Enhanced Thermal Stability and Electrochemical Performance of Polyacrylonitrile/Cellulose Acetate‐Electrospun Fiber Membrane by Boehmite Nanoparticles: Application to High‐Performance Lithium‐Ion Batteries

Abstract In this study, polyacrylonitrile/cellulose acetate (PAN/CA) composite nanofiber membranes with different boehmite contents are prepared by electrospinning. The physical and electrochemical properties of the composite nanofiber membrane as a separator in lithium batteries are investigated. In contrast to commercial polypropylene membrane (PP), the nanocomposite fiber membrane has a 3D network structure, higher porosity, higher thermal stability, higher electrolyte absorptivity, higher ionic conductivity, and better cycling performance. The PAN/CA composite membrane with 12 wt% boehmite has the highest ionic conductivity (1.694 mS cm −1 ); the specific discharge capacity is 160 mAh g −1 at 0.2 C discharge density and the highest capacity retention rate is 99.3% after 100 cycles. The cycle rate at 2 C has a higher capacity retention rate (88.75%). These results indicate that the PAN/CA/AlOOH composite nanofiber membrane can be expected to replace the commercial polyolefin membrane and behave as a high‐performance separator for lithium‐ion batteries.