Enhanced thermoelectric performance in TiNiSn-based half-Heuslers

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectricity

Background:

• Thermoelectric materials convert heat to electricity.
• Half-Heusler alloys are promising thermoelectric materials.
• Optimizing thermoelectric performance requires balancing electrical and thermal conductivity.

Purpose of the Study:

• To investigate thermoelectric properties of TiNiSn-based alloys.
• To achieve a high figure of merit (ZT) exceeding 0.5.
• To understand the role of excess nickel in enhancing thermoelectric performance.

Main Methods:

• Arc-melting synthesis of TiNiSn-based ingots.
• Characterization of thermoelectric properties, including figure of merit (ZT).
• Analysis of lattice thermal conductivity and its correlation with material composition.

Main Results:

• Achieved thermoelectric figures of merit (ZT) greater than 0.5.
• Observed low lattice thermal conductivity in the TiNiSn-based system.
• Attributed the enhanced performance to the presence of excess nickel within the half-Heusler structure.

Conclusions:

• TiNiSn-based alloys demonstrate significant potential for thermoelectric applications.
• Excess nickel is a key factor in reducing thermal conductivity and improving ZT.
• Further research into optimizing nickel content could lead to even higher efficiencies.