Self-Powered CeO2/Ag Sensors Powered by a Triboelectric Nanogenerator for Humidity Monitoring in High-Voltage Substations

Abstract

Abnormal humidity in high-voltage substations poses a critical threat to the insulation safety of electrical equipment. Conventional humidity sensors rely on external power sources or batteries, which limits their feasibility for distributed deployment in complex electromagnetic environments. In this work, a self-powered wireless humidity monitoring system is developed by integrating a CeO₂/Ag heterojunction composite sensor with a triboelectric nanogenerator (TENG) and a self-starting power management module, enabling ambient wind energy harvesting. The CeO₂/Ag composite is synthesized via a hydrothermal method followed by in situ reduction. Characterization results reveal that Ag nanoparticles are uniformly distributed on the CeO₂ surface. The sensor operates over a wide relative-humidity range of 0–97% RH and reaches a maximum response of 96.98% at 97% RH, with response and recovery times of 8.7 and 17.9 s, respectively. Density functional theory calculations demonstrate that the CeO₂/Ag heterointerface significantly enhances water molecule adsorption and charge transfer through Schottky barrier modulation, with an adsorption energy of –1.447 eV. The TENG achieves a peak power of 732 μW, and the integrated system enables wireless data transmission every 75 s at a rotational speed of 200 rpm. This work offers a promising solution for self-powered, distributed humidity monitoring in substations and other complex industrial environments.