Printable ionic liquid-based gel polymer electrolytes for solid state all-organic batteries

The development of all-organic batteries promises novel customizable energy storage devices by fabrication processes based on roll-to-roll casting or printing techniques. Despite a continuous effort to improve the electrode materials, barely any attention has been paid to a suitable electrolyte system providing a sufficient ionic conductivity and mechanical stability. Here, we report a printable gel polymer electrolyte (GPE) designed for all-organic batteries, which consists of an ionic liquid gelled in a methacrylate-based polymer matrix. The system is optimized to be applied directly on the battery electrodes by printing techniques. Our straightforward approach comprises a UV-induced film formation in the presence of all GPE components without further processing steps and is designed for the application in continuous manufacturing processes. For this purpose, the polymerization time was significantly reduced and the influence of oxygen on the film formation was investigated. The obtained GPEs revealed high ionic conductivities in the range of 10−4 S cm−1 at room temperature and sufficient mechanical stability for the separation of the electrodes. Furthermore, their application in all-organic batteries revealed a positive effect of the gel matrix on the capacity of the composite electrodes based on redox-active polymers compared to the pristine ionic liquid electrolyte.