Long-term Stability of Ni-YSZ Anodes Fabricated by Polymeric Precursor Infiltration

摘要

Infiltration of Ni nitrate solutions into pre-constructed ceramic matrices to form Ni nanoparticles has been considered to be a very promising approach for the construction of high performance Ni-YSZ (yttria stabilized zirconia) anodes that can also be tolerant to redox cycling. However, such anodes have been shown to suffer from a rapid loss of electrochemical performance and electrical conductivity, mainly due to the loss of connectivity between the Ni nanoparticles (with no significant particle growth) at temperatures above 600 °C. To address this issue, a polymeric NiO precursor solution, which forms a continuous film rather than aggregated nanoparticles upon decomposition, was used here to infiltrate pre-sintered porous YSZ scaffoldings. The effect of the microstructure of the YSZ matrix was determined by using two types of porous YSZ layers with controlled pore and grain sizes. It is shown that infiltration of NiO into porous YSZ containing small pores and small grains (~200 nm pores and grains) resulted in the best stability. Scanning electron microscopy images revealed that the changes observed in the electrical conductivity are accompanied and/or caused by Ni particle growth, unlike what has been reported for Ni-YSZ anodes prepared by other infiltration methods.