Zn/MnO Battery Chemistry With H and Zn Coinsertion.

Rechargeable aqueous Zn/MnO battery chemistry in a neutral or mildly acidic electrolyte has attracted extensive attention recently because all the components (anode, cathode, and electrolyte) in a Zn/MnO battery are safe, abundant, and sustainable. However, the reaction mechanism of the MnO cathode remains a topic of discussion. Herein, we design a highly reversible aqueous Zn/MnO battery where the binder-free MnO cathode was fabricated by in situ electrodeposition of MnO on carbon fiber paper in mild acidic ZnSO+MnSO electrolyte. Electrochemical and structural analysis identify that the MnO cathode experience a consequent H and Zn insertion/extraction process with high reversibility and cycling stability. To our best knowledge, it is the first report on rechargeable aqueous batteries with a consequent ion-insertion reaction mechanism.