3D braided yarns to create electrochemical cells

• First demonstration of braiding technology in yarn supercapacitor fabrication
• Easy integration of multiple fibre electrodes in one yarn for high capacitance
• The yarn supercapacitor demonstrates a high capacitance of 1.71 mF cm− 1.
• A widely used industry technology makes sale up feasible.
• A new direction for large-scale manufacturing of electrochemical devices

The demands for new configurations of electrochemical cells continue to grow and novel approaches are being enabled by the advent of new electromaterials and novel fabrication strategies. Wearable energy storage devices that can be seamlessly integrated into garments are a critical component of the wearable electronics genre. Recently, flexible yarn supercapacitors have attracted significant attention due to their ability to be integrated into fabrics, or stitched into existing textiles. Large-scale production of yarn supercapacitors using conventional manufacturing processes, however, is still a challenge. Here, we introduce the use of braiding technology to achieve a predetermined arrangement of fibre electrodes, the basis of a mass fabrication protocol to produce specific electrochemical cells: wearable supercapacitors. The resultant supercapacitors show a high capacitance of 1.71 mF cm− 1. The structure is highly flexible with a 25% capacitance loss recorded after 1000 bending cycles.