Contribution of Cation Addition to MnO Nanosheets on Stable Co O Nanowires for Aqueous Zinc-Ion Battery.

Zinc-based electrochemistry attracts significant attention for practical energy storage owing to its uniqueness in terms of low cost and high safety. In this work, we propose a 2.0-V high-voltage Zn-MnO battery with core@shell CoO@MnO on carbon cloth as a cathode, an optimized aqueous ZnSO electrolyte with Mn additive, and a Zn metal anode. Benefitting from the architecture engineering of growing CoO nanorods on carbon cloth and subsequently deposited MnO on CoO with a two-step hydrothermal method, the binder-free zinc-ion battery delivers a high power of 2384.7 W kg, a high capacity of 245.6 mAh g at 0.5 A g, and a high energy density of 212.8 Wh kg. It is found that the Mn cations are converted to MnO during electrochemical operations followed by a phase transition into electroactive MnO in our battery system. The charge-storage mechanism of the MnO-based cathode is Zn/Zn and H insertion/extraction. This work shines light on designing multivalent cation-based battery devices with high output voltage, safety, and remarkable electrochemical performances.