Batch fabrication and characterization of aligned PAN-based nanofiber membranes for lithium-ion battery separators

Due to their excellent porosity, large specific surface area and unique pore structure, the electrospun nanofiber membranes (NFMs) have been widely studied as separators for high-performance lithium-ion batteries (LIBs). Here, an improved funneling air-jet electrospinning device was proposed to fabricate high-quality aligned polyacrylonitrile (PAN)-based NFMs for LIB separators in large quantities. Its spinning mechanism and effect were studied by combining numerical analysis and experiments. On this basis, the aligned PAN-based NFMs obtained were applied to the LIB separators, and their thermal stability, electrolyte affinity and related electrochemical performance were investigated. The results showed that the properties of aligned PAN separator were better than those of disordered PAN separator, and the addition of polymethyl methacrylate (PMMA) and single-wall carbon nanotubes (SWCNTs) could further improve the separator properties. Finally, the LIB assembled by superposing the aligned PAN/PMMA/SWCNTs NFM and polypropylene (PP) separator as a LIB separator (PAN/PMMA/SWCNTs//PP) had better electrochemical stability, rate and cycling capabilities (capacity retention of 102.81 % after 100 cycles), indicating that PAN/PMMA/SWCNTs//PP was a potential highperformance LIB separator.