Biomorphic composites composed of octahedral Co3O4 nanocrystals and mesoporous carbon microtubes templated from cotton for excellent supercapacitor electrodes

Biomorphic Co₃O₄ nanocrystal/mesoporous carbon microtube composites have been hydrothermally prepared and subsequent calcinated using cotton as biotemplate and precursor. The as-prepared composites are fabricated by octahedral Co₃O₄ nanocrystals with high exposed {1 1 1} facets supported on the porous carbon microtubes and exhibit a unique tubular morphology and porous features. The specific capacitance of the present biomorphic materials is 284.2F⋅g⁻¹ at 1 A⋅g⁻¹, which is 4.8-fold larger than that of pristine Co₃O₄ prepared without cotton template. The excellent pseudocapacitive performance is attributed to the introduction of porous carbon, the high exposed active facets, the high specific surface area and the optimized hierarchical microstructure inherited from the biotemplate.