Improving zinc anode reversibility by hydrogen bond in hybrid aqueous electrolyte

Rechargeable aqueous zinc-ion batteries is a promising candidate for next generation batteries. However, the deposition and dissolution of zinc is unavoidably accompanied by irreversibility including hydrogen evolution reaction (HER), dendritic growth and other issues, resulting in low Coulombic efficiency (CE). Here, we report a new aqueous electrolyte which reconstructs a new hydrogen-bond network by the interaction between 1,3-dioxolane (DOL) and H₂O molecular, thus expanding the hydrogen evolution potential by 0.197 V and maintaining high conductivity of 30 mS cm⁻¹. The hybrid electrolyte enabled an unusual Zn/Zn²⁺ reversibility CE of 98.6% in Zn/Ti cell along with smooth zinc deposition over 300 cycles. Besides, the Zn/V₂O₅ full cell could stably work during 1500 cycles with ~94% capacity retention. In addition, the assembled full cell exhibited a superior low-temperature performance over 300 cycles (average capacity: 131 mA h g⁻¹) at −30 °C, which means the proposed electrolyte has been tested by severe cold.