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.