The journey to find the display of the future goes on. Most efforts so far have focused on making flexible displays, with interesting advances from Professor Peng Huisheng at Fudan University, who wants to turn your T-shirt into a screen.

Even if we succeed in making a flexible screen, there's still the matter of the power supply. What we need is a flexible battery. Professor Peng showed me the wire-shaped battery his team just developed.

This is the thinnest, lightest, and softest battery that I have ever seen. Scientists say the design is the same as a traditional lithium-ion battery. 

“Lithium is the most suitable element for a battery. It's very light compared with other elements.  A lithium battery has high voltage, which means it will release more energy. So when we develop flexible batteries, lithium is still the first choice,” said Chen Taixiang, researcher at Peng’s lab.

They also kept the structure of the lithium-ion battery which has a positive and a negative electrode. There's a separator between the two electrodes to keep them from touching each other and shorting the circuit, which can cause explosions.

The only change is its shape, into a soft fiber.  That's thanks to a newly-developed material, carbon nano-tubing.

“We used a carbon nano-tubing as the electrode…It’s super light, strong, and conductive. We used it to make electrodes by spraying lithium on it. Carbon nano tubing has a huge surface area, that means it absorbs more lithium, carrying more power,” said researcher Hong Dongsheng.

In the traditional lithium-ion battery, electrodes and separators are surrounded by the liquid electrolyte. Once it leaks, it may have caused short circuit and explosion. That’s why batteries always comes with a rigid structure. But the research team at Fudan University creatively used conductive hydrogel as an electrolyte. The jelly-like material has both the flexibility of a fluid and the stability of a solid, can hold the two electrodes in place so that the separator is no longer needed. Even after being stabbed by a knife, the battery won’t explode because the gel electrolyte stays trapped inside.

The most exciting part is this battery can also be used to weave, just like the luminescent fibers.

“We can integrate them to make a fiber that can emit light automatically without the need for an external power source. That means clothes made of such integrated fibers can display TV and movies. It will fundamentally change our way of life,” said Peng.