High‐Current Capable and Non‐Flammable Protic Organic Electrolyte for Rechargeable Zn Batteries

Abstract Rechargeable Zinc batteries (RZBs) are considered a potent competitor for next‐generation electrochemical devices, due to their multiple advantages. Nevertheless, traditional aqueous electrolytes may cause serious hazards to long‐term battery cycling through fast capacity fading and poor Coulombic efficiency (CE), which happens due to complex reaction kinetics in aqueous systems. Herein, we proposed the novel adoption of the protic amide solvent, N ‐methyl formamide (NMF) as a Zinc battery electrolyte, which possesses a high dielectric constant and high flash point to promote fast kinetics and battery safety simultaneously. Dendrite‐free and granular Zn deposition in Zn‐NMF electrolyte assures ultra‐long lifespan of 2000 h at 2.0 mA cm −2 /2.0 mAh cm −2 , high CE of 99.57 %, wide electrochemical window (≈3.43 V vs. Zn 2+ /Zn), and outstanding durability up to 10.0 mAh cm −2 . This work sheds light on the efficient performance of the protic non‐aqueous electrolyte, which will open new opportunities to promote safe and energy‐dense RZBs.