A high-temperature stable composite polyurethane separator coated Al2O3 particles for lithium ion battery

PUC separator filled with ceramic (Al2O3) materials were prepared by electrostatic spinning technique in polyurethane (PU) with three-dimensional nanofiber structure, which has a smaller average pore size (1.088 μm), higher porosity (63.7%), higher liquid absorption (371%) and higher ionic conductivity (6.5 × 10-4 S cm-1) compared with commercial polypropylene (Celgard, PP) separators. The electrode composed of a separator and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material has a low interfacial resistance and good rate performance (139.5 mAh g-1) at 5C, furthermore, it keeps 82.7% discharge capacity after 200 cycles at 1C, which is slightly higher than that of Celgard as separator (78.8%), it shows that PUC separator is conducive to the infiltration of electrolyte, and has no obvious effect on circulation performance.