High-alkali poly (sodium acrylate) hydrogels with high conductivities and soft deformability for flexible Zn-air batteries

Developing hydrogel electrolytes with excellent deformability and desirable conductivity is of paramount importance in improving flexible solid-state aqueous energy devices. Herein high-alkali contained poly (sodium acrylate) hydrogel electrolytes with high conductivities, soft deformability, and considerable freezing resistance are designed and developed for flexible Zn-air batteries. The electrolytes are simply prepared by swelling a high content of 5 M KOH solutions within a homogenous crosslinked poly (sodium acrylate) network. The homogenous crosslinked networks in the electrolytes ensure robust fracture toughness (600 J m −2 ) during diverse deformation, while the high content of KOH solutions (80 wt%) enable soft feature of low Young’s modulus (1.4 kPa), desirable ion conductivity (246 mS cm −1 ), and anti-freezing performance (<-30 °C) for the electrolytes. Based on these, the derived Zn-air batteries show satisfactory energy density (0.1 W cm −2 ), multiple flexibility, and wide operating temperatures (−30 °C to r.t.), which are practically applied as flexible energy-consuming devices in different situations. The work here provides a promising approach to develop desirable hydrogel electrolytes for various alkaline energy devices.