Oxygen Defects in ?-MnO2 Enabling High-Performance Rechargeable Aqueous Zinc/Manganese Dioxide Battery.

ABSTRACT: Rechargeable aqueous Zn/manganese dioxide (Zn/MnO2) batteries are attractive energy storage technology owing to their merits of low cost, high safety, and environmental friendliness. However, the ?-MnO2 cathode is still plagued by the sluggish ion insertion kinetics due to the relatively narrow tunneled pathway. Furthermore, the energy storage mechanism is under debate as well. Here, ?-MnO2 cathode with enhanced ion insertion kinetics is introduced by the efficient oxygen defect engineering strategy. Density functional theory computations show that the ?-MnO2 host structure is more likely for H+ insertion rather than Zn2+, and the introduction of oxygen defects will facilitate the insertion of H+ into ?-MnO2. This theoretical conjecture is confirmed by the capacity of 302 mA h g-1 and capacity retention of 94% after 300 cycles in the assembled aqueous Zn/?-MnO2 cell. These results highlight the potentials of defect engineering as a strategy of improving the electrochemical performance of ?-MnO2 in aqueous rechargeable batteries.

SUBMITTER: Han M 

PROVIDER: S-EPMC6957857 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature