Poly(Ethylene Oxide)−LiTFSI Solid Polymer Electrolyte Filaments for Fused Deposition Modeling Three-Dimensional Printing

Additive manufacturing technologies open the way to the direct-integration of electronics and solid-state battery within the final 3D object. Here, a 3D printable polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) filament (2.18 × 10⁻³ S cm⁻¹ at 90 °C) optimized to be used as solid polymer electrolyte in a lithium-ion battery is produced to feed a fused deposition modeling (FDM) 3D-printer. Due to its relatively poor mechanical properties compared to classical polymer filament such as polylactic acid (PLA), deep modifications of the 3D-printer were implemented in order to facilitate its printability. The solid polymer electrolyte thermal, structural, morphological, mechanical and electrical characterization is reported. Interestingly, using three different electrochemical impedance spectroscopy sample holders (lateral, sandwich and interdigitated-comb), we demonstrate that conductivity values differs for a same sample, highlighting the PEO chains orientation effect on the conductivity measurements.