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

Zinc manganese spinel composite oxide ZnMn 2 O 4 is an important inorganic material, which is rich in natural resources and environment-friendly. Herein, pure phase ZnMn 2 O 4 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(CF 3 SO 3 ) 2 /AN-H 2 O) was used as the electrolyte of the zinc ion battery. The influence of different experimental conditions on the electrochemical properties of ZnMn 2 O 4 was studied by orthogonal experiment. In order to improve its electrochemical performance and cycling ability, the non-equivalent substitution of pure ZnMn 2 O 4 was performed by adding Al 3+ . The non-equivalent substitution of Al 3+ reduced the cell volume of ZnMn 2 O 4 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 ZnMn 2 O 4 is a promising cathode material for zinc ion batteries, which expands the application of spinel oxide in zinc ion batteries.