Manganese dioxide coated with tin oxide as cathode material for high-performance aqueous zinc-ion battery.

Abstract

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted increasing attention as an energy storage technology due to their high energy density, low cost, and environmental friendliness. However, the application of manganese dioxide as the cathode for aqueous Zn-ion batteries (ZIBs) is restricted by the solubility of manganese dioxide in aqueous electrolytes and the formation of byproducts during the charge/discharge process, causing severe capacity fading and limited cycle life. Surface modification is one of the interesting techniques to improve zinc-ion batteries electrochemical performance. Here, we report an ultrathin SnO2 film as an artificial solid electrolyte interphase (SEI) to modify the surface of manganese dioxide by sub-monolayer SnO2 coating on the electrodes. Here, SnO2 is coated with different proportions: 0.1, 0.2, 0.3 and 0.4 g. As a result, the SnO2-coated MnO2 cathode yields the best electrode, 0.3MnO2@SnO2 positive electrode. This results in a higher capacity (365.37 mAh/g@100 mA/g) and better cycle life compared with pristine MnO2 (199.02 mAh/g@100 mA/g). The presence of the SnO2 layer acts as an artificial cathode electrolyte interface, the electrochemical kinetical studies reveal that the SnO2 coating greatly improves the diffusion coefficient of zinc ions and investigation reveals the SnO2 greatly improves the electrical conductivity. This research contributes to the development of MnO2-based cathode materials for high-performance and flexible ZIBs.