Electrochemical transformation method for the preparation of novel 3D hybrid porous CoOOH/Co(OH)₂ composites with excellent pseudocapacitance performance

Novel 3D hybrid porous CoOOH/Co(OH)₂ composites are prepared through the electrochemical transformation of the precursor that is synthesized using the hydrothermal method. The CoOOH/Co(OH)₂ has a good specific area of 10.88 m² g⁻¹, which is obviously larger than the 1.48 m² g⁻¹ of the precursor. The CoOOH/Co(OH)₂ has a high specific capacitance (4.721 F cm⁻² at 2 mA cm⁻²) and good stability (94.4% capacitance retention after 5000 cycles at 64 mA cm⁻²). Furthermore, an asymmetric supercapacitor that is fabricated using CoOOH/Co(OH)₂ and α-Fe₂O₃@carbon cloth has a high specific capacitance (1.667 F cm⁻² at 2 mA cm⁻²) and excellent cyclic stability (103.6% capacitance retention after 10000 cycles at 80 mA cm⁻²). These fascinating electrochemical properties result from the 3D hybrid porous CoOOH/Co(OH)₂ composites that formed during the transformation process, demonstrating their potential application as an electrode material for pseudocapacitors.