La0.6Sr0.4MO3 (M=Co,Mn,Cr) interconnects in a 4-leg all-oxide thermoelectric generator at high temperatures

We herein report tests at high temperatures of a 4-leg oxide thermoelectric generator consisting of two pairs of p-type Ni 0.98 Li 0.02 O (Li–NiO) and n-type Zn 0.98 Al 0.02 O (Al–ZnO), assembled with various conducting perovskite oxides as interconnects. Using a custom-built testing system, we evaluated performance and stability at a hot side (furnace) temperature of up to 1000 °C under temperature differences up to Δ T = 600 °C in air. With a La 0.6 Sr 0.4 CoO 3 (LSC) interconnect, a maximum power output of 18 mW was achieved with T H = 940 and T C = 340 °C (Δ T = 600 °C). Power maxima with La 0.8 Sr 0.2 MnO 3 (LSM) and La 0.8 Sr 0.2 CrO 3 (LSCr) as interconnects were lower, 6 mW and 2 mW, respectively, under similar conditions, attributed to their lower thermal and electrical conductivities. This demonstrates the requirements and potential of oxide interconnects for stable use of all-oxide thermoelectric generators at high temperatures in ambient air. • Conducting perovskite oxide interconnects between NiO and ZnO thermoelectric legs. • Stable operation to 1000 °C in air in 4-leg thermoelectric generator (TEG). • High temperature gradient of 600 °C generates outputs in the mW range. • Interconnect La 0.6 Sr 0.4 CoO 3 superior to La 0.6 Sr 0.4 MnO 3 and La 0.6 Sr 0.4 CrO 3 . • Interconnect performance correlates with high electronic and thermal conductivities.