Quaternary Ti3C2Tx enhanced ionic conduction in quaternized polysulfone membrane for alkaline anion exchange membrane fuel cells

Abstract

Anion exchange membranes (AEMs) have been studied to improve conductivity for their high performance. The functional groups with positive charge could construct ion channels, which is the significant factor in determining the anions conductivity through the membrane. This report demonstrates the use of a new 2D nanomaterial as filler used in the quaterized polysulfone (QPSU) matrix for composite membrane performance enhancement of alkaline anion exchange membrane fuel cells (AAEMFCs). Ti3C2Tx is functionalized with quaternary ammonium groups successfully etched by NH4HF2. The two kinds Ti3C2Tx are synthesized and incorporated into QPSU based membranes by using a solution blending method. The QPSU/NH4HF2-Ti3C2Tx composite membrane exhibits the hydroxide ionic conductivity nearly 2 times higher than that both of pristine QPSU and QPSU/LiF-Ti3C2Tx membranes among 20–60 °C, and leads to substantial increase in peak power density of AAEMFCs by ~ 30% at 60 °C. The results indicate NH4+ groups on the MXene surface further enhance the OH- conductivity. Furthermore, the QPSU membranes addition with two kinds Ti3C2Tx both exhibit good mechanical property and thermal stability, and hold promise for application in AAEMFCs.