High-Performance SiO₂ Nanoparticle Ionogels for Continuous Heat-To-Electricity Conversion.

Area of Science:

• Materials Science
• Energy Science
• Electrochemistry

Background:

• Ionic thermoelectric (TE) materials offer high thermopower but face challenges in continuous heat-to-electricity conversion due to ion transport limitations.
• Conventional TE generators (TEGs) rely on electron transport, limiting their application in certain scenarios.

Purpose of the Study:

• To develop ionogels capable of continuous heat harvesting into electricity under a steady temperature gradient.
• To investigate the role of SiO2 nanoparticles in enabling sustained ionic thermoelectric performance.

Main Methods:

• Fabrication of ionogels composed of 1-ethyl-3-methylimidazolium dicyanamide (EMIM:DCA), SiO2 nanoparticles, polyethylene glycol (PEG), and sodium dicyanamide (Na:DCA).
• Characterization of thermopower and ionic conductivity of the synthesized ionogels.
• Evaluation of continuous electricity generation under a steady temperature gradient.

Main Results:

• The developed ionogels achieved a high thermopower of 35 mV K⁻¹ and ionic conductivity of 27 mS cm⁻¹ at room temperature.
• Ionogels with SiO2 nanoparticles demonstrated stable output voltage generation, unlike control samples.
• The enhanced performance is attributed to SiO2 nanoparticles providing ion conduction channels and synergistic effects including charge tunneling and the Soret effect.

Conclusions:

• SiO2 nanoparticle-based ionogels represent a significant advancement in ionic thermoelectric materials, enabling continuous heat-to-electricity conversion.
• These ionogels show promise as next-generation thermoelectric generators (TEGs) for sustainable energy harvesting.
• The findings highlight the potential of engineered ionogels for overcoming limitations in ionic charge transport for TE applications.