High performance of polyacrylonitrile/[Mg[sbnd]Al]-layered double hydroxide composite nanofiber separators for safe lithium-ion batteries

Abstract

There is a great need for a thermally stable separator to meet the application requirements in high-power lithium batteries. In this paper, Polyacrylonitrile (PAN) /[MgAl]-layered double hydroxide (LDH) composite nanofiber membranes were produced by electrospinning mixed solution which is prepared by dispersing different content of LDH particles into PAN. The results of Energy Disperse Spectroscopy (EDS) indicates that special LDH has been successfully compounded into nanofibers. The morphology of PAN/LDH nanofiber composite membranes by Scanning Electron Microscope (SEM) shows that it has a distinctive three-dimensional porous structure, among them, the PAN/15%LDH nanofiber composite membrane exhibits high porosity (87%), high electrolyte uptake (1053%), high ionic conductivity (4.25 mS cm−1), low interface resistance (106 Ω) and wide electrochemical stability window (5.4 V). In addition, high-temperature performance tests show that PAN/15%LDH membranes have no thermal shrinkage at 200 °C. More importantly, the overpotential of Li/ PAN/15%LDH/ Li symmetrical batteries is very low during the cycle, which can inhibit the growth of lithium dendrites to a certain extent. These advantages indicate that PAN/LDH composite nanofiber membranes are a promising candidate for high-performance lithium-ion battery separators.