Facile Fabrication of Isomorphicnico(Co3)(Oh)2-Co(Co3)0.5(Oh)Nanowires and Flexible Aecc for High-Performance Supercapacitors

Nickel-cobalt carbonate hydroxides have been widely used as battery-type electrode materials. However, in contrast to batteries, these materials' electrochemical performance still need to be improved. Previous studies have shown that one- dimensional (1D) nanowire has the advantages of large effective specific surface area, short and efficient ion/electron transport pathway, highly exposed electrochemical active sites and structural stability. Hence, the electrochemical properties of basic nickel-cobalt carbonate can be improved by constructing 1D nanowire structures. A facile two-step hydrothermal strategy was used to synthesize isomorphic NiCo(CO 3 )(OH) 2 -Co(CO 3 ) 0.5 (OH) nanowires (NCCH-CCH) on the nickel foam. The electrochemical performances of the synthesized electrodes were tested with a three-electrode system. Impressively, the obtained composite electrode performs a large specific capacity of 937 C g -1 at 1 A g -1 (1.550 C cm -2 at 1 mA cm -2 ), and retains 87.5% capacity after 5000 cycles at 20 A g -1 . Additionally, employing acid-etched carbon cloth (AECC) as the negative electrode, a NiCo(CO 3 )(OH) 2 -Co(CO 3 ) 0.5 (OH) //AECC hybrid supercapacitor (HSC) is assembled, which delivers a high energy density of 156.7 μWh cm -2 at 0.8 mW cm -2 , and exceptional cycling stability (92.4% of capacitance retention after 5000 cycles). Moreover, the change in pH value at various stages of the reaction was used to roughly analyse the cause of two-step hydrothermal products' disparate morphologies in this study.