Co3O4 nanoparticles are prepared via converting cobalt oxide subunits in a cobalt metal-organic framework (Co3(NDC)3(DMF)4, NDC=2,6-naphthalene- dicarboxylate; DMF=N,N′-dimethylformamide) by pyrolysis in air. The as-prepared Co3O4 shows an agglomerated secondary structure with an average diameter of around 250nm comprised of small primary Co3O4 particles with a size of about 25nm. This agglomerated structure favors the enhanced capacity, improved rate capability and prolonged cycle life as an electrode material for lithium ion batteries.