Fabrication of porous carbon materials derived from high sulfur coal for enhanced lithium sulfur batteries performance
Porous carbon materials with superior performance and low-cost have emerged as the preferred sulfur host materials in lithium-sulfur batteries,however,utilizing cheap raw materials to achieve large-scale preparation still faces great challenge.In this study,por-ous carbon materials were synthesized using abundant high sulfur coal as the feedstock and magnesium oxide and potassium hydroxide both as templates and activators.The study delved into the investigation of structure-activity relationship of these materials when employed as sulfur host materials in lithium sulfur batteries.It is observed that mesoporous(constituting 74％)are predominantly generated due to the templating action of MgO.KOH serves as an active agent primarily responsible for the formation of micropores(constituting 72％).The combined use of MgO and KOH leads to the creation of carbon material,PCMgO+KOH,characterized by large specific surface area(1 616 m2/g),high pore volume(1.02 m3/g),and rich pore structure(54％mesoporous and 46％microporous).The results of electro-chemical performance test show that the S@PCMgO+KOH has good rate performance and excellent cycle stability.After 500 cycles of charging ang discharging at 1 C,it can still retain 553.2 mAh/g,with a capacity retention rate of 65.5％and a decay rate of only 0.075％per cy-cle,demonstrating good rate performance and excellent cycling stability.The excellent electrochemical properties of PCMgO+KOH can be at-tributed mainly to its low ohmic resistance and charge transfer resistance,rapid polysulfide redox reaction kinetics,and exceptional capa-bility in binding lithium polysulfide.This study provides an alternative route for the preparation of low-cost and high-performance host ma-terials for lithium-sulfur batteries.
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