Electrospun PMIA and PVDF-HFP composite nanofibrous membranes with two different structures for improved lithium-ion battery separators

In this study, two methods were used to combine poly (m-phenylene isophthalamide) fPMIA) with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The first PMIA@PVDF-HFP consisted of coaxial electrospinning and the second PMIA/PVDF-HFP was based on simultaneous electrospinning using two solutions. The morphology, mechanical and thermal properties, ionic conductivity and electrochemical stability of the as-obtained composite membranes were all investigated. Compared to properties of commercial Celgard membrane, the composite membranes PMIA@PVDF-HFP and PMIA/PVDF-HFP effectively combined the advantages of separate PMIA and PVDF-HFP. They exhibited not only excellent thermal stability and mechanical strength but also outstanding electrochemical stability and battery cycle performance. Moreover, PMIA@PVDF-HFP composite nanofibrous membrane with core (PMIA)-shell (PVDF-HFP) structure showed superior properties than PMIA/PVDF-HFP membrane prepared by simultaneous electrospinning. Hence, it could be used as ideal separator material in lithium-ion batteries.