Realizing Ultrahigh Conversion Efficiency of ≈9.0% in YbCd₂Sb₂/Mg₃Sb₂ Zintl Module for Thermoelectric Power...

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• YbCd2Sb2 Zintl compounds show promise for thermoelectric applications.
• Crystal field splitting in YbCd2Sb2 offers opportunities for band structure engineering.
• No YbCd2Sb2-based thermoelectric devices have been reported previously.

Purpose of the Study:

• To synthesize and characterize novel YbCd2Sb2-based compounds.
• To optimize thermoelectric properties through doping and alloying.
• To fabricate and evaluate the performance of a YbCd2Sb2-based thermoelectric module.

Main Methods:

• Precise chemical composition control to synthesize single-phase YbCd1.5Zn0.5Sb2.
• YbMg2Sb2 alloying to enhance defect formation energy and optimize carrier concentration.
• Band structure manipulation and experimental investigation.
• Transient liquid phase bonding with Fe90Sb10 diffusion barrier for module fabrication.

Main Results:

• A high peak ZT value of ~1.43 at 700 K was achieved for YbCd1.425Zn0.475Mg0.1Sb2.
• A YbCd2Sb2/Mg3(Sb,Bi)2 thermoelectric module demonstrated a conversion efficiency of ~9.0% at a 430 K heat difference.
• The fabricated module exhibited good thermal stability.

Conclusions:

• This study successfully developed YbCd2Sb2-based materials with enhanced thermoelectric properties.
• The first YbCd2Sb2-based thermoelectric device was fabricated, achieving high conversion efficiency.
• The findings pave the way for YbCd2Sb2 materials and devices in mid-temperature heat recovery.