Enhancement on the thermostability and wettability of lithium-ion batteries separator via surface chemical modification

Abstract The separator is one of the most important components of the battery, which is related to safety performance of the battery. The traditional polyolefin separators have disadvantages such as the poor thermal stability and weak surface hydrophilicity. Herein, we introduced a SiO 2 /PAM-grafted polypropylene (PP) separator by surface chemical modification. Compared with unmodified separator, the results showed that the modified separators had better thermal stability and superior wettability. The shrinkage of the bare PP and SiO 2 /PAM-grafted PP separators were 70% and 12% at 150 °C for 30 min, respectively. In addition, the surface contact angle of PP separator is reduced from 105° to 37° after grafting modification. Therefore, modified separator not only improves the thermal stability and the wettability but also thickness of separator increase slightly. The dis/charge capacity of different separators were investigated. It was showed that the cell with SiO 2 /PAM-grafted PP separator had better electrochemical performance than that with bare PP.