Spine-like battery could power flexible electronics

Scientists have developed a lithium ion battery shaped like the human spine that can power flexible and wearable electronics.
The rapid development of wearable electronics such as smart watches, fabrics, glasses, sensors, and more has increased the demand for high-performance flexible batteries.
Up to now, however, researchers have had difficulty obtaining both good flexibility and high energy density concurrently in lithium-ion batteries.
Researchers at Columbia University in the US developed a prototype battery shaped like the human spine that addresses this challenge.
The battery allows remarkable flexibility, high energy density and stable voltage no matter how it is flexed or twisted, researchers said.

"The energy density of our prototype is one of the highest reported so far," said Yuan Yang, from Columbia University.

"We've developed a simple and scalable approach to fabricate a flexible spine-like lithium ion battery that has excellent electrochemical and mechanical properties," said Yang, who led the study published in the journal Advanced Materials.
"Our design is a very promising candidate as the first- generation, flexible, commercial lithium-ion battery. We are now optimising the design and improving its performance," he said.
Researchers were inspired by the suppleness of the spine while doing sit-ups in the gym.
The human spine is highly flexible and distortable as well as mechanically robust, as it contains soft marrow components that interconnect hard vertebra parts. Yang used the spine model to design a battery with a similar structure.

The prototype has a thick, rigid segment that stores energy by winding the electrodes around a thin, flexible part that connects the vertebra-like stacks of electrodes together.
The design provides excellent flexibility for the whole battery.
"As the volume of the rigid electrode part is significantly larger than the flexible interconnection, the energy density of such a flexible battery can be greater than 85 per cent of a battery in standard commercial packaging," Yang said.
"Because of the high proportion of the active materials in the whole structure, our spine-like battery shows very high energy densityhigher than any other reports we are aware of," he said.

"The battery also successfully survived a harsh dynamic mechanical load test because of our rational bio-inspired design," he added.