Novel self-regenerative and non-flammable high-performance hydrogel electrolytes with anti-freeze properties and intrinsic redox activity for energy storage applications

Abstract

Hydrogel electrolytes are essential components of a plethora of functional devices due to their flexibility and high electronic and ionic conductivity. However, they suffer from poor water retention (dehydration) during operation. Consequently, the overall performance of the hydrogel-based devices is severely declined as a result of conductivity fading of the hydrogel with poor self-regeneration. To this end, the rational tailoring of hydrogel electrolytes with high conductivity, self-regeneration, non-flammability, anti-freezing ability, stability, and intrinsic redox activity is necessary to enable the fabrication of highly durable devices. Herein, we demonstrate the design and synthesis of highly ionic conductive LiBr@PVA-based electrolytes. Upon the use of the synthesized hydrogel electrolytes in supercapacitor devices, they revealed intrinsic redox activity with outstanding water retention capability and self-regeneration characteristics. The mechanism of regeneration and water retention is thoroughly investigated. Also, the devices showed an improved self-discharge potential (SDP) rate compared to those previously reported using polymeric electrolytes with redox additives. Moreover, the synthesized LiBr@PVA-based electrolytes exhibited high anti-freezing properties with stable electrochemical performance before and after regeneration. Our study provides a universal method to fabricate large-scale hydrogel electrolytes with unique properties and opens the door to fabricate high-performance solid state devices.