High-performance zinc-ion battery cathode enabled by deficient manganese monoxide/graphene heterostructures

Rechargeable aqueous zinc-ion battery (ZIB) with manganese-based cathode has attracted much attention in recent years. However, the electrochemical performance of ZIBs are limited by cathode materials. Herein, an accordion-like heterostructure of manganese monoxide uniformly grown between graphene layers (A-MnO/G) is developed for ZIB cathode. The covalent bonded graphene-MnO interphase facilitates the formation of vacancies/defects that result in a disordered phase of MnO, contributing to easy access for Zn2+ to abundant active sites. As a result, A-MnO/G-based ZIB delivers a high capacity of 398.5 mAh g−1 at 0.1 A g−1. Meanwhile, the battery exhibits 70% capacity retention after 2000 cycles at 3 A g−1. First principles calculations reveal that the heterostructures significantly lower the formation energy of oxygen vacancies which further lower the adsorption energy of Zn2+ to boost capacity. Furthermore, flexible transparent batteries assembled with A-MnO/G cathode demonstrate great potential for serving as power sources for practical use.