Organic‐Inorganic Composite Porous Membrane for Stable and High‐Performance Lithium‐Ion Battery

Abstract

AbstractThe ionic conductivity of the separator is the essential parameter for performance of lithium ion batteries. Herein, we synthesize a new composite separator through coating of the mixture of poly (methyl methacrylate) and alpha alumina on the surface of commercial polyethylene separator. Benefiting from the excellent electrolyte wettability and high ionic conductivity of the poly (methyl methacrylate), the synthesized separator exhibits promising electrochemical properties. The lithium ion diffusion coefficient of the synthesized separator is 1.48×10−15 cm2 s–1, higher than that of the pristine polyethylene separator (0.808×10−15 cm2 s–1). Furthermore, the introduced alumina can prevent the blockage of the ion transport channels from the electrolyte absorption‐induced swelling of poly (methyl methacrylate), which in turn can improve the cycle performance of the thus‐assembled cells. it means that the cell assembled form the synthesized composite separator shows high charge–discharge cyclability, i. e. the cell assembled from the synthesized composite separator maintains 93.9% of initial discharge capacity after 200 charge‐discharge cycles under the rate of 1 C.