General formation of MS (M = Ni, Cu, Mn) box-in-box hollow structures with enhanced pseudocapacitive properties

Complex hollow structures of metal sulfides could be promising materials for energy storage devices such as supercapacitors and lithium-ion batteries. However, it is still a great challenge to fabricate well-defined metal sulfides hollow structures with multi-shells, hierarchical architectures, and non-spherical shape. In this work, a template-engaged strategy is developed to synthesize hierarchical NiS box-in-box hollow structures with double-shells. The NiS box-in-box hollow structures constructed by ultrathin nanosheets are evaluated as electrode materials for supercapacitors. As expected, the NiS box-in-box hollow structures exhibit excellent rate performance and impressive cycling stability due to their unique nano-architecture. More importantly, the synthetic method can be easily extended to synthesize other transition metal sulfides box-in-box hollow structures. For example, we have also successfully synthesized similar CuS and MnS box-in-box hollow structures. The present work makes a significant contribution to the design and synthesis of transition metal sulfides hollow structures with non-spherical shape and complex architecture, as well as their potential applications in electrochemical energy storage