The practical application of lithium-sulfur batteries with a high energy density has been plagued by the poor cycling stability of the sulfur cathode, which is a result of the insulating nature of sulfur and the dissolution of polysulfides. Much work has been done to construct nanostructured or doped carbon as a porous or polar host for promising sulfur cathodes, although restricting the polysulfide shuttle effect by improving the redox reaction kinetics is more attractive. Herein, we present a well-designed strategy by introducing graphitic carbon nitride (g-C₃N₄) into a three-dimensional hierarchical porous graphene assembly to achieve a synergistic combination of confinement and catalyzation of polysulfides. The porous g-C₃N₄ nanosheets in situ formed inside the graphene network afford a highly accessible surface to catalyze the transformation of polysulfides, and the hierarchical porous graphene-assembled carbon can function as a conductive network and provide appropriate space for g-C₃N₄ catalysis in the sulfur cathode. Thus, this hybrid can effectively improve sulfur utilization and block the dissolution of polysulfides, achieving excellent cycling performance for sulfur cathodes in lithium-sulfur batteries.

中文翻译：

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gC 3 N 4在石墨烯网络中催化长寿命锂硫电池的多硫化物转化

具有高能量密度的锂硫电池的实际应用受到硫阴极的不良循环稳定性的困扰，这是由于硫的绝缘性和多硫化物的溶解导致的。尽管通过改善氧化还原反应动力学来限制多硫化物的穿梭效应更具吸引力，但已经进行了许多工作来构建纳米结构的碳或掺杂的碳作为多孔或极性主体，以用于有希望的硫阴极。在这里，我们提出了一种精心设计的策略，即将石墨化碳氮化物（gC ₃ N ₄）引入三维分层多孔石墨烯组件中，以实现聚硫化物的约束和催化的协同组合。多孔gC ₃ N ₄石墨烯网络内部原位形成的纳米片提供了高度可及的表面，以催化多硫化物的转化，而分层的多孔石墨烯组装碳可以充当导电网络，并为硫阴极中的gC ₃ N ₄催化提供适当的空间。因此，该杂化物可以有效地提高硫利用率并阻止多硫化物的溶解，从而实现锂硫电池中硫阴极的优异循环性能。