Synergistic effect of carbon nanotube and encapsulated carbon layer enabling high-performance SnS₂-based anode for lithium storage

Tin disulfide (SnS₂), due to large interlayer spacing and high theoretical capacity, is regarded as a prospective anode material for lithium-ion batteries. Nevertheless, the poor electron conductivity of SnS₂ and huge volumetric change during the lithiation/delithiation process lead to a rapid capacity decay of the battery, hindering its commercialization. To address these issues, herein, SnS₂ is in-situ grown on the surface of carbon nanotubes (CNT) and then encapsulated with a layer of porous amorphous carbon (CNT/SnS₂@C) by simple solvothermal and further carbonization treatment. The synergistic effect of CNT and porous carbon layer not only enhances the electrical conductivity of SnS₂ but also limits the huge volumetric change to avoid the pulverization and detachment of SnS₂. Density functional theory calculations show that CNT/SnS₂@C has high Li⁺ adsorption and lithium storage capacity achieving high reaction kinetics. Consequently, cells with the CNT/SnS₂@C anode exhibit a high lithium storage capacity of 837 mAh/g after 100 cycles at 0.1 A/g and retaining a capacity of 529.8 mAh/g under 1.0 A/g after 1000 cycles. This study provides a fundamental understanding of the electrochemical processes and beneficial guidance to design high-performance SnS₂-based anodes for LIBs.