3D-Printed Ultra-Thin Solid Polymer Electrolytes with Superior Dielectric Properties for Wide Temperature Range...

The development of all-solid-state batteries (ASSBs) is critical for overcoming the safety and performance limitations of conventional lithium-ion batteries with liquid electrolytes. Solid polymer electrolytes (SPEs) offer promising processability and interfacial contact but suffer from low room-temperature ionic conductivity. Liquid crystal electrolytes (LCEs) have emerged as a solution, leveraging their self-assembling mesophases to create ordered ion transport channels that enhance conductivity. However, translating the molecular advantages of LCEs into high-performance devices requires advanced manufacturing techniques capable of precise structural control. This work introduces a novel 3D-printed, ultra-thin (20 µm) composite LCE membrane engineered for high dielectric constant (ε_r' ∼ 40) and ionic conductivity (~10^-3 S cm^-1). The membrane is composed of a polymer matrix (PVDF), a polymer network formed by the reaction of liquid crystal (LC) monomer RM257 and thiol monomers, and the high-dielectric small molecule LC 4-cyano-4'-pentylbiphenyl (5CB). When integrated into ASSBs with a lithium metal anode and LiCoO₂ cathode, the printed LCE membrane enables outstanding long-term cycling stability (retaining a capacity of 76.6% over 3000 cycles). This study demonstrates that combining molecular design with additive manufacturing provides a powerful strategy for developing high-performance, durable, and safe ASSBs.