Hierarchically Hollow and Porous NiO/NiCo<sub>2</sub>O<sub>4</sub> Nanoprisms Encapsulated in Graphene Oxide for Lithium Storage
Yingying Wang, Yang Wang, Longgang Lu, Bin Zhang, Chengxin Wang, Bin He, Ren Wei, Dongdong Xu, Qingli Hao, Ben Liu
Abstract
Engineering materials nanostructures is key for developing renewable energy technologies for lithium-ion batteries (LIBs) but remains a long-term research challenge. In this paper, heterostructured NiO/NiCo2O4 nanoprisms with a hierarchically hollow cavity and porous framework are rationally designed and further encapsulated in graphene oxide (NiO/NiCo2O4@GO) as a highly efficient anode nanomaterial for LIBs. Heterostructured NiO/NiCo2O4 hollow/porous nanoprisms are derived by the ionic exchange of Ni precursors with [Co(CN)6]3– (CoNi-metal–organic framework (MOF)) and then annealed under air. The encapsulation is achieved by fast assembly of GO and NiO/NiCo2O4. Thanks to hierarchically hollow and porous nanostructure, heterostructured NiO/NiCo2O4, and overcoated GO, the NiO/NiCo2O4 electrode shows excellent electrochemical performance toward lithium storage, disclosing a large rate capacity of 468 mA h g–1 at 3.0 A g-1 and a good capacity retention of 561 mA h g-1 at 1 A g-1 after 800 cycles. This work paves a facile ionic exchange method for the controllable construction of hierarchically hollow MOFs and their derived composite nanomaterials for various energy-related applications.