Dual-function modulated MnO cathode for high-performance aqueous zinc-ion batteries

Abstract

Enhancing the properties of cathode materials could improve cycle life in rechargeable aqueous zinc-ion batteries (ZIBs). MnO is a promising high-performance ZIBs cathode material by virtue of high theoretical capacity and low cost. However, the original MnO lacks open framework structure with low electrochemical activity and low electrical conductivity, limiting its practical application. Herein, a novel Fe-containing MnO material (Fe/MnO@cPAN) with a dense carbonized polyacrylonitrile (cPAN) coating and rich manganese/oxygen defects is constructed by the dual-function modulation of defect engineering and coating strategy. Fe doping introduces more oxygen vacancies, the cPAN layer possesses high electronic conductivity and provides physical protection. The synergistic effect of the two is conducive to Zn²⁺ storage and reduces manganese dissolution. Thus, the Zn||Fe/MnO@cPAN battery exhibits a superior capacity of 161.2 mAh g⁻¹ at 0.5 A g⁻¹ and a high reversible capacity of 93.5 mAh g⁻¹ with capacity retention of 79 % after 1500 cycles at 1 A g⁻¹. This work contributes an advanced design idea for durable manganese-based cathodes in ZIBs.