Surface modification of a LiNi0.5Mn1.5O4 cathode with lithium boron oxide glass for lithium-ion batteries

Abstract

Lithium boron oxide glass (LBO-glass) coated LiNi_0.5Mn_1.5O₄ cathode materials have been synthesized by a solution method to enhance the electrochemical performances. The structure and morphology of the as-prepared materials have been characterized by XRD, SEM, and TEM. The results indicate that the LiNi_0.5Mn_1.5O₄ is coated with a layer of amorphous LBO-glass. The electrochemical properties are characterized by galvanostatic charge–discharge cycling, cyclic voltammetry, electrochemical impedance spectroscopy and a self-discharge test. Differential scanning calorimetry is carried out to confirm the improved safety by LBO-glass coating. The LBO coating can effectively enhance the electrochemical kinetics of the LiNi_0.5Mn_1.5O₄ phase and improve the cycling performance. Among the as-prepared samples, the 1 wt% LBO-glass coated LiNi_0.5Mn_1.5O₄ presents optimal electrochemical behaviors with a capacity retention of 91.4% after 100 cycles at 1 C and a discharge capacity of 105.8 mA h g⁻¹ at 10 C. Besides, the electrochemical impedance spectroscopy analysis shows the 1 wt% LBO-glass coating reduces the electrochemical impedance and improves the ability to conduct Li⁺ in the cells to a great extent.