A team of researchers from the National University of Singapore (NUS) has created a novel film that is very effective in evaporating sweat from our skin to keep us cool and comfortable when we exercise.

 

The moisture harvested from human sweat can be used to power wearable electronic devices such as watches, fitness trackers, and more.

 

Sweating is a natural process for our body to reduce thermal stress.

 

“In our new invention, we created a novel film that is extremely effective in evaporating sweat from our skin and then absorbing the moisture from sweat. We also take this one step further – by converting the moisture from sweat into energy that could be used to power small wearable devices,” explained Assistant Professor Tan Swee Ching, who is from the NUS Department of Material Science and Engineering.

 

The main components of the novel thin film are two hygroscopic chemicals – cobalt chloride and ethanolamine.

 

Besides being extremely moisture-absorbent, this film can rapidly release water when exposed to sunlight, and it can be ‘regenerated’ and reused for more than 100 times.

 

To make full use of the absorbed sweat, the NUS team has also designed a wearable energy harvesting device comprising eight electrochemical cells (ECs), using the novel film as the electrolyte.

 

Each EC can generate about 0.57 volts of electricity upon absorbing moisture. The overall energy harvested by the device is sufficient to power a light-emitting diode.

 

This proof-of-concept demonstration illustrates the potential of battery-less wearables powered using human sweat, said the study reported in the scientific journal Nano Energy.