Microstructure boosting the cycling stability of LiNi0.6Co0.2Mn0.2O2 cathode through Zr-based dual modification

Ni-rich NCM (LiNixCoyMnzO2, 0.6 < x < 1, 0 < y < 1, 0 < z 1) are up-and-coming cathode materials with high working voltage (similar to 3.8 V) for usage in lithium ion batteries. In order to achieve higher capacity through lithium extraction, higher cutoff voltages (>4.3 V) are applied on these materials. Consequently, the batteries will suffer from aggravated side reactions at the cathode/electrolyte interface and the inherent instabilities of Ni-rich NCM cathodes, and thus exhibit rapid capacity fading and voltage decay. Herein, we report a facile and scalable strategy that employs Zr doping concurrent with LixZryOz surface coating, contributing to outstanding capacity retentions of 97.8% at 0.2C and 91.6% at 2C after 100 cycles over 2.8-4.5 V. The improved cycling stability can be attributed to the enhanced bulk stability and suppressed nonequilibrium diffusion reactions, which are further ascribed to the reduced oxygen vacancies and optimized microstructure.

Automated summary

The study introduced a strategy of Zr doping and LixZryOz surface coating to improve the cycling stability and capacity retention of Ni-rich NCM cathode materials, with enhanced bulk stability and optimized microstructure contributing to the improved performance.