Fabrication and characterization of 900 °C-sintered Ni/Cu/YSZ cermet high temperature electrolysis cathode material prepared by high-energy ball-milling method

Abstract

Ni/Cu/YSZ cermet (volume ratio of Ni:Cu:YSZ=40:20:40) is more electronically conductive than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of nickel, copper, and YSZ powders, pressing into pellets (Ø 10mm×1mm) and subsequent sintering process at 900°C under flowing 5%-H2/Ar gas. The Ni/Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as SEM, XRD, and laser diffraction and scattering method. Electrical conductivity of sintered Ni/Cu/YSZ cermet pellets fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermet. The effect of ball-milling time on electrical conductivity and microstructure of Ni/Cu/YSZ cermets for HTE was investigated. The particle size of Ni/Cu/YSZ decreased while electrical conductivity increased with milling time: enhanced electrical conductivity is attributed to well-connected Ni/Cu/YSZ particles rendered by increased ball-milling time.