Flexible, Solid Electrolyte-Based Lithium Battery Composed of LiFePO₄Cathode and Li₄Ti₅O₁₂Anode for Applications in Smart Textiles

Here we report fabrication of flexible and stretchable battery composed of strain free LiFePO 4 cathode, Li 4 Ti 5 O 12 anode and a solid poly ethylene oxide (PEO) electrolyte as a separator layer. The battery is developed in a view of smart textile applications. Featuring solid thermoplastic electrolyte as a key enabling element this battery is potentially extrudable or drawable into fibers or thin stripes which are directly compatible with the weaving process used in smart textile fabrication. The paper first details the choice of materials, fabrication and characterisation of electrodes and a separator layer. Then the battery is assembled and characterised, and finally, a large battery sample made of several long strips is woven into a textile, connectorized with conductive threads, and characterised. Two practical aspects of battery design are investigated in details: first is making composites of cathode/anode material with optimized ratio of conducting carbon and polymer binder material, and second is battery performance including cycling, reversibility, and compatibility of the cathode/anode materials.