Aluminum doping and lithium tungstate surface coating double effect to improve the cycle stability of lithium-rich manganese-based cathode materials

Abstract

Al doped lithium-rich manganese-based Li1.2Mn0.54−xAlxNi0.13Co0.13O2 (x = 0, 0.03) cathode materials for lithium-ion batteries were synthesized with sol-gel method, and then Li2WO4 coating was prepared by one-step liquid phase method. The effects of Al doping and Li2WO4 coating on the electrochemical properties of lithium-rich manganese-based cathode materials were systematically studied. The results show that Al doping significantly improves the cycle stability of lithium-rich manganese-based cathode material, and the coating Li2WO4 significantly improves its magnification performance and the voltage attenuation of discharge plateau. The coating amount of Li2WO4 is 5%, and the specific capacity of Li1.2Mn0.51Al0.03Ni0.13Co0.13O2 cathode material is still up to about 110 mAh·g−1 in the charge and discharge voltage range of 2.0-4.8 V and the current density of 1,000 mA·g−1. At the same time, the capacity retention rate of 300 cycles at the current density of 100 mA·g−1 is 78%, and the voltage attenuation of the discharge plateau during the cycle is also significantly reduced. This work provides a new idea for solving the cycle stability and platform voltage attenuation of lithium-ion battery lithium-rich manganese-based cathode materials.