Theory-Driven Design of a Cationic Accelerator for High-Performance Electrolytic MnO₂–Zn Batteries

Aqueous electrolytic MnO₂–Zn batteries are considered as one of the most promising energy-storage devices for their cost effectiveness, high output voltage, and safety, but their electrochemical performance is limited by the sluggish kinetics of cathodic MnO₂/Mn²⁺ and anodic Zn/Zn²⁺ reactions. To overcome this critical challenge, herein, a cationic accelerator (CA) strategy is proposed based on the prediction of first-principles calculations. Poly(vinylpyrrolidone) is utilized as a model to testify the rational design of the CA strategy. It manifests that the CA effectively facilitates rapid cations migration in electrolyte and adequate charge transfer at electrode–electrolyte interface, benefiting the deposition/dissolution processes of both Mn²⁺ and Zn²⁺ cations to simultaneously improve kinetics of cathodic MnO₂/Mn²⁺ and anodic Zn/Zn²⁺ reactions. The resulting MnO₂–Zn battery regulated by CA exhibits large reversible capacities of 455 mAh g^–1 and 3.64 mAh cm^–2 at 20 C, as well as a long lifespan of 2000 cycles with energy density retention of 90%, achieving one of the best overall performances in the electrolytic MnO₂–Zn batteries. This comprehensive work integrating theoretical prediction with experimental studies provides opportunities to the development of high-performance energy-storage devices.