Flexible Lithium Textile Battery Could be a Breakthrough in Wearable Tech

The lightweight Textile Lithium Battery offers high energy density and excellent flexibility. 

A group of scientists at the Hong Kong Polytechnic University has developed a thin, highly flexible textile lithium battery that could safely power wearable electronics used in healthcare monitoring, smart clothes and Internet of Things (IoT). 

The battery, which is less than 0.5 mm thick, possesses fast charging/discharging capability and also has a long cycle life compared with conventional lithium batteries. 

“Global market revenues for wearable devices are forecasted to grow by leaps and bounds, of over 20 percent annually, to reach USD 100 billion by 2024,” said Zheng Zijian, who led the research team.  “As all wearable electronics will require wearable energy supply, our novel technology in fabricating Textile Lithium Battery offers a promising solution to a wide array of next-generation applications, ranging from healthcare, infotainment, sports, aerospace, fashion, IoT to any sensing or tracking uses that may even exceed our imagination of today.”

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. The Textile Lithium Battery overcomes the bottlenecks over energy density, flexibility, mechanical robustness and cycling stability. 

To create the battery, researchers deposited highly conductive metal, copper (Cu) and nickel (Ni) uniformly onto pre-treated fabrics. Such fabricated metallic fabrics, featuring low sheet resistance and large surface area, serve as current collectors in the 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, researchers said. 

Laboratory tests conducted by the team showed the extremely high mechanical stability, durability and safety of the Textile Lithium Battery under deformation. When the battery is repeatedly folded in half, twisted at different angles or freely crumpled, its voltage window remained unchanged. 

Bending test showed that the battery can be bent over 1,000 times with marginal capacity degradation. 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.