Tunable Electrochemical Properties Brought About by Partial Cation Exchange in Hydrotalcite-Like Ni-Co/Co-Ni Hydroxide Nanosheets

Layered bimetal (Ni-Co/Co-Ni) hydroxide nanosheets with tunable chemical composition could be successfully constructed through a one-step partial cation exchange method by immersing Ni(OH)(2)/Co(OH)(2) in aqueous solution of the related cobalt/nickel nitrate directly under moderate conditions. XRD, SEM, EDS, HRTEM, ICP, TGA, elemental analysis, FT-IR, and UV-vis analysis were used to identify the structure and composition of such as-prepared Ni-Co/Co-Ni hydroxide nanosheets. Enormous variants from nanostructured Ni(OH)(2)/Co(OH)(2) could be achieved through a simple progress of one-step cation exchange. The electrochemical tests show that the as-prepared nanoscale products not only perform a larger number of exchangeable electrons (1.6e) than that of the materials with approximately the same central metal composition, which were synthesized by conventional coprecipitation method, but also exhibit lower peak oxidation potential and better reversibility. These excellent electrochemical properties could be beneficial for high-energy and high-rate power application. Moreover, the results of systemic cyclic voltammogram investigations of composition-tunable layered bimetal (Ni-Co) hydroxide nanosheets display that the trend of negative shifts of anodic current peak positions is consistent with the decrease in Ni-s/Co-s ratios. However, there exists a range of metal ratios for keeping the electrochemical properties. Importantly, the change and maintenance of electrochemical properties with the change of metal ratios of products could provide a new way of tuning and controlling property-aimed products. In addition, this simple method can be used as an effective tool to construct nanostructures with different compositions to optimize various properties.