Electrochemical behavior of carbon-coated SnS2 for use as the anode in lithium-ion batteries

Carbon-coated SnS₂ nanoparticles were prepared by a simple solvothermal route at low temperature. A carbon coating with a thickness of about 5 nm was deposited on nano-sized SnS₂ particles to serve as the anode in lithium-ion batteries. Both the nanostructure and the morphology of the SnS₂ powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The coated samples were used as active anode materials for lithium-ion batteries, and their electrochemical properties were examined by constant current charge-discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. The reversible capacity of the carbon-coated SnS₂ after 50 cycles was 668 mAh/g, which was much higher than that of the uncoated SnS₂ (293 mAh/g). The carbon-coated SnS₂ also had a better rate capability than the uncoated SnS₂ in the range of 0.008-1 C. The capacity retention of the carbon-coated SnS₂ was improved due to its good conductivity and the effective buffer matrix that alleviated volume expansion during the charge-discharge process.