Design and self-assembly of metal-organic framework-derived porous Co3O4 hierarchical structures for lithium-ion batteries

Porous metal oxides hierarchical structures with controlled morphologies have received great attention because of their promising applications in catalysis, energy storage, gas sensing, etc. Porous Co3O4 hierarchical structures with controlled morphologies were synthesized on the basis of a pyrolytic conversion of Co-based metal-organic frameworks (Co-MOFs), which were initially grown in solutions containing Co(NO3)2·6H2O, 1,3,5-Benzentricarboxylic acid and pyrazine as solute and N,N-dimethylformamide (DMF) as solvent under a solvothermal condition. Porous Co3O4 with twin hemispherical and flower-like structures were obtained with the assistance of PVP by adjusting the amount of pyrazine. The results of nitrogen adsorption-desorption indicate the BET surface area (22.6 m2 g−1) of twin hemispherical Co3O4 structures is lower than that (33.3 m2 g−1) of flower-like Co3O4 structures. However, the pore size of twin hemispherical Co3O4 structures is smaller, which is centered at about 2.5, 4.0 and 20.0 nm. The Co3O4 with twin hemispherical structures exhibit more excellent electrochemical performance as anode materials for lithium ion batteries than that of flower-like Co3O4 structures, which may be attributed to the smaller particle size and compact porous structures with suitable pore size.