Facile synthesis of triple‐network organo‐hydrogel for all‐temperature flexible supercapacitors

A new triple‐network organo‐hydrogel with high anti‐freezing and thermally‐stable performance is prepared for application in all‐temperature flexible supercapacitor. It is composed of boric acid/graphene/polyvinyl alcohol matrix and H 2 SO 4 /dimethyl sulfoxide mixing solution. The incorporation of graphene and boric acid into polymer matrix can improve thermal stability and ionic conductivity of organo‐hydrogel. The H 2 SO 4 and dimethyl sulfoxide are key roles for improving anti‐freezing of organo‐hydrogel. The organo‐hydrogel exhibits high ionic conductivity of 1.6 and 3.1 S/m at −80 and 90°C, respectively. As a result, the assembled supercapacitor delivers a high capacitance retention of 84.5% and 113.3% at ultra‐low temperature (−80.0°C) and high temperature (90.0°C), respectively. The work provides a new route to design and prepare flexible supercapacitor with wide temperature range.