Direct successive ionic layer adsorption and reaction (SILAR) synthesis of nickel and cobalt hydroxide composites for supercapacitor applications.

Mesoporous nickel and cobalt hydroxide composites are directly grown onto 3D macro-porous Ni foam as a binder-free electrode for supercapacitors by using the successive ionic layer adsorption and reaction (SILAR) method. This method is the cheapest and simplest among several deposition processes for supercapacitor applications. An as-obtained porous NiCo(OH) 2 electrode exhibits a remarkable specific capacity (1113.6 mAh g −1 at a current density of 3 A g −1 ) and excellent cycling stability (85.62% capacity retention after 5000 cycles). Furthermore, an asymmetric supercapacitor assembled with NiCo(OH) 2 as a positive electrode and graphene as a negative electrode shows a high energy density of 20.07 W h kg −1 at a power density of 2302.73 W kg −1 and excellent cycling stability (76.46% retention after 5000 cycles). As a result, it shows that the NiCo(OH) 2 fabricated by the SILAR method can be a promising electrode towards energy-storage devices with high energy and power densities. [ABSTRACT FROM AUTHOR]