Composite Solid Electrolyte with Continuous and Fast Organic–Inorganic Ion Transport Highways Created by 3D Crimped Nanofibers@functional Ceramic Nanowires

A 3D crimped sulfonated polyethersulfone-polyethylene oxide(C-SPES/PEO) nanofiber membrane and long-range lanthanum cobaltate(LaCoO₃) nanowires are collectively doped into a PEO matrix to acquire a composite solid electrolyte (C-SPES-PEO-LaCoO₃) for all-solid-state lithium metal batteries(ASSLMBs). The 3D crimped structure enables the fiber membrane to have a large porosity of 90%. Therefore, under the premise of strongly guaranteeing the mechanical properties of C-SPES-PEO-LaCoO₃, the ceramic nanowires conveniently penetrated into the 3D crimped SPES nanofiber without being blocked, which can facilitate fast ionic conductivity by forming 3D continuous organic–inorganic ion transport pathways. The as-prepared electrolyte delivers an excellent ionic conductivity of 2.5 × 10⁻⁴ S cm⁻¹ at 30 °C. Density functional theory calculations indicate that the LaCoO₃ nanowires and 3D crimped C-SPES/PEO fibers contribute to Li⁺ movement. Particularly, the LiFePO₄/C-SPES-PEO-LaCoO₃ /Li and NMC811/C-SPES-PEO-LaCoO₃/Li pouch cell have a high initial discharge specific capacity of 156.8 mAh g⁻¹ and a maximum value of 176.7 mAh g⁻¹, respectively. In addition, the universality of the penetration of C-SPES/PEO nanofibers to functional ceramic nanowires is also reflected by the stable cycling performance of ASSLMBs based on the electrolytes, in which the LaCoO₃ nanowires are replaced with Gd-doped CeO₂ nanowires. The work will provide a novel approach to high performance solid-state electrolytes.