Hierarchically Porous Fiber‐Based Nanofluidic Diode as an Efficient Multimode Hygroelectric Generator

• Published in: Advanced energy materials Vol. 12; no. 47
• Main Authors: Lu, Xulei, Yang, Tingting, Fu, Chunqiao, Jiang, Zhongbao, Zhang, Yong, Shang, Kedong, He, Changliu, Zhou, Jian, He, Qi‐Chang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.12.2022; Wiley-VCH Verlag
• Subjects: Aluminum oxide; Carbon fibers; Circuits; Clean energy; Electric fields; Electrodes; Energy harvesting; Engineering Sciences; Fluidics; hierarchical porous structures; hydrovoltaic effect; hygroelectric generators; Moisture effects; Molecular structure; multimode; Nanofibers; nanofluidic diodes; Nanofluids; Relative humidity; Water chemistry; Water drops
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202202634

Harvesting electrical energy from different forms of water by using the hydrovoltaic effect is a promising approach to green energy acquisition. However, at present, different devices are required to obtain electrical energy from different water forms, and the output performance of the devices is not high, which greatly reduces the convenience and effectiveness of harvesting electrical energy from different water forms. Here, a carbon nanofiber electrode with a hierarchical porous structure capable of promoting water molecule adsorption, rapid penetration, and diffusion is reported. Besides, the electrode acts as a nanofluidic diode with anodic aluminum oxide in which the built‐in electric field drives selective separation and directional transport of ions and efficient ion/electron current conversion at the electrodes. Unlike typical hygroelectric devices, the device can work with moisture (93% relative humidity, 25 °C, open‐circuit voltage (VOC) ≈ 1.1 V, short‐circuit current density (JSC) ≈ 27 µA cm−2), water droplets (2 µL, VOC ≈ 1.03 V, JSC ≈ 640 µA cm−2), and bulk water (VOC ≈ 1.15 V, JSC ≈ 256 µA cm−2). It provides an efficient way to generate electricity in multiform water environment, greatly broadening the working scene and improving the adaptability of the device in complex weather environments. A nanofluidic diode which is based on a hierarchical pore structure has been proposed and used to fabricate multimode hygroelectric generator. Such device can satisfy the rich working modes (moisture, droplet, bulk water), exhibit good environmental adaptability, and has been proven to work reliably in different weather environments.