A droplet-based electricity generator with high instantaneous power density

Wanghuai Xu; Huanxi Zheng; Yuan Liu; Xiaofeng Zhou; Chao Zhang; Yuxin Song; Xu Deng; Michael Leung; Zhengbao Yang; Ronald X Xu; Zhong Lin Wang; Xiao Cheng Zeng; Zuankai Wang

doi:10.1038/s41586-020-1985-6

A droplet-based electricity generator with high instantaneous power density

Nature. 2020 Feb;578(7795):392-396. doi: 10.1038/s41586-020-1985-6. Epub 2020 Feb 5.

Authors

Wanghuai Xu^#^{1

2}, Huanxi Zheng^#¹, Yuan Liu^#^{3

4}, Xiaofeng Zhou^#¹, Chao Zhang¹, Yuxin Song¹, Xu Deng⁵, Michael Leung⁶, Zhengbao Yang¹, Ronald X Xu², Zhong Lin Wang⁷, Xiao Cheng Zeng^{8

9}, Zuankai Wang^{10

11}

Affiliations

¹ Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China.
² Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui, China.
³ Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA.
⁴ Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA.
⁵ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, China.
⁶ School of Energy and Environment, City University of Hong Kong, Hong Kong, China.
⁷ Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, China. [email protected].
⁸ Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA. [email protected].
⁹ Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA. [email protected].
¹⁰ Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China. [email protected].
¹¹ Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China. [email protected].

^# Contributed equally.

PMID: 32025037
DOI: 10.1038/s41586-020-1985-6

Abstract

Extensive efforts have been made to harvest energy from water in the form of raindrops^1-6, river and ocean waves^7,8, tides⁹ and others^10-17. However, achieving a high density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with low water supply. An alternative, the water-droplet/solid-based triboelectric nanogenerator, has so far generated peak power densities of less than one watt per square metre, owing to the limitations imposed by interfacial effects-as seen in characterizations of the charge generation and transfer that occur at solid-liquid^1-4 or liquid-liquid^5,18 interfaces. Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene film on an indium tin oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges the originally disconnected components into a closed-loop electrical system, transforming the conventional interfacial effect into a bulk effect, and so enhancing the instantaneous power density by several orders of magnitude over equivalent devices that are limited by interfacial effects.

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