Facile fabrication of safe and robust polyimide fibrous membrane based on triethylene glycol diacetate-2-propenoic acid butyl ester gel electrolytes for lithium-ion batteries

Highlights: • Uniform PI membranes are fabricated by electrospinning. • PI-GEL electrolyte is synthesized by incorporating TEGDA-BA copolymer. • It shows high ionic conductivities and electrochemical stabilities. • The mechanical properties of PI-GEL are highly improved. • The cells using PI-GEL demonstrate stable charge/discharge performance. - Abstract: Robust electrospun polyimide (PI) membranes are simply fabricated by polymerization of oxidianiline (ODA) and pyromellitic dianhydride (PMDA). The as-prepared PI membranes, with reliable safety (self-extinguishing) and excellent mechanical property, exhibit highly uniform morphology with an average fiber diameter ∼ 600 nm, high porosity ∼67%, high electrolyte uptake ∼534% and good relative absorption ratio ∼75% of the initial absorption (electrolyte uptake until 240 min). With the presence of triethylene glycol diacetate-2-propenoic acid butyl ester (TEGDA-BA) gel electrolytes, the resulting polyimide-gel electrolytes (PI-GEL) show a high ionic conductivity up to 2.0 × 10⁻³ S cm⁻¹ at 25 °C, coupled with high electrochemical stability (>4.5 V vs. Li/Li⁺). The Li/PI-GEL/LiFeO₄ cells demonstrate remarkably stable charge/discharge performance and excellent capacity retention of ∼146.8 mAh g⁻¹ (0.1 C) after 100 cycles. The results suggest a facile strategy for scalable fabrication of high-performance polymer electrolyte membrane for lithium ion batteries