中文摘要：

分别以多巴胺和正硅酸乙酯为碳源和硅源,先采用一步法合成出球形C@SiO_2复合材料,然后通过化学刻蚀制得一种表面积达875 m2·g-1、表面富含N原子的中空炭微球（N-HCS）。N-HCS独特的纳米结构可以有效地抑制硫在充放电过程中的体积膨胀和聚硫化物的穿梭效应,同时表面掺杂的氮能够提高活性物质的导电性,进而提高正极材料的循环稳定性和大倍率性能。结果表明,该碳/硫复合材料的在0.2 C电流密度下的首次放电容量达1 179 mAh·g~（-1）;经100次反复充放电后,其放电容量仍可保持在540 mAh·g~（-1）;具有较好的大电流倍率性能,在电流密度为1 C和2 C时,其可逆放电容量可分别稳定在343 mAh·g~（-1）和247 mAh·g~（-1）。

英文摘要：

SiO2 @ C nanospheres were fabricated by polymerization of dopamine in the presence of tetraethyl orthosilicate followedby carbonization and the SiO2 was chemically etched away to obtain hollow N-doped carbon nanospheres （N-CNs） to host sulfur. The resulting material （S@ N-CNs） was used as the cathode material of a Li-S battery. Results indicate that the S@ N-CNs can ef-fectively suppress the volume expansion of sulfur and the shuttle effect of polysulfides during charge and discharge. Nitrogen doping improves the electrical conductivity of the N-CNs. The initial reversible capacity of the S @ N-CN electrode at 0.2 C is 1 179 mAh＊g-1, which remains at 540 mAh＊g-1 after 100 cycles. The electrode has excellent rate capability （343 mAh＊g-1 at 1 C and 247 mAh.g-1 at 2 C）.