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

Abstract

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 (1molL−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 200cycles 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 reach1.03×10−3Scm−1 at room temperature and the electrochemical stability window is up to 5.2V (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 155.4mAhg−1 at a current density of 0.1C after 50 charge–discharge cycles and a discharge capacity of 122.5mAhg−1 at a current density of 2C, respectively. Owing to the beneficial properties, the MB-PCPE is considered to have significant potential applications for rechargeable lithium-ion batteries.