Ingeniously controlling interface diffusion endows the Skutterudite thermoelectric device with ultra-high service stability

Building a barrier layer/thermoelectric material interface with high-bonding strength, low-contact resistivity, and high-thermal stability is a prerequisite for reliable applications of thermoelectric devices and is currently a bottleneck problem. Herein, we designed a unique Ni-Cr barrier layer with a narrow-channel structure for thermoelectric skutterudite (SKD) to ingeniously control the diffusion/reaction process of Sb and Ni (Co, Fe) at the interface, affecting the interfacial phase structure and then preventing the interface structural damage caused by thermal mismatch during thermal aging while ensuring strong metallurgical bonding. After enduring at 823 K for 70 days, the contact resistivities of Ni ₄₅Cr ₅₅/n-SKD and Ni ₇₅Cr ₂₅/p-SKD joints increase slowly and their bonding strengths remain stable, based on which the calculated annual attenuation rates of conversion efficiency and output power are both less than 2 %, reaching a leading level. The assembled 8-pair SKD module shows no performance degradation after 168-hour continuous service test with hot-side temperature of 823 K. This work not only strongly elevated the service stability of SKD device, but also opens the new horizon of designing barrier layers for other TE materials.