Limited Domain SnSb@N-PC Composite Material as a High-Performance Anode for Sodium Ion Batteries

Abstract

Anode materials have a vital influence on the performance of sodium ion batteries. In this paper, SnSb nanoparticles were distributed uniformly in N-doped three-dimensional porous carbon (SnSb@N-PC), which effectively avoided the agglomeration of alloy nanoparticles and greatly improved the capacity retention rate of SnSb@N-PC. At the same time, the porous carbon substrate brings higher conductivity, larger specific surface area, and more sodium storage sites, which makes the material obtain excellent sodium storage properties. The first discharge-specific capacity of SnSb@N-PC was 846.3 mAh g−1 at the current density of 0.1 A g−1, and the specific capacity remained at 483 mAh g−1 after 100 cycles. Meanwhile, the specific capacity of SnSb@N-PC was kept at 323 mAh g−1 after 400 cycles at a high current density of 1.5 A g−1, which indicated that the recombination of SnSb with porous carbon played a key role in the electrochemical performance of SnSb. The contribution of capacitance contrast capacity was able to reach more than 90% by the cyclic voltammetry (CV) test at high sweep speed, and larger Na+ diffusivity was obtained by the constant current intermittent titration technique (GITT) test, which explains the good rate performance of SnSb@N-PC.