A Review on Gel Polymer Electrolytes for Electrochemical Energy Storage: Materials, Design, and Applications

Gel polymer electrolytes (GPEs) have the mechanical strength and safety of solid-body systems, the superior ionic conductivity properties of a liquid electrolyte, and the potential to be a substitute family of materials in the upcoming generation of electrochemical energy storage devices. The components, architectures, and applications of GPEs in various energy storage devices, including supercapacitors, lithium-ion, sodium-ion, as well as zinc-ion batteries, are thoroughly examined in this study. The discussion will start with the principle of GPEs, where polymer matrices, plasticisers, and ionic salts play essential roles in allowing effective ion transport and electrochemical stability. The focus is on recent material innovations, including nanocomposite GPEs, crosslinked networks, and bio-based polymers, that will seek to increase performance, safety, and environmental sustainability. On top of this, the interfacial behaviour of GPEs and electrodes, as well as the method of enhancing compatibility and inhibiting the growth of dendrites, are also highly scrutinised. The review ends with a conclusion covering the existing issues- long-term stability is limited, scale-up is not a problem, and conductivity-mechanical trade-offs, and the research directions in the near future in the rational design of high-performance GPEs. This is a resource that can be used by the researcher who is interested in creating more efficient, safer, and environmentally friendly energy storage devices.