Li-ion battery that dissolves in water a breakthrough for transient electronics
American researchers have developed a lithium ion battery that dissolves in water in 30 minutes, marking a major step in the development of so-called transient electronics.
The inventors from Iowa State University said the device, which can provide 2.5 volts of electrical potential, is the first dissolvable battery with characteristics suitable for commercial applications.
Transient electronics, which melt upon contact with water or when exposed to light and heat, are promising for applications in healthcare or as environmental sensors. The biodegradable technology would basically serve for a certain amount of time and then completely dissolve, leaving minimal traces behind. Such systems could also be used by the military to protect classified information.
"Unlike conventional electronics that are designed to last for extensive periods of time, a key and unique attribute of transient electronics is to operate over a typically short and well-defined period and undergo fast and, ideally, complete self-deconstruction and vanish when transiency is triggered," the team wrote in a paper published in the latest issue of the Journal of Polymer Science.
The battery, which can power a desktop calculator for about 15 minutes, is the first with sufficient power, stability and shelf life to allow practical use, the team said.
"Any device without a transient power source isn't really transient," said Reza Montazami, the leader of the team. "This is a battery with all the working components. It's much more complex than our previous work with transient electronics."
The battery, measuring 1 x 5 x 6mm, consists of eight layers including an anode, a cathode and an electrolyte separator. The whole structure is wrapped in two layers of a polyvinyl alcohol-based polymer.
When in touch with water, the polymer casing breaks apart and dissolves. Montazami admitted that some nanoparticles used in the battery don’t dissolve completely but disperse.
The researchers believe the technology could be modified to provide more power by connecting several smaller batteries.
Montazami's team previously developed transient prototypes of electronics printed on a single layer of a degradable polymer composite.