3D substrate self-sacrifice Ni2P integrated anode for high-performance sodium-ion battery

Abstract

Carbon-coated 3D self-growing Ni2P were prepared on the foamed nickel substrate by hydrothermal activation combined with carbonization and phosphating strategy. The crystal structure and elemental composition of the samples were obtained by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the microscopic morphology and crystallographic information of the materials were obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that uniform carbon-coated Ni2P was successfully self-grown on the smooth three-dimensional nickel foam substrate. Meanwhile, the investigation results of energy storage capacity show that the synthesized anode material exhibits excellent sodium storage specific capacity and rate performance. After more than 100 cycles of galvanostatic charge and discharge at a current density of 100 mA.g−1, as-synthesized material still maintains a reversible specific capacity of over 300 mAh.g−1. In addition, the pseudocapacitive behavior of the electrode was judged by kinetic calculation, and then the contribution rate of the pseudocapacitive behavior to the charge storage was calculated. Apparent activation energy, sodium ion diffusion coefficient and diffusion apparent activation energy were used to analyze the rapid reaction kinetics of materials with diffusion-controlled battery behavior.