A self-healing hydrogel electrolyte towards all-in-one flexible supercapacitors

The self-healing electrolytes play an essential role in self-healing supercapacitors. Herein, poly (vinyl alcohol)/sulphuric acid (PVA/H2SO4) hydrogel electrolytes with self-healing properties are prepared, which has been achieved by dynamic hydrogen bonds between PVA chains. The obtained PVA hydrogel displays fast self-healing capability, reliable mechanical performance (stress at 0.29 MPa after stretching to 238%) and high ionic conductivity (57.8 mS cm−1). Based on these excellent properties, an all-in-one self-healing supercapacitor is assembled by in situ polymerization of aniline on the surface of PVA/H2SO4 hydrogel electrolyte. The assembled all-in-one supercapacitor shows outstanding capacitance performance (specific capacitance 504 mF cm−2 at current density of 0.2 mA cm−2 and energy density 35 μWh cm−2 at power density 100 μW cm−2), good cycle stability (after 5000 cycles of charging and discharging, the capacitance retention rate is 77%), excellent flexibility and considerable self-healing performance (69% capacitance retention rate after the fifth self-healing cycle). This self-healing supercapacitor will promote the development of self-healing energy storage devices in wearable electronics.