High-Performance Ag-Se-Based n-Type Printed Thermoelectric Materials for High Power Density Folded Generators

Area of Science:

• Materials Science
• Energy Harvesting
• Thermoelectrics

Background:

• Thermoelectric (TE) materials convert waste heat into electricity.
• Developing efficient, printable TE materials for room-temperature applications remains a challenge.
• Existing TE materials often lack the flexibility and processability required for wearable devices.

Purpose of the Study:

• To develop high-performance, n-type printed thermoelectric materials using a facile synthesis approach.
• To fabricate and evaluate flexible thermoelectric generators (flexTEGs) using the developed materials.
• To demonstrate the potential of these materials for energy harvesting in wearable applications.

Main Methods:

• A novel and facile synthesis method was employed to create Ag-Se-based n-type printed films.
• Key thermoelectric properties, including Seebeck coefficient, power factor, figure-of-merit (ZT), and thermal conductivity, were measured.
• A flexible folded thermoelectric generator (flexTEG) with 13 thermocouples was fabricated using the printed n-type material.
• The performance of the flexTEG was tested under various temperature differences (ΔT) and demonstrated in a wearable scenario.

Main Results:

• Achieved a high Seebeck coefficient up to 220 μV K^-1 and a TE power factor > 500 μW m^-1 K^-2 for the n-type printed film.
• Obtained a figure-of-merit (ZT) of ~0.6 with low in-plane thermal conductivity (κ_F) of ~0.30 W m^-1 K^-1.
• Fabricated flexTEGs demonstrated significant open-circuit voltages (71.1 mV at ΔT=30 K, 181.4 mV at ΔT=110 K) and high output power densities (6.6 μW cm^-2 at ΔT=30 K, 321 μW cm^-2 at ΔT=110 K).
• Demonstrated wearable energy harvesting, achieving ~72.2 mV with ΔT ≈ 30 K when worn on the wrist.

Conclusions:

• The developed Ag-Se-based n-type printed TE materials exhibit excellent performance for room-temperature energy harvesting.
• The fabricated flexTEGs show promising potential for powering wearable electronic devices using waste heat.
• This work paves the way for the widespread integration of efficient thermoelectric solutions in wearable technology.