Hybrid polymer gels for energy applications

Abstract

Polymer gels, specifically conducting polymer gels, share the benefits of gels, like large specific surface area, excellent flexibility, three-dimensional accommodative framework, elasticity, tunable mechanical strength, and excellent electronic, optoelectronic, and electrochemical properties. Various carbon, metal, and other nanoparticles can be accommodated abruptly changing not only the physical and mechanical properties of the polymer gels but also improving their electronic and electrochemical properties enormously making them suitable for different energy applications. Here, we shall discuss different polymer/conducting polymer hybrid (dihybrid and trihybrid) gels for energy generation (solar cell, fuel cell) and energy storage applications such as supercapacitors and batteries. To make the conducting polymer gels, supramolecular cross-linkers (gelators) such as folic acid, dibenzoyl-L-cystine (DBC), and phytic acid have been used and hybrid hydrogels are constructed by blending conducting polymers such as polyaniline, polythiophene, polypyrrole, and PEDOT:PSS, with graphene oxide (GO), Ag NPs, and molybdenum sulphide quantum dots (MoS₂ QDs). Nanoparticles are tightly bound with fibrils of the network due to large surface forces resulting in a synergic improvement in all the electronic and electrochemical properties. The energy devices such as dye-sensitized solar cells, fuel cells, supercapacitors, batteries, mostly use hybrid xerogels. Apart from conducting polymers, we will highlight the use of other synthetic and natural polymer gels used for energy applications. This review thus embodies the synthetic strategy of producing conducting polymer hybrid gels, presents their properties, illustrates their applications in energy generation and storage, and discusses future opportunities and challenges.