Resilient 3D porous self-healable triple network hydrogels reinforced with graphene oxide for high-performance flexible supercapacitors

The application of gel polymer electrolyte (GPE) in flexible supercapacitor (FSC) has attracted much attention due to its excellent mechanical properties and chemical stability. However, traditional polymer substrates have high crystallinity, resulting in sluggish ion migration and low ionic conductivity. This study reports the successful fabrication of a resilient highly porous triple hydrogel network (TNH) comprising the natural polymer of sodium alginate and biocompatible components of polyvinyl alcohol and graphene oxide (GO), exhibiting remarkably high ionic conductivity and astonishing mechanical strength, self-healing, and flame retardant properties. The physical and electrochemical features of the GPEs were optimized by tuning the GO wt% within the polymeric matrix. Adding a low wt% of GO (0.8 wt%) led to remarkable improvements in ionic conductivity (83.33 mS cm- 1), mechanical strength (2.21 MPa), and self-healing and flame-retardant properties of the resulting PVA/ SA/GO GPE than the pristine GPE. This was attributed to the formation of a microporous three-dimensional polymeric network based on reversible non-covalent bonds. The carbon cloth-based symmetric SC prepared based on this GPE exhibited a long cycle life, high specific capacitance of 633.3 mF cm- 2 at 0.5 mA cm- 2, and an energy density of 84 mWh cm- 2 at a high power density of 500.2 mW cm- 2 (at 1 mA cm- 2)), which surpassed the values reported in previous studies. The electrochemical performance of the FSC prepared based on PVA/SA/ GO GPE remained constant when subjected to bending deformation, indicating the harmonious physical, chemical, and electrochemical properties of the developed GPE and its suitability for flexible energy storage devices, and wearable electronics