Development of ionogel synthesis for electrolytes and electrodes
摘要
Ionogels have attracted considerable attention in recent years as an electrolyte in lithium-ion batteries. By immobilizing ionic liquids within a solid matrix, materials that behave macroscopically as a solid but have the ionic transport properties of a liquid can be obtained. Sol-gel processing provides an appealing method to synthesize ionogels, as a metal oxide matrix, typically silica, can be formed around an ionic liquid with a one-pot synthesis. Decades of research into sol-gel chemistry allow for control of many properties relevant to the electrochemical performance of ionogels, such as pore structure and surface functional groups. Recently, sol-gel-derived ionogels have seen considerable improvements in conductivity through tailored interactions between silanol groups and water, leading to highly mobile Li+ ions. Another new direction in ionogel design involves replacing silica with a redox-active matrix. These materials offer the potential for new types of electrochemical design. Redox-active ionogels can serve as anolytes and catholytes with high ionic and electronic conductivity. This concept was demonstrated through the synthesis of V2O5 ionogels with carbon nanotubes for electronic conductivity and ionic liquid for ionic conductivity. The high surface area and facile ionic transport of these systems suggest that these ionogels can be optimized for high-power applications, as diffusion lengths throughout the catholyte can be minimized for rapid kinetics.
Graphical Abstract