Vat photopolymerization of gel polymer electrolytes with solvent-dependent performance and complex geometries for Li-ion batteries.

Abstract

Additive manufacturing offers new opportunities for fabricating next-generation battery components with unprecedented control over three-dimensional architecture and spatial complexity. This study presents the development and electrochemical characterization of 3D printable gel polymer electrolytes (GPEs) based on a UV-curable PEGDA resin and a liquid electrolyte composed of 1 M LiClO₄ in EC:DEC or EC:PC (1:1 v/v). The impact of resin-to-electrolyte ratios on ionic conductivity and processability is systematically evaluated, with 1:4 v/v identified as the optimal formulation. GPEs fabricated via vat photopolymerization exhibit high ionic conductivities of up to 3.4 × 10^-3 S.cm^-1 (DEC-based) and 3.1 × 10^-3 S.cm^-1 (PC-based), closely matching their tape-cast counterparts. Electrochemical stability is maintained up to ~4.5 V vs. Li⁰/Li⁺, with symmetric cell testing confirming effective Li⁰ plating/stripping over 100 cycles. The 3D printed GPEs retain their electrochemical performance despite performing the printing process in ambient air, demonstrating robustness and compatibility with scalable manufacturing. In addition, the GPEs can be printed into complex geometries, further underscoring their suitability for advanced device architectures. This work highlights the critical role of solvent selection and printing parameters in designing printable GPEs and paves the way toward shape-conformable, solid-state battery systems.