Hierarchical Assemblies of Carbon Nanotubes for Ultraflexible Li-Ion Batteries

The flexible batteries that are needed to power flexible circuits and displays remain challenging, despite considerable progress in the fabrication of such devices. Here, it is shown that flexible batteries can be fabricated using arrays of carbon nanotube microstructures, which decouple stress from the energy-storage material. It is found that this battery architecture imparts exceptional flexibility (radius ≈ 300 μm), high rate (20 A g(-1) ), and excellent cycling stability.