A straightforward fabrication of solid-state lithium secondary batteries based on multi-functional poly(arylene ether sulfone)-g-poly(ethylene glycol) material

Lithium ion conductive poly(arylene ether sulfone)-g-poly(ethylene glycol) (PAES-g-PEG) is synthesized for the application of solid state electrolyte membrane and electrode binder. The solid polymer electrolyte (SPE) system prepared from PAES-g-PEG and 1-butyl-1-methylpyrrollidum bis(fluoromethane sulfonyl) (PYR-1,4-TFSI) ionic liquid illustrates high ion conductivity of 8.48 × 10⁻⁴ S cm⁻¹ and low interfacial resistance at room temperature, along with excellent thermal and mechanical stability (degradation temperature > 180 °C and tensile strength > 0.8 MPa). As the PAES-g-PEG containing lithium bis (fluoromethane sulfonyl) (LiTFSI) salt exhibits not only such high conductivity of 2.11 × 10⁻⁴ S cm⁻¹ but also excellent adhesive strength (>23 MPa), it plays an important role as a binder for the electrode. As the active electrode materials such as LiCoO₂ (LCO) and LiNi_0.6Mn_0.2Co_0.2O₂ (NMC 622) are quite well compatible with PAES-g-PEG, the battery cells fabricated by binding the synthesized SPE and cathode layer show excellent cell performance of 139.01 mAh g⁻¹ (LCO) and 158.15 mAh g⁻¹ (NMC 622) at 0.1C. When this multi-functional PAES-g-PEG material is applied to the lithium sulfur battery system, the resulting cell discharge capacity is even higher than 925 mAh g⁻¹ at 0.1C with long term cyclic stability.