Application of 2D nanomaterial MXene in anion exchange membranes for alkaline fuel cells: Improving ionic conductivity and power density

Two types of new 2D MXenes (LiF–Ti 3 C 2 T x and NH 4 HF 2 –Ti 3 C 2 T x ) were prepared by selective etching of Ti 3 AlC 2 with LiF/HCl and NH 4 HF 2 aqueous solutions, respectively, and they were introduced as nanofillers into quaternized polysulfone/polyquaternium-10 (QPSU/PQ-10) anion exchange membranes (AEMs) with semi-interpenetrating polymer network, thereby preparing two types of MXene-doped QPSU/PQ-10 AEMs. The resulting MXene-doped QPSU/PQ-10 AEMs have obvious nanoscale microphase-separated morphologies, and their ionic conductivity and power density are significantly improved compared with the pristine QPSU/PQ-10 AEM. Among them, the ionic conductivity and power density of NH 4 HF 2 –Ti 3 C 2 T x MXene-doped AEM can reach 88.76 mS/cm at 80 °C and 106.28 mW/cm 2 at 60 °C, respectively, which are 26.3% and 37.5% higher than those of the pristine QPSU/PQ-10 AEM. Additionally, the MXene-doped QPSU/PQ-10 AEMs with semi-interpenetrating network have moderate water uptake and swelling ratio, excellent thermal and mechanical properties , as well as good oxidation resistance and alkaline stability, which can meet the application requirements of AEMs for fuel cells, exhibiting their bright application prospects in fuel cells.