Synthesis of Cu-YSZ and Ni-Cu-YSZ cermets by a novel electroless technique for use as solid oxide fuel cell anode: Application potentiality towards fuel flexibility in biogas atmosphere

A novel electroless technique is employed for synthesizing Cu-YSZ cermet with discrete deposition of Cu onto 8 mol% yttria-stabilized zirconia (YSZ) and alloyed with 90 weight % Ni using electroless Ni-YSZ cermet by mechanical mixing and heat treatment under controlled atmosphere for the application as solid oxide fuel cell anode. X-ray diffractograms using Lorentzian fits revealed a shift of Ni-Cu (111) and Ni-Cu (200) peaks suggesting the solid solution of the bimetallic phases. Unique core-shell microstructures for both Cu-YSZ and Ni-Cu-YSZ with YSZ as core and Cu/Ni-Cu as shell are observed. EDAX analyses confirms 90:10 weight ratios (Ni:Cu) in the shell position for the alloy cermet. While only 23 vol% of metal content in Cu-YSZ gives electrical conductivity of 700 S cm^-1, a reasonably high value of 490 S cm^-1 is obtained with 32 vol% of metal in Ni-Cu-YSZ. Electroless Ni-Cu-YSZ exhibits 98% efficiency towards methane reforming in simulated biogas environment and also shows significant tolerance to H₂S (upto 25 ppm) in the input stream of the gas.