聚丙烯膜辐射接枝聚丙烯酰胺制备锂离子二次电池隔膜研究

Lithium-ion secondary battery separator prepared by radiation graft polymerization of polyacrylamide onto polypropylene membrane

通过共辐射接枝的方法将聚丙烯酰胺(Polyacrylamide,PAAm)接枝到聚丙烯(Polypropylene,PP)膜上,研究了丙烯酰胺单体浓度对接枝率的影响。接枝前后隔膜的红外光谱(Fourier transform infrared spectroscopy,FT-IR)对比表明,聚丙烯酰胺已经成功接枝到PP膜上,对隔膜的热性能、机械性能、电导率等性能进行了表征。将隔膜组装成扣式电池后,充放电循环性能测试结果表明,在相同条件下以PP-g-PAAm作为隔膜的锂离子电池性能优于以原始PP作为隔膜的电池性能。

Background：The separator is an important part of the battery, which prevents physical contact between electrodes during enable lithium ionic transportation. But most commercialized polyolefin porous membranes show low ion conductivity due to their inherent hydrophobic property and low porosity （45%）.Purpose：The aim is to introduce polyacrylamide （PAAm） onto polypropylene （PP） separator, which could improve the affinity between nonaqueous electrolytes and electrodes.Methods： PP-g-PAAm separator was prepared by irradiation graft polymerization technique. The structure and the performance of pristine PP and PP-g-PAAm separator were analyzed by Fourier transform infrared spectroscopy （FT-IR） and scanning electron microscope （SEM） from the aspects of mechanical property, liquid electrolyte uptake and lithium-ion conductivity. The coin cell was assembled in the Ar-filled glove box and investigated.Results and Conclusion： The results indicate that the coin cell with the PP-g-PAAm separator performs better than that one with the pristine PP separator under the same condition.