废旧高镍三元正极材料在锂-氧气电池中的催化性能研究

Regeneration of Waste High Nickel Ternary Cathode Materials as Catalysts for Lithium-Oxygen Batteries

采用碱洗煅烧法回收废旧锂离子电池高镍三元正极材料,制备得到含Ni、Co、Mn 3种过渡金属元素氧化物,并用作锂-氧气电池的正极催化剂.根据XRD和XPS结果,回收的高镍三元正极材料与原始材料相比,回收的Spent 811材料表面存在较严重的锂镍混排,具有较厚的氧化镍岩盐相.电化学测试结果显示,基于Spent 811为正极催化剂的锂-氧气电池表现出较大的比容量和良好的循环稳定性.在100 mA·g^(-1)的电流密度下放电比容量可达5307.5 mAh·g^(-1),且在限定容量800 mAh·g^(-1)下可以稳定循环80圈.本文认为回收的Spent 811材料在长循环后形成的氧化镍相与表面缺陷之间的协同作用,大大提升了Spent 811材料的催化活性,促进了放电产物的可逆形成与分解,从而改善锂-氧气电池的循环性能.

In this paper,the transition metal oxides containing Ni,Co and Mn were prepared by the alkaline washing calcination method to recycle the NCM811 cathode material from waste lithium-ion batteries.It was used as a cathode catalyst for the lithium-oxygen battery to turn waste into treasure.According to the XRD and XPS results,the recycled Spent 811 has more serious Li-Ni mixing on its surface after a long cycle,forming a thicker NiO rock-salt phase,compared with the original material.The electrochemical test results show that the lithium-oxygen battery with the Spent 811 as the cathodic catalyst has better electrochemical performance.The specific capacity can reach 5307.5 mAh·g^(-1) under the current density of 100 mA·g^(-1).With a limited capacity of 800 mAh·g^(-1) and the current density of 100 mA·g^(-1),the lithium-oxygen battery with the Spent 811 can operate stably for 80 cycles.The superior catalytic activity of the Spent 811 is mainly attributed to the synergistic effect between its rock-salt structure and surface defects,which can promote the reversible formation and decomposition of discharge products,and improve the cycling stability of the lithium-oxygen battery.