Supramolecular gels as materials for energy storage devices

The advancement in science and technology behests the scientists for a more reliable energy storage device. Therefore, this has driven the researchers to find a better storage system with high efficiency. Electrochemical energy storage devices are in the limelight since it serves as the main supply of energy owing to their greatly improved energy density, power density, and high lifespan. The use of nanomaterials greatly enhances their performances. The drawback of such materials is their hindrance in the transport of electrons in energy devices. The emerging solution to such existing materials is supramolecular gels. Supramolecular gels are materials architected using small molecules via non-covalent interactions into a polymeric system. The dynamicity in the structure of supramolecular gels with reversibility in their network exhibits versatile properties. Therefore, suitably assembled supramolecular robust gels can be promising candidates in electrochemical energy storage. The interesting feature in supramolecular gels compared to other conventional materials is their reversible cross-linking, which enables them to fabricate 3D flexible electrodes, to exhibit resistance to high and low temperatures, and overcome external electrode damage reversibly. Supramolecular gel materials have been synthesized and their properties have been explored. The hierarchical pores, high surface area with tailorable strength, and the possibility of hybrid gels make them more suitable for various energy storage devices as electrolytes, electrode materials, and binding materials. Also, the macropores and micropores present in them pave the way for the diffusion of ions, addressing both the leakage and dendrite growth problems. Composite gels have been found to exhibit stable mechanical properties and could be used without the aid of any binding agent. Many conducting polymeric gels have been evolved to enhance the transport of electrons. The advantages of preparing hybrid supramolecular gels by incorporating the traditional nanomaterials into supramolecular gels are discussed. The various routes available for the synthesis of supramolecular gels and their potential applications as electrodes, electrolytes, and binders in energy storage devices are compiled in this review. The futuristic scope of supramolecular gels in the field of energy storage is also highlighted.