Hydrovoltaic technology: from mechanism to applications

Wang, Xiaofan; Lin, Fanrong; Wang, Xiang; Fang, Sunmiao; Tan, Jianguo; Chu, Weicun; Rong, Rong; Yin, Jun; Xuan, Xiaoyu; Liu, Yanpeng; Guo, Wei

doi:10.1039/d1cs00778e

Cited by 117 publications

(85 citation statements)

References 99 publications

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“…The separation of positive and negative ions thus achieved leads to opposite charges on the two sides of the CA gradient paper, which has been confirmed by KPFM (Figure S16). The oppositely charged surface induces electron/hole separation in the MXene electrode through electrostatic forces (Figure b-II), , which is rich in electrons like the metal wires in the external circuit. The result is the formation of two electric double layers (EDLs) at the interfaces of the two electrodes and the CA gradient paper, leading to pseudocapacitance at the interface, which is similar to an electric double-layer capacitor .…”

Section: Resultsmentioning

confidence: 99%

Harvesting Electricity from Atmospheric Moisture by Engineering an Organic Acid Gradient in Paper

Yang

Zhang

Sun

2022

ACS Appl. Mater. Interfaces

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Moisture-activated electric generators (MEGs) that harvest clean energy from atmospheric humidity offer exciting opportunities for upgraded energy conversions. However, it is challenging to obtain MEGs that are both easy to fabricate and of high output power, due to the requirement for particular functional materials and the cumbersome manufacturing process. Herein, a simple and general method is adopted to prepare MEGs with chemically gradient structures. As a specific example, a gradient distribution of citric acid was successfully constructed inside an A4 printer paper by asymmetric drying, which can generate a continuous voltage of tens of millivolts by ambient humidity, and even to volts (275 mV and 7.6 μA cm −2 ) under asymmetric humidity stimulation, and the maximum power density output was 2.1 μW cm −2 . The driving force behind this energy conversion is a self-maintained ionic gradient created within the paper by the asymmetric ionization of gradient organic acids when exposed to gradient or nongradient humid air. This work broadens the class of materials and possibilities for the rapid development of MEGs, shedding new light on the revolution of generators that harvest green and sustainable energy for power generation.

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Section: Resultsmentioning

confidence: 99%

Harvesting Electricity from Atmospheric Moisture by Engineering an Organic Acid Gradient in Paper

Yang

Zhang

Sun

2022

ACS Appl. Mater. Interfaces

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“…The electricity generation process at the solid-liquid interface may be accompanied by ion diffusion, moisture absorption, phase transition, and bulk flow [40]. Contact electrification (CE) affects electricity generation, which refers to the phenomenon that excessive charge exists on the surface of the solid after contacting the liquid.…”

Section: Mechanisms Of the Water-driven Electricity Generatormentioning

confidence: 99%

“…Ambient moisture, arising from liquid water after absorbing heat, is a "high-energy" substance. Due to technical limitations, energy harvesting from ambient moisture was once considered difficult [40],…”

Section: Bio-inspired Moisture-driven Electricity Generatormentioning

confidence: 99%

Bio-inspired water-driven electricity generators: From fundamental mechanisms to practical applications

Wang¹,

Xu²,

Zhang³

et al. 2023

Nano Research Energy

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Harvesting water energy in various forms of water motion, such as evaporation, raindrops, river flows, ocean waves, and other, is promising to relieve the global energy crisis and reach the aim of carbon neutrality. However, this highly decentralized and distributed water energy poses a challenge on conventional electromagnetic hydropower technologies that feature centralization and scalization.Recently, this problem has been gradually addressed by the emergence of a myriad of electricity generators that take inspiration from natural living organisms, which have the capability to efficiently process and manage water and energy for survival in the natural competition. Imitating the liquid-solid behaviors manifested in ubiquitous biological processes, these generators allow for the efficient energy conversion from water-solid interaction into the charge transfer or electrical output under natural driving, such as gravity and solar power. However, in spite of the rapid development of the field, a fundamental understanding of these generators and their ability to bridge the gap between the fundamentals and the practical applications remains elusive. In this review, we first introduce the latest progress in the fundamental understanding in bio-inspired electricity generators that allow for efficient harvesting water energy in various forms, ranging from water evaporation, droplet to wave or flow, and then summarize the development of the engineering design of the various bio-inspired electricity generator in the practical applications, including self-powered sensor and wearable electronics. Finally, the prospects and urgent problems, such as how to achieve large-scale electricity generation, are presented.

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“…1−5 The preferential electrokinetic interaction in a MEG occurs during directional moisture evaporation, which spatially dissociates the attractive charges on the surface from the unbound counter-charges, thereby giving rise to the characteristic built-in charge potential. 6,7 As a pioneering work, Ghosh et al observed an output voltage between two electrodes placed on carbon nanotubes when water flowed through the nanotube network. 8 Numerous efforts have been made to further facilitate the preferential charge separation in a MEG by developing materials with various surface functional groups, 9,10 high surface area, 11 and high conductivity.…”

Section: Introductionmentioning

confidence: 99%

Humidity-Tolerant Moisture-Driven Energy Generator with MXene Aerogel–Organohydrogel Bilayer

Zhao

Lee

et al. 2023

ACS Nano

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Free-standing and film-type moisture-driven energy generators (MEGs) that harness the preferential interaction of ionized moisture with hydrophilic materials are interesting because of their wearability and portability without needing a water container. However, most such MEGs work in limited humidity conditions, which provide a substantial moisture gradient. Herein, we present a high-performance MEG with sustainable power-production capability in a wide range of environments. The bilayer-based device comprises a negatively surface-charged, hydrophilic MXene (Ti3C2T x ) aerogel and polyacrylamide (PAM) ionic hydrogel. The preferential selection on the MXene aerogel of positive charges supplied from the salts and water in the hydrogel is predicted by the first-principle simulation, which results in a high electric output in a wide relative humidity range from 20% to 95%. Furthermore, by replacing the hydrogel with an organohydrogel of PAM that has excellent water retention and structural stability, a device with long-term electricity generation is realized for more than 15 days in a broad temperature range (from −20 to 80 °C). Our MXene aerogel MEGs connected in series supply sufficient power for commercial electronic components in various outdoor environments. Moreover, an MXene aerogel MEG works as a self-powered sensor for recognizing finger bending and facial expression.

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Hydrovoltaic technology: from mechanism to applications

Abstract: This tutorial review provides a fundamental understanding of different mechanisms, material selection, device optimization and applications of hydrovoltaic technology and provides a systematic collection of recent advances.

Cited by 117 publications

References 99 publications

Harvesting Electricity from Atmospheric Moisture by Engineering an Organic Acid Gradient in Paper

Harvesting Electricity from Atmospheric Moisture by Engineering an Organic Acid Gradient in Paper

Bio-inspired water-driven electricity generators: From fundamental mechanisms to practical applications

Humidity-Tolerant Moisture-Driven Energy Generator with MXene Aerogel–Organohydrogel Bilayer

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