In the quest for high-energy-density lithium-ion batteries (LIBs), tin-based chalcogenides (SnX, where X = S, Se, Te) have emerged as promising anode materials due to their high theoretical capacity and unique structural features. However, a long-overlooked puzzle has persisted in that while SnS and SnSe share the same orthorhombic layered structure, SnTe crystallizes in a cubic phase, challenging the conventional assumption that all SnX compounds share the same structure.
Now, researchers have systematically investigated this structural divergence and its electrochemical consequences. Using a combination of high-energy ball-milling synthesis, advanced characterization, and first-principles calculations, the team demonstrated that the structural transition originates from atomic-level mismatches. The large differences in atomic radius and electronegativity between S/Se and Sn induce severe lattice distortion and bond breaking, forcing SnS and SnSe into an orthorhombic phase. In contrast, Te shares similar physicochemical properties with Sn, allowing SnTe to retain a cubic structure akin to metallic Sn.
This cubic architecture endows SnTe with remarkable advantages: metallic-level conductivity (3.31×10³ S m⁻¹), high tap density (6.48 g cm⁻³), and faster lithium-ion diffusivity. As an anode for LIBs, SnTe delivered outstanding cyclability (698 mAh g⁻¹ after 200 cycles) and rate performance (236 mAh g⁻¹ at 10 A g⁻¹). Moreover, its high pseudocapacitive contribution (up to 94%) enabled the fabrication of an AC//SnTe lithium-ion capacitor, achieving an energy density of 114 Wh kg⁻¹, a power density of 7000 W kg⁻¹, and exceptional longevity (92.7% retention after 8000 cycles).
This work not only resolves a fundamental structural mystery but also provides a clear roadmap for designing high-performance electrode materials through phase engineering. The work titled “Unveiling the Structural Transition and Electrochemical Evolution of Tin-based Chalcogenides for Advanced Lithium Storage” was published in Advanced Powder Materials (Available online on 4 March 2026).
DOI：10.1016/j.apmate.2026.100413