Abstract
Conventional robotics face fundamental trade-offs among energy-autonomy, actuation efficiency, and manufacturing simplicity. Here, we break this dilemma through a universal material design strategy of “bioinspired asymmetric engineering”. This concept is materialized through a one-step, scalable coordination of metal-organic framework UIO-66(Hf) with a piezoelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)), yielding a hierarchical hemispherical-pore composite that achieves record piezoelectricity (d33 = 46.7 ± 0.4 pC/N), and generating considerable piezoelectric outputs (open-circuit voltage (Voc) = 32.0 V, short-circuit current (Isc) = 2.2 μA, Power density (PD) = 10.9 μW cm−2). The same asymmetry principle enables a Janus actuator, where programmed elastic modulus gradation and porous ion channels co-produce ultrafast response (0.8 ms) and large bending (18.0 mm). Crucially, we first demonstrate the strategy’s versatility by integrating these components into a closed-loop, and self-powered robotic system capable of direct piezopotential-driven actuation. This work establishes asymmetric structural design as a versatile materials paradigm, opening the pathways toward intelligent soft robotics and autonomous embodied systems.
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All data used are available within this paper and Supplementary Information. Any data deemed relevant are available from the corresponding author upon request.
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (Grant No. 52272093) and the "Leading Goose" R&D Program of Zhejiang Province (No.2022C01136). The authors thank Mrs. Jing He for her assistance in performing PFM and AFM-IR characterizations at State Key Laboratory of Chemical Engineering (Zhejiang University).
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Q.L.Z acheived funding, provided the resources and supervision. H.Y and Q.L.Z conceived the project, designed studies. H. Y executed the experiments, spanning from material preparation, characterization to device fabrication. Y.Z.J., Z.Y.X., and H.L. participated in the testing of piezoelectric outputs, actuation performances, and the demonstration of self-powered bioinspired robotic system. H.Y. wrote the original manuscript. Subsequent revisions were guided by Y.J.C., H.Y., and Q.L.Z.; All authors discussed the results and commented on the final version.
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Yao, H., Jiao, Y., Xia, Z. et al. Bioinspired asymmetric structural synergy for soft robotics: closed-loop piezoelectric harvesting and ionic actuation. npj Flex Electron (2026). https://doi.org/10.1038/s41528-026-00570-4
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DOI: https://doi.org/10.1038/s41528-026-00570-4
