An Electrolytic Zn–MnO₂ Battery for High‐Voltage and Scalable Energy Storage

Zinc-based electrochemistry is attracting significant attention for practical energy storage owing to its uniqueness in terms of low cost and high safety. However, the grid-scale application is plagued by limited output voltage and inadequate energy density when compared with more conventional Li-ion batteries. Herein, we propose a latent high-voltage MnO₂ electrolysis process in a conventional Zn-ion battery, and report a new electrolytic Zn-MnO₂ system, via enabled proton and electron dynamics, that maximizes the electrolysis process. Compared with other Zn-based electrochemical devices, this new electrolytic Zn-MnO₂ battery has a record-high output voltage of 1.95 V and an imposing gravimetric capacity of about 570 mAh g^-1 , together with a record energy density of approximately 409 Wh kg^-1 when both anode and cathode active materials are taken into consideration. The cost was conservatively estimated at <US$ 10 per kWh. This result opens a new opportunity for the development of Zn-based batteries, and should be of immediate benefit for low-cost practical energy storage and grid-scale applications.