Synthesis and electrochemical characterization of mesoporous CoxNi1−x layered double hydroxides as electrode materials for supercapacitors

A novel nanostructured mesoporous CoxNi1−x layered double hydroxides (CoxNi1−x LDHs), which both Co(OH)2 and Ni(OH)2 exhibit, has been successfully synthesized by a chemical co-precipitation route using polyethylene glycol as the structure-directing reagent. Structural and morphological characterizations were performed using powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The component and thermal stability of the sample were measured by energy dispersed X-ray spectrometry (EDS), FT-IR and thermal analyses, including thermogravimetry (TG) and differential thermal analysis (DTA). Cyclic voltammogram and galvanostatic charge–discharge testified that the CoxNi1−x LDH has a specific capacitance of 1809 F g−1 at a current density of 1 A g−1 and remains at about 90.2% of the initial value after 1000 cycles at a current density of 10 A g−1. The relationship between the chemical composition and the capacitance is discussed.