In this study, a boron-doped microporous carbon (BMC)/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries. The cell with this cathode exhibits an ultrahigh cycling stability and rate capability. After activation, a capacity of 749.5 mAh/g was obtained on the 54th cycle at a discharge current of 3.2 A/g. After 500 cycles, capacity of 561.8 mAh/g remained (74.96% retention), with only a very small average capacity decay of 0.056%. The excellent reversibility and stability of the novel sulfur cathode can be attributed to the ability of the boron-doped microporous carbon host to both physically confine polysulfides and chemically bind these species on the host surface. Theoretical calculations confirm that boron-doped carbon is capable of significantly stronger interactions with the polysulfide species than undoped carbon, most likely as a result of the lower electronegativity of boron. We believe that this doping strategy can be extended to other metal-air batteries and fuel cells, and that it has promising potential for many different applications.
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机译：在这项研究中，硼掺杂的微孔碳（BMC）/硫纳米复合材料被合成，并用作先进的Li-S电池的新型阴极材料。具有此阴极的电池具有超高的循环稳定性和倍率性能。活化后，在第54次循环中以3.2A / g的放电电流获得749.5mAh / g的容量。在500次循环后，仍保留561.8 mAh / g的容量（保留74.96％），而平均容量衰减仅为0.056％，很小。新型硫阴极的优异可逆性和稳定性可归因于掺硼的微孔碳主体既能物理限制多硫化物，又能将这些物质化学结合在主体表面上。理论计算结果证实，掺杂硼的碳与未硫化碳相比，与多硫化物的相互作用更强，这很可能是由于硼的负电性较低。我们认为，这种掺杂策略可以扩展到其他金属空气电池和燃料电池，并且在许多不同的应用中都具有广阔的前景。
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