Synthesis and Characterization of Ni2P@CoP3 Core-Shell Nanospheres for Supercapacitors

Ni nanospheres and Ni@ Co(OH)(2) nano-urchin-spheres precursor were successively fabricated with hydrothermal technique, and then the latter were changed into NiO@CoO by high temperature calcination process, and Ni2P@CoP3 core - shell nanospheres were finally obtained using sodium hypophoshpite as raw material by high temperature phosphating process. The morphologies, structures and compositions of the as-obtained products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), X-ray powder diffractometer (XRD), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). At the same time, the electrochemical performance of the electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and cycling stability experiments. The results showed that as-obtained Ni2P@CoP3 core-shell nanospheres with diameter of similar to 400 nm were composed of hexagonal Ni2P nanocore and cubic CoP3 nanoshell. Compared with pure Ni2P or CoP3 nanospheres, Ni2P@CoP3 core-shell nanospheres are more conducive to the mass transfer of electrolyte and promote the pseudo capacitive reaction because of its synergistic effect of composite structure, which shows higher specific capacity, stability and longer cycle life.