A first object of the present invention is to provide a separator including a polyethylene microporous membrane and a heat-resistant porous layer, and that has a sufficient shutdown function and a sufficient heat resistance, and can be formed with a reduce...

A lithium secondary battery includes a cathode, an anode, a separator interposed between the cathode and the anode, and a non-aqueous electrolytic solution obtained by dissolving lithium salt to a non-aqueous solvent. The separator includes a porous substr...