Conformal carbon coating on WS₂ nanotubes for excellent electrochemical performance of lithium-ion batteries

WS₂ nanotubes with carbon coatings in a core-shell structure (i.e. WS₂@C) are synthesized through a facile method based on the Lewis acid-activated thioglycosylation chemistry. The obtained WS₂@C shows a conformal coverage of conductive amorphous carbon on the surface of WS₂ after thermal treatment, with the thickness of carbon layer being controlled by adjusting the molar ratios of saccharide to nanotube during the synthesis process. When applied in lithium-ion batteries, the WS₂@C structures show higher reversible capacity of 638 mAh g^-1 at a current density of 500 mA g^-1 and significantly improved cycling stability as compared to the pristine WS₂ nanotubes. Post-mortem examinations of the electrode materials reveal that the carbon coatings could preserve the morphology of WS₂ nanotubes and assist in forming stable solid electrolyte interface layers, leading to enhanced cycling stability. As such, the WS₂@C structures show great potential in the application of lithium-ion batteries for achieving excellent electrochemical performances.