In order to solve the problem of poor stability of traditional electrolyte membrane in all solid state lithium battery, a preparation method of thermally crosslinkable polymer electrolyte membrane for all solid state lithium battery of electric vehicle was proposed. Using 2-mercapto benzoxazole, sodium 5-sulfonate dihydro-2-mercapto benzimidazole complex as raw materials, then using toluene and dimethylformamide as preparation reagents, using high-speed centrifuge, magnetic stirrers and other preparation instruments for the preparation of all solid state lithium battery can be thermocrosslinked polymer preparation, and using the thermocrosslinked polymer to prepare the electrolyte membrane. The performance of the electrolyte membrane prepared is verified by comparative experiments. The experimental results show that the electrolyte membrane prepared by this method has smaller ion exchange capacity and higher proton conductivity, indicating that the preparation method has better stability.
相比于商业化的锂离子电池,固态电池具有更高的能量密度和更好的安全性.然而,固体电解质依旧面临锂枝晶生长的问题.以目前已大规模工业化的聚氧化乙烯(PEO)基电解质作为研究对象,通过将PEO与高杨氏模量的石榴石型电解质复合,抑制了锂枝晶在PEO基复合电解质中的生长,不仅使电解质膜的离子电导率从9.8×10-6 S/cm增加到了3.8×10-4 S/cm,还使锂/锂对称电池的临界电流密度从0.4 mA/cm2提高到1.6 mA/cm2.与此同时,组装的基于金属锂负极与传统石墨负极的软包电池可分别获得334.5 W·h/kg与218.2 W·h/kg的能量密度.其中,钴酸锂/复合电解质/石墨软包全电池循环1000次后的容量保持率可达92.3％,能够满足新能源汽车的需求.
通过两步法修饰商用PP隔膜,制备具有较好浸润性和大比表面积纳米孔ZIF-P@PP隔膜.结果表明:ZIF-P@PP隔膜在25～75℃时,可以维持80 MPa以上的拉伸强度,安全性能也得到提升.经过修饰的ZIF-P@PP隔膜表面形成网络状纳米结构.由ZIF-P@PP隔膜组装的电池,电流密度为0.2 A/g时,经过200圈循环,电池的放电比容量可以达到932 mAh/g以上,且库伦效率达到101％.修饰层能够起"分子桥"作用,形成良好的浸润界面,用于锂电隔膜呈现优异的循环性能.
