Washable, weavable, rechargeable thermally drawn fiber battery

A team of researchers led by ISN-affiliated MIT faculty members Yoel Fink, John Joannopoulos, and Ju Li has succeeded in thermally drawing a 140-meter-long fiber battery less than a millimeter in diameter. The battery is weavable, washable, and rechargeable, and could be integrated into existing platforms or spawn the development of new implements, including fully fiber-based devices and systems
An oblong black tube, wrapped in a black wire, with an MIT logo on top and a propeller at one end.

This submarine drone is powered by a 20-meter-long fiber battery that is wrapped on its surface. Image: Courtesy of the researchers

A fiber battery, lighting an LED via an alligator clip connection, is clipped by a wire cutter

The fiber battery continues to power an LED even after partial cutting indicating that the fiber battery system is free from electrolyte loss and from short-circuiting. Image: Courtesy of the researchers

A schematic of the thermal drawing process and proposed integration with fabrics and a quadcopter drone.

Thermal fiber battery drawing including multiple gels and its expansion into 2D and 3D flexible multidimensional electronics. The thermally drawn fiber battery consists of lithium-iron-phosphate (LFP) gel for the cathode, lithium titanate (LTO) gel for the anode, electrolyte gel, cyclic olefin copolymer (COC) cladding, and metal wires embedded in carbon-loaded polyethylene (CPE). The PVDF and EC:PC solvent mixture in LFP, LTO, and electrolyte gels are homogenized at the elevated temperature (in the furnace) and then phase-separated at room temperature (outside the furnace) forming interconnected pore structures with minimal gaps between cathode, anode, and electrolyte. The fiber battery can be integrated with electronic components to form 1D, 2D, and 3D electronic devices. Image: T. Khudiyev, B. Grena,et al. Thermally drawn rechargeable battery fiber enables pervasive power, Materials Today, Volume 52, 2022, Pages 80-89.