CoS2/N-Doped Hollow Spheres as an Anode Material for High-Performance Sodium-Ion Batteries

In this work, we first synthesized polyacrylic acid (PAA) spheres and then used PAA as a template to load Co(OH)(2) particles onto its surface. The product of CoS2 nanoparticles dispersed in N-doped hollow spheres (N-HCS) was prepared through sulfurization treatment (CoS2/S@N-HCS). During the sulfuration process, sulfur penetrates into the PAA, embedding into the graphite layer along with the carbonization process. It was found that during the charging and discharging process, the sulfur in the carbon layer will gradually dissolve out, thereby forming new ion diffusion channels in the carbon spheres and exposing more CoS2 active sites. The CoS2/S@N-HCS composite exhibits a specific capacity of 729.6 mAh g(-1) after 500 cycles at a current density of 1 A g(-1). The sodium-storage mechanism and reaction kinetics of the materials were further measured by in-situ electrochemical impedance spectroscopy, ex-situ X-ray diffraction, capacitance performance evaluation, and galvanostatic intermittent titration technique. The excellent cycling performance and rate capability demonstrated that the CoS2/S@N-HCS is a potential and prospective anode material for sodium-ion batteries.

Automated summary

The CoS2/S@N-HCS composite material prepared in the study exhibits excellent cycling performance and rate capability in sodium-ion batteries, making it a potential anode material.