Metal–Organic Framework Derived Core–Shell Co/Co3O4@N-C Nanocomposites as High Performance Anode Materials for Lithium Ion Batteries

Metal–organic frameworks (MOFs) with diverse structures, adjustable pore sizes, and high surface areas have exhibited awesome potential in many fields. Here we report a simple carbonization strategy to obtain a series of core–shell structured Co/Co3O4 nanoparticles encapsulated into nitrogen-doped carbon shells from cobalt-based metal–organic framework precursors at different carbonization temperatures. When it is applied as an anodes for lithium ion batteries, the Co/Co3O4@N-C-700 electrode delivers a maximum initial discharge capacity of 1535 mAh g–1, the highest reversible capacity (903 mAh g–1 at a current density of 100 mA g–1 after 100 cycles), and the best rate performance (i.e., 774 mAh g–1 at a current density of 1.0 A g–1 after 100 cycles) in comparison with those of Co/Co3O4@N-C-600 and Co/Co3O4@N-C-800 electrodes. The excellent electrochemical performance could be mainly attributed to the unique core–shell structure, abundant graphited carbon, and the well-dispersed Co/Co3O4 nanoparticles which can promote the specific capacity through conversion reactions.