Trimethyl Glycine Additive Realizes a High-Performance Water-Based Zinc-Ion Battery through Double-Effect Regulation

Among all kinds of energy storage systems, water-based zinc-ion batteries have attracted much attention due to their high theoretical capacity (820 mAh g–1), intrinsic safety, and low cost. However, zinc metal anodes are facing severe challenges in practical application, including parasitic reactions, dendrite growth, and hydrogen evolution, which significantly limit the application of aqueous zinc-ion batteries (AZIBs). Introducing trimethyl glycine (Tri) into the aqueous electrolyte forms a unique anode/electrolyte interface and enhances steric effects. Theoretical calculations elucidate the mechanism by which the Tri additive influences the Zn metal anode and electrolyte, while experimental results further confirm the critical role of Tri in simultaneously regulating anode interfacial chemistry and the electrolyte environment. Therefore, the cycle life of the Zn//Zn symmetrical battery is extended to 4000 h at 1 mA cm–2, and it can maintain a stable cycle for 600 h even at a high current density of 3 mA cm–2. In addition, the Zn//V2O5 battery assembled with the Tri additive also showed a stable cycle performance of more than 1500 cycles and a high residual discharge specific capacity of 185.8 mAh g–1. A novel and simple electrolyte additive strategy was put forward in this work, which realized dendrite-free zinc anodes and a stable full battery, providing a reference for surpassing the most advanced AZIBs.