Development and characterization of covalently cross-linked SPEEK/Cs-TPA/CeO_2 composite membrane and membrane electrode assembly for water electrolysis

摘要

Covalently cross-linked SPEEK/Cs-TPA/CeO_2 composite membrane was prepared for the polymer electrolyte membrane water electrolysis. Tungstophosphoric acid (TPA) with a cesium was added to the SPEEK to increase proton conductivity. CeO_2 was used to scavenge free radicals which attack the membrane in the water electrolysis and to improve the durability of the membrane. The composite membrane featured the electrochemical characteristics, such as 0.130 S/cm of proton conductivity at 80 ℃, and 2.324 meq./g-dry-memb. of ion-exchange capacity. Pt(NH_3)_4Cl_2, Pd(NH_3)_4Cl_2, RhCl_3 and Co(NH_6)_4Cl_3 were used to prepare a variety of the membrane electrode assemblies (MEAs) as electrocatalytic precursors. Electrochemical activity surface area (ESA) of the Pt-Pd electrode prepared with 2 mM Pt(NH_3)_4Cl_2 and 2 mM Pd(NH_3)_4Cl_2 showed the best properties of 26.2 m~2/g with CL-SPEEK/Cs-TPA/CeO_2 membrane. In water electrolysis performance, the cell voltage of Pd/PEM/Pt-Pd MEA with CL-SPEEK/Cs-TPA/CeO_2(l%) composite membrane showed cell property of 1.82 V at 1 A cm~(-2) and 80 ℃.