Homogeneous precipitation of α-phase Co-Ni hydroxides hexagonal platelets

【摘要】：This paper describes the synthesis of -phase Co-Ni hydroxides hexagonal platelets through homo- geneous precipitation, using hexamethylenetetramine (HMT) or urea as a hydrolytic agent. In the CoCl 2 -NiCl 2 -HMT system, pure α-phase can be synthesized at the concentrations of both metal ions higher than 20 mM, while in the CoCl 2 -NiCl 2 -urea system, the formation of pure α-phase is independent of the concentrations of the metal ions. When using HMT, monodisperse hexagonal platelets of α-phase Co-Ni hydroxides can be produced in the presence of polyvinylpyrrolidone (PVP). Cyclic voltammogram curve of the hexagonal platelets prepared with HMT demonstrates electrochemical performance superior to that of urea.