Power generation from ambient humidity using protein nanowires


Harvesting energy from the environment offers the promise of clean power for self-sustained systems1,2. Known technologies—such as solar cells, thermoelectric devices and mechanical generators—have specific environmental requirements that restrict where they can be deployed and limit their potential for continuous energy production3,4,5. The ubiquity of atmospheric moisture offers an alternative. However, existing moisture-based energy-harvesting technologies can produce only intermittent, brief (shorter than 50 seconds) bursts of power in the ambient environment, owing to the lack of a sustained conversion mechanism6,7,8,9,10,11,12. Here we show that thin-film devices made from nanometre-scale protein wires harvested from the microbe Geobacter sulfurreducens can generate continuous electric power in the ambient environment. The devices produce a sustained voltage of around 0.5 volts across a 7-micrometre-thick film, with a current density of around 17 microamperes per square centimetre. We find the driving force behind this energy generation to be a self-maintained moisture gradient that forms within the film when the film is exposed to the humidity that is naturally present in air. Connecting several devices linearly scales up the voltage and current to power electronics. Our results demonstrate the feasibility of a continuous energy-harvesting strategy that is less restricted by location or environmental conditions than other sustainable approaches.

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Fig. 1: Nanowire devices and electric output.
Fig. 2: Moisture gradient in nanowire film and electric output.
Fig. 3: Mechanisms for electric output.
Fig. 4: Powering from nanowire devices.

Data availability

The data that support the findings of this study are available within the paper and Supplementary Information. Additional supporting data generated during the present study are available from the corresponding author upon reasonable request.


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J.Y. and D.R.L. acknowledge support from a seed fund through the Office of Technology Commercialization and Ventures at the University of Massachusetts, Amherst. J.C. and Xiaorong L. acknowledge support from the National Institutes of Health (grant GM114300 to J.C.). Part of the device fabrication work was conducted in the Center for Hierarchical Manufacturing (CHM), a National Science Foundation (NSF) Nanoscale Science and Engineering Center (NSEC) located at the University of Massachusetts Amherst.

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J.Y. and Xiaomeng L. conceived the project and designed experiments. D.R.L. oversaw material design and production. Xiaomeng L. carried out experimental studies. H.G. helped with device fabrication and characterization. J.E.W. performed material synthesis and imaging. Xiaorong L. and J.C. designed the computational study and analysis. Xiaorong L. performed simulations and analysis. B.Y. performed resistance simulations. T.F. helped with electrode fabrication. J.Y. and D.R.L. wrote the paper. All authors discussed the results and implications and commented on the manuscript at all stages.

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Correspondence to Jun Yao.

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Peer review information Nature thanks Liangti Qu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Liu, X., Gao, H., Ward, J.E. et al. Power generation from ambient humidity using protein nanowires. Nature 578, 550–554 (2020). https://doi.org/10.1038/s41586-020-2010-9

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