Synthesis and Electrochemical Properties of Hierarchical Porous (Nickel/Cobalt)‐Carbonate‐Hydroxide Structures

Abstract

AbstractHierarchical porous Ni3(CO3)(OH)4 and (NixCo1‐x)6(CO3)2(OH)8 ⋅ H2O (x=0, 1/3, 1/2, and 2/3) structures have been synthesized via a hydrothermal route. The chloride ions in the precursor play an important role in the morphology of (Ni,Co)6(CO3)2(OH)8 ⋅ H2O. The formation mechanism and growth process of urchin‐like (Ni,Co)6(CO3)2(OH)8 ⋅ H2O structure was investigated by adjusting the reaction time. The electrochemical properties of the products depend on the chemical composition and surface property. Ni3(CO3)(OH)4 exhibits higher specific capacitance at a low current density due to its porous structure and larger specific surface area. However, its rate property and cycle stability are much poorer. Co6(CO3)2(OH)8 ⋅ H2O nanorod‐assembled structure possesses better cyclic performance but lower specific capacitance. (Ni,Co)6(CO3)2(OH)8 ⋅ H2O electrodes behave improved rate property and cycle stability in comparison with Ni3(CO3)(OH)4, and higher specific capacitance than Co6(CO3)2(OH)8 ⋅ H2O, which can be attributed to the synergistic effect of bimetal species and unique surface property.