Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g−1); however, its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Here we report a facile in situ method for preparing three-dimensional porous graphitic carbon composites containing sulfur nanoparticles (3D S@PGC). With this strategy, the sulfur content of the composites can be tuned to a high level (up to 90 wt%). Because of the high sulfur content, the nanoscale distribution of the sulfur particles, and the covalent bonding between the sulfur and the PGC, the developed 3D S@PGC cathodes exhibit excellent performance, with a high sulfur utilization, high specific capacity (1,382, 1,242 and 1,115 mA h g−1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C) and excellent rate capability at a high charge/discharge current.
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机译：硫由于其理论容量高（1,675 mA h g -1 ）而成为锂-硫电池的有希望的正极材料。但是，其低电导率和硫基电极的不稳定性限制了其实际应用。在这里，我们报告了一种简便的原位制备含硫纳米粒子（3DS @ PGC）的三维多孔石墨碳复合材料的方法。通过这种策略，可以将复合材料的硫含量调整到很高的水平（最高90 wt％）。由于高硫含量，硫颗粒的纳米级分布以及硫与PGC之间的共价键，已开发的3D S @ PGC阴极表现出优异的性能，具有高硫利用率，高比容（1,382，1,242和分别在0.5、1和2 C时为1,1151mAuph g −1 ），循环寿命长（在2 C下1,000次循环中，每循环0.039％的小容量衰减）和出色的倍率性能高充电/放电电流。
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