An imidazolium-type hybrid alkaline anion exchange membrane with improved membrane stability for alkaline fuel cells applications

Imidazolium-type hybrid alkaline anion exchange membranes (Im-hybrid AAEMs) were prepared based on poly(2-bromomethyl-,6-methyl-1,4-phenylene oxide) matrix employing 1-vinylimidazole and modified hollow mesoporous silica spheres (mHMSS). 1-Vinylimidazole, which is introduced into the casting system via pre-functionalization, can not only produce imidazolium side groups which impart the resultant membrane with an anion conduction capability, but also help form a crosslinked membrane structure via irradiation with ultraviolet (UV) light, contributing to the membrane stability. Hollow mesoporous silica particles are functionalized with amino groups and then incorporated into the membrane for the enhanced compatibility and membrane stability. The Im-hybrid AAEMs exhibit an improved alkaline stability at a high pH solution and elevated temperature. The effects of the amount of 1-vinylimidazole, UV crosslinking time, and loading of mHMSS on the membrane properties were investigated. The results illustrate that Im-hybrid AAEMs with the mHMSS loading of 0.5 wt% possess the best overall performance including enhanced membrane stability and suitable conductivity, which are critical for alkaline fuel cells applications.