锂离子二次电池纳米复合聚合物电解质研究进展

聚合物锂离子电池具有重量轻，比能量高，安全性能好等优点，是本世纪发展的理想能源。锂离子电池用聚合物电解质的研究包括全固态聚合物电解质（SPE），凝胶聚合物电解质（GPE）和复合聚合物电解质（CPE）。本文重点综述了纳米复合聚合物电解质在锂离子电池中的应用研究进展及展望。     

锂离子电池高容量硅负极嵌锂过程中的表面成膜研究

采用交流阻抗法、EDS与XPS成分分析对锂离子电池高容量硅负极在首次嵌锂过程中的表面成膜行为进行了研究, 并对膜组分进行了详细测试与分析. 交流阻抗分析发现硅负极的表面成膜现象出现在较低的嵌锂电位下, 膜厚随着嵌锂过程的进行而增加, 其组分以LiF和Li₂CO₃为主. 通过Ar离子流对硅负极表面的深度刻蚀的XPS分析发现, 其表面的膜层为非均质层, 暴露于电解液中一侧的膜层组分中碳酸盐含量较高, 而随着深度的增加, LiF的相对含量增加, 靠近电极一侧的膜层可能存在着少量硅的氧化物及其与电解液的反应产物. 少量Si由于不可逆反应形成的化合物也存在于SEI膜的膜层中.     

Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries

Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries were investigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materials. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemical impedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.     

用于锂离子电池的全固态聚合物电解质

用全氟醚作为增塑剂对PEO改性,并与双三氟甲烷磺酰亚胺锂复合,制备了全固态聚合物电解质。采用SEM、交流阻抗、稳态电流法及恒电流恒电压充放电等对固态聚合物电解质的性能进行了测试表征,结果表明:m(PFPE)∶m(PEO)=0.6的固态聚合物电解质膜的电导率30℃时为2.6×10-3 S·cm-1,同条件下电解质溶液电导为8.2×10-3 S·cm-1,二者处于同一个数量级;随PFPE的量增加,锂离子的迁移数增大;与液态电解质电池相比,固态聚合物电解质制成的电池具有更好的循环容量保持特性,固态聚合物电解质电池500次循环的容量保持率在88.1%,液态电解质电池循环容量保持率在64.5%左右;固态聚合电解质有很优异的耐高温安全性,在130℃和150℃下经1~2h热箱试验,用固态聚合物电解质制作的锂离子电池没出现明显体积变化,而相同条件下的液态电解质锂离子电池已发生爆裂或起火。     

Effect of Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries

Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochem-ical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries wereinvestigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materi-als. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemicalimpedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.     

静电纺丝法制备氧化锰纳米丝电极及其电化学性能

利用静电纺丝技术成功制备了φ60～80nm的氧化锰纳米纤维丝,并构建了三维纳米丝网状结构电极,应用于锂离子二次电池. 使用扫描电子显微镜、X射线衍射、循环伏安和电池充放电等研究手段,表征了纳米纤维丝的结构和电化学性能. 研究结果发现:氧化锰构建的纳米丝在嵌锂和脱锂的过程中没有出现纳米纤维丝的结构塌陷问题,在高能量密度下表现出较大的可逆循环容量,放电容量达到160mAh/g. 经过50次循环后, 容量可达132.5mAh/g, 平均每次循环的容量衰减在1%以下. 这些结果表明了氧化锰纳米纤维丝可作为三维锂离子电池中的阴极材料.     

Nanostructured Silicon Anodes for Lithium Ion Rechargeable Batteries

Rechargeable lithium ion batteries are integral to today's information‐rich, mobile society. Currently they are one of the most popular types of battery used in portable electronics because of their high energy density and flexible design. Despite their increasing use at the present time, there is great continued commercial interest in developing new and improved electrode materials for lithium ion batteries that would lead to dramatically higher energy capacity and longer cycle life. Silicon is one of the most promising anode materials because it has the highest known theoretical charge capacity and is the second most abundant element on earth. However, silicon anodes have limited applications because of the huge volume change associated with the insertion and extraction of lithium. This causes cracking and pulverization of the anode, which leads to a loss of electrical contact and eventual fading of capacity. Nanostructured silicon anodes, as compared to the previously tested silicon film anodes, can help overcome the above issues. As arrays of silicon nanowires or nanorods, which help accommodate the volume changes, or as nanoscale compliant layers, which increase the stress resilience of silicon films, nanoengineered silicon anodes show potential to enable a new generation of lithium ion batteries with significantly higher reversible charge capacity and longer cycle life.     

锂离子电池正极材料LiNi-x-yCoxMnyO2的研究现状

正极材料对锂离子电池的性能和价格具有决定性的作用，对正极材料的研究一直是锂离子电池研究中的热点。主要对一类新型正极材料LiNi-x-yCoxMnyO2的国内外研究现状进行了综述，并比较了不同合成方法对其电化学性能的影响，最后对这类正极材料的研究给予了展望。     

Cover Picture: Nanostructured Electrodes and the Low‐Temperature Performance of Li‐Ion Batteries (Adv. Mater. 1/2005)

The cover image shows a scanning electron micrograph of a commercially available track‐etch polycarbonate filter. This porous membrane serves as the host for the template‐synthesis of V₂O₅ nanowires of various diameters. Nanowires that are 70 nm in diameter are shown in the inset. Because V₂O₅ reversibly intercalates Li‐ions, it has potential for use as a cathode material in Li‐ion batteries. On p. 125, Sides and Martin report the use of these V₂O₅ nanowires as tools to investigate the poor low‐temperature performance of Li‐ion batteries.     

Fading Mechanisms and Voltage Hysteresis in FeF2–NiF2 Solid Solution Cathodes for Lithium and Lithium‐Ion Batteries

The rapid development of ultrahigh‐capacity alloying or conversion‐type anodes in rechargeable lithium (Li)‐ion batteries calls for matching cathodes for next‐generation energy storage devices. The high volumetric and gravimetric capacities, low cost, and abundance of iron (Fe) make conversion‐type iron fluoride (FeF₂ and FeF₃)‐based cathodes extremely promising candidates for high specific energy cells. Here, the substantial boost in the capacity of FeF₂ achieved with the addition of NiF₂ is reported. A systematic study of a series of FeF₂–NiF₂ solid solution cathodes with precisely controlled morphology and composition reveals that the presence of Ni may undesirably accelerate capacity fading. Using a powerful combination of state‐of‐the‐art analytical techniques in combination with the density functional theory calculations, fundamental mechanisms responsible for such a behavior are uncovered. The unique insights reported in this study highlight the importance of careful selection of metals and electrolytes for optimizing electrochemical properties of metal fluoride cathodes.     

锂离子二次电池多孔集流体的制备与应用

金属基负极材料具有超高的理论容量,是新一代锂离子二次电池理想的负极材料。但是,金属基负极材料在充放电过程中会产生严重的体积膨胀,从而导致负极材料的粉化和脱落,使其循环性能迅速恶化。采用多孔集流体能够充分利用三维连通的孔隙和高的比表面积来显著提高锂离子二次电池的循环性能和能量密度,是缓解金属基负极材料体积膨胀的有效方法之一。本文总结了近年来微米多孔、纳米多孔和双尺度多孔集流体的制备方法及其在锂离子二次电池中的应用。     

Synthesis of MoS2@C Nanotubes Via the Kirkendall Effect with Enhanced Electrochemical Performance for Lithium Ion and Sodium Ion Batteries

A MoS₂@C nanotube composite is prepared through a facile hydrothermal method, in which the MoS₂ nanotube and amorphous carbon are generated synchronically. When evaluated as an anode material for lithium ion batteries (LIB), the MoS₂@C nanotube manifests an enhanced capacity of 1327 mA h g^?1 at 0.1 C with high initial Coulombic efficiency (ICE) of 92% and with capacity retention of 1058.4 mA h g^?1 (90% initial capacity retention) after 300 cycles at a rate of 0.5 C. A superior rate capacity of 850 mA h g^?1 at 5 C is also obtained. As for sodium ion batteries, a specific capacity of 480 mA h g^?1 at 0.5 C is achieved after 200 cycles. The synchronically formed carbon and stable hollow structure lead to the long cycle stability, high ICE, and superior rate capability. The good electrochemical behavior of MoS₂@C nanotube composite suggests its potential application in high‐energy LIB.     

锂离子电池正负极材料的研究

锂离子电池作为新一代的充电电池,近年来得到了飞速的发展.它以高的性能被用于手机电池、笔记本电脑和其它便携式电器.不久的将来,它将会为电动汽车或大型储存电能的电池提供能量.本文阐述了锂离子电池技术发展的现状,其中包括正极材料、负极材料、电解质以及与之发展相关的问题的成因,并分析了它们的优缺点.