Sulfolane-based solid-state electrolyte for high-capacity rechargeable zinc-air batteries operating at a wide temperature range

Polymer-based gel membranes are highly appealing as solid electrolytes for zinc-air batteries due to their excellent electrochemical properties and stable performance across a wide range of operating temperatures. In this study, a novel gel polymer electrolyte (GPE) based on polyvinylidene-co-hexafluoropropylene (PVdF-HFP) with incorporated sulfolane (ionic liquid) and adiponitrile (plasticizer additive) (PVdF-HFP-Sul-Adn) was synthesized and tested with full cell system using a zinc foil as anode and synthesized zinc vanadate (ZVO) as the cathode. The developed GPE exhibited remarkable thermal stability up to 250 °C, excellent resistance to open flames, and high ionic conductivities across varying temperatures: 142 mS/cm at −10 °C, 288 mS/cm at 35 °C, and 76 mS/cm at 90 °C. In the full cell using zinc vanadate as the cathode and zinc foil as the anode, the PVdF-HFP-Sul-Adn GPE achieved a high specific capacity of up to 193 mAh/g at 2 mA/cm², with a retention capacity of 94 % after 120 cycles at 35 °C. Significant capacity retention was also observed after 120 cycles at −10 °C, 70 °C, 90 °C, and 100 °C. The newly developed GPE demonstrates substantial potential for advancing zinc-air batteries as a safer alternative to lithium-ion batteries, particularly for applications in regions with hot climates where safety concerns are more pronounced.