Synthesis of boric ester type ion-gels by dehydrocoupling of cellulose with hydroboranes in ionic liquid

Novel organoboron ion-gel electrolytes bearing boric ester were prepared under a mild reaction condition by dehydrocoupling of cellulose with hydroborane in ionic liquid. The organoboron ion-gels obtained showed ionic conductivity of 6.3 × 10− 4–1.1 × 10− 4 S cm− 1 at 324 K. The desired ion-gels were successfully prepared during the reactions for 1 h. The ion-gels prepared using mesitylborane showed higher ionic conductivity in comparison with ion-gels prepared from BH3–THF complex. Different from ordinary polymer ion-gels, the addition of lithium salt led to further increased ionic conductivity. This should be due to the high dissociation degree of LiCl in the presence of boron, as indicated from increased VFT (Vogel–Fulcher–Tammann) parameter corresponding to carrier ion number in the matrices.