Quasi-Solid-State Zinc Ion Rechargeable Batteries for Subzero Temperature Applications

The emerging zinc-ion rechargeable batteries have attracted much attention because of their intrinsic safety and low cost resulting from the use of aqueous electrolytes and zinc anodes that come from abundant sources. However, it is impossible to use zinc-ion batteries in frigid environments because of their liquid aqueous electrolytes. Herein, we have prepared a quasi-solid-state zinc-ion battery employing an anti-freezing quasi-solid-state electrolyte and a high-capacity NH4V3O8·1.9H2O cathode. High-concentration zinc salts are used in the electrolyte to depress its freezing point, and xanthan gum is employed to convert the electrolyte into the quasi-solid state, for operations at subzero temperatures and maintaining good performance while mechanically bent. When cycled at 0.2 A g-1, the quasi-solid-state battery cells exhibit a discharge capacity of 283 mAh g-1 at 20 °C, 215 mAh g-1 at 0 °C, and 119 mAh g-1 at -20 °C. The capacity retention can reach 90.3% and 90.7% at 20 and 0 °C after 800 cycles when cycled at 1.5 A g-1. The battery can still exhibit 83% of the initial capacity over 450 cycles at -20 °C when cycled at 0.5 A g-1. In addition, the battery well maintains its capacity while being bent at 90 and 180°at either 20 or -20 °C. Hence, this work is a creative effort to achieve quasi-solid-state ZIBs that can be used either in cold environments or as power sources in wearable electronics, purely based on safe aqueous electrolytes without using any organic compounds or organic synthesis other than commercial edible xanthan gum.