A team of researchers from UC San Diego has developed a revolutionary wearable device that generates energy from the sweat droplets on fingertips, potentially revolutionizing the power source for devices like Fitbits. The device, resembling a plaster-like strip worn on the finger, can produce electricity when pressed and convert it from excreted sweat, even during sleep. This innovation offers a more reliable energy source compared to weather-dependent renewables like solar and wind.
Led by Joseph Wang, known for his earlier breakthrough with a rechargeable battery powered by a temporary tattoo, the team has advanced wearable energy technology. Previously, they developed stretchable biofuel cells capable of withstanding wear and tear while on the skin. The new finger strip represents a significant leap forward, harnessing the high concentration of sweat glands in fingertips with minimal effort.
Unlike previous wearables requiring strenuous physical activity, just 10 hours of sleep while wearing the finger strip can produce 400 millijoules—sufficient energy to power a battery-operated watch for 24 hours. This development has the potential to transform the future of wearable devices, addressing the current limitation of battery size.
The conventional link between power capability and battery volume makes sophisticated tech bulkier. Sweat-based charging could make devices like heart rate monitors, hearing aids, and augmented-reality contact lenses less cumbersome as more power-hungry features emerge. Additionally, it offers a sustainable alternative to lithium polymer batteries, addressing environmental concerns associated with lithium mining, such as water depletion and pollution in regions like Chile and Argentina.
The broader environmental impact is significant, as the demand for lithium increases with the rise of smartphones and electric cars. By transitioning to alternative wearable energy sources, such as sweat-based charging, there is potential to stall this growth and align with increased battery collection and recycling efforts.
Joseph Wang envisions a future where charging becomes an afterthought, with flexible, conformable, durable, and self-sustainable systems seamlessly integrated into the human body. This breakthrough marks a step toward a more environmentally friendly and convenient future for wearable technology.