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

Abstract

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 beneficia...