Engineering and understanding SnS0.5Se0.5@N/S/Se triple-doped carbon nanofibers for enhanced sodium-ion batteries

Tin-based chalcogenides have attracted tremendous attention as an anode material for sodium storage owing to their unique structure and high theoretical capacity. Unfortunately, the large volume change and poor conductivity lead to sluggish reaction kinetics and poor cycling performance. Herein, SnS0.5Se0.5 nanoparticles coupled with N/S/Se triple-doped carbon nanofibers (SnS0.5Se0.5@NSSe-C) are designed and synthesized through electrospinning and annealing process. Benefiting from the synergistic effects of SnS0.5Se0.5 and NSSe-C, the SnS0.5Se0.5@NSSe-C nanofibers exhibit a high reversible capacity and ultralong cycle life at higher current density for sodium-ion batteries. Furthermore, the sodium storage mechanism and electrochemical reaction kinetics of the SnS0.5Se0.5@NSSe-C composite are characterized by the in-situ measurements. The theoretical calculations further reveal the structural advantages of SnS0.5Se0.5@NSSe-C composite, which exhibits a high adsorption energy of Na+. This work can provide a novel idea for the synthesis of ternary tin-based chalcogenides and is beneficial for the investigation of their reaction kinetics.