Abstract
Harvesting low-grade heat from the environment and converting it into electricity holds the potential to power devices independent of cables or batteries. However, their effectiveness is limited by weak ion selectivity and insufficient concentration gradients. Here, we introduce the use of a calix[4]pyrrole as effective anion traps to selectively capture Fe(CN)64– and Cl− anions, enabling simultaneous modulation of redox ion distribution and suppression of anion mobility under a temperature gradient. This strategy combines desolvation-induced entropy gain with thermodiffusion enhancement arising from the mobility asymmetry between cations and anions. This leads to a synergistic boost in thermopower to an impressive 8.1 mV K−1, and results in a 20-fold increase in output power compared to the PVA/Fe(CN)63–/4– system. Demonstrated through a proof-of-concept wearable device with 36 unipolar elements, our system generated nearly 3 volts under ambient conditions. This strategy offers a promising route toward thermoelectric materials with enhanced thermopower for efficient harvesting low-grade thermal energy.
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All data supporting the findings of this study are available in the manuscript and its Supplementary Information. All data are available from the corresponding author upon request. Source data are provided with this paper.
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Acknowledgements
The authors thank the Analytical & Testing Center of HUST for XRD, NMR spectroscopic, and XPS studies, and the research core facilities for life science (HUST) for ITC studies. X.C. is grateful to the National Natural Science Foundation of China (Grant No.22271110), Shenzhen Science and Technology Program (Grant No. GJHZ20240218114701003), and Natural Science Foundation of Hubei Province, China (Grant No. 2022CFA031) for financial support.
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X.C. conceived the project. H.L. performed experiment and data analyses. Y.L. and Y.Z. performed the synthesis, Z.G., Z.J., and J.T. performed the sensing experiments. Y.C created schematic illustrations. X.C. supervised the study. H.L. and X.C. wrote the manuscript. All authors discussed the results and commented on the manuscript.
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Li, H., Gu, Z., Zhu, Y. et al. Synergistic dual anion regulation unlocks giant thermopower and power density in hydrogel. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71285-3
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DOI: https://doi.org/10.1038/s41467-026-71285-3
