Fiber-crafted biofuel cell bracelet for wearable electronics

Area of Science:

• Skin electronics
• Biofuel cells
• Wearable power generation

Background:

• Wearable devices require efficient power sources, especially those utilizing biofluids like sweat.
• Existing sweat-based power generation methods often face challenges with low power output and stability.

Purpose of the Study:

• To develop a high-power biofuel cell bracelet utilizing lactate present in human sweat.
• To enhance sweat collection and storage for improved biofuel cell performance.

Main Methods:

• Fabrication of a biofuel cell using lactate oxidase and bilirubin oxidase enzymes integrated with carbon nanotube fibers.
• Weaving enzyme-modified fibers into a hydrophilic textile for sweat storage, sandwiched between hydrophobic and hydrophilic textiles for efficient sweat management.
• Series connection of multiple biofuel cell units to achieve higher voltage output.

Main Results:

• The biofuel cell bracelet achieved a power density of 74 μW at 0.39 V using artificial sweat with 20 mM lactate.
• Sustained performance exceeding 80% for 12 hours demonstrated the device's stability.
• A series-connected six-cell bracelet generated 2.0 V, sufficient for powering digital wristwatches.

Conclusions:

• The developed biofuel cell bracelet offers a promising solution for self-powered wearable electronics.
• The innovative textile-based design enhances sweat collection and utilization for efficient energy harvesting.
• This technology paves the way for sustainable and continuous power for low-power wearable devices.