Proton-reservoir hydrogel electrolyte for long-term cycling Zn/PANI batteries in wide temperature range
Doudou Feng, Yucong Jiao*, and Peiyi Wu*. Proton-reservoir hydrogel electrolyte for long-term cycling Zn/PANI batteries in wide temperature range. Angew. Chem. Int. Ed. 2022, e202215060.
Advanced aqueous batteries are promising for next generation flexible and wearable devices owing to the high safety, yet still requiring better cycling stability and high specific capacity in wide temperature range. Herein, a polymeric acid hydrogel electrolyte (PAGE) with 3 M Zn(ClO4)2 was fabricated for high performance Zn/polyaniline (PANI) batteries. The -SO3-H+ function group in PAGE can endow the Zn/PANI battery with following merits: firstly, accelerating the redox reaction kinetics for PANI by constant proton generation; secondly, increasing the specific capacity by boosting the reaction sites between ions and PANI functional groups; thirdly, suppressing the side reaction and dendrites by inducing the (002) crystal plane formation. In addition, the anti-freezing performance for the hydrogel is also optimized by the salt and hydrogel, with a high ionic conductivity of 14.2 mS cm-1 at -35oC. As a consequence, even at -35oC, 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 mA h g-1 for more than 70,000 cycles at 15 A g-1. This proton-supplying strategy by polymeric acid hydrogel may further propel the development of high performance aqueous batteries.