Abstract
The strategy of combining well-designed hollow structure with compositional engineering has been aroused wide interest in the fields of energy storage. Herein, starting from Ni-Co coordination polymer spheres as self-templates, the NiCo2S4/CoO multi-shelled hollow spheres (NiCo2S4/CoO HMSs) are constructed through calcination and sulfurization, in which the shells consist of a large number of nanoparticles with heterostructures. By virtue of its structural and compositional advantages, the NiCo2S4/CoO HMSs present desirable energy storage properties including high specific capacity (860.1 C g?1 at 1 A g?1), outstanding rate performance and good cycling durability. It is also found that the NiCo2S4/CoO HMSs possess accelerated reaction kinetics. Furthermore, a hybrid supercapacitor device, assembled by NiCo2S4/CoO as the positive electrode and hierarchically porous carbon as the negative electrode, yields a high energy density of 55.35 Wh kg?1 at 790 W kg?1. This work would contribute to designing advanced heterostructures for high-performance electrode materials.
NSTL
Elsevier