Enhanced lithium storage capacity of Co3O4 hexagonal nanorings derived from Co-based metal organic frameworks

Abstract

Co₃O₄ with high capacities and energy density has potential applications to be electrode materials for lithium ion batteries, one of the most important power sources. For improving the cycling stability, the Co₃O₄ nanostructures are required. Herein, we report successful construction of Co₃O₄ hexagonal nanorings and nanoplates/nanoparticles via treating Co-based metal organic frameworks (MOFs) with organic amine. The studies show that the release rate of Co(II) to the reaction system and the spatial hindrance of the organic linkers of MOFs determine the final morphology of Co₃O₄. As an anode for lithium ion batteries, Co₃O₄ hexagonal nanorings with 1370 mA h g⁻¹ specific capacity after 30 cycles displayed higher reversible capacity and better stability than commercial Co₃O₄ particles with only 117 mA h g⁻¹ specific capacity after 30 cycles. The improved performance of Co₃O₄ hexagonal nanorings could be attributed to the shortened transfer path for Li⁺ afforded by the special morphology. It is expected that plentiful metal oxide nanostructures could be constructed from MOFs due to the available versatile categories of MOFs.