Graphene oxide assisted triple network hydrogel electrolyte with high mechanical and temperature stability for self-healing supercapacitor

Abstract

Supercapacitors (SCs) are an ideal choice for wearable energy storage devices due to its high power density and high security. In order to meet the flexible and mechanical properties required by wearable electronic products, it is urgent to develop a high performance supercapacitor with good mechanical properties. Herein, a novel triple network hydrogel electrolyte (PVA/Agar/GO-EMIMBF4-Li2SO4) is designed using agar, polyvinyl alcohol and graphene nanosheets as raw materials by freeze-thaw cycle method. The cross-linked triple structure forms a robust polymer skeleton and excellent flexible enough to maintain its chemical and physical stability against external test. Therefore, an activated carbon-based supercapacitor with PVA/Agar/GO-EMIMBF4-Li2SO4 hydrogel electrolyte can provide high specific capacitance (130 F g−1 at 0.3 A g−1), excellent ion conductivity (39.2 mS cm−1), outstanding self-healing (95 % of initial state after five heals), wide range of working temperature (−30–80 °C), and long cycle life. In this paper, we propose a new strategy to construct such flexible supercapacitors with multiple functions, providing a new idea for the development of wearable devices.