تهيه ماده فعال كاتدي باتري ليتيم گوگرد براساس نانوساختارهاي كربني

Lithium-sulfur batteries are a promising alternative to lithium-ion batteries due to their high theoretical energy density an‎d low-cost active cathode materials. However, the shuttle phenomenon is considered one of the major challenges in the commercialization of these batteries. The shuttle effect leads to a reduction in practical capacity, Coulombic efficiency, an‎d poor cycle life in these batteries. Therefore, the use of rational design of cathode an‎d interlayer materials to improve the electrical conductivity of sulfur an‎d prevent the excessive leaching of polysulfides is crucial. In this study, to overcome the challenges facing lithium-sulfur batteries, a variety of materials such as activated carbon (AC), porous g-C3N4, hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2), boron carbide (B4C), an‎d graphite were used as cathode an‎d interlayer materials. First, sulfur was uniformly dispersed in the structure of activated carbon using an advanced melt-diffusion method, an‎d this composite was used as a stable base for the fabrication of various batteries. Characterization techniques such as thermogravimetric analysis, X-ray diffraction, an‎d field-emission scanning electron microscopy (FESEM) were employed to confirm the proper mixing of sulfur an‎d activated carbon. Furthermore, by simply coating graphite on the separator an‎d molybdenum disulfide on the cathode material as interlayer materials, the performance of the batteries was improved. The use of graphite as an anode interlayer material was also investigated. In this regard, a battery with a sulfur/activated carbon cathode an‎d a graphite separator exhibited a specific capacity of 795.5 mAh g−1 in the first cycle an‎d 540.2 mAh g−1 after 20 charge-discharge cycles. Additionally, the use of porous g-C3N4, synthesized from melamine an‎d cyanuric acid as nitrogen an‎d carbon sources, as a cathode material along with sulfur an‎d activated carbon, resulted in a specific capacity of 1034 mAh g−1 in the second discharge cycle, demonstrating the positive effect of this material. Finally, other synthesized materials such as molybdenum disulfide, boron carbide, an‎d boron nitride were also eva‎luated an‎d compared with each other. The results of this study indicate that the rational design of cathode an‎d interlayer materials can significantly improve the performance of lithium-sulfur batteries an‎d largely overcome the commercialization barriers of these batteries.

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