An Investigation into the Charge Storage Mechanism and Cycling Performance of Mn2O3 as the Cathode Material for Zinc-Ion Batteries

In this work, highly crystalline, nanosize Mn2O3 powder is synthesized via a precipitation and calcination method for utilization as the cathode in aqueous zinc-ion batteries (aZIBs). The resultant electrodes are characterized using electrochemical and microstructural methods to determine the mechanisms associated with charge and discharge. In addition, a few quantitative testing methods are used to investigate cycling performance stability. A specific capacity of 211 mAh g(-1) is retained after 200 cycles at a current density of 500 mA g(-1) with 93 % capacity retention. Also, 73 % capacity retention can be reached after 1100 cycles at 2000 mA g(-1). The energy storage mechanism associated with Mn2O3 is for the first time proposed to be a chemical conversion reaction type with two steps involving the formation/decomposition of ZnMn2O4 (hetaerolite) and zinc sulphate hydroxide (ZHS). Also, capacity fading is directly linked to the incomplete reversibility of the chemical conversion reaction mechanism.

Automated summary

Highly crystalline, nanosize Mn2O3 powder is synthesized and used as the cathode in aqueous zinc-ion batteries. The electrodes show good cycling performance and stability, with a specific capacity of 211 mAh g(-1) retained after 200 cycles at a current density of 500 mA g(-1) and 93% capacity retention. The energy storage mechanism of Mn2O3 is proposed to be a chemical conversion reaction type, and capacity fading is attributed to the incomplete reversibility of the reaction.