Na离子电池正极材料的结构设计与性能分析

Structure Design and Performance Analysis of Cathode Materials for Sodium Ion Batteries

Na离子电池由于其低成本和丰富的Na资源储备,已成为电能存储和低速电动汽车中最有前途的候选设备。正极材料是Na离子电池的关键,对电化学性能具有显著影响。系统地总结了现有的Na离子电池正极材料,有过渡金属氧化物类、聚阴离子类、普鲁士蓝类和有机分子聚合物类等材料。目前,这些正极材料存在两个缺点:Na离子的半径比Li离子的大,在离子脱嵌过程中会对材料的结构造成严重影响,进而导致体积膨胀和容量衰减;动态过程缓慢,导致充放电倍率表现不佳。总结了用以提高正极材料电化学性能的掺杂/替代和涂覆等改性方法,为以后的Na离子电池改性和正极材料的选择提供了研究方向。

The sodium ion battery has become the most promising candidate device for electric energy storage and low-speed electric vehicles because of its low cost and abundant Na resource reserve.Cathode materials are the key of sodium ion battery and have a significant impact on the electrochemical performance.The existing cathode materials for sodium ion battery were systematically summarized,including transition metal oxide materials,polyanionic materials,Prussian blue materials,organic molecular polymers,and so on.At present,these cathode materials have two disadvantages:the radius of sodium ion is larger than that of lithium ion,which seriously affects the structures of materials in the ion deintercalation process,and then causes the volume expansion and capacity attenuation;the dynamic process is slow,resulting in poor performance of charge discharge ratio.The modification methods such as doping/substitution and coating to improve the electrochemical properties of cathode materials were also summarized,which provides a research direction for the modification of sodium ion battery and the selection of cathode materials in the future.