Promising cermets of TiN-Ni for intermediate temperature solid oxide fuel cell interconnects application

Novel TiN-Ni cermets as potential interconnects for intermediate temperature solid oxide fuel cells (IT-SOFCs) are proposed in this study. The cermets with 30, 50 and 70 vol% Ni are fabricated by optimizing the process parameters of the hot-pressed sintering method. With the increase of Ni content in the cermets, the relative density, electrical conductivity, and thermal conductivity are pronounced improved, and the maximum values reach 99.6%, 1.7 × 104 S cm−1 and 45 W m−1 K−1, respectively. In addition, the coefficient of thermal expansion (CTE) of the TiN-Ni cermets in the range of (9.7-13.2) × 10−6 K−1 shows a superior match with other components of IT-SOFCs. Furthermore, the cermets with 70 vol% Ni exhibit excellent oxidation resistance and electrical conductivity retention with a weight gain of only 0.7% and a high conductivity of 1.6 × 104 S cm−1 after oxidizing at 800 °C for 100 h. Our work demonstrates that the TiN-Ni cermets can be used as promising interconnects for the practical application of IT-SOFCs.