Synthesis Routes on Electrochemical Behavior of Co-Free Layered LiNi0.5Mn0.5O2 Cathode for Li-Ion Batteries

Co-free layered LiNi0.5Mn0.5O2 has received considerable attention due to high theoretical capacity (280 mAh g(-1)) and low cost comparable than LiCoO2. The ability of nickel to be oxidized (Ni2+/Ni3+/Ni4+) acts as electrochemical active and has a low activation energy barrier, while the stability of Mn4+ provides a stable host structure. However, selection of appropriate preparation method and condition are critical to providing an ideal layered structure of LiNi0.5Mn0.5O2 with good electrochemical performance. In this study, Layered LiNi0.5Mn0.5O2 has been synthesized by sol-gel and solid-state routes. According to the XRD, the sol-gel method provides a pure phase, and solid-state process only minimize the secondary phases to certain limit. The Ni2+/Mn4+ content in the sol-gel process was higher than in the solid-state reaction, which may be due to the chemical composition homogeneity of the sol-gel samples. Regarding the electrochemical behavior, sol-gel process is better than solid-state reaction. The discharge capacity is 145 mAh/g and 91 mAh/g for the sol-gel process and solid-state reaction samples, respectively.

Automated summary

Co-free layered LiNi0.5Mn0.5O2 has high theoretical capacity and low cost compared to LiCoO2. The preparation method and condition greatly influence the electrochemical performance of LiNi0.5Mn0.5O2. Sol-gel synthesis provides samples with a pure phase and better electrochemical behavior compared to solid-state reaction.