Anchoring SnS₂ on TiC/C Backbone to Promote Sodium Ion Storage by Phosphate Ion Doping

Tin disulfide (SnS₂) shows promising properties toward sodium ion storage with high capacity, but its cycle life and high rate capability are still undermined as a result of poor reaction kinetics and unstable structure. In this work, phosphate ion (PO₄³⁻)-doped SnS₂ (P-SnS₂) nanoflake arrays on conductive TiC/C backbone are reported to form high-quality P-SnS₂@TiC/C arrays via a hydrothermal–chemical vapor deposition method. By virtue of the synergistic effect between PO₄³⁻ doping and conductive network of TiC/C arrays, enhanced electronic conductivity and enlarged interlayer spacing are realized in the designed P-SnS₂@TiC/C arrays. Moreover, the introduced PO₄³⁻ can result in favorable intercalation/deintercalation of Na⁺ and accelerate electrochemical reaction kinetics. Notably, lower bandgap and enhanced electronic conductivity owing to the introduction of PO₄³⁻ are demonstrated by density function theory calculations and UV–visible absorption spectra. In view of these positive factors above, the P-SnS₂@TiC/C electrode delivers a high capacity of 1293.5 mAh g⁻¹ at 0.1 A g⁻¹ and exhibits good rate capability (476.7 mAh g⁻¹ at 5 A g⁻¹), much better than the SnS₂@TiC/C counterpart. This work may trigger new enthusiasm on construction of advanced metal sulfide electrodes for application in rechargeable alkali ion batteries.