Wet ball-milling synthesis of high performance sulfur-based composite cathodes: The influences of solvents and ball-milling speed

• Sulfur-carbon nanotubes composites are prepared via wet ball-milling method.
• The influences of solvents and ball-milling speed on the structure are investigated.
• The composite prepared by adding ethanol exhibits greatly enhanced discharge performance.
• High-energy ball milling is not conducive to obtain high electrochemical performance.
• High capacity of 861.6 mAh g-1 at the current density of 800 mA g-1 after 150 cycles is obtained.

Wet ball-milling route is employed to prepare sulfur-carbon nanotubes composites. The influences of solvents, including ethanol and chloroform, on the structure and electrochemical performance of the composites are firstly investigated. As compared to the conventional dry-milling process, high loose structure and uniform distribution of sulfur can be obtained by adding ethanol during the ball-milling process, and significant enhancement of electrochemical performance is presented. At the current density of 800 mA g−1, the discharge capacity can be stably retained at 861.6 mAh g−1 after 150 cycles for the composite prepared by adding ethanol, showing obvious advantages over the dry-milling sample and the composite prepared by adding chloroform. When the current density increase to 1600 mA g−1, it can still demonstrate a high reversible capacity of 640.9 mAh g−1 after 200 cycles. Furthermore, the influence of ball-milling speed is also investigated, but a low utilization of sulfur active materials is obtained after high-energy ball milling process.