A Novel Perovskite Electron-Ion Conductive Coating to Simultaneously Enhance Cycling Stability and Rate Capability of Li1.2 Ni0.13 Co0.13 Mn0.54 O2 Cathode Material for Lithium-Ion Batteries.
A Novel Perovskite Electron-Ion Conductive Coating to Simultaneously Enhance Cycling Stability and Rate Capability of Li1.2 Ni0.13 Co0.13 Mn0.54 O2 Cathode Material for Lithium-Ion Batteries.
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DOI：
10.1002/smll.202008132
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发表时间：
2021-03
期刊：
影响因子：
13.3
通讯作者：
M. Gao;Che Yan;Qinong Shao;Jian Chen;Chenyang Zhang;Gairong Chen;Yinzhu Jiang;T. Zhu;Wenping S
中科院分区：
文献类型：
--
作者：
M. Gao;Che Yan;Qinong Shao;Jian Chen;Chenyang Zhang;Gairong Chen;Yinzhu Jiang;T. Zhu;Wenping S
循环稳定性和倍率性能差是锂离子电池富锂锰氧化物正极材料需要解决的两个关键问题。本文采用新型钙钛矿型电子-离子混合导体Nd0.6Sr0.4CoO3（NSCO）作为包覆层，在Li1.2Ni0.13Co0.13Mn0.54O2（LNCMO）上包覆，同时提高其循环稳定性和倍率性能。通过涂覆3wt%NSCO，LNCMO-3 NSCO表现出最佳的循环性能，在0.1C（1C = 200 mA g-1）下60次循环后的容量保持率为99%，在1C下300次循环后的容量保持率为91%，在20 C下1000次循环后的容量保持率为54%，分别远优于LNCMO的78%，63%和3%。即使在50 C的高充放电速率下，LNCMO-3 NSCO也表现出53 mAh g-1的放电容量和2.88 V的中点放电电压，远高于LNCMO（分别为24 mA h g-1和2.40 V）。NSCO涂层具有较高的电子电导率（1.46 S cm-1）和离子电导率（1.48 × 10-7 S cm-1），不仅抑制了过渡金属的溶解和结构转变，而且使LNCMO的电子电导率和Li+扩散系数显著提高了一个数量级。
Poor cycling stability and rate capability are two key issues needing to be solved for Li- and Mn-rich oxide cathode material for lithium-ion batteries (LIBs). Herein, a novel perovskite electron-ion mixed conductor Nd0.6 Sr0.4 CoO3 (NSCO) is used as the coating layer on Li1.2 Ni0.13 Co0.13 Mn0.54 O2 (LNCMO) to simultaneously enhance its cycling stability and rate capability. By coating 3 wt% NSCO, LNCMO-3NSCO exhibits an optimal cycling performance with a capacity retention of 99% at 0.1C (1C = 200 mA g-1 ) after 60 cycles, 91% at 1C after 300 cycles, and 54% at 20C after 1000 cycles, much better than 78%, 63%, and 3% of LNCMO, respectively. Even at a high charge and discharge rate of 50C, LNCMO-3NSCO exhibits a discharge capacity of 53 mAh g-1 and a mid-point discharge voltage of 2.88 V, much higher than those of LNCMO (24 mA h g-1 and 2.40 V, respectively). Benefiting from the high electronic conductivity (1.46 S cm-1 ) and ionic conductivity (1.48 × 10-7 S cm-1 ), NSCO coating not only suppresses transition metals dissolution and structure transformation, but also significantly enhances electronic conductivity and Li+ diffusion coefficient of LNCMO by an order of magnitude.