The lightweight Textile Lithium Battery demonstrates high energy density of more than 450 Wh/L. It also has a bending radius of less than 1mm and foldability of over 1,000 cycles with marginal capacity degradation.
In comparison, the existing bendable lithium battery can only reach a bending radius of about 25mm, and with much lower performance of less than 200 Wh/L. The Textile Lithium Battery, of less than 0.5 mm thick, also possesses fast charging/discharging capability, and long cycle life comparable with conventional lithium batteries.
Professor Zheng Zijian, who leads the ITC research team, said, "Wearable technology has been named as the next global big market opportunity after smartphones. Global market revenues for wearable devices are forecasted to grow by leaps and bounds, of over 20% annually, to reach $100 billion by 2024.
“As all wearable electronics will require wearable energy supply, our novel technology in fabricating Textile Lithium Battery offers promising solution to a wide array of next-generation applications.”
Lithium battery is currently the dominant rechargeable battery in the market due to its relatively high energy density and long cycle life. As conventional bulky heavy lithium battery is hard for use in wearable devices, over the past decade, scientists have put in efforts in developing bendable lithium battery, often by using metal foils as current collectors.
According to PolyU, with its Textile Lithium Battery the bottlenecks over energy density, flexibility, mechanical robustness and cycling stability can finally be addressed.
Applying PolyU's patented technology of Polymer-Assisted Metal Deposition (PAMD), highly conductive metal, copper (Cu) and nickel (Ni) are uniformly and conformally deposited onto pre-treated fabrics. Such fabricated metallic fabrics, featuring low sheet resistance and large surface area, serve as current collectors in battery. After adding active materials to act as cathode and anode, the metallic fabrics, together with separator and electrolyte, are assembled into the Textile Lithium Battery.
When the battery is repeatedly folded in half, twisted at different angles or freely crumpled, its voltage window remained unchanged, according to PolyU. Bending test showed that the battery can be bent over 1,000 times with marginal capacity degradation. While safety tests conducted by continuous hammering, trimming with scissors and penetrating with nail proved the battery can stably provide power output for the electronic components with no risk of catching fire or burst.
