Conductive Gels for Energy Storage, Conversion, and Generation: Materials Design Strategies, Properties, and Applications

Gel-based materials have garnered significant interest in recent years, primarily due to their remarkable structural flexibility, ease of modulation, and cost-effective synthesis methodologies. Specifically, polymer-based conductive gels, characterized by their unique conjugated structures incorporating both localized sigma and pi bonds, have emerged as materials of choice for a wide range of applications. These gels demonstrate an exceptional integration of solid and liquid phases within a three-dimensional matrix, further enhanced by the incorporation of conductive nanofillers. This unique composition endows them with a versatility that finds application across a diverse array of fields, including wearable energy devices, health monitoring systems, robotics, and devices designed for interactive human-body integration. The multifunctional nature of gel materials is evidenced by their inherent stretchability, self-healing capabilities, and conductivity (both ionic and electrical), alongside their multidimensional properties. However, the integration of these multidimensional properties into a single gel material, tailored to meet specific mechanical and chemical requirements across various applications, presents a significant challenge. This review aims to shed light on the current advancements in gel materials, with a particular focus on their application in various devices. Additionally, it critically assesses the limitations inherent in current material design strategies and proposes potential avenues for future research, particularly in the realm of conductive gels for energy applications.