Proton‐Reservoir Hydrogel Electrolyte for Long‐Term Cycling Zn/PANI Batteries in Wide Temperature Range

Abstract Advanced aqueous batteries are promising for next generation flexible devices owing to the high safety, yet still requiring better cycling stability and high capacities in wide temperature range. Herein, a polymeric acid hydrogel electrolyte (PAGE) with 3 M Zn(ClO 4 ) 2 was fabricated for high performance Zn/polyaniline (PANI) batteries. With PAGE, even at −35 °C the Zn/Zn symmetrical battery can keep stable for more than 1 500 h under 2 mA cm −2 , and the Zn/PANI battery can provide ultra‐high stable specific capacity of 79.6 mAh g −1 for more than 70 000 cycles at 15 A g −1 . This can be mainly ascribed to the −SO 3 − H + function group in PAGE. It can generate constant protons and guide the (002) plane formation to accelerate the PANI redox reaction kinetics, increase the specific capacity, and suppress the side reaction and dendrites. This proton‐supplying strategy by polymeric acid hydrogel may further propel the development of high performance aqueous batteries.