A scalable sulfuration of WS2 to improve cyclability and capability of lithium-ion batteries

Two-dimensional transition-metal dichalcogenides (WS 2 and SnS 2 ) have recently joined the family of energy storage materials (for lithium-ion batteries and supercapacitors) as a result of their favorable ion intercalation. So far, challenges in the synthesis of phase-pure WS 2 , restacking between WS 2 nanosheets, low electronic conductivity, and the brittle nature of WS 2 , severely limit its use Li-ion battery application. Herein, we develop a facile low temperature solution sulfuration process to improve battery performance dramatically. The sulfuration process is demonstrated to be effective in converting WO 3 impurities to WS 2 , and in repairing the sulfur vacancies, to improve cyclability and rate capability. Lithium-ion battery measurements demonstrate that the stable capacity of the WS 2 anode could be enhanced by 48.4% via sulfuration reprocessing, i.e., from 381.7 to 566.8 mAh/g at a relatively high current density of 0.8 A/g after 50 cycles. We further show that the sulfuration process can be readily extended to other dichalcogenides, and may provide a class of versatile electrode materials for lithium-ion batteries with improved electrochemical characteristics.