Proton-Coupled Electron Transfer Aided Thermoelectric Energy Conversion and Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Low-grade heat is abundant but challenging to convert efficiently using traditional thermoelectric materials.
• Ionic conductors often suffer from low efficiency and poor sustainability for thermoelectric applications.
• Developing sustainable and efficient methods for thermoelectric conversion is crucial for waste heat recovery.

Purpose of the Study:

• To enhance thermoelectric performance by combining the Soret effect of protons with proton-coupled electron transfer (PCET) reactions.
• To investigate the potential of hydrogels as a medium for efficient thermoelectric energy conversion.
• To explore the possibility of integrating energy storage capabilities into thermoelectric devices.

Main Methods:

• Utilized hydrogels incorporating benzoquinone and hydroquinone redox couples.
• Leveraged the Soret effect of protons to drive thermoelectric conversion.
• Integrated proton-coupled electron transfer (PCET) reactions to enhance charge transport.
• Characterized thermoelectric properties including thermopower, power factor, and figure of merit.

Main Results:

• Achieved significant enhancements in thermopower (25.9 mV K⁻¹), power factor (5 mW m⁻¹ K⁻²), and figure of merit (>2.4).
• Demonstrated continuous power output through the combined Soret effect and PCET.
• Showcased energy storage capability with retained power output of 27.7% (14 mW m⁻²) for over 3 hours after temperature gradient removal.

Conclusions:

• The synergistic combination of proton Soret effect and PCET in hydrogels offers a promising route for efficient low-grade heat thermoelectric conversion.
• The developed system exhibits improved thermoelectric performance and integrated energy storage, enhancing sustainability.
• This approach paves the way for novel, sustainable thermoelectric generators and energy harvesting devices.