Boosting the mechanical strength and electrochemical performance of PEO/LiTFSI polymeric solid electrolyte via nylon nanofibers

Poly(ethylene oxide) (PEO)-based polymeric solid electrolytes (PSEs) hold great promise for all-solid-state lithium batteries, but the intrinsic low mechanical strength of PEO limits their practical application and scale production. Herein, PSEs consisting of PEO and lithium bis(trifluoromethanesulfonyl)-imide (LiTFSI) supported on poly(hexamethylene adipamide) (nylon) nanofiber matrix (nylon@PEO/LiTFSI PSEs) are designed and prepared in situ on the Al, Cu foils, and the LiFePO 4 electrodes through coaxially electrospinning at 45 °C. The nylon@PEO/LiTFSI PSEs show nonporous morphology due to in situ melting of the PEO/LiTFSI shell. The mechanical strength of the nylon@PEO/LiTFSI PSE can reach to 3.32 and 2.44 MPa at 25 and 60 °C, respectively, which is stronger than that of the pure PEO membrane or the PSEs prepared via conventional solution casting. The nylon@PEO/LiTFSI PSEs also show tight interfacial contact with LiFePO 4 electrode, resulting in small charge transfer resistance of 376 Ω, and thus afford the LiFePO 4 half coin cells with long charge/discharge cycling stability.