苯并咪唑液晶/磷酸二元体系固态电解质的无水质子传导性能

Anhydrous Proton Conduction in Binary Complexes of Benzimidazole Liquid Crystal and Phosphoric Acid

以端部含溴基的棒状液晶为前体,利用亲核取代法合成了热致性近晶相苯并咪唑液晶。近晶相下苯并咪唑基团自组装形成二维的质子传导通道,在150℃下其无水质子传导率可达3.6×10-5 S cm-1。通过适量的磷酸掺杂(5%质量比)制备苯并咪唑分子/磷酸二元体系以提升其质子传导性能。液晶相及电化学测试显示,5%磷酸的二元体系近晶相得以保留,磷酸的掺杂为质子通道提供了额外的质子源,其无水质子传导率提升了约一个数量级,达到3.0×10-4 S cm-1。

A thermotropic smectic liquid crystal containing a benzimidazole moiety was synthesized via nuclear substitution with a rod-shaped liquid crystal containing a terminal bromine moiety.Two-dimensional proton conductive pathways were constructed by self-assembly of the benzimidazole moieties in the smectic phase.Anhydrous proton conductivities resulted by the benzimidazole liquid crystal reached 3.6×10-5 S cm-1 at 150℃.A binary mixture was prepared for enhancement of proton conduction by doping of the liquid crystal with phosphoric acid(5%wt).Mesomorphic and electrochemical characterization revealed that the smectic phase was preserved for the complex with 5%phosphoric acid.The proton conductivities of this complex were one order of magnitude enhanced owing to the excess proton source in the conductive pathways by phosphoric acid doping,reaching 3.0×10-4 S cm-1.