Battery Technology

Sweat-Fueled Fingertip Wearable

A new wearable device turns the touch of a finger into a source of power for small electronics and sensors. Engineers at the University of California San Diego  developed a thin, flexible strip that can be worn on a fingertip and generate small amounts of electricity when a person’s finger sweats or presses on it. The device generates power even while the wearer is asleep or sitting still. It also generates extra power from light finger presses like typing and texting. The device derives most of its power from sweat produced by the fingertips, which are 24-hour factories of perspiration. A padding of carbon foam electrodes absorbs sweat and converts it into electrical energy. The electrodes are equipped with enzymes that trigger chemical reactions between lactate and oxygen molecules in sweat to generate electricity. Underneath the electrodes is a chip made of a piezoelectric material, which generates additional electrical energy when pressed.