Manipulating the Electronic Structure of Li-Rich Manganese-Based Oxide Using Polyanions: Towards Better Electrochemical Performance
Manipulating the Electronic Structure of Li-Rich Manganese-Based Oxide Using Polyanions: Towards Better Electrochemical Performance
复制标题
使用聚阴离子操纵富锂锰基氧化物的电子结构：实现更好的电化学性能
DOI：
10.1002/adfm.201400436
复制
发表时间：
2014-08-27
影响因子：
19
通讯作者：
Wu, Ziyu
中科院分区：
文献类型：
--
作者：
Li, Biao;Yan, Huijun;Wu, Ziyu
富锂锰基层状氧化物作为锂离子电池的高容量阴极材料显示出巨大的潜力，但通常表现出差的循环寿命、在循环期间逐渐的电压下降以及在高度脱锂状态下的低热稳定性。在此，开发了一种策略，以促进这种材料的电化学性能，通过操纵电子结构，通过纳入含硼聚阴离子。与原始Li[Li0.2Ni0.13Co0.13Mn0.54]O-2相比，所制备的Li[Li0.2Ni0.13Co0.13Mn0.54]（BO 4）（0.015）（BO 3）（0.005）O-1.925显示出降低的M-O共价和降低的O 2 p带顶。结果表明，改性后的正极材料在80次循环后具有上级可逆容量300 mA h g（-1），在300次循环中容量保持率为89%，热稳定性和氧化还原电位均有所提高。这些改进与源自调谐电子结构的增强的氧稳定性相关。这种简单的策略可以进一步扩展到其他高容量电极系统。
Lithium-rich manganese-based layered oxides show great potential as high-capacity cathode materials for lithium ion batteries, but usually exhibit a poor cycle life, gradual voltage drop during cycling, and low thermal stability in the highly delithiated state. Herein, a strategy to promote the electrochemical performance of this material by manipulating the electronic structure through incorporation of boracic polyanions is developed. As-prepared Li[Li0.2Ni0.13Co0.13Mn0.54](BO4)(0.015)(BO3)(0.005)O-1.925 shows a decreased M-O covalency and a lowered O 2p band top compared with pristine Li[Li0.2Ni0.13 Co0.13Mn0.54]O-2. As a result, the modified cathode exhibits a superior reversible capacity of 300 mA h g(-1) after 80 cycles, excellent cycling stability with a capacity retention of 89% within 300 cycles, higher thermal stability, and enhanced redox couple potentials. The improvements are correlated to the enhanced oxygen stability that originates from the tuned electronic structure. This facile strategy may further be extended to other high capacity electrode systems.