Electrochemical Deposition of Porous Co(OH)2 Nanoflake Films on Stainless Steel Mesh for Flexible Supercapacitors

Flexible porous Co(OH)2 nanoflake films were prepared by galvanostatic electrodeposition on lightweight and inexpensive stainless steel mesh. The as-prepared porous Co(OH)2 nanoflake films were characterized by X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Electrochemical tests including cyclic voltammetry, constant current charge-discharge, and electrochemical impedance spectroscopy were also used to investigate the electrochemical performance. The results show that the highest capacitance is 609.4 F g-1, the specific capacitance decreases by less than 5% as the mass loading of Co(OH)2 increases by more than 340%, and the specific capacitance only decreases by less than 15% when the current densities increase up to 10 times, indicating the good high-rate performance. The electrochemically active specific surface area of the annealed porous Co(OH)2 nanoflake films remained virtually unchanged after 3000 cycles, showing the stability of the microstructure.