A novel polymeric electrolyte based on a copolymer containing self-assembled stearylate moiety for lithium-ion batteries

A novel polymeric electrolyte based on a self-assembled copolymer moiety has been prepared by a simple method of photo-induced radical polymerization of a mixture consisting of stearylmethacrylate (SMA) and poly(ethylene glycol)-monomethacrylate (PEM) that dissolves LiBF4 as the electrolytic salt. The SMA moiety work as mechanically stable backbone and the PEM unit dissolving the salts serves as ion-conducting path in the polymeric composite. Solid-state NMR measurements indicated that the resulting polymer composite consists of PEM-rich and SMA-rich phases, each of which exists within several nanometers apart. The ionic conductivity of the polymer electrolyte with the composition of PEM/SMA=7/3 (by mass ratio) was 2.8×10−5Scm−1 at 50°C, which was significantly higher than that of the polymer electrolyte based on cross-linked PEM copolymer without SMA.