Reactable ionic liquid assisted preparation of porous Co3O4 nanostructures with enhanced supercapacitive performance

Abstract

Porous hierarchical broom-like and rod-like Co₃O₄ nanostructures have been successfully prepared in the presence of a reactable ionic liquid 1-hexadecyl-3-methylimidazolium trifluoroacetate [C₁₆mim]CF₃COO by a hydrothermal method in combination with calcination of Co(CO₃)_0.5(OH)·0.11H₂O precursors. During the reaction process, the ionic liquid [C₁₆mim]CF₃COO performed three roles: as the reactant, template and co-solvent. A possible formation mechanism of the structures was proposed on the basis of the experimental results. After the thermal decomposition treatment of the precursors, the as-obtained porous Co₃O₄ samples well retain the hierarchical broom-like and rod-like nanostructures. Subsequently, they are applied as the electrode materials for supercapacitors. The electrochemical experiments reveal that the porous hierarchical broom-like Co₃O₄ nanostructures exhibit a higher capacitance (722.2 F g⁻¹ at 1 A g⁻¹) compared to the porous rod-like Co₃O₄ nanostructures (191.2 F g⁻¹ at 1 A g⁻¹).