A Singapore research team from Nanyang Technological University (NTU) have developed a flexible battery that runs off human sweat. The prototype is made from printed silver flake electrodes, is as thin as a small band-aid, and can be attached to wearable devices such as watches, arm bands and wrist straps.
Trial results showed that a person wearing the device and cycling for 30 minutes generated 4.2V worth of power – enough to power a commercial temperature sensor device and send the data continuously to a smartphone via Bluetooth.
“Our technology heralds a previously unreachable milestone in the design of wearable devices,” said study lead Professor Lee Pooi See. “By capitalising on a ubiquitous product, perspiration, we could be looking at a more environmentally friendly way of powering wearable devices that does not rely on conventional batteries. It is a near-guaranteed source of energy produced by our bodies. We expect the battery to be capable of powering all sorts of wearable devices.”
While conventional battery models typically contain high rates of toxic chemicals and metals, the new sweat-based one is made from ink containing silver flakes which function as the battery electrodes. These are then applied to a flexible textile. When the flakes come into contact with perspiration, they cluster together and so their conductive properties are increased.
Dr Lyu Jian, co-first author of the study, said: “Conventional batteries are cheaper and more common than ever, but they are often built using unsustainable materials which are harmful to the environment. They are also potentially harmful in wearable devices, where a broken battery could spill toxic fluids onto human skin. Our device could provide a real opportunity to do away with those toxic materials entirely.”
A patent for the technology has been filed through the university’s enterprise and innovation company, NTUitive. Further investigation is expected to determine the impact of body temperature on the device.
