The porous polyimide membranes were prepared by a wet phase inversion process based on the organo-soluble polyimide. The influence of coagulation bath composition and casting polymer solution concentration on the morphology of membranes was investigated. A series of spongy-like porous polyimide membranes with different porosity were obtained and characterized. These porous polyimide membranes exhibited excellent thermal stability and dimensional stability with the glass transition temperature of 274 C and thermal shrinkage less than 1% after stored at 200 degrees C. All the porous polyimide membranes exhibited good wettability with electrolyte uptake of 190-378% due to their high surface polarity and high porosity. The discharge curves for the lithium-ion cells using porous polyimide membranes as separator displayed relatively flatter voltage plateaus than that for Celgard 2400 membrane and gave the discharge capacity of 129-131 mAh/g. The thermal stable porous polyimide membranes are favorable to be applied as separator in the lithium-ion cell and can be expected to provide excellent battery performance at elevated temperature. (C) 2013 Elsevier Ltd. All rights reserved.