Self-Sustained Moisture Energy Harvesting Using Carbon Black-Cellulose Galvanic Paper.

Area of Science:

• Materials Science
• Energy Harvesting
• Electrochemistry

Background:

• Moisture-enabled electric generators (MEGs) offer portable power for outdoor use by harvesting ambient moisture.
• Conventional MEGs suffer from low power density, limiting their practical applications.

Purpose of the Study:

• To develop a novel galvanic effect-enhanced moisture-enabled electric generator (GEMEG) with significantly improved power density.
• To demonstrate the potential of GEMEGs for powering electronic devices and charging mobile phones in outdoor environments.

Main Methods:

• Constructed GEMEGs using a nanoporous substrate coated with carbon black nanoparticles on cellulose paper.
• Enhanced moisture harvesting by incorporating hygroscopic CaCl2.
• Integrated a FeCl3-based galvanic cell into the negative electrode to boost energy output.

Main Results:

• Achieved a stable open-circuit voltage of ~0.99 V for over 120 hours at 40-55% relative humidity.
• Demonstrated a volumetric power density of 98.04 µW cm⁻³.
• Attained an areal power density of 10.74 µW cm⁻² by stacking 20 GEMEGs in parallel, a 15.1% improvement over state-of-the-art MEGs.

Conclusions:

• The GEMEG exhibits significantly enhanced power density and a compact form factor.
• The sustainable GEMEGs show strong potential for portable energy solutions in outdoor settings, including charging mobile phones.
• The device successfully powered an LED and charged a mobile phone via a supercapacitor.