A novel plastic crystal composite polymer electrolyte with excellent mechanical bendability and electrochemical performance for flexible lithium-ion batteries

•A novel plastic crystal composite polymer electrolyte has been synthesized.•The novel electrolyte has been not broken down after 200 bending cycles.•The novel electrolyte shows no obvious weight loss until above 200 °C.•Electrochemical window of the novel electrolyte is up to 5.2 V (vs. Li/Li +).•The ionic conductivity of electrolyte is 1.03 × 10–3 S cm−1 at room temperature.

A novel type of plastic c'rystal composite polymer electrolyte has been synthesized by UV-irradiation process successfully. This new polymer electrolyte (denoted as “MB-PCPE”) is composed of a UV-cured trimethylolpropane propoxylate triacrylate (TPPTA) macromer/poly(vinylidene fluoride-co-hexafluoropropylene (P(VDF-HFP))/Al2O3 nanoparticles and the succinonitrile-mediated plastic crystal electrolyte (1 mol L− 1 lithium bis-trifluoromethane sulphonimide/succinonitrile (LiTFSI/SN)). The unique composition/structure of MB-PCPE brings remarkable improvement in mechanical flexibility and thermal stability. The MB-PCPE has not broken down after 200 cycles in the bending test. The thermogravimetric analytical result shows that no obvious weight loss can be found for the MB-PCPE until above 200 °C. Moreover, the MB-PCPE can display favorable electrochemical performances. The ionic conductivity of MB-PCPE may reach1.03 × 10− 3 S cm− 1 at room temperature and the electrochemical stability window is up to 5.2 V (vs. Li/Li+). Furthermore, the MB-PCPE shows outstanding interfacial stability toward lithium metal electrodes. The LiFePO4/Li cell assembled with MB-PCPE reveals excellent cycling performance and rate capability, which can exhibit a discharge capacity of 155.4 mAh g− 1 at a current density of 0.1 C after 50 charge–discharge cycles and a discharge capacity of 122.5 mAh g− 1 at a current density of 2 C, respectively. Owing to the beneficial properties, the MB-PCPE is considered to have significant potential applications for rechargeable lithium-ion batteries.