A review on the development of electron and ion conductive polymer hydrogels and their composites for flexible and smart supercapacitors

Stretchable and smart supercapacitors showcased their robustness under extreme mechanical deformation, amplifying their acceptance rate in diverse fields, including health care, wearable electronics, and so on. Electro-conductive hydrogels are three-dimensional crosslinked conductive polymer gels with high porosity, flexibility, and excellent conductivity. This material paves the way to develop next-generation flexible energy storage devices. Besides inherent softness, the porous structure improves the ion and electron transfer from the electrolyte to the electrode, thus improving conductivity. The synthesis method and fabrication technique of conducting polymer hydrogel are very effective in regulating the chemical and physical properties of the developed electroactive material and open up new opportunities in the energy storage research field for further development. This review innovatively speculated the basics of supercapacitors and conducting hydrogel as electrodes and electrolytes. At first, crosslinking mechanisms have been discussed, followed by multiple synthesis methods of conducting polymer hydrogel and their composite. Finally, the conclusion has been drawn after summarizing the present challenges and future scope of conducting polymer hydrogel as an emerging material for energy storage applications.