Synthesis of mesoporous Co(OH)^sub 2^ nanocubes derived from Prussian blue analogue and their electrocapacitive properties

Taking Prussian blue analogue (Co3[Co(CN)6]2) nanocubes as precursor, mesoporous Co(OH)2 nanocubes were synthesized by simply reacting Co3[Co(CN)6]2 nanocubes with NaOH aqueous solution. Their morphology and microstructures were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and micropore and chemisorption analyzer. Electrocapacitive properties of mesoporous Co(OH)2 nanocubes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge method. Results show that the mesoporous Co(OH)2 nanocubes have mainly mesoporous structure with the specific surface area as high as 297 m2 g− 1, a high specific capacitance of 420 F g− 1 at 1 A g− 1 and excellent rate performance (80.9% retention from 1 A g− 1 to 10 A g− 1). In addition, the capacitance of the mesoporous Co(OH)2 nanocubes retained 82.4% of the initial value after 5000 cycles even at a high current density of 10 A g− 1. These indicates that the mesoporous Co(OH)2 nanocubes are good candidates for supercapacitor electrode material.