In order to prepare microporous polymer electrolyte used in lithium ion batteries

two types (A-series and B-series) of microporous PAN membranes with high porosity were prepared in vapour atmosphere or coagulating bath from PAN-DMF solutions

respectively．SEM observed the sections of those membranes．It was found that there was a kind of honeycomb structure in the A-series microporous membrane

the size of the pores was inthe order of μm

and their porosity was about 80％．While in the B-series microporous membrane there was an asymmetric structure composed of three layers．The highest ion conductivity of microporous PAN electrolyte of A-series was about 4×10-3 S/cm at room temperature．While the ion conductivity of microporous PAN electrolyte of B-series was relatively low．The effect of influence factors of the microporous membrane on the ion conductivity of microporous PAN electrolytechanges in an order：membrane structure＞porosity＞pore size．