Abstract
The liquid-like feature of thermoelectric superionic conductors is a double-edged sword: the long-range migration of ions hinders the phonon transport, but their directional segregation greatly impairs the service stability. We report the synergetic enhancement in figure of merit (ZT) and stability in Cu1.99Se-based superionic conductors enabled by ion confinement effects. Guided by density functional theory and nudged elastic band simulations, we elevated the activation energy to restrict ion migrations through a cation–anion co-doping strategy. We reduced the carrier concentration without sacrificing the low thermal conductivity, obtaining a ZT of ∼3.0 at 1,050 K. Notably, the fabricated device module maintained a high conversion efficiency of up to ∼13.4% for a temperature difference of 518 K without obvious degradation after 120 cycles. Our work could be generalized to develop electrically and thermally robust functional materials with ionic migration characteristics.
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Acknowledgements
This work was supported by a Basic Science Center Project of the National Natural Science Foundation of China (52388201) and the National Key R&D Program of China (2023YFB3809400). J.Y. gratefully acknowledges financial support from the International Postdoctoral Exchange Fellowship Program (Talent-Introduction Program) (YJ20220135) and Shuimu Tsinghua Scholar Program.
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H.H., J.Y. and J.-F.L. designed this work. H.H. prepared the samples and carried out the thermoelectric property measurements. Y. Ju, Z.W., H.Z. and J.Z. conducted the STEM observations and analysis. J.P., H.-C.T., Z.H. and B.-P.Z. carried out the DFT calculations. H.H. and J.Y. carried out the stability test. H.H., J.-W.L., B.C., F.L., H.-L.Z. and B.S. built the thermoelectric devices and performed the energy conversion efficiency measurements. H.-L.Z., B.S., H.L. and Q.L. provided helpful discussions. H.H. and Y. Jiang carried out the Hall measurements. All authors conceived the experiments, analysed the results and co-edited the manuscript.
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Hu, H., Ju, Y., Yu, J. et al. Highly stabilized and efficient thermoelectric copper selenide. Nat. Mater. 23, 527–534 (2024). https://doi.org/10.1038/s41563-024-01815-1
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DOI: https://doi.org/10.1038/s41563-024-01815-1
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