We have proposed SnS2 as promising Li-ion battery anode materials in our previous study. Nanoparticles of this material were synthesized by a sonochemical method. In this work, smaller SnS2 particles were obtained by diluting the starting solution of the synthesis, and particles of 30nm were observed in the Field Emission SEM (FE-SEM) images. From such SnS2 particles, higher discharge capacity of 620mAh/g and suppressed electrode degradation were observed in charge–discharge experiments. This indicates that the enlargement of the surface area was effective in facilitating the Li-ion diffusion through the active material, in simplifying the electrochemical reaction and in restraining the stress within the electrode, caused during charge and discharge. The discharge capacity in the 30th cycle was improved from 319 to 404mAh/g by annealing the sample. It is suggested that this may be due to the change in its structure.