锂离子电池纳米钒基正极材料的研究进展

Research developments of V-based nanomaterials as cathodes for lithium batteries

锂离子电池因为其较高的能量密度、优良的循环性能及较强的荷电保持能力被广泛应用于便捷式电子器件中。同时作为混合动力汽车(HV)和电动汽车(EV)潜在的电源设备也被广泛地研究,但是,目前其电化学性能还不能完全满足高能量密度、大功率的要求。主要是因为商品化和即将进入开发性研究的正极材料大多是嵌锂过渡金属氧化物,这些正极材料存在致命的本征制约——较低的比容量。钒基正极材料,如V2O5、LiV3O8和Li3V2(PO4)3等,由于可以嵌入多个Li+离子,从而具有较高的理论比容量,但受材料微结构的影响,这类材料的实际比容量远低于理论值。材料微结构纳米化,可以形成独特形貌,获得高比表面积,缩短Li+离子的扩散距离,使这类材料的实际比容量接近理论值,从而有可能在能量的高效率储存中扮演十分重要的角色。本文作者重点综述钒基正极材料的主要晶体结构特点和相关纳米材料合成方法、结构表征及其对应电化学性能的研究进展。

Lithium-ion batteries（LIBs） were widely used in portable electronic devices,mainly due to their high energy density,good cycle performance and charge retention ability.Moreover,as the potential power sources of the hybrid vehicles（HV） and electric vehicles（EV）,LIBs were widely studied.But at present their electrochemical properties cannot fully meet the requirements of high energy density,high power for power sources of HV and EV.This is mainly because most commercial and studied cathode materials are lithium transition metal oxides,which have an intrinsic constraint,i.e.low capacity.V-based cathode materials,such as V2O5,LiV3O8 and Li3V2（PO4）3,possess relatively high theoretical specific capacity because of their abilities to intercalate more Li＋ ions per formula.However,due to the structure limitation of these materials,their actual capacity is much lower than the theoretical value.Synthesis of these materials with nanostructures can greatly enlarge their surface areas and reduce the Li＋ ion diffusion distance significantly,resulting in the fact that the actual specific capacity is closer to the theoretical value.Such V-based nanomaterials may make LIBs play an important role in the high efficiency store of energy,especially for power sources of HV and EV.This review focuses on the research development of synthesis of V-based nanomaterials,characterization and their corresponding electrochemical properties.