Synergistic modification of Ni-rich full concentration gradient materials with enhanced thermal stability

Abstract

Major challenge hindering the large-scale applications of Ni-rich cathode materials (CAMs) lies on the poor cycle (especially under elevated temperature or high cutoff voltage) and thermal stability due to the highly reactive Ni4+. Herein, the full concentration strategy is combined with Ti pillar and Li2ZrO3 (LZO) coating modification, on which a high-performance CAM with elevated kinetics and stability, CGTZ-1, is obtained. It proves that both cycle and thermal stability can be greatly enhanced by the concentration gradient design and the LZO coating. Whereas the promoted Li+ diffusion coefficient is largely attributed to the Ti pillar. The optimal resultant CAM shows high capacity retention of 88.1% after 200 cycles under 55°C, while that of pristine is only 32.1%. More importantly, it also shows a high thermal release temperature of 261.5°C (vs 222.3°C of the pristine), which demonstrates the effectiveness of this synergistic modification strategy.