Utilizing Diverse Functions of Zirconium to Enhance the Electrochemical Performance of Ni-Rich Layered Cathode Materials

Ni-rich cathode (Ni > 0.8) provides a low-cost and high-energy-density solution to the next-generation lithium-ion batteries. Unfortunately, severe capacity fading of Ni-rich cathode caused by the interfacial and bulk structural degradation impeded its application. Herein, Zr doping and Li6Zr2O7 coating are applied to a Ni-rich LiNi0.83Co0.12Mn0.05O2 (NCM) layered cathode material, and the modified material exhibits excellent cycle stability. The 1%Zr-NCM cathode material maintains a discharge capacity of 173.9 mAh g-1 at 1 C after 200 cycles in the 2.5-4.3 V voltage range at 25 °C, corresponding to a capacity retention of 94.6%; however, the unmodified NCM only delivers 129.9 mAh g-1 (capacity retention 68.6%). The synergistic effect of bulk Zr doping and surface Li6Zr2O7 coating improves the cycle stability of the Ni-rich material. Zr doped into the bulk could form a strong Zr-O bond to stabilize the layered structure, and Zr located in the Li layer can act as a pillar to maintain the layered structure and reduce Li+/Ni2+ mixing. In addition, the Li6Zr2O7 coating layer can also play a dual role in promoting Li+ migration and suppressing surface side reactions. This work demonstrates that sufficiently utilizing zirconium to enhance the electrochemical performance of cathode materials is a feasible and promising strategy.