One-Step Ball-Milling Synthesis of Ti/SnS/Sn₃S₄/Sn-G Multiphase Heterostructures for Long-Term Stable Sodium-Ion Battery Anodes

Tin monosulfide (SnS) has emerged as a highly promising anode material for sodium-ion batteries (SIBs), owing to its high theoretical specific capacity (≈1022 mAh g –1 ), moderate operating voltage plateau, and abundant natural reserves. However, its practical application is hindered by several intrinsic drawbacks, including poor electrical conductivity, severe volume expansion, and limited cycling stability. To this end, a green and efficient one-step high-energy ball-milling strategy was employed to construct a multicomponent composite structure (Ti/SnS/Sn 3 S 4 /Sn-G) consisting of SnS, Sn 3 S 4, transition metal titanium (Ti), post-transition metal tin (Sn), and graphite (G). This design leverages the combined effects of the components to modulate the electronic structure and interfacial stability, thereby enhancing the overall electrochemical performance. Both theoretical calculations and experimental results confirm that the introduction of Ti not only reinforces the structural integrity of SnS and improves the reversibility of sodium-ion storage via interfacial interactions but also enhances the cycling stability by approximately five times compared to the Ti-free SnS-G counterpart. Meanwhile, the layered structure of graphite offers continuous electron pathways and buffer spaces on the microscale, effectively mitigating volume expansion. Therefore, the Ti/SnS/Sn 3 S 4 /Sn-G electrode exhibits excellent cycling stability, delivering 211.4 mAh g –1 after over 1100 cycles, along with outstanding rate capability, achieving 117.4 mAh g –1 at a high current density of 10 A g –1 . The Ti/SnS/Sn 3 S 4 /Sn-G composite achieves a favorable balance among capacity, rate performance, and structural stability, demonstrating the effectiveness of the multicomponent design strategy in achieving high-performance SIB anodes and providing valuable insights and theoretical guidance for the development of next-generation electrode materials.