A Universal Principle to Design Reversible Aqueous Batteries Based on Deposition–Dissolution Mechanism

Abstract Conventional charge storage mechanisms for electrode materials are common in widely exploited insertion/extraction processes, while some sporadic examples of chemical conversion mechanisms exist. It is perceived to be of huge potential, but it is quite challenging to develop new battery chemistry to promote battery performance. Here, an initiating and holistic deposition–dissolution battery mechanism for both cathodes and anodes is reported. A MnO 2 –Cu battery based on this mechanism demonstrates outstanding energy density (27.7 mWh cm −2 ), power density (1232 mW cm −2 ), high reversibility, and unusual Coulombic efficiency. It can be charged to 0.8 mAh cm −2 within 42 s and possessees a stable rate cyclability within vastly varied discharging current density (4–64 mA cm −2 ). Moreover, the deposition–dissolution mechanism can be universally adopted and derived such that the corresponding MnO 2 –Zn and MnO 2 –Bi batteries are successfully constructed. The material selection principle, deposition–dissolution behaviors of cathode/anode materials, and battery performance are systematically elaborated. Since the electrodeposition chemistry is capable of involving a large family of materials, for example, metal oxides as cathode materials, or metals as anode materials, the research could be a model system to open a door to explore new aqueous battery materials and chemistry.