Truncated octahedral LiNi0.5Mn1.5O4 with excellent electrochemical properties for lithium-ion batteries prepared by a graphite assisted calcination method

Abstract

A truncated octahedron structured LiNi_0.5Mn_1.5O₄ (denoted as EG-LNMO) is synthesized by a graphite assisted calcination method. Herein, we introduce a possible growth model, graphite–ethanol synergism, for the formation of the truncated octahedral morphology LiNi_0.5Mn_1.5O₄ based on a series of experimental results. The electrochemical test results indicate that EG-LNMO materials exhibit excellent electrochemical performances, attributed to the unique truncated octahedron structure. It has a high stability {111} crystal plane group and high lithium conductivity {100} crystal plane group, which can meet the requirements of large rate and long cycling performance. Moreover, the electrochemical properties of EG-LNMO under extreme conditions are tested (rapid charge–discharge performance and cycling performance at high rate). The results show that the capacity decay of the electrode material mainly depends on the later stage of the cycling process, which may be ascribed to the synergistic effect of the electrolyte decomposition and corrosion reaction, as well as the phase change inactivation of the electrode material.