Performance of solid alkaline fuel cells employing anion-exchange membranes

For the performances of solid alkaline fuel cells (SAFCs) using anion-exchange membranes (AEMs), anion-exchange membranes were prepared via chloromethylation and amination of polysulfone and membrane-electrode assemblies (MEAs) were fabricated using the AEMs as an electrolyte, the ionomer binder prepared by the AEMs and Pt/C and Ag/C electrocatalysts as an anode and a cathode, respectively. Anion-exchange membranes were aminated by a mixing amine agent of trimethylamine (TMA) as a monoamine and various diamines such as N,N,N′,N′-tetramethylmethanediamine (TMMDA), N,N,N′,N′-tetramethylethylenediamine (TMEDA), N,N,N′,N′-tetramethyl-1,3-propandiamine (TMPDA), N,N,N′,N′-tetramethyl-1,4-butanediamine (TMBDA) and N,N,N′,N′-tetramethyl-1,6-hexanediamine (TMHDA). Amination using various diamines enabled to investigate the effect of the length of alkyl chain of the diamines on membrane properties such as ion conductivity and thermal characteristics. The AEMs aminated by the amination agent of mixing TMA and TMHDA (with longer alkyl chain) showed better hydroxyl ion conductivity and thermal stability than those aminated by a diamine. The H₂/air SAFC performance of the MEA with 0.5 mg cm⁻² Pt/C at the anode and the cathode, respectively, was comparable to one with 0.5 mg cm⁻² Pt/C at the anode and 2.0 mg cm⁻² Ag/C at the cathode, i.e., approximately 28–30 mW cm⁻² of the peak power density range.