Zhang Mingxiang, Duan Zaihua, Yuan Zhen, Jiang Yadong, Tai Huiling
State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, P. R. China.
ACS Nano. 2024 Dec 17;18(50):34158-34170. doi: 10.1021/acsnano.4c10432. Epub 2024 Dec 3.
Electrochemical humidity (ECH) sensors that integrate power generation and humidity sensing have attracted great research attention in recent years. However, the design of high-performance ECH sensors faces many challenges. Namely, the working mechanism of the ECH sensors is still controversial, and related self-powered applications have not been well implemented. To overcome these limitations, this study constructs an ECH sensor with high power-generation and humidity-sensing performance using the KCl/carbon black/halloysite nanotubes (KCl/CB/HNTs) as a humidity-sensing electrolyte. The proposed ECH sensor has a wide humidity-sensing response of 10.9%-91.5% relative humidity (RH), and a single ECH sensor can output 1.46 V with a maximum power of 133.2 μW at 91.5% RH. Particularly, the unprecedented mixed chemical reactions at the positive electrode, including the hydrogen evolution reaction and oxygen reduction reaction, are analyzed using multiple characterization and testing techniques. The analysis results provide solid experimental evidence for the current controversial working mechanism of ECH sensors. Due to the advantage of high-power generation, the proposed ECH sensor can be used for self-powered humidity detection. This study provides a valuable reference for improving the power generation of ECH sensors and solid evidence for clarifying their working mechanism, which could be beneficial for guiding the future development of ECH sensors.
近年来，集成发电与湿度传感功能的电化学湿度（ECH）传感器引起了广泛的研究关注。然而，高性能ECH传感器的设计面临诸多挑战。具体而言，ECH传感器的工作机制仍存在争议，相关的自供电应用也尚未得到很好的实现。为克服这些限制，本研究使用氯化钾/炭黑/埃洛石纳米管（KCl/CB/HNTs）作为湿度传感电解质，构建了一种具有高发电性能和湿度传感性能的ECH传感器。所提出的ECH传感器具有10.9%-91.5%相对湿度（RH）的宽湿度传感响应，单个ECH传感器在91.5%RH时可输出1.46V电压，最大功率为133.2μW。特别地，利用多种表征和测试技术分析了正极前所未有的混合化学反应，包括析氢反应和氧还原反应。分析结果为当前有争议的ECH传感器工作机制提供了确凿的实验证据。由于具有高发电优势，所提出的ECH传感器可用于自供电湿度检测。本研究为提高ECH传感器的发电性能提供了有价值的参考，并为阐明其工作机制提供了确凿证据，这可能有助于指导ECH传感器的未来发展。
