Developing High-Performance and Low-Cost Paint Thermoelectric Materials for Low-Midtemperature Applications

Area of Science:

• Materials Science
• Energy Conversion
• Nanotechnology

Background:

• Conventional thermoelectric (TE) materials face challenges including high cost, toxicity, complex synthesis, poor reproducibility, and limited scalability.
• These limitations hinder the widespread adoption of TE technology for energy harvesting applications.

Purpose of the Study:

• To develop an inexpensive, non-toxic, scalable, and highly reproducible paint-based TE module for efficient heat-to-electricity conversion.
• To investigate the structure-property relationships governing the electrical conductivity and Seebeck coefficient of the paint TE material.
• To evaluate the performance and suitability of the developed TE module for practical applications, including wearable devices.

Main Methods:

• Synthesis of n- and p-type Bi-Sb-Te based thermoelectric paints with varying concentrations of graphite and sodium silicate.
• Structural analysis and transport property measurements to understand material behavior.
• Fabrication and testing of a paint-based TE module under different operating conditions and on various body parts.
• Performance evaluation based on power factor, operating temperature, output voltage, and output power.

Main Results:

• Electrical conductivity is controlled by graphite and sodium silicate concentration; Seebeck coefficient is dominated by the n- and p-type Bi-Sb-Te ratio.
• The TE module operates effectively up to 160 °C.
• Peak power factors of 1.34 μW/(cm·K²) for n-type and 1.42 μW/(cm·K²) for p-type paints were achieved at 57 °C.
• The highest open-circuit voltage of 1.9 mV was recorded on the wrist, indicating potential for wearable applications.
• A maximum output power of 6.8 μW was achieved with a 30 °C temperature gradient.

Conclusions:

• The developed paint-based TE module offers a cost-effective, non-toxic, and scalable alternative to traditional TE materials.
• The material's properties are tunable through controlled synthesis, enabling optimization for specific applications.
• The TE module's performance, particularly its suitability for wearable energy harvesting, highlights its potential for diverse thermal energy conversion applications.