Ni0.33Co0.66(OH)F hollow hexagons woven by MWCNTs for high-performance lithium-ion batteries†
A template-free two-step strategy is successfully developed for the low-cost one pot production of Ni0.33Co0.66(OH)F hollow hexagons woven by multi-walled carbon nanotubes (MWCNTs). The MWCNTs in situ thread the hollow Ni0.33Co0.66(OH)F hexagons and form an interconnected three-dimensional network. Owing to the integration of MWCNTs and the formation of a fluoride derivative as well as the unique hollow structure of the Ni0.33Co0.66(OH)F hexagon, the composite presents excellent electrochemical properties including high reversible capacity and stable cycle performance. As materials for lithium ion batteries, the Ni0.33Co0.66(OH)F hollow hexagons woven by MWCNTs deliver a high reversible capacity of 1014 mA h g−1 after 100 charge–discharge cycles (current density of 100 mA g−1). At a current density of 1000 mA g−1, a high capacity of 585 mA h g−1 also could be achieved, indicating the potential application of these materials in high-performance electrochemical energy storage.