Humidity-sensitive chemoelectric flexible sensors based on metal-air redox reaction for health management

• Published in: Nature communications Vol. 13; no. 1; pp. 5416 - 10
• Main Authors: Li, Shuo, Zhang, Yong, Liang, Xiaoping, Wang, Haomin, Lu, Haojie, Zhu, Mengjia, Wang, Huimin, Zhang, Mingchao, Qiu, Xinping, Song, Yafeng, Zhang, Yingying
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.09.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 147/135; 147/143; 147/3; 639/301/1005/1009; 639/925/357; 639/925/927/511; 9/10; Fabrication; Fibroins; Flexible components; Graphene; Graphite; Humanities and Social Sciences; Humans; Humidity; Hygroscopic water; Hygroscopicity; Man-machine interfaces; Metal air batteries; Metals; Monitoring; multidisciplinary; Oxidation-Reduction; Redox reactions; Science; Science (multidisciplinary); Sensors; Silk fibroin; Wearable technology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-33133-y

Numerous studies have shown flexible electronics play important roles in health management. The way of power supply is always an essential factor of devices and self-powered ones are very attractive because of the fabrication easiness, usage comfort and aesthetics of the system. In this work, based on the metal-air redox reaction, which is usually used in designing metal-air batteries, we design a self-powered chemoelectric humidity sensor where a silk fibroin (SF) and LiBr gel matrix containing parallel aligned graphene oxide (GO) flakes serve as the electrolyte. The abundant hydrophilic groups in GO/SF and the hygroscopicity of LiBr lead to tight dependence of the output current on the humidity, enabling the sensor high sensitivity (0.09 μA/s/1%), fast response (1.05 s) and quick recovery (0.80 s). As proofs of concept, we design an all-in-one respiratory monitoring-diagnosing-treatment system and a non-contact human-machine interface, demonstrating the applications of the chemoelectric humidity sensor in health management. Self-powered sensors are of interest in wearable technology and other applications. Here, the authors report on the creation of a metal-air redox reaction humidity sensor where the conductance and charge generated is influenced by the amount of absorbed water and demonstrate application in respiration monitoring.