Synthesis of NiO/Ag nancomposites by micro-emulsion method and the capacitance performance as electrodes

Oxidized nickel/silver (NiO/Ag) nanocomposites were prepared via micro-emulsion method. In the method, the NiO nanospheres were dispersed in ethanol including sodium dodecyl sulfonate (SDS) and sonicated to form homogeneous suspension, and then an appropriate amount of AgNO₃ aqueous solution was added to this suspension above, forming a micro-emulsion. In the micro-emulsion, the NiO nanospheres were surrounded with many Ag⁺ ions. With the adding of NaBH₄, Ag⁺ ions were reduced to Ag nanospheres. Finally, a series of NiO/Ag nanocomposites were prepared successfully. The microstructures of as-prepared samples were characterized by the XRD, SEM. The results showed that NiO and Ag nanospheres formed uniform nanocomposites. The capacitance performance of NiO/Ag nanocomposites electrodes with different Ag loading contents was investigated. The results showed that the capacitance performance of NiO/Ag nanocomposites was accordingly increased as the Ag content increases. The capacitance of the NiO/Ag electrodes with 3 % Ag loading was effective to obtain fully reversible and higher specific capacitance of ~322 F g⁻¹ at 1 A g⁻¹ current density.