n-Type PVP/SWCNT Composite Films with Improved Stability for Thermoelectric Power Generation.

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Single-walled carbon nanotubes (SWCNTs) are promising for thermoelectric devices powering wearable electronics.
• The electrical performance of n-type SWCNTs degrades rapidly in air due to oxidation and hydration, limiting their practical use.
• Effective and low-cost solutions for enhancing SWCNT stability are needed.

Purpose of the Study:

• To investigate the stability of Polyvinylpyrrolidone (PVP)/SWCNT composite films in ambient conditions.
• To develop a protective coating to improve the air stability of n-type SWCNT-based thermoelectric materials.
• To fabricate and evaluate a thermoelectric generator utilizing the stabilized SWCNT films.

Main Methods:

• Fabrication of PVP/SWCNT composite films.
• Coating PVP/SWCNT films with a Polyvinylidene fluoride (PVDF) layer to prevent oxygen and moisture penetration.
• Fabrication of a thermoelectric generator using stabilized PVP/SWCNT films and poly(dimethylsiloxane) (PDMS) coating.
• Testing the thermoelectric performance and stability of the generator under various environmental conditions.

Main Results:

• A PVP/PVDF coating effectively prevented degradation of PVP/SWCNT films in air for 60 days, maintaining thermoelectric performance.
• A thermoelectric generator fabricated with coated SWCNT legs achieved an open-circuit voltage of 10.6 mV and power density of 312.2 μW cm^-2 at ΔT = 50 K.
• The generator demonstrated excellent stability, with performance remaining unchanged after 30 days in high-humidity air.

Conclusions:

• A novel coating strategy significantly enhances the air and humidity stability of n-type SWCNT thermoelectric films.
• The developed thermoelectric generator exhibits high output performance and remarkable long-term stability.
• This coating technology is applicable to other air-sensitive materials, advancing thermoelectric device development.