Chinese Scientists Develop Stretchable Batteries with Stable Capacity, Potential for Flexible Electronics
A research team led by Professor Wen-Yong Lai at Nanjing University of Posts and Telecommunications has developed a lithium-ion battery capable of stretching up to 5,000%, as reported by Interesting Engineering on July 17. The new research was published in the journal ACS Energy Letters.
New lithium-ion battery contains stretchable components. (Photo: ACS Energy Letters).
Traditionally, batteries are rigid blocks that are difficult to puncture and bend. However, as the world sees an increase in flexible devices such as foldable phones, rollable screens, and wearable health monitors, the batteries powering them need to be improved as well.
Previous efforts to create flexible batteries have utilized conductive fabrics and origami folding techniques, where rigid components are folded into various shapes and can stretch within certain limits. However, Professor Wen-Yong Lai’s team aimed to create a soft, flexible battery where all components are elastic, allowing the battery to be truly bendable and capable of being compressed into any shape without breaking.
Initially, they spread a layer of conductive adhesive film containing silver nanowires, carbon black, and materials for the lithium-based anode and cathode onto a flat surface. They then coated the conductive adhesive layer with a polydimethylsiloxane layer, a highly flexible material used for contact lenses.
The research team proceeded to add a highly conductive liquid, lithium salt, and all necessary raw materials to create a polymer with significant stretchability. This layer is then activated by light, becoming a solid that can not only transport lithium ions but also stretch. On top, the experts added another layer of electrode film and encased the entire device in a protective shell.
The result is a new flexible battery that can stretch up to 5,000% of its original length. The scientists also increased the average charging capacity of the battery to six times the average when using liquid electrolyte. The battery retains good capacity after 70 charge-discharge cycles.
The research team acknowledges that this new battery is not yet perfect and requires further improvements. However, the success of this battery prototype paves the way for the application of flexible batteries in electronic devices.
