Carbon-Coating Co-Doped α-Ni(OH)2 for High-Performance Supercapacitors

A carbon-coated Co-doped α-Ni(OH)₂ nano-sheet was synthesized by a one-pot co-precipitation method. To confirm the existence of the carbon coating and the Co doping, TEM, EDS, XPS, and Raman analyses were employed, and, to verify their roles in the electrochemical process, comparison experiments were carried out. The results showed that the carbon coating layer improves the conductivity of α-Ni(OH)₂, and the doped Co enhances the structural stability of α-Ni(OH)₂ during repeated cycles. Benefiting from these merits, the composite showed good performance as the electrode in a supercapacitor. At three electrodes aqueous, the specific capacitance approached 1865 F g⁻¹ at 1 A g⁻¹, and 95% capacitance was reserved after 2000 cycles. Furthermore, asymmetric supercapacitor testing was also conducted.