Cailiao gongcheng (Mar 2019)
Fabrication and electrochemical performance of Li[Li<sub>0.2</sub>Ni<sub>0.2</sub>Mn<sub>0.6</sub>]O<sub>2</sub> coated with Li<sub>2</sub>ZrO<sub>3</sub> as cathode material for lithium-ion batteries
Abstract
Lithium-rich manganese-based materials have attracted much attention because of their high charge-discharge capacity. In order to solve the problems of low coulombic efficiency, poor cycling performance and poor rate capability, lithium-ion conductor Li2ZrO3 with three-dimensional Li+ channel was employed to coat lithium-rich manganese-based cathode material Li[Li0.2Ni0.2Mn0.6]O2. According to the structure and morphological analysis, different amounts of Li2ZrO3 were successfully coated on the surface of the sample. When the thickness of the coating layer is 3 nm (1% coating amount, mass fraction), the electrochemical performance of the composite material is significantly improved. The first discharge specific capacity is 271.5 mAh·g-1 and the first coulombic efficiency is 72.4%. The first irreversible capacity loss is obviously reduced. The discharge specific capacity at 0.5 C is 191.5 mAh·g-1 and the capacity retention is 89.5%. The specific capacity at 5 C is 75 mAh·g-1 and the rate performance is improved. The results show that a uniform thickness of Li2ZrO3 coating layer can form a core-shell structure on the surface of the sample to make the sample more stable. It can reduce surface side reactions and prevent the formation of thicker SEI films. All of these results benefit from the high conductivity, high electrochemical stability and good lithium ion conductivity of Li2ZrO3 coating layer.
