Skip to main content

Stretchable battery to be step for flexible devices?

Could this be the year of flexible electronics? Probably not, but a group of researchers are pushing in that direction.

According to a study published in Nature Communications, the team has created a thin, stretchable battery that can be expanded up to three times its size without loss of power or performance, the BBC reported.

"Batteries are particularly challenging because, unlike electronics, it's difficult to scale down their dimensions without significantly reducing performance," John Rodgers, co-author of the study, told BBC News.

After testing various methods like radio frequency energy harvesting and solar power, researchers landed on two approaches. The first is a speckled slice of stretchable polymer, dotted with "pop-up" architecture — tiny, widely spaced embedded circuits connected via wires. The second involves long, S-shaped wires that expand and contract upon flexing of the battery.

The "pop-up" concept works for circuits, but not a stretchable battery, which requires a more tightly packed grouping of components, which the "pop-up" technology does not provide. The serpent-like S-shaped wires, however, fill the small spaces between battery components.

"When we stretch the battery, the wavy interconnecting lines unfurl, much like yarn unspooling," Northwestern University's Yonggang Huang, co-author of the study, said in a statement. "And we can stretch the device a great deal and still have a working battery."

Once expanded, the battery returns to its original state, without losing precision; the design also allows for wireless charging up to 20 cycles without with little loss of capacity.

The battery joins a growing list of flexible devices, including Samsung's Youm display technology, "curved OLED" TVs from LG and Samsung, and a patent for a slap bracelet-like smartwatch from Apple.

See the research team's stretchable battery in action in the video below.