Scale-Up Manufacturing of PEG-Based Electrolytes for All-Solid-State Batteries Using Slot-Die Coating

Abstract

As demand for safer, higher-performance batteries continues to grow, scaling up all-solid-state battery manufacturing has become a critical challenge. Slot-die coating offers a promising first step toward continuous, roll-to-roll production of solid electrolytes. In this study, we demonstrate the feasibility of slot-die coating a poly(ethylene glycol) (PEG)-based photopolymer electrolyte to produce uniform, scalable films. The electrolyte formulation was adapted from compositions reported in the literature, while coating and curing conditions were optimized by integrating a UV lamp into the slot-die coater and systematically adjusting the curing distance. Silica nanoparticles concentration was varied from 4–12 wt.% to tune the rheological properties of the electrolyte and improve the coating quality. This approach produced homogeneous PEG-based electrolyte films directly on graphite electrodes. The coated electrolytes on electrodes were incorporated into coin cells and characterized using electrochemical impedance spectroscopy (EIS). The slot-die- coated electrolytes exhibited ionic conductivities on the order of 10−6 S cm−1, comparable to values reported for polymer electrolytes in the literature (10−6 -10−4 S cm−1). These results demonstrate the viability of slot-die coating as a scalable manufacturing method for PEG-based solid polymer electrolytes and establish an important foundation for their future roll-to-roll production.