Negative-thermal-expansion particles enable high-performance and ultradurable thermoelectric modules

Area of Science:

• Materials Science
• Nanotechnology
• Thermoelectrics

Background:

• Interfacial compatibility is crucial for device stability in solid-state batteries, flexible electronics, and fuel cells.
• Controlling the coefficient of thermal expansion (CTE) is a key challenge in thermoelectric device development.

Purpose of the Study:

• To introduce a novel strategy using negative-thermal-expansion (NTE) particles to regulate CTE and improve interfacial compatibility in thermoelectric materials.
• To enhance thermoelectric performance, alleviate thermal stress, and ensure interfacial stability across a wide temperature range.

Main Methods:

• Incorporation of predesigned, interface reaction-free NTE particles into various thermoelectric materials (Bi2Te3-based, Mg3Sb2-based, PbTe-based).
• Evaluation of thermoelectric performance, interfacial stress, and long-term stability under thermal cycling.

Main Results:

• NTE particle incorporation effectively improved thermoelectric performance and alleviated thermal stress in multiple material systems.
• A modified Mg3(Sb,Bi)2/Bi0.4Sb1.6Te3 module achieved 8.4% conversion efficiency with 71% interfacial thermal stress reduction.
• The NTE-modified module demonstrated stable interface and maintained efficiency over 1000 hours of thermal cycling.

Conclusions:

• The proposed NTE particle strategy offers a universal approach for enhancing interfacial compatibility in high-temperature functional modules.
• This method significantly improves thermoelectric device performance and long-term operational stability.
• The strategy is applicable to other high-temperature applications like thermal-barrier coatings and solar thermophotovoltaic devices.