Lithium-sulfur batteries have attracted increasing attention because of their high theoretical capadty. Using sulfur/carbon composites as the cathode materials has been demonstrated as an effective strategy to optimiz...Lithium-sulfur batteries have attracted increasing attention because of their high theoretical capadty. Using sulfur/carbon composites as the cathode materials has been demonstrated as an effective strategy to optimize sulfur utilization and enhance cycle stability as well. In this work hollow-in-hollow carbon spheres with hollow foam-like cores （HCSF@C） are prepared to improve both capability and cycling stability of lithium-sulfur batteries. With high surface area and large pore volumes, the loading of sulfur in HCSF@C reaches up to 70 wt.%. In the resulting S/HCSF@C composites, the outer carbon shell serves as an effective protection layer to trap the soluble polysulfide intermediates derived from the inner component. Consequently, the S/HCSF@C cathode retains a high capacity of 780 mAh/g after 300 cycles at a high charge/discharge rate of 1 A/g.展开更多
为了满足储能市场对高功率电池的需求,开发具有高功率性能的锂离子电池负极材料成为必然发展趋势。本文通过湿式合成法将软碳和硬碳的前驱体进行复合,开发了一种新型的复合碳锂离子电池负极材料。考察了其克比容量、库仑效率、倍率性能...为了满足储能市场对高功率电池的需求,开发具有高功率性能的锂离子电池负极材料成为必然发展趋势。本文通过湿式合成法将软碳和硬碳的前驱体进行复合,开发了一种新型的复合碳锂离子电池负极材料。考察了其克比容量、库仑效率、倍率性能以及循环稳定性。用X射线粉末衍射(XRD)、拉曼、扫描电镜(SEM)以及透射电子显微镜(TEM)对所制备的复合碳材料的结构和表面形貌进行表征。结果表明,该复合碳材料同时具有软碳和硬碳的优点,且性能优于机械混合碳,在保持高比容量和高效率的前提下,倍率性能尤为突出,其2C容量可达154 m A·h/g,且2C/0.2C的容量保持率为64.2%;同时0.2C克比容量为240 m A·h/g,库仑效率为82%。经过5C充放电后,恢复0.2C小电流充放电后,容量保持率达99.8%,循环稳定性很好。XRD、拉曼以及透射电子显微镜的表征结果均表明软、硬碳在复合过程中不只是简单机械共混而是具有协同效应。展开更多
基金We thank the National Basic Research Program of China （Nos. 2011CB932403 and 2015CB932300） and the National Natural Science Foundation of China （Nos. 21301144, 21390390, 21131005, 21333008, and 21420102001） for financial support.
文摘Lithium-sulfur batteries have attracted increasing attention because of their high theoretical capadty. Using sulfur/carbon composites as the cathode materials has been demonstrated as an effective strategy to optimize sulfur utilization and enhance cycle stability as well. In this work hollow-in-hollow carbon spheres with hollow foam-like cores （HCSF@C） are prepared to improve both capability and cycling stability of lithium-sulfur batteries. With high surface area and large pore volumes, the loading of sulfur in HCSF@C reaches up to 70 wt.%. In the resulting S/HCSF@C composites, the outer carbon shell serves as an effective protection layer to trap the soluble polysulfide intermediates derived from the inner component. Consequently, the S/HCSF@C cathode retains a high capacity of 780 mAh/g after 300 cycles at a high charge/discharge rate of 1 A/g.
文摘为了满足储能市场对高功率电池的需求,开发具有高功率性能的锂离子电池负极材料成为必然发展趋势。本文通过湿式合成法将软碳和硬碳的前驱体进行复合,开发了一种新型的复合碳锂离子电池负极材料。考察了其克比容量、库仑效率、倍率性能以及循环稳定性。用X射线粉末衍射(XRD)、拉曼、扫描电镜(SEM)以及透射电子显微镜(TEM)对所制备的复合碳材料的结构和表面形貌进行表征。结果表明,该复合碳材料同时具有软碳和硬碳的优点,且性能优于机械混合碳,在保持高比容量和高效率的前提下,倍率性能尤为突出,其2C容量可达154 m A·h/g,且2C/0.2C的容量保持率为64.2%;同时0.2C克比容量为240 m A·h/g,库仑效率为82%。经过5C充放电后,恢复0.2C小电流充放电后,容量保持率达99.8%,循环稳定性很好。XRD、拉曼以及透射电子显微镜的表征结果均表明软、硬碳在复合过程中不只是简单机械共混而是具有协同效应。
