Power generation humidity sensor based on primary battery structure

The power generation humidity sensors based on the principles of triboelectricity, piezoelectricity and ion diffusion have been proposed in recent years. However, these power generation humidity sensors usually have complex preparation process and application limitation. Here we develop a simple Cu/NaCl paper/Al power generation (CPG) humidity sensor based on primary battery structure. Combined with the hydrophilicity of paper and the chemical reactions of primary battery, the CPG humidity sensor can spontaneously output voltage and shows good humidity sensing properties at 41.1–91.5% relative humidity (RH). Specifically, a single CPG humidity sensor can output 0.58 V at 91.5% RH with a power of 1.33 μW. Benefiting from good humidity sensing performance and material safety, the CPG humidity sensor has been proved to have potential applications in respiratory rate, diaper monitoring and non-contact switch. Through the series integration of 8 CPG humidity sensors, it can realize an output voltage of 4.21 V and charge the capacitor, proving the potential self-powered characteristic of the CPG humidity sensor. This research not only proposes a simple, low-cost and eco-friendly power generation humidity sensor, but also opens a new pathway for power generation humidity sensor.