Stable polyaniline/sodium alginate/graphene oxide composite hydrogels as binder-free supercapacitor electrodes

Conducting hydrogels are considered one of the key materials for the fabrication of supercapacitors. But it is a significant requirement for the design of rational structures and simultaneous realization of high electrochemical performance and mechanical strength. Herein, the stable polyaniline/sodium alginate/graphene oxide composite hydrogels are prepared by aniline polymerization in the aqueous solution containing graphene oxide (GO) and sodium alginate (SA). Owing to the multiple interactions among polyaniline (PANi), GO, and SA, three components are intertwined, which leads to the production of the three-dimensional hydrogel network and endows the hydrogel with relatively high mechanical strength and electrochemical performance. The obtained PANi/SA/GO hydrogel exhibits high mechanical strength of more than 50 kPa and displays excellent specific capacitance of 457 F g−1 at 0.5 A g−1 and long-term cyclability. Moreover, the fabricated supercapacitor composed of PANi/SA/GO hydrogel possesses satisfied flexibility and outstanding capacitance. This work presents a simple integration route for the synthesis of conducting hydrogels with outstanding performance in the field of supercapacitors for flexible electronics.