In situ growth and electrochemical characterization versuslithium of a core/shell-structured Ni2P@C nanocomposite synthesized by a facile organic-phase strategy

Abstract

Nickel phosphide (Ni₂P) hollow spheres were facilely prepared via an organic-phase strategy using nickel(II) acetylacetonate as a metal precursor, trioctylphosphine as a phosphorus source, and octyl ether as solvent. A core/shell-structured Ni₂P@C nanocomposite was grown in situ by employing oleylamine and 1-octadecene as capping agent and solvent, respectively, and the hollow Ni₂P spheres were homogeneously wrapped by an amorphous carbon shell. The reversible capacity of the Ni₂P@C nanocomposite after 50 cycles is 435 mAh g⁻¹ at 0.1 C and 303 mAh g⁻¹ at 0.5 C, respectively, much higher than that of Ni₂P (184.2 mAh g⁻¹ at 0.1 C and 123 mAh g⁻¹ at 0.5 C). These improvements are attributed to the carbon shell, which can enhance the conductivity of Ni₂P, suppress the aggregation of active particles, and increase their structure stability during cycling.