as soon as possible. At present, it takes a couple of days to get the results of a blood test, with a detectibility limit of 0.02 nanograms per milliliter. Lieber's students Yi Cui and Wayne Wang tested a nanowire detector that pushes this limit down to 0.005. What's more, the result is obtained immediately. With a commercial version, a physician could do the test in one office visit, or a patient might monitor his PSA at home, the way diabetics now track their blood sugar levels. Cui and Wang did their tests on PSA samples of known concentration sent by collaborators at the University of California Medical School, San Francisco. "We're now attempting to get certification to test blood samples from people who had or have prostate cancer and those who don't have the disease," notes Lieber. "We need to prove that we can detect PSA in a fluid full of other charged proteins. Tests we've done so far make us reasonably confident that we can." Detecting malignant changes When a cell becomes transformed from normal to cancerous, PSA is not the only thing that changes. A sick cell has at least six other proteins not present in a well cell. A capability to detect all these changes could conceivably give scientists a better understanding of how this cancer develops in the first place. "We can make a chip with 10 wires holding 10 different antibodies as easily as you can do it with one," Lieber comments. "It takes up only nanospace." Keener insight into how a normal cell progresses to a malignant one may solve the biggest dilemma facing every prostate cancer patient: which treatment he should choose. Choices include surgery, two types of radiation, hormones, and doing nothing. The last has appeal because many tumors grow so slowly that the chances of an older man dying from the disease are lower than dying from some other cause. On the other hand, more aggressive tumors can kill a patient if he doesn't choose a treatment in time. Being able to test for the complex of proteins associated with development of the tumor holds the potential for determining both how aggressive a malignancy is and what might be the best course of treatment. "We've also begun to look past prostate cancer to other cancers and diseases, especially breast cancer," Lieber notes. "Breast cancer will be more difficult because we don't have a robust marker like PSA. Markers for breast and ovarian cancer are not as positive. We would probably need a combination of antibodies on several wires." Taking another step into the future, Lieber and his students, in collaboration with Xiaowei Zhuang, assistant professor of chemistry, are setting up a capability to detect low levels of viruses. They will start with a flu virus. These experiments should be easier than working with PSA because viruses are larger than the PSA protein and carry a higher electrical charge. "The natural charge is what gives us the detection signal," Lieber explains. "We should be able to easily detect a single virus." Small, cheap, simple detectors could warn people about the presence of pathogens that cause natural epidemics, or that have been introduced by terrorists. Lieber believes they would be more effective than any system now in place. He also thinks that, once developed, nanowire devices could become a valuable tool for use at Harvard's new research center, the Molecular Target Laboratory. The center, just funded by a $40 million grant from the National Cancer Institute, has a goal of determining the role of proteins in disease and investigating which natural or synthetic molecules might be used in drug treatments. Gently scan your fellow man. - Burns
The induced stress in Li-ion batteries electrode(LIBs) will be discussed in this article, which focus mainly on the modeling and simulating. Two papers from JPS: "Zhang et.al, JPS, 2012, 220-227" and "Haftbaradaran et.al, JPS, 2011, 361-370" are analysed to demonstrate the latest development of this problem. The internal stress will increase the density of defects in batteries, which as a result will affect the capacity and life span of them. The poor cyclic performance of battery could be modeled by strongly coupled diffusion-stress model.Haftbaradaran et.al has developed it to deal with the highly nonlinear behavior of diffusion process in high solute concentration.The validity ofcontinuumhas been proved by comparing with simulation results by Molecular dynamics, one of thecomparisonis demonstrated below, the discrete point are results obtained by MD method while the line represent calculation of thecontinuummodel. Four points concerning the nonlinear behavior of diffusion behavior has been discussed in the work by Haftbaradaran et.al byeliminating their effects one by one in new comparisons between the theoretical and simulating results. In the work of Zhang et.al, more attentions has been paid to the layered structure of electrode in LIBs. Their model has been adapted to discuss the symmetry of of electrode plate, conditions bilayer electrode plate and the effects of charging conditions. The role of current collector in relation with the electrode has been discussed and it has been concluded that the materials of current collector should be as thin as possible and the elastic modulus should be smaller to enhance a much lower stress in the electrode. That is to say, the diffusion induced stress could be well modeled nowadays to predict the performance of new materials in battery electrode. From my perspective, the applicable of models in different kind of materials should be evaluated because the structure and and chemical properties vary between different kind of electrode materials.
This blog is about a short review of the current papers——carbon based materials for anode in Lithium-ion Batteries(LIB). Most of the contents are points from "A review of application of carbon nanotubes for lithium ion battery material, JPS, 2012, 74-85". The application mentioned in this paper is interesting and I'm happy to share this information to my friends. The great demand of high performance LIBs are in great need with the advent of plug-in hybrid vehicles. The schematic above illustrate the mechanism of working in a LIB, that is to say, materials of anode, cathode and the electrolyte will play a great role in the development of supper batteries. When put into practice, the capacity and life span are two characters which scientist care most about. Previously,LiM0x are used as the anode for its great theoretical capacities. However, there will also been a great expansion for the overall volume during the working cycle. Graphite was then chose as a better material due to its special layered structure. The insertion of Lithium ions in to the spacing of different layers will not cause a significant expansion of the overall voulme. However, six carbon atoms are needed to store one lithium ion, which induce a great lose of the theoretical capacity.Schematic of insertion mechanism of Lithium ions are illustrated below: In order to improve this situation, carbon nanotubes(CNTs) are introduced due to its special one-dimensional structure.Nevertheless, the research of CNTs for anodes are quite recent. There are drawbacks which could not be overcome currently. In the first place, the consumption of lithium ions could never be neglected, what's more, there is a lack of voltage plateau during the discharging procedure. Those are both morphology dependent factors, which is supposed to be solved by decorating metal nanoparticles and core-shell composite anodes. Problems might occur due to the controlling of defects when preparing and using. More discuss could be made concerning the formation and interaction of defects in this new generation of anode materials.
Wang QS, Ping P, Sun JH, Chen CH, Cresyl diphenyl phosphate effect on the thermal stabilities and electrochemical performances of electrodes in lithium ion battery, Journal of Power Sources, 2011;196: 5960-65. http://www.sciencedirect.com/science/article/pii/S0378775310022597 Abstract To improve the safety of lithium ion battery, cresyl diphenyl phosphate (COP) is used as a flame-retardant additive in a LiPF6 based electrolyte. The electrochemical performances of LiCoO(2)/CDP-electrolyte/Li and Li/CDP-electrolyte/C half cells are evaluated. The thermal behaviors of Li(0.5)CoO(2) and Li(0.5)CoO(2)-CDP-electrolyte, and Li(x)C(6) and Li(x)C(6)-CDP-electrolyte are examined using a C80 micro-calorimeter. For the LiCoO(2)/CDP-electrolyte/Li cells, the onset temperature of single Li(0.5)CoO(2) is put off and the heat generation is decreased greatly except the one corresponding to 5% CDP-containing electrolyte. When Li(0.5)CoO(2) coexists with CDP-electrolyte, the thermal stability is enhanced. COP improves the thermal stability of lithiated graphite anode effectively and the addition of 5% CDP inhibits the decomposition of solid electrolyte interphase (SEI) films significantly. The electrochemical tests on LiCoO(2)/CDP-electrolyte/Li and Li/CDP-electrolyte/C cells show that when less than 15% COP is added to the electrolyte, the electrochemical performances are not worsen too much. Therefore, the addition of 5-15% COP to the electrolyte almost does not worsen the electrochemical performance of LiCoO(2) cathode and graphite anode, and improves theirs thermal stability significantly; thus, it is a possible choice for electrolyte additive. (C) 2011 Published by Elsevier B.V. 5960 Cresyl diphenyl phosphate effect on the thermal stabilities.pdf
课题研究项目/RESEARCH PROJECT) 题目/TITLE: Fabrication and Modification of Different Electrocatalysts of Oxygen Reduction Reaction in Metal/ Air Battery Keywords: Metal/ air battery, Oxygen reduction reaction, Electrocatalyst, Electrochemistry 研究课题在国内外研究情况及水平THE CURRENT RESEARCH CONDITION AND LEVEL OF THE RESEARCH PROJECT AT HOME AND ABROAD: The electrocatalysts of oxygen reduction reaction (simply called ORR) are the key electrode materials for the metal/ air battery. Noble metal and alloy, such as Pt and alloy, are widely used as catalysts because of their highest catalytic activity and most stable performance in all the materials. Considering their high price, however, Pt and alloy are not suitable to be applied in large-scale industry. Therefore, it is significant to find a less expensive catalyst to replace Pt and alloy . Recently three types of transition metal oxides are considered to be the excellent catalysts with wide application prospect due to low cost and high performance. In this essay I will introduce them as follows. The first type is the series of Manganese oxides. Manganese oxide is cheap and its source is abundant. It has been widely reported that the series of Manganese oxides show well catalytic activity on the decomposition of ORR and H2O2. They are usually prepared by adopting the method of thermal treatment. The temperature of pyrolysis influences greatly the activity of catalysts. L. Jaakko discovers that the activity of MnO2 prepared by using pyrolysis at 500℃ is very well. Z. D. Wei fabricated MnO2 with high catalytic performance by the pyrolysis of Manganese Nitrate at 340℃. The optimal weight ratio of MnO2 in the electrode is 6.7%. T. X. Jiang prepared low cost and high effective electrocatalyst with MnO2 and rare earth chloride. It is shown in the experimental results that the optimal temperature of calcining is 300℃, and the time is 20 hours. It is generally thought that catalytic activity of the series of Manganese oxide in ORR is realized by the Mn(Ⅳ)/Mn(Ⅲ) electrode. The catalytic activity of γ-MnOOH is the highest among a series of Manganese oxide. J. S. Yang synthesised nano finestra amorphism Manganese oxide by adopting the method of low temperature liquid phase redox. Its catalytic activity center is considered to be more than that of crystal MnO2, and this type of material with poriferous structure is more suitable to be used to make poriferous electrode. Perovskite complex metal oxide is another type of catalyst studied by many researchers. The structure of perovskite complex metal oxides is ABO3, of which A is rare earth element and B is transition metal element. Due to its high conductivity (about 104 Ω-1•cm-1) and well ORR electrocatalytic activity, it is a kind of excellent double function ORR catalyst material. It is shown in researches that the catalytic activity of oxide with structure of pure ABO3 is not very high. When A position is partly replaced by some low valence metal ions, the property of B position ion and vicinal oxygen ion can be improved. Complex valence of B position ion and vacancy of cation can be formed, which heightens the catalytic activity of complex oxide. The catalytic activity is better when A position ion is La or Pr, so the research of this respect is very common. B position ion plays a decisive role in the catalytic activity of this type of oxides. The sequency of catalytic activity is CoMnNiFeCr. The catalytic activity is the highest when B position is Fe. Both activity and stability of complex oxides are better when B position is Mn or Ni. There are several methods of fabricating perovskite complex metal oxide. The method of Acetate Decomposition (AD) is used commonly in the early stage. The temperature of calcining is between 800 and 900℃ and time of calcining is as long as about 10 hours. The method of amorphism citric acid precursor (ACP) is a modified method of AD. The temperature of calcining is fall at 600℃ and time is shortened to 2 hours. The sol-gel method can obtain nano material with larger specific surface area and better catalytic activity. Therefore, it is widely used in the fabrication of perovskite metal oxide catalyst. Finally, the spinel transition metal oxide is one type of catalyst with bright prospect. The general formula of its molecule is AB2O4. In this type of compound the vacancy of tetrahedron and octahedron and oxygen co-ordination was occupied by the transition metal ion with approximate radius. It is approved by many researchers that the catalytic mechanism of spinel transition metal oxide on ORR is similar with that of perovskite transition metal oxide. Although there are many kinds of material which can cause catalytic effect on ORR, few can be used in practical industry. The noble metal, such as Pt and alloy, possess high catalytic activity and stability, but it can not be used in large-scale industry because of their expensive price. Transition metal oxides are thought to have a wide application future because of their well catalytic activity, high stability and low cost. However, the catalytic mechanism is still unknown to us. The structure, the component and ratio of elements can not be designed under the direction of theory. Much exploration work need us to finish. 研究课题的目的及预期目标THE AIM AND EXPECTATION OF THE RESEARCH: I will engage in the research under the direction of Professor *** at *** University and Professor *** at *** University. They recommended me to research fabrication and modification of different electrocatalysts of oxygen reduction reaction in metal/ air battery, which will be very interesting in the future. Under their direction, theoritically, I will investigate the mechanism of fabrication of transition metal oxide, seek an effective and economical method to prepare the electrocatalyst, get the optimal experimental parameters of preparation process, and I will also explore the mechanism of ORR. During this period I will publish several papers or apply some patents related with my research if possible. And I will finish my dissertation of PhD./ 拟留学院校在此学科领域的水平和优势THE LEVEL AND ADVANTAGE OF THE HOSTING FOREIGN INSTITUTION ON THIS PROJECT:, The institution I wants to work in is the school of chemistry at Monash University. It has at least three advantages as follows. Firstly, there are advanced experiment instruments. Facilities in the laboratory are Zeta Potential and Size Analyzer, XRD, XRF, AFM, Electrochemical Impedance Analyzer, Polarization Apparatus, Capillary Electrophoresis, etc. And in the department there are also SEM, TEM, EPMA, etc. Secondly, solid basic research work has been done by the researchers in the laboratory. Great work about the research of electrocatalysts in metal/ air battery has been finished by them. Finally, excellent research environment has formed in the institution. The fabrication technology of electrocatalysts in metal/ air battery is advanced in Australian manufacture. There is frequent cooperation between these manufacturers and the institution, so I can learn the most advanced technology in this field. 回国后工作/学习计划THE STUDY/WORK PLAN AFTER RETURNING TO CHINA: After I finish my PhD study and return to my home country, I will do some further reserch on the preparation of electrocatalysts in metal/ air battery. I will investigate the most proper method to fabricate the catalysts with high performance. And I wants to grasp the optimal parameters of the production technology. I hope the technology can be applied widely in the industry of my country.
据《纳米快报》（ NANO Letters ） 网站2011年3月17日报道，美国史丹福大学（Stanford University）、宾州州立大学（ Penn State University ）和意大利米兰大学（ Università degli Studi di Milano ）的科学家联合研制出一种被称之为“混合熵电池”（mixing entropy battery），其工作原理是利用海水与河水之间的含盐量不同即盐度差来进行发电。海水和河水的含盐量差异是一种可再生资源,虽然其中蕴藏着巨大的潜能，但有效提取并作为一种有用的能量加以利用仍然存在很多挑战。“混合熵电池”是迎接这种挑战的一种产物,它可以提取并作为有用的电化学能量加以存储。该电池包含钠锰氧体{Na_(2-x)Mn_5O_(10)}纳米电极,可以适用于多种不同盐度的水体，能量提取效率可以达到74%。试验结果显示，每升淡水可以获得2.2 kJ的能量，考虑到河水流量因素限制,这种可再生能源总量可能会达到2 TW，相当于当今世界能耗总量的13%。“混合熵电池”制作简单，对于未来可再生能源的利用会有所贡献。 更多信息请浏览 http://pubs.acs.org/doi/abs/10.1021/nl200500s
David Bradwell, 28 MIT Cheap, reliable batteries to store renewable energy Liquid battery: An early prototype battery has been sawed in half to reveal its electrodes and electrolyte, which are liquid during operation. Credit: Joshua Scott In the fall of 2007, David Bradwell, an MIT grad student, created a new kind of battery--one that might eventually be used to store massive amounts of solar and wind energy for use at night or when the wind isn't blowing. Unlike existing batteries, it has active components that are liquid, which enables it to handle high currents without fracturing (the battery is kept at 700 degrees Celcius with the help of insulation). Last year Bradwell's research attracted a total of about $11 million from the U.S. Department of Energy's new Advanced Research Projects Agency-Energy (ARPA-E) and the French oil company Total. Bradwell's battery is based on an electrolyte that can dissolve a compound consisting of two metals, such as magnesium and antimony. Applying a current in one direction splits the compound, and the two metals are deposited onto opposite electrodes. When no electricity is delivered, a voltage difference between the electrodes drives a current in the other direction. That generates electricity and causes the metals to recombine in the electrolyte. The system could eventually cost less than $100 per kilowatt-hour for a new installation--about the same as pumping water up a hill to be released later to spin a turbine (the cheapest conventional approach for large-scale energy storage), says Arun Majumdar, the director of ARPA-E. The battery, however, would have the advantage of working in places without hills or large amounts of water, where many renewable power resources are located. --Kevin Bullis from:http://www.technologyreview.com/TR35/Profile.aspx?Cand=TTRID=972
锂离子电池是电子行业领域最关键的技术之一，可以说是支撑电子、信息产业等发展的关键环节之一！ 上世纪九十年代初，锂离子电池在日本商业化以来，电极材料的更新换代推动着锂电技术的发展，开发新的电极材料成为推动锂电技术的关键！ 目前被开发利用的锂离子电池电极材料主要有： 正极材料：钴酸锂、锂锰氧、镍酸锂、三元系、磷酸铁锂、硅酸铁锂等，负极材料：石墨、 Sn 氧化物、 Co 氧化物、 Si 、 Ge 以及新近的碳管负极材料等，而由于矿物资源的缺乏，磷酸铁锂、硅酸铁锂等正极材料被研究人员广泛研究，对于负极材料，新近研究较多的则是氧化物、 Si 、碳管负极材料。 锂电正极材料目前主要的是如何提高倍率性能，大电流放电技术是其广泛应用于电动汽车等动力型电池技术领域的关键，目前较有希望的正极材料则是由 Goodenough 在 1997 年发现的锂铁磷酸盐，这种橄榄石型结构的材料，脱嵌 Li 后材料的晶体结构仍为橄榄石型的 FePO4 ，结构稳定，安全性能高，不足之处主要在于其电导率较低，因此如何提高其电导率是其性能提升的最关键，因而，科研人员对其掺杂与碳包覆被用来提升其电化学性能！然而这两种方法改进性能的同时，则不同程度的破坏了其晶体结构，因此，探索新的方法改进性能将是未来研究的重点。日前，有日本学者报道，采用聚合限制法制备得到的纳米晶 LiFePO4 ，尺寸在 30 40nm ，得其 50C 下容量为 90mAh/g ，而韩国学者则在 10C 下得到容量超过 150mAh/g ，表现出较好的高倍率性能。 对于负极材料，商业化的石墨容量偏低，而新的负极材料目前虽然具有较高的理论容量，但是其稳定性不高，容量衰减很快，目前报道的高容量、高稳定性的新型负极材料合成条件苛刻，成本高，仅仅停留在实验室阶段，如斯坦福大学的 Cui 报道的 Si 纳米线电极，虽然其容量接近理论容量，但是其制备采用 CVD 沉积技术，对于工业化则其成本偏高，金属氧化物负极材料，则尚处在微观结构和形貌控制的 Papers 中间，前途未得而知。而碳管负极，虽然最近研究比较热烈，但是其容量衰减快而碳管大规模生产成本还是偏高，因此更新尚未完成，同志任需努力！ 如上仅为一些浅显见解，如有不当之处，还请诸位大家见谅并指出，小生当感激不尽！ Y. G. Wang, Y. R. Wang, H. S. Zhou, et al. Angew. Chem. Int. Ed. 2008, 47, 1 6 S. Y. Lim, C. S. Yoon and J. P. Cho. Chemistry of Materials, 20(14):4560-4564 ,2008.
Introduction New Energy and Material Chemistry laboratory in INET, Tsinghua University was established in 1996. There are now more than 60 members in the laboratory, including 1 academician, 3 professors, 4 associate professors, 2 senior engineer, 8 assistant professors, 12 technicians and more than 30 graduate students. The RD activities of laboratory are mainly focused on the engineering and engineering fundamentals of advanced materials, core components and system integration in the areas of fuel cells and lithium ion batteries, which can be used as portable and stationary power sources, due to their high energy density, long lifetime, environmental benign. A fruits of achievements on fuel cell and lithium ion battery materials have been acquired. High level specialists and experts in the fields of electrochemistry, chemical engineering, materials science, and catalysis have been cultivated in order to make a valuable contribution to the economic construction and sustainable social development of the country. Research Fields The Research fields conducted in the laboratory comprise fuel cell, hydrogen energy, lithium ion batteries and Electrochemical Capacitor. Fuel cell stack; Fuel cell bipolar plate Advanced electrode and electrolyte materials Design and integration of stacks and power generation systems Modeling calculation and computer simulation of fuel cell and lithium ion battery Diagnosis and control of system Direct methanol fuel cells(DMFCs) Electrochemical Capacitors Nano materials for energy conversion and storage Oxide cathode materials for lithium ion batteries Alloy anode materials for lithium ion batteries Polymer materials for lithium ion batteries Lithium sulfur batteries
标签: battery
