Abstract
Intrinsically elastic thermoelectric generators with superior conformal coverage and shape adaptability are highly desirable for developing self-powered wearable electronics, soft bioelectronics and personal temperature regulators1,2. Until now, all reported high-performance thermoelectric materials have realized only flexibility, rather than elasticity3,4. Here we present one of the first n-type thermoelectric elastomers by integrating uniform bulk nanophase separation, thermally activated crosslinking and targeted doping into a single material. The thermoelectric elastomers could exhibit exceptional rubber-like recovery of up to 150% strains and high figure of merit values rivalling flexible inorganic materials even under mechanical deformations. Conventional wisdom suggests that incorporating insulating polymers should dilute the active component in organic thermoelectrics, resulting in lower performance. However, we demonstrate that carefully selected elastomers and dopants can promote the formation of uniformly distributed, elastomer-wrapped and heavily n-doped semiconducting polymer nanofibrils, leading to improved electrical conductivity and decreased thermal conductivity. These thermoelectric elastomers have the potential to make elastic thermoelectric generators in wearable applications much more conformable and efficient.
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Data availability
All data supporting the findings of this study are available in the paper and its Supplementary Information. Other related raw data are fully and freely available from the corresponding author at the point of publication. Source data are provided with this paper.
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Acknowledgements
We acknowledge the financial support from the National Natural Science Foundation of China (T2425010 (T.L.), 52303216 (K.L.), 52403219 (Z.Z.), 52373010 (J.H.), and T2441002 (Y.G.)), the Beijing Natural Science Foundation (JQ22006 (T.L.)), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0520000 (Y.G. and C.D.)) and the CAS Project for Young Scientists in Basic Research (YSBR-053 (Y.G.)). K.L. appreciates the Boya Postdoctoral Fellowship of Peking University. We acknowledge the Molecular Materials and Nanofabrication Laboratory, the Materials Processing and Analysis Center and the Electron Microscopy Laboratory of Peking University for instrument use. The computational part is supported by the High-Performance Computing Platform of Peking University. We thank beamline BL14B1 (Shanghai Synchrotron Radiation Facility) for providing beamtime for part of the X-ray scattering measurement. We also acknowledge technical support of mechanical property measurements from the State Key Laboratory of Advanced Optical Polymer and Manufacturing Technology.
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Authors and Affiliations
Contributions
T.L. conceived the idea and supervised the project. K.L., J.W. and T.L. designed the experiments. X.P., J.C. and C.W. synthesized the conjugated polymers and crosslinker. K.L. explored the bulk nanophase separation and the thermally activable crosslinking. K.L. and J.W. performed the selection of n-type dopants and the generality of the TEE design strategy. J.W. fabricated the elastic TEG and conducted the performance testing. S.-Y.T. and X.-Y.D. performed the atomistic molecular dynamics simulation. K.L. and Yudong Liu conducted the mechanical property characterizations. K.L. and P.L. did the GIWAXS measurement. Y.D., D.W. and C.D. conducted the thermal conductivity measurements. C.-K.P. and J.P. synthesized the thermally activatable n-dopant TAM. F.Q., J.L. and J.H. supplied the insulating elastomers and performed the mechanical tests. Y.G. and Yunqi Liu provided the AFM, UV–vis absorption and surface energy measurements and helped with the data analysis. K.L., J.W., Z.Z. and T.L. wrote the paper. All authors discussed and revised the paper.
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K.L., J.W. and T.L. have filed a patent application on this work (202510116577.7). The other authors declare no competing interests.
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Extended data figures and tables
Extended Data Fig. 1 Hansen solubility parameters (HSPs) of the thermoelectric polymers (a, N1 and b, N2) and elastomers.
HSP consists of three parameters representing different interactions, including δd for dispersion (van der Waals interactions), δp for polarity (dipole moment interactions), and δh for hydrogen bonding. The solubility distance (Ra) between the conjugated polymer and elastomer is determined by the formula: (Ra)2 = 4(δd2-δd1)2 + (δp2-δp1)2 + (δh2-δh1)2. Lower Ra implies better miscibility between two materials. The HSPs and Ra of the thermoelectric polymers and elastomers are summarized in Supplementary Table 2.
Extended Data Fig. 2 Vertical phase separation analysis of the polymer/elastomer blending system.
a, ToF-SIMS depth profiles of the characteristic F− ion for polymer N1 in composite films. Inset, the corresponding 3D illustration of F− ions in the composite film as a function of film depth. b, Ratio changes between S(2p) and C(1 s) peak (S/C ratio) obtained from the XPS profile element analysis of the N2/elastomer composites. Inset, the corresponding 3D illustration of the vertical phase separation. c, ToF-SIMS depth profiles of the characteristic CN− ion for polymer N2 in composite films. Inset, the corresponding 3D illustration of CN− ions in the composite film as a function of film depth.
Extended Data Fig. 3 Uniform bulk nanophase separation and thermally activable crosslinking to enhance elastic resilience.
a, The first stretching-releasing cycles of the pristine N1, N1/SEBS and c-N1/SEBS (5 wt% crosslinker). b, The second to fifth stretching-releasing cycles of c-N1/SEBS. c, Photograph of a freestanding c-N1/SEBS film on a stretching station. d, Energy loss rate of the first stretching-releasing cycle for pristine N1, N1/SEBS, and c-N1/SEBS films under different strains ranging from 15% to 150%.
Supplementary information
Supplementary Information
Supplementary Materials and Methods, Supplementary Figures, legends for Supplementary Videos, Supplementary Tables and Supplementary References.
Supplementary Video 1
Tensile strains of the free-standing N1 and c-N1/SEBS composite films.
Supplementary Video 2
Demonstration of the c-N1/SEBS as an elastomer material.
Supplementary Video 3
Stretching (beyond 150% strain)–releasing cycles of the free-standing c-N1/SEBS composite film.
Supplementary Video 4
Operation of an in-plane elastic TEG containing four c-TEE-1 legs after sequential bending, twisting and stretching, with a stable output voltage of approximately 1.20 mV when using skin temperature as the hot side and using ambient air temperature as the cold side (ΔT ≈ 4 K).
Supplementary Video 5
Operation of an out-of-plane elastic TEG featuring three c-TEE-2 thermoelectric pillars after sequential bending, twisting and stretching, with a stable output voltage of around 3.30 mV when using a 45 °C hot stage as the hot side and using a glove box temperature of approximately 30 °C as the cold side.
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Liu, K., Wang, J., Pan, X. et al. n-Type thermoelectric elastomers. Nature 644, 920–926 (2025). https://doi.org/10.1038/s41586-025-09387-z
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DOI: https://doi.org/10.1038/s41586-025-09387-z
