High Performance Stretchable Wire Li‐Ion Batteries

Abstract The development of integrated micro‐power sources is mainly driven by innovative investigations in materials chemistry, battery designs, and microfabrication processes. Here, a new technique is described for the development of coaxial wire‐shaped Li‐ion batteries by successfully adopting the unidirectional helical winding method starting from a twisted Cu fabric. Such a coaxial wire battery is examined by scanning electron microscopy and characterized by electrochemical techniques. These investigations reveal that the proposed approach is definitely suitable for achieving wire batteries showing high energy storage capacity while being highly flexible and stretchable without compromising the whole electrochemical performance even under mechanical deformations. The full cell based on the Li 4 Ti 5 O 12 /LiCoO 2 system delivers an outstanding linear capacity of 137 µAh cm −1 at a 0.1C rate with nearly 100% coulombic efficiency and is further capable of being operated at various kinetics. It is also shown that such a coaxial wire battery can be used to power different electronic devices, which is of significance for the development of autonomous wearable applications like electronic textiles