Optimization mechanism of Li2ZrO3-modified lithium-rich cathode material Li[Li0.2Ni0.2Mn0.6]O2 for lithium-ion batteries

Abstract

To achieve lithium-ion batteries with high energy and power density, it is necessary to develop alternative high-capacity cathode materials for traditional LiCoO2 or LiFePO4, such as lithium-rich manganese-based cathode materials. However, there are still some practical problems that Li-rich materials need to be further improved, such as structure transformation issue and poor rate capability. Here, the modification of Li[Li0.2Ni0.2Mn0.6]O2 cathode material by lithium-ion conductor (Li2ZrO3) has been achieved by a sol–gel method, and the optimization mechanism is preliminarily explored. The first charge/discharge specific capacities of the modified material coated with 1 wt.% Li2ZrO3 can reach 272.1 and 196.1 mAh g− 1 at 0.5 C, which are obviously higher than those of the pristine material. The rate capability has also been improved at 2 C and 5 C. As a fast lithium-ion conductor with good chemical stability, Li2ZrO3 material can form a continuous and uniform coating layer on the surface of active particles, which can inhibit the side reaction between the electrolyte and the electrode material, effectively prevent the corrosion of cathode material by HF attack, and reduce electrode polarization at high rates, leading to the improvement of the specific capacity and the structure stability of Li-rich material.