Graphene-Wrapped MnO/C Composites by MOFs-Derived as Cathode Material for Aqueous Zinc ion Batteries

Abstract

ABSTRACT Aqueous zinc ion batteries (AZIBs) show tremendous application prospect in the fields of energy storage for smart grid and electric tools because of their high safety, environmental benignity and low cost. However, the sluggish zinc ion diffusion kinetics and the serious manganese dissolution issue seem to impede its practical application. Herein, the MnO/C@rGO composites are fabricated via an in situ strategy of one-step MOFs-derived solvothermal method, combined with a calcination step at 570 °C under Ar for 2 h. As further evaluated as a cathode for AZIBs, it can maintain a discharge capacity of 170.6 mAh g-1 after 300 cycles at 500 mA g-1. Importantly, even as the current density reaches up to 2.0 A g-1, it still delivers a reversible capacity as high as 110.1 mAh g-1. The excellent cycleability, superior rate capability and smaller self-discharge phenomenon are ascribed to the inhibition of manganese dissolution and the conductivity improvement. Therefore, this work may give a new insight into improving the comprehensive electrochemcial performances of manganese-based cathode materials for AZIBs with large power densities and long cycle life.