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.