Dual-Functional Additives Boost Zinc-Ion Battery Electrolyte over Wide Temperature Range

Traditional aqueous electrolyte systems in zinc-ion batteries (ZIBs) often face challenges such as sluggish ion transfer kinetics, dendrite formation, and sudden battery failures in harsh temperature environments. Herein, we introduce a pioneering approach by integrating a bifunctional additive composed of ethylene glycol (EG) and sodium gluconate (Ga) into ZnSO₄ (ZSO) electrolyte to overcome these obstacles. The polyhydroxy structures of EG and Ga can reconstruct the hydrogen bond network of H₂O to improve its liquid stability, and also adjust the coordination environment around hydrated Zn²⁺. Additionally, Ga in the H₂O–EG mixture leads to the formation of a robust protective layer that promotes uniform deposition of Zn²⁺ ions and minimizes unwanted side reactions. Therefore, Zn anodes with 40% ZSO–Ga electrolyte can cycle for more than 3,000 h at 25 °C and 800 h at 50 °C. Furthermore, Zn||NH₄V₄O₁₀ (NVO) full batteries demonstrate remarkable cycle stability, lasting up to 10,000 cycles at 1 A g⁻¹ with a capacity retention of 79.1%. The multifunctional electrolyte additive employed in this study emerges as a promising candidate for enabling highly stable zinc anodes under diverse temperature conditions.