Effect of OctaphenylPolyhedral oligomeric silsesquioxane on the electrospun Poly-m-phenylene isophthalamid separators for lithium-ion batteries with high safety and excellent electrochemical performance

In this study, a hybrid Poly-m-phenyleneisophthalamide/Octaphenyl-Polyhedral oligomeric silsesquioxane (PMIA/Octaphenyl-POSS) membrane (HPPS) was fabricated by electrospinning technique and its application performance as lithium-ion battery separators was discussed. The organic-inorganic feature of Octaphenyl-POSS (OPS) endowed admirable compatibility of membrane matrix for the HPPS membranes. The nanofiber membranes with OPS nanoparticles were provided with commendable thermal stability, robust mechanical strength (21.79 MPa), high porosity and electrolyte uptake, which laid a good foundation for improving the safety and cycle performance of the cells with the separator. The lithium-ion battery with the HPPS separator displayed a high ionic conductivity of 1.93 × 10−3 S·cm−1 and a stable electrochemical window of 4.98 V. More significantly, the HPPS nanofiber membrane based Li/LiCoO2 cell exhibited excellent cycling stability with high first discharge capacity up to 157.9 mAh·g−1 and superior capacity retention of 89.04% after 100 cycles. Therefore, the HPPS separator has extraordinary potential to be used in high-performance lithium-ion battery.