Preparation Of PPEK Porous Membrane Used In Lithium-ion Battery Separator

Lithium-ion batteries are widely used in household appliances due to their high energy density, high efficiency, no memory effect etc. With the problem of energy and increasing exhaust pollution,many people want to explore a kind of new battery which have a higher power density and capacity to drive the car, large-scale devices or electricity storage to reduce the consumption of fuel resources. This made lithium-ion batteries to satisfy a higher requirements.Corresponding this trend lithium-ion battery separator should also improve their own electrochemical performance to support the safe operation of the battery,lithium-ion battery separator is a kind of porous film which is placed between the positive electrode and the negative electrode.lt isolates the two levels and maintain ion transmission and it is a key component to protect the battery stable and safe to use.This article prepared PPEK lithium-ion battery separator by the following two methods.-(1) PEG as porogen to prepare a kind of high-temperature resisted lithium-ion battery separator through a phase inversion method.Experimental results show that using PEG4K as pore maker, under the ration:PPEK/PEG4K=10:4, the membrane obtain the best electrochemical performance. The SEM image revealed a uniform porous structure of the membrane, and its porosity is43%, the electrolyte uptake is56%and at200℃it could maintain a stable shape for half an hour. The ion conductivity of the separator is1.62x10-5S/cm.(2) In this paper, PPEK was used as base-material and different molecular weight By immersion precipitation phase transition method prepared PPEK membrane which has a more uniform sponge-like structure, the porosity of membrane is73.6%, electrolyte uptakes is234%, tensile strength is2.78MPa, ionic conductivity is5.98><10-5S/cm.