Synthesis and Optimization of ZnMn2O4 Cathode Material for Zinc-Ion Battery by Citric Acid Sol-Gel Method

Abstract

Zinc manganese spinel composite oxide ZnMn2O4 is an important inorganic material, which is rich in natural resources and environment-friendly. Herein, pure phase ZnMn2O4 was prepared by a simple sol-gel process as cathode material for zinc ion batteries. In order to improve the cycle performance of the material while maintaining the capacity, acetonitrile/aqueous co-solvent electrolyte (0.5 M Zn(CF3SO3)2/AN-H2O) was used as the electrolyte of the zinc ion battery. The influence of different experimental conditions on the electrochemical properties of ZnMn2O4 was studied by orthogonal experiment. In order to improve its electrochemical performance and cycling ability, the non-equivalent substitution of pure ZnMn2O4 was performed by adding Al3+. The non-equivalent substitution of Al3+ reduced the cell volume of ZnMn2O4 and the mixed manganese valence appeared. The specific capacity of initial discharge increases from 52.9 mAh·g−1 to 109.4 mAh·g−1 at 0.05C, and the cycle stability is also greatly improved. After 100 cycles, the capacity retention rate was 82.3%. This work shows that ZnMn2O4 is a promising cathode material for zinc ion batteries, which expands the application of spinel oxide in zinc ion batteries.