柔性抗冻水凝胶电解质的快速制备与性能研究

Rapid preparation and properties of flexible antifreeze hydrogel electrolyte

以丙烯酰胺(AM)作为聚合单体加入交联剂亚甲基双丙烯酰胺(MBAA)、引发剂过硫酸铵(APS)与L型卡拉胶(LC)和氯化钾(KCl)通过一锅法交联聚合制备出复合水凝胶(PAM-LC)。为了拓展该水凝胶作为电解质在极寒条件下的应用,研究了锂盐浓度及浸泡时间对提高PAM-LC基水凝胶电解质的抗冻性、导电性及机械稳定性的影响。结果表明:未浸泡过的水凝胶在-12.68℃时会发生冻结,而经过在氯化锂溶液中浸泡的水凝胶在-75℃下都不会发生冻结,且通过电化学阻抗EIS的测试,可以得出在-30℃的环境下凝胶导电率可以达到8.03 ms/cm,并且在室温下也能达到22.77 ms/cm,具有良好的导电性能。通过机械性能测试得到在常温下未浸泡的水凝胶具有优异的力学性能但抗冻性差,经过5M氯化锂溶液浸泡24 h后的水凝胶(PAM-LC-LiCl)在-20℃冷冻后仍表现出较好的机械稳定性。

The composite hydrogel(PAM-LC)was prepared by one pot crosslinking polymerization with acrylamide(AM)as a monomer added into the crosslinking agent methylenebisacrylamide(MBAA)and ammonium sulfate(APS),the L-type Kara gum(LC)and potassium chloride(KCl)as the initiator.In order to expand the application of this hydrogel as an electrolyte in extreme cold conditions,the effects of lithium salt concentration and immersion time on the freezing resistance,conductivity and mechanical stability of PAM-LC based hydrogel were studied.The results show that the unsoaked hydrogel freezes at-12.68℃,while the hydrogel soaked in lithium chloride solution will not freeze at-75℃.Through electrochemical impedance spectroscopy(EIS)test,it can be concluded that the conductivity of hydrogel can reach 8.03 ms/cm at-30℃,and also reach 22.77 ms/cm at room temperature,with the better conductivity than common hydrogel.The mechanical property test shows that the hydrogel not soaked at room temperature has excellent mechanical properties but poor frost resistance.After immersion in 5M lithium chloride solution for 24 hours,the hydrogel(PAM LC LiCl)still shows good mechanical stability after freezing at-20℃.