Dry-Processed Electrolytes and Electrodes for Liquid and Solid-State Batteries

The dry process is a promising fabrication method for electrolyte and electrodes to eliminate energy-intense drying and solvent recovery steps and to prevent degradation of sensitive component such as solid-state electrolytes (SSEs) in the wet process. While previous studies have utilized the dry process to enable thin films, systematic studies on their fabrication, physical and electrochemical properties, and electrochemical performance are unprecedented. Here, different fabrication parameters were studied to understand polytetrafluoroethylene (PTFE) binder fibrillation and its impact on the physio-electrochemical properties of electrode and electrolyte films, as well as the cycling stability of batteries resulted from such SSEs. A counter-balancing relation between the physio-electrochemical properties and cycling stability was observed, which is due to the propagating behavior of PTFE reduction (both chemically and electrochemically) through the fibrillation network, resulting in cell failure from current leakage and ion blockage. By controlling PTFE fibrillation, we demonstrate a bilayer configuration of SSE film to enable physio-electrochemically durable electrode and electrolyte film for both good cycling stability and charge storage capability.