Structure and Charge Regulation Strategy Enabling Superior Cycling Stability of Ni-Rich Cathode Materials

Ni-rich layered oxides LiNixCoyMn1–x–yO2 (NCMs, x > 0.8) are the most promising cathode candidates for Li-ion batteries because of their superior specific capacity and cost affordability. Unfortunately, NCMs suffer from a series of formidable challenges such as structural instability and incompatibility with commonly used electrolytes, which seriously hamper their practical applications on a large scale. Herein, the Al/Ta codoping modification strategy is proposed to improve the performance of the LiNi0.83Co0.1Mn0.07O2 cathode, and the as-prepared Al/Ta-modified LiNi0.83Co0.1Mn0.07O2 delivers exceptional cycling stability with a capacity retention of 97.4% after 150 cycles at 1C and an excellent rate performance with a high capacity of 143.2 mAh g–1 even at 3C. Based on the experimental study, it is found that the structural stability of NCM is strengthened due to the regulated coordination of oxygen by introducing a robust Ta–O covalent bond, which prevents the layered structure from collapsing. Moreover, the reconstructed rock-salt-like surface is capable of effectively inhibiting interfacial side reactions as well as the overgrowth of the cathode–electrolyte interface. Theoretically, the energy of Li/Ni mixing is significantly increased with the introduction of Al and Ta elements in Al/Ta codoped NCM, leading to inhibited adverse phase transition during cycling. A feasible pathway for designing and developing advanced Ni-rich cathode materials for Li-ion batteries is provided in this work.