Hierarchical CuCo2S4 hollow nanoneedle arrays as novel binder-free electrodes for high-performance asymmetric supercapacitors.

Hierarchical CuCo2S4 hollow nanoneedle arrays have been firstly synthesized on a Ni foam using a facile template-free hydrothermal method and applied as novel binder-free electrodes for high-performance asymmetric supercapacitors with ultrahigh specific capacitance, high energy density, excellent rate capability and outstanding long-term cycling stability.