Complete encapsulation of sulfur in porous carbon: a key process for high-performance lithium-sulfur batteries
발표자
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초록
내용
Lithium-sulfur batteries rely on the reaction of sulfur to lithium sulfide or vice versa. For the cathode of a lithium-sulfur battery, it is highly required to completely contain sulfur in the porous carbon. This is to minimize the loss of lithium polysulfide due to its high solubility in the electrolyte. However, the relatively low affinity between sulfur and carbon makes it difficult for sulfur to penetrate completely into the porous structure of carbon, so a strategy is needed. As a way to tackle this, we suggest engineering a porous structure. By using a polymer colloid sacrificial template, pores are formed in the spherical CNT assembly, which improves the capillary action. In addition, we introduce the control of the interfacial energy of a solution containing sulfur. This is obtained by adding a solution having high compatibility with carbon to the sulfur-solution. Finally, we present the coating of metal compound nanoparticles with chemical affinity with sulfur on the carbon surface. The complete and uniform encapsulation of sulfur by each of these methods immediately improves the performance of the lithium-sulfur battery; we analyze the influence of the sulfur loading on the electrochemical reaction.