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Updated: May 28, 2026
09:09
Asymmetric Thermoelectrochemical Cell for Harvesting Low-grade Heat under Isothermal Operation
Published on: February 5, 2020
An n-Type Ionic Thermoelectric Device Enabled by Synergistic Interactions Between Electrodes and PVA Hydrogel
1Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
Materials (Basel, Switzerland)
|May 27, 2026
Summary
Researchers developed a new n-type ionic thermoelectric (i-TE) hydrogel device by using graphite paper electrodes. This electrode engineering strategy enables efficient low-grade heat harvesting and energy storage.
Area of Science:
- Materials Science
- Energy Harvesting
- Thermoelectrics
Background:
- Ionic thermoelectric (i-TE) materials are promising for low-grade heat harvesting due to high thermovoltage.
- Developing n-type i-TE materials is challenging, limiting device applications.
- Electrode modification offers a strategy to overcome material limitations.
Purpose of the Study:
- To develop an n-type i-TE device using electrode engineering.
- To investigate the mechanism of polarity regulation by electrodes.
- To explore the potential for simultaneous heat harvesting and energy storage.
Main Methods:
- Fabrication of a poly(vinyl alcohol) (PVA)-based ionic hydrogel using DMSO and KCl via freeze-thaw.
- Comparison of thermoelectric behavior using copper (Cu) and graphite paper (GP) electrodes.
- Morphological and spectroscopic analyses to understand ion-electrode interactions.
Main Results:
- The PVA hydrogel device exhibited p-type behavior with Cu electrodes and switched to n-type with GP electrodes.
- Graphite paper electrodes selectively adsorbed K+ ions, enabling Cl- dominated ion migration.
- The PVA-GP device achieved a maximum Seebeck coefficient (S_i) of -4.36 mV K-1, a power factor (PF_i) of 57.668 μW m-1 K-2, and a ZT of 0.0864.
- The device demonstrated transient power density and functioned as an ionic thermoelectric supercapacitor.
Conclusions:
- Electrode engineering is an effective strategy for developing n-type i-TE devices.
- The developed hydrogel device enables simultaneous low-grade heat harvesting and energy storage.
- This approach provides a feasible route for advanced energy applications.
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