Robust thin gel polymer electrolyte membrane reinforced by the electrospun polyimide nanofibers for high-voltage lithium-ion batteries

Gel polymer electrolytes (GPEs) are considered to promise the safety and high performance of lithium-ion batteries (LIBs), but fabrication of thin GPE membrane with high mechanical property remains a great challenge. Herein, we demonstrate that a robust polyimide nanofiber-reinforced GPE (P@PI) membrane can be fabricated by in-situ polymerization of low-molecular-weight poly(ethylene glycol diacrylate). Thanks to the fibrous structure, it presents not only close contact of electrolyte with electroactive particles but also strong mechanical strength in spite of 12 μm in thickness. It possesses a high ionic conductivity up to 1.18 × 10 −3 S cm −1 at 30 °C, a large lithium transference number of 0.61, and an electrochemical window of 4.84 V (vs. Li + /Li). Benefiting from the artificial solid electrolyte interface, the LiǁP@PIǁLi symmetrical cells achieve a stable long-term cycling over 600 h at 0.1 mA cm −2 . When assembled with the Li anode, the integrated cathode/GPE loaded with 10 mg cm −2 of LiNi 0.8 Co 0.1 Mn 0.1 O 2 can deliver a specific capacity of 130 mAh g −1 at 5 C rate and 30 °C, and retains 94.7 % of the initial capacity at 2 C rate after 500 cycles; when assembled with the graphite anode, it can also realize a capacity retention of 70.8 % at 1 C rate after 500 cycles. The results suggest that the thin GPE membrane prepared by this strategy can promote the development of quasi-solid-state LIBs significantly.