Weak solvent chemistry enables stable aqueous zinc metal batteries over a wide temperature range from -50 to 80 °C

The development of electrolytes with a wide temperature range, no dendrite growth and corrosion resistance is essential for the practical application of aqueous zinc metal batteries. Herein, γ-valerolactone is developed as the co-solvent to extend the operating temperature range of the aqueous electrolyte and stabilize the zinc metal anode interface. This weak solvent acts as a strong hydrogen bonding ligand and "diluent" to break the hydrogen bonds between free water molecules, thus enhancing the temperature tolerance and chemical stability of the electrolyte. The γ-valerolactone can also be adsorbed on the anode surface to achieve a dendrite-free zinc deposition behavior by promoting zinc nucleation and regulating zinc growth texture. The optimized electrolyte enables the symmetric cell to deliver a cycle/rest life of 2160 h and operate stably over a wide temperature range of -50 to 80 °C. The corresponding Zn||AC and Zn||PANI cells exhibit capacity retention of 92.5% and 85% after 8100 and 1600 cycles, respectively. This mechanism of weak solvent-regulated hydrogen bonding and solvent sheath provides new insights into the design of advanced aqueous electrolytes.