Self-powered temperature and humidity sensing platform based on Ag2S/ poly(5-carboxyindole)/hydroxyethyl cellulose nanocomposite

A self-powered dual-function temperature and humidity sensing platform is constructed based on Ag2S/poly(5carboxyindole)/hydroxyethyl cellulose composite material (Ag2S/P5ICA/HEC). The Ag2S nanomaterial with reticular porous structure is successfully synthesized via a solvothermal method for use as electrodes in supercapacitors and temperature sensors. Then, a highly sensitive Ag2S/P5ICA/HEC-based humidity sensor is successfully prepared by drop-coating the surface of Ag2S material with P5ICA/HEC composite. The analysis results reveal that the Ag2S electrode material shows good electrochemical properties with high specific capacitance (6.11F/cm3 at 0.04 A/cm3 current density) and cycle stability. Moreover, the symmetric supercapacitor constructed based on the Ag2S electrode material also exhibits high energy storage capacity and long term cycling stability. Additionally, the Ag2S material showed temperature sensitivity, with its resistance values positively correlated with temperature in a linear relationship (R2 = 0.992). The rough and reticular porous structure of Ag2S/P5ICA/HEC provides large surface area for adsorbing more water molecules, thereby increasing the sensitivity of humidity detection. The analysis results show that the sensor is sensitive to humidity at room temperature. In the detection range of 20-80 % relative humidity (RH), the natural logarithm of the resistance response signal shows a good linear relationship with humidity (R2 = 0.996). The sensor exhibits a sensitivity of 0.078 Omega / % RH, coupled with excellent repeatability and stability. Finally, a self-powered temperature and humidity sensing platform is constructed using a symmetric supercapacitor with Ag2S electrodes as the energy storage component, and Ag2S/P5ICA/HEC composite material as the temperature and humidity sensing component. This platform exhibits excellent temperature and humidity detection capabilities and holds potential for applications in areas such as pharmaceutical storage, food storage, and agriculture.