Synthesis of dinickel phosphide (Ni2P) for fast lithium-ion transportation: a new class of nanowires with exceptionally improved electrochemical performance as a negative electrode

Abstract

Single-crystalline dinickel phosphide (Ni₂P) nanowires with a uniform diameter of about 8 nm and lengths of 100–200 nm were synthesized from the thermal decomposition of continuously delivered Ni-TOP complexes using a syringe pump. These Ni₂P nanowires deliver specific reversible capacities of 434 mA h g⁻¹ at 0.1 C, 326 mA h g⁻¹ at 0.5 C after 50 cycles, and also exhibit good rate performance. The improved electrochemical performance is attributed to the small size and stable cylindrical structure, which result in a high interfacial contact area with the electrolyte, and relieve the strain or accommodate volume expansion/contraction of these Ni₂P nanowires. Electrochemical impedance spectra confirms that these Ni₂P nanowires possess enhanced electrical conductivity, which facilitates the lithium ion and electron transportation in the electrode.