Facile and Reliable in Situ Polymerization of Poly(Ethyl Cyanoacrylate)-Based Polymer Electrolytes toward Flexible Lithium Batteries

Abstract

Polycyanoacrylate is a very promising matrix for polymer electrolyte, which possesses advantages of strong binding and high electrochemical stability owing to the functional nitrile groups. Herein, a facile and reliable in situ polymerization strategy of poly(ethyl cyanoacrylate) (PECA) based gel polymer electrolytes (GPE) via a high efficient anionic polymerization was introduced consisting of PECA and 4 M LiClO₄ in carbonate solvents. The in situ polymerized PECA gel polymer electrolyte achieved an excellent ionic conductivity (2.7 × 10^-3 S cm^-1) at room temperature, and exhibited a considerable electrochemical stability window up to 4.8 V vs Li/Li⁺. The LiFePO₄/PECA-GPE/Li and LiNi_1.5Mn_0.5O₄/PECA-GPE/Li batteries using this in-situ-polymerized GPE delivered stable charge/discharge profiles, considerable rate capability, and excellent cycling performance. These results demonstrated this reliable in situ polymerization process is a very promising strategy to prepare high performance polymer electrolytes for flexible thin-film batteries, micropower lithium batteries, and deformable lithium batteries for special purpose.