Dual Proton Conducting Channels Constructed by Acid‐Base Double‐Shell Carbon Nanotubes to Boost the Proton Conductivity of SPEEK

Abstract

AbstractSulfonated poly(ether ether ketone) (SPEEK) has been widely investigated as a substitution of commercial Nafion as proton exchange membranes (PEMs). However, the disadvantages such as shrinkage of proton transfer channels at high temperature and low humidity conditions cannot be neglected. In this manuscript, the carboxyl and imidazole double‐shelled carbon nanotubes(CNTs−C@N) was incorporated into the SPEEK matrix to fabricate composite PEM (denoted as SPEEK/CNTs−C@N−Y, Y is the percentage composition of CNTs−C@N), serving as one‐dimensional fillers. SPEEK/CNTs−C@N‐1.0 composite membrane performed a higher horizontal proton conductivity (0.302 S/cm) under 80 °C and 100 % relative humidity (RH) compared with original SPEEK membrane 0.181 S/cm. The high proton conductivity could be mainly attributed to the dual proton conducting channel formed by two types of acid‐base pairs, which immensely promote the Grotthuss mechanism. Therefore, SPEEK/CNTs−C@N composite membranes are expected to develop PEMs with high proton conductivity at high temperature and low humidity.