Facile synthesis of Cu-PBA nanocubes/graphene oxide composite as binder-free electrodes for supercapacitor

Highlights: • A novel hybrid Cu-PBA@GO was deposited on SS using the green SILAR method. • The hybrid electrode delivers an eminent specific capacitance of 611.6 F/g at an applied current density of 0.5 A/g. • The Cu-PBA@GO composite could achieve a supreme energy density value of 54.37 Wh/kg at a specific power of 200 W/kg. • The effective synergism was elucidated between the Cu-PBA and graphene oxide. • The supercapacitor electrode shows better cycle stability (capacitance retention of 86% after 2000 cycles). -- Abstract: Prussian blue and its analogues as one of the metal-organic frameworks are commonly used for fabricating energy storage electrodes due to their outstanding properties such as the high surface area, 3D porous networks, and the low cost. However, they are suffering from ther low energy density and conductivity that can limit their further applications. Herein we utilize a facile and new bottom-up protocol for the deposition of copper hexacyanoferrate nanocubes (Cu-PBA) on the surface of graphene oxide (GO) as a binder-free electrode for supercapacitors. This paper draws a complete picture for the merits of handy successive ionic layer adsorption and reaction (SILAR) technique for coating Cu-PBA@GO nanocomposite on the inexpensive stainless steel substrate. The effect of the reaction cycles on the morphology, crystallinity, and electrochemical behavior of Cu-PBA@GO nanocomposite, besides the effective synergism between the Cu-PBA and graphene oxide were studied. FTIR, XPS, SEM, TEM and XRD assured the formation of cubic Cu-PBA in the hybrid Cu-PBA/GO thin films. Interestingly, the hybrid SS/Cu-PBA@GO-12 could deliver an eminent specific capacitance of 611.6 F/g which is 2.7 times of that for the pure Cu-PBA (225.93 F/g) at an applied current density of 0.5 A/g with better cycling stability as it could retain approximately 86% of its initial capacitance after performing 2000 cycles at a current density of 4 A/g. Additionally, the hybrid electrode could achieve a supreme energy density value of 54.37 Wh/kg at a specific power of 200 W/kg. Such an outstanding electrochemical behavior of Cu-PBA@GO hybrid could open the way for the development of smart and flexible supercapacitors by using a green and cost-effective method instead of the organic-based ones.