High-Power-Density and High-Energy-Efficiency Zinc-Air Flow Battery System for Long-Duration Energy Storage

To achieve long-duration energy storage (LDES), a technological and economical battery technology is imperative. Herein, we demonstrate an all-around zinc-air flow battery (ZAFB), where a decoupled acid-alkaline electrolyte elevates the discharge voltage to -1.8 V, and a reaction modifier KI lowers the charging voltage to -1.8 V. This ZAFB exhibits a long discharge duration of over 4 h, a high power density of 178 mW cm-2 (about 76 % higher than conventional ZAFB), and unprecedented energy efficiency of nearly 100 %. Moreover, the ZAFB demonstrates outstanding fast charging ability, mitigated zinc dendrite growth and parasitic hydrogen evolution, enhanced cathode protection, and good resistance to environmental disturbance. This all-around ZAFB will not only become a very promising option for LDES but also promote the development of other LDES systems.