Multifunctional and self-healable conductive IPN hydrogels functionalized with reduced magnetite graphene oxide for an advanced flexible all in one solid-state supercapacitor

Abstract

The all in one solid-state (AIOS) stretchable and flexible hydrogel electronic devices play a pivotal role in the development of elastic supercapacitors for energy storage and fast charging–discharging rates. However, poor ionic, electrochemical, electronic conductivity, self-healing ability, bioavailability, and weak mechanical stability have limited the use of such hydrogels in supercapacitors for real applications. In the present work, we report an interpenetrating network (IPN) of poly(vinyl alcohol) (PVA)-based green polymeric composite hydrogel, synthesized with a two-pot method. The first polymeric network consisted of guar gum (GG) which is used as a bio-template for the dispersant for the uniform distribution of sonicated reduced magnetite graphene oxide (rMGO) to produce rMGO-GG. This was blended with PVA and then physically crosslinked with borate ions to produce the IPN. The viscoelastic properties of the hydrogels were tested rheologically, and the storage modulus was found to be 3.86 kPa within the linear viscoelastic region (LVR). The hydrogels exhibited an excellent healing potential which occurred in 5 to 10 s. The practical and self-assembled AIOS supercapacitor demonstrated a cyclic voltammetry capacitance of 85 F g⁻¹, whereas the galvanostatic charge discharge (GCD) specific capacitance was 106.66 F g⁻¹. The electrochemical impedance spectroscopy (EIS) of the materials also found an internal resistance of 1.22 Ω. The capacitance retention after 5000 cycles was 94.97%, demonstrating the cyclic stability of the hydrogels. The gauge factor (GF) was 8.25, with a conductivity of 0.89 S m⁻¹ at 200% strain. The material was found to be efficient when applied as a practical device.