Corresponding Author

Qing-chi XU(xuqingchi@xmu.edu.cn);
Jian-feng LI(li@xmu.edu.cn)


With the increasing demand for large-scale energy storage, great progress has been made in discovering new advanced energy storage materials. Sodium-ion batteries (SIBs) have attracted much attention in recent years due to their use of abundant sodium resources and their comparable electrochemical capacity to lithium-ion batteries (LIBs). In this paper, we developed novel hollow core-shell Ni-Co bimetallic phosphide nanocubes with N-doped carbon coatings (Ni1.2Co0.8P@N-C) as the anode material for SIBs. The material was synthesized through a low-temperature phosphorization method using resorcinol formaldehyde (RF) resin coating with a Ni-Co Prussian blue analogue (PBA) as a template and a subsequent thermal annealing process. The size of the as-obtained nanocubes was about 310 nm with a 19 nm N-doped carbon shell. When used as the anode material of SIBs, Ni1.2Co0.8P@N-C exhibited the excellent electrochemical cycling stability and demonstrated an especially high coulombic efficiency of 99.3%, even after 200 cycles with current density of 100 mA·g-1. Furthermore, in-situ Raman spectroscopy was used to investigate the electrode material in order to understand the electrochemical processes in the N-doped carbon shell of Ni1.2Co0.8P@N-C. The results showed that the intercalation and de-intercalation behavior of sodium ions in the N-doped carbon shell was almost reversible, providing valuable information about the charge and discharge processes in SIBs for the follow-up electrochemical studies.

Graphical Abstract


sodium-ion batteries, anode material, bimetallic phosphide, hollow core-shell structure, N-doped carbon, Raman spectroscopy

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