A strategy to optimize the thermoelectric performance in a spark plasma sintering process.

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectric Materials

Background:

• Spark plasma sintering (SPS) is a common method for improving alloy properties.
• Optimizing SPS conditions for thermoelectric materials like antimony-indium tellurides (Sb2-xInxTe3) is challenging.
• Enhancing the figure of merit (zT) is crucial for efficient thermoelectric energy conversion.

Purpose of the Study:

• To develop a systematic strategy for optimizing SPS conditions.
• To independently optimize the Seebeck coefficient (S) and the electrical to thermal conductivity ratio (σ/κ).
• To maximize the thermoelectric figure of merit (zT) in Sb2-xInxTe3 alloys.

Main Methods:

• Investigated the effect of sintering temperature and pressure on Sb2-xInxTe3 properties.
• Determined optimal sintering temperature based on Seebeck coefficient degradation.
• Identified optimal sintering pressure for maximum σ/κ ratio.

Main Results:

• High sintering temperature and pressure initially improve compactness and electrical conductivity.
• Excessive sintering can degrade the Seebeck coefficient and increase thermal conductivity.
• Optimal conditions were found to be specific temperatures and pressures that balance these effects.
• Achieved a zT of 0.92 at 600 K for Sb1.9In0.1Te3, an 84% enhancement.

Conclusions:

• A facile strategy for selecting optimal SPS conditions was developed.
• Independent optimization of S and σ/κ leads to enhanced zT.
• The findings provide a pathway to improve thermoelectric performance in bulk materials.