Attapulgite/Fe3O4 synergistically enable the nanofiber composite separator with high ionic transport ability for lithium batteries

High-safety and high-performance separators with exceptional mechanical and thermal stability are highly desired for simultaneously providing fast ion transport channels and achieving uniform Li + flux distribution to suppress dendrite growth. In this work, nanofiber composite separators (PAF) are fabricated by the electrospinning of polyacrylonitrile and the subsequent coating with an inorganic hybrid of conductive Fe 3 O 4 spherical particles and non-conductive attapulgite (ATP) rod-shaped particles. The PAF composite separator exhibits superior ionic transport ability with high ionic conductivity of 1.07 mS/cm and Li + transference number of 0.56, which can be attributed to the synergistic effect of the nanofiber substrate and the hybrid coatings. The high porosity and excellent electrolyte wettability of the separator, as well as the octahedral and tetrahedral voids in Fe 3 O 4 , provide more storage space for Li + ; the oxygen vacancies in nanoparticles are prone to combine with solvent molecules, and the hydroxyl groups adsorb PF- 6, thereby effectively accelerating the migration of cations. The battery with the composite separator, therefore, maintains a discharge specific capacity of 90 mAh/g after 500 cycles at 1 C rate and has a discharge capacity of 83 mAh/g at 5 C. Together with the improved mechanical and thermal stability, the nanofiber composite separator exhibits great potential for the advancement of lithium batteries with high safety and high performance.