In this paper, a composite membrane with nonwoven polyimide (PI) membrane as structural support and
polyethylene (PE) particles coating layer as a thermal shutdown layer, is fabricated as the separator for
lithium-ion battery. Different from PI nonwoven membrane, the PE coating PI nonwoven composite
membrane (PEePIeS) not only shows excellent thermal shutdown function, similar to traditional
multilayer PP/PE/PP separator, but also exhibits much higher thermal stability, better wettability to the
polar electrolyte and lower internal resistance than the PP/PE/PP separator. The electrolyte uptake and
ionic conductivity of PEePIeS increase from 58%, 0.84 mS cm1 to 400%, 1.34 mS cm1
, respectively.
Furthermore, the thermal shutdown function of PEePIeS can be controlled widely in the temperature
range from 120 C to more than 200 C while the multilayer PP/PE/PP separator only with a shutdown
temperature range from 130 C to 160 C. Lithium ion battery with PEePIeS nonwoven separator also
shows excellent stable cycling and good rate performance.
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