Enhanced electrochemical performance of a ZnO–MnO composite as an anode material for lithium ion batteries

Abstract

A ZnO–MnO composite was synthesized using a simple solvothermal method combined with a high-temperature treatment. To observe the phase change during the heating process, in situ high-temperature XRD analysis was performed under vacuum conditions. The results indicated that ZnMn₂O₄ transformed into the ZnO–MnO composite phase starting from 500 °C and that this composite structure was retained until 700 °C. The electrochemical performances of the ZnO–MnO composite electrode were evaluated through galvanostatic discharge–charge tests and cyclic voltammetry analysis. Its initial coulombic efficiency was significantly improved to 68.3% compared to that of ZnMn₂O₄ at 54.7%. Furthermore, the ZnO–MnO composite exhibited improved cycling performance and enhanced rate capability compared with untreated ZnMn₂O₄. To clarify the discharge–charge mechanism of the ZnO–MnO composite electrode, the structural changes during the charge and discharge processes were also investigated using ex situ XRD and TEM.