Chinese Scientists Develop Ultrathin Batteries for Contact Lenses Charged by Human Tears

Scientist Lee Seok Woo from the School of Electrical and Electronic Engineering at Nanyang Technological University in China has developed ultrathin batteries for smart contact lenses. His inspiration came from the fourth film in the "Mission: Impossible" franchise, where one of the characters wears contact lenses capable of facial recognition, reports CNBC.

Together with his team, Lee created a miniature battery that can be powered using a biocompatible saline solution. The device is coated with glucose, and when immersed in the saline solution, the glucose reacts with sodium and chloride ions, initiating the charging process. Since human tears also contain glucose, the battery can recharge directly when the lenses are worn. This potentially allows the lenses to be used throughout the day.

“Tear fluid also contains glucose. This means that when you wear contact lenses, your tears can also charge the battery. If you cry more, you can charge the battery more,” said Lee Seok Woo.

Currently, the capacity and voltage of the invented battery are quite low—it can only produce a voltage of approximately 0.3 to 0.6 V. In comparison, the standard voltage for a single AA battery is 1.5 V. Therefore, this power is not yet sufficient to support data storage or internet connectivity.

However, the scientists are working on advancing this technology. They hope to increase the battery's capacity in the future while keeping it very thin, which is crucial for its use in contact lenses. “The thickness of our battery is about 0.2 mm, roughly twice the thickness of human hair,” explained the scientists.

The researchers also believe that once commercial production of these batteries begins, their cost will be only a few dollars, promoting the development of smart contact lens technology.