Preparation and Properties of Sulfur/Activated Carbon/Carbon Nanotube Composite Cathode Materials for Lithium-Sulfur Batteries

Lithium-sulfur batteries are widely regarded as one of the most promising new types of batteries, and the sulfur-based cathode with high-performance is the key to promoting the success of lithium-sulfur batteries. In this work, the sulfur (S)/activated carbon (AC)/carbon nanotube (CNT) composite cathode materials for lithium-sulfur batteries are prepared by simple mixing and heating fusion. It is observed that the S/AC/CNT composites have obvious structural properties of S and consist of many irregular small-sized particles and some large-sized ellipsoids with rough surfaces. The electrochemical properties of the S/AC/CNT composite cathode are evaluated by matching the lithium metal anode and liquid electrolyte (LE). The cell delivers a high initial discharge capacity of 1077.0 mAh g-1 at 0.1 mA cm-2, and when the current density increases to 0.5 mA cm-2, the cell has a discharge capacity of 712.8 mAh g-1. In addition, the cell can retain the discharge capacities of 437.6 mAh g-1 after 200 cycles and 273.6 mAh g-1 after 500 cycles at 0.5 mA cm-2, showing good cycling stability. This work provides promising S/AC/CNT composite cathode materials with high capacity and good electrochemical stability for lithium-sulfur batteries.