Ultrafine ternary metal oxide particles with carbon nanotubes: a metal–organic-framework-based approach and superior lithium-storage performance†
Aiming to achieve metal–oxide-based electrodes for Li-ion batteries with enhanced energy density and cycling life, especially overcoming their negative volume expansion during cycling, more effort should be devoted to the exploration of the combination of morphology-controlled metal oxides with carbonaceous materials. In this work, we select dual/single-metallic organic frameworks immobilized on the surface of carbon nanotubes as the precursors to synthesize composites of ternary/single metal oxides with carbon nanotubes (ZnCo2O4@CNTs and ZnO@CNTs). The main product, ZnCo2O4@CNTs, consists of ultrafine ZnCo2O4 nanoparticles embedded deeply in the carbon nanotubes. The existence of small-size ternary metal oxides as well as the carbon nanotubes results in outstanding lithium-storage properties of the ZnCo2O4@CNT anode for lithium-ion batteries. It delivers an extremely high capacity (1507 mA h g−1, 100 mA g−1) after 200 cycles, which is larger than the theoretical value.