Self-Powered Flexible Humidity Sensor Based on HACC/LiCl Composite Electrolyte

Area of Science:

• Materials Science
• Sensor Technology
• Electrochemistry

Background:

• Traditional flexible humidity sensors face challenges like external power dependency and complex fabrication.
• There is a need for low-cost, self-powered sensors for energy-limited environments.

Purpose of the Study:

• To develop a cost-effective, scalable, and self-powered flexible humidity sensor.
• To address limitations of existing humidity sensing technologies.

Main Methods:

• Screen-printing of hydroxypropyl trimethyl ammonium chitosan/lithium chloride (HACC/LiCl) composite electrolyte on A4 paper substrate.
• Fabrication of interdigitated manganese dioxide (MnO2) and zinc (Zn) electrodes.
• Optimization of the HACC/LiCl electrolyte system.

Main Results:

• Developed a self-powered flexible humidity sensor with a wide detection range (11-97% RH).
• Achieved a strong quadratic relationship between output voltage and humidity (R² = 0.996), with a peak voltage of 1.2 V.
• Demonstrated excellent cyclic, long-term, and bending stability.

Conclusions:

• The HACC/LiCl based sensor provides a feasible solution for low-cost, passive humidity monitoring.
• The sensor shows promise for applications in respiratory monitoring and non-contact sensing.
• Screen-printing offers a scalable fabrication method for self-powered flexible sensors.