Cross-linked polysulfone membranes with controllable cross-linkers for anion-exchange membrane water electrolysis

We report polysulfone-based anion-exchange membranes cross-linked using three distinct cross-linkers (i.e., 4,4 '- trimethylenebis(1-methyl-piperidine) (BMP), N,N,N ',N '-tetramethyl-1,6-diaminohexane (TMHDA), and 1,4-diazabicyclo[2.2.2]octane (DABCO)), designed for water electrolysis application. The cross-linked chloromethylated polysulfone membranes exhibit quaternization functionality, which can facilitate hydroxide-ion transport. Additionally, the cross-linked polysulfone membranes exhibit high thermal and mechanical stability. Among the cross-linked polysulfone membranes, the BMP-induced cross-linked polysulfone membrane displays an ion- exchange capacity of 1.58 mmol/g and an ion conductivity of 53.7 mS/cm at 80 degrees C, along with a water uptake of 50 % and a swelling ratio of 23 %, demonstrating good electrochemical properties and high dimensional stability. Moreover, the BMP-induced cross-linked polysulfone membrane exhibits a higher anion-exchange membrane water electrolysis performance and lower impedance than the other cross-linker-induced cross- linked polysulfone membranes. More importantly, it exhibits better water electrolysis cell performance than commercial FAA-3-50 membranes.