Strong and Highly Ionic Conductive Ionogel for Wearable Solid State Supercapacitor

To follow the pace of the high-speed development of wearable electronic devices, the mechanical and electrochemical performances of the corresponding flexible and stretchable solid state energy storage devices need to be further improved. As a kind of solid polymer electrolyte for wearable energy storage devices, ionogel is a promising candidate exhibiting a broad stability window, exceptional mechanical performance, exceptional thermal stability, and low vapor pressure. Nevertheless, it is difficult to simultaneously enhance the mechanical and electrochemical performances of ionogel. In this work, we constructed an ionogel using polymerized poly (acrylic acid) and polyvinyl alcohol interpenetrating polymer networks as the host material and injecting 1-Ethyl-3-methylimidazolium dicyanamide ionic liquid as a filling solvent. Adequate contorted polymer chains and abundant reversible hydrogen bonds within the network aided in energy dissipation during tensile and compression, contributing to the exceptional mechanical properties. The improved electrochemical performances of ionogel result from the development of ion transfer kinetics. In particular, the subsequent ions impregnation and solvent exchange procedures modified the network structure and elevated the ion concentration in the ionogel. Concurrently, ionic liquid occupied in the networks rendered this ionogel with an outstanding stability of volume, mass, and ionic conductivity under conditions of low relative humidity. After a series of treatments, this ionogel performed a remarkable strain of 2500 %, an exceptional ionic conductivity of 3.18 S/m at room temperature, and a virtually constant weight, volume, and ionic conductivity over about forty hours at a relative humidity of 20%. Sandwiching this ionogel electrolyte using electrospun polyacrylonitrile-based carbon fibers electrodes, a solid-state supercapacitor exhibited remarkable areal capacity, outstanding power density, and exceptional energy density. As a result, we synthesized a novel ionogel that breaks long-standing confinement while simultaneously exhibiting expected mechanical and electrochemical properties, thereby promoting the development of ubiquitous solid-state energy storage devices.