MnCo₂O₄ Nanosheet/NiCo₂S₄ Nanowire Heterostructures as Cathode Materials for Capacitors

Structural design and regulation of composite electrode materials is crucial for a highly efficient energy storage devices. In this work, we report three-dimensional MnCo2O4/NiCo2S4 nanostructures grown in situ on a Ni foam substrate via a multistep hydrothermal process. The obtained product delivers a specific capacity of 600 C g–1 at 0.5 A g–1 and retains 75% of the initial capacity after 10 000 cycles at 6 A g–1. Furthermore, an assembled asymmetric capacitor possesses an energy density of 90.37 Wh kg–1 at 1349.9 W kg–1 and exhibits a capacity retention of 68% after cycling, demonstrating its potential applications in future smart micro/nano energy storage devices.