Here lithium acetate modified PU/graphene composites were prepared from a simple electrospun method. The electrochemical properties, thermal stability, and mechanical properties of polyurethane (PU) separator have been improved remarkably by the addition of lithium acetate and graphene. The composite separator can maintain the dimension size even after being treated at 170 degrees C for 1 h. High ionic conductivity of 2.47 mS.cm(-1) can be reached. The results show that the as -prepared lithium acetate modified PU/graphene separator is a promising candidate for commercial polyolefin separators.