Electrochemical Characteristics and Capacitive Deionization Performance of Asymmetric Nanoengineered CoFe2O4 Carbon Nanomaterials Composite

Abstract Capacitive deionization (CDI) is a relatively new technique that uses electric double layers (EDLs) effects, high affinity chemical groups, redox-active materials, and membranes capacitive electrosorption principle for the desalination. In this paper, hydrothermal synthesis of CFO metal oxide NPs coupled with the vacuum filtration method, or the freeze-drying method is used to fabricate high-performance nanocomposite: CFO-Graphene, CFO-CNTs, and CFO-3DrGO. Two times of hydrothermal reaction methods were conducted to fabricate the CFO-3DrGO Nanoengineered as a pseudocapacitive/EDL electrode. The results have demonstrated that the SAC of CFO–3DrGO/CFO (64.5 mg g− 1) is greater than that of the CFO–graphene/CFO (55.16 mg g− 1) and CFO–CNTs/CFO (21.5 mg g− 1) due to the better surface area of the CFO–3DrGO nanocomposite (330 m2 g− 1). The higher surface area of the CFO–3DrGO is due to the porous and interconnected 3D structure of the 3DrGO, and it provides a larger surface area to form EDL capacitance. In addition, the added porous 3DrGO entangled with the spinel crystals (CoFe2O4) in the composite allowed for a quick ion diffusion across the interconnected open macroporous structures.