材料期刊网

为提高锂离子电池聚偏氟乙烯(PVDF)基聚合物隔膜的导电性和降低 PVDF 基聚合物隔膜的结晶度,引入聚甲基丙烯酸甲酯(PMMA)与聚偏氟乙烯(PVDF)进行共混,掺杂有机添加剂 PEG 和无机纳米材料 TiO2,采用相转化方法制备 PVDF/PMMA/PEG/TiO2型聚合物隔膜.通过对制备的 PVDF/PMMA/PEG/TiO2型多孔膜吸液率、离子电导率、微观形貌和电化学性能等的分析研究,确定制膜的最佳工艺条件为聚合物浓度为8％, PMMA占聚合物质量百分比为30％,PEG含量为30％,纳米TiO2含量为5％,C2 H5 OH 含量为3％,反应温度为45℃.该最优方案下制备的多孔膜结晶度较纯 PVDF 薄膜结晶度降低,多孔膜吸液率达345％,离子电导率达5．2 mS/cm,拉伸强度为1183 kg/cm2,电化学稳定窗口为4．68 V,高于4．5 V,能够满足锂离子电池正常工作需要.

Lithium ion battery gel polymer electrolyte is a kind of special state between solid and liquid,gel pol-ymer electrolyte has both solid electrolyte and good mechanical properties,but also has similar conductivity of liquid electrolyte ion,which plays an important role to improve the comprehensive performance of the battery. In order to improve the electrical conductivity and reduce the crystallinity of PVDF based polymer membranes, the main research of this topic is the contents for modified the PVDF polymer material,the concrete content is that blend PVDF and PMMA polymer,inorganic nano materials TiO2 and PEG,with the modified of the wet process(dry-wet process)to make it.Through testing the porosity and fluid absorption rate,the combination of scanning electron microscopy SEM and electrochemical workstation to test the sample characterization,finally the best one is:polymer of solvent percentage is 8%,PMMA accounted for 30% of the polymer mass,PEG content is 30%,nano TiO2 addition amount of 5%,the solvent content is 3%,the reaction temperature is 45 ℃.Ionic conductivity of PVDF/PMMA/PEG/TiO2 polymer of up to 5.2 mS/cm,the imbibition rate reached 345%,tensile strength is 1 183 kg/cm2 ,the electrochemical stability window was 4.68 V,higher than 4.5 V, the electrolyte system compatibility and conductivity is significantly improved.To meet the normal needs of lithium ion batteries.