Hollow Carbon Nanofibers Filled with MnO2 Nanosheets as Efficient Sulfur Hosts for Lithium-Sulfur Batteries

• Published in: Angewandte Chemie (International ed.) Vol. 54; no. 44; pp. 12886 - 12890
• Main Authors: Li, Zhen, Zhang, Jintao, Lou, Xiong Wen (David)
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.10.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Batteries; Carbon fibers; carbon nanofibers; Cathodes; Dissolution; Electrochemistry; Electrodes; Energy storage; Entrapment; Flux density; Lithium; Lithium sulfur batteries; Manganese dioxide; Nanofibers; Nanosheets; Polysulfides; Redox reactions; Specific capacity; Storage batteries; Storage systems; Sulfur; Sulfur content; electrochemistry; lithium-sulfur batteries; carbon nanofibers; manganese dioxide; nanosheets
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201506972

Lithium–sulfur batteries have been investigated as promising electrochemical‐energy storage systems owing to their high theoretical energy density. Sulfur‐based cathodes must not only be highly conductive to enhance the utilization of sulfur, but also effectively confine polysulfides to mitigate their dissolution. A new physical and chemical entrapment strategy is based on a highly efficient sulfur host, namely hollow carbon nanofibers (HCFs) filled with MnO2 nanosheets. Benefiting from both the HCFs and birnessite‐type MnO2 nanosheets, the MnO2@HCF hybrid host not only facilitates electron and ion transfer during the redox reactions, but also efficiently prevents polysulfide dissolution. With a high sulfur content of 71 wt % in the composite and an areal sulfur mass loading of 3.5 mg cm−2 in the electrode, the MnO2@HCF/S electrode delivered a specific capacity of 1161 mAh g−1 (4.1 mAh cm−2) at 0.05 C and maintained a stable cycling performance at 0.5 C over 300 cycles. Keep the sulfur: Hollow carbon nanofibers filled with MnO2 nanosheets (MnO2@HCF) were synthesized and shown to be a suitable sulfur host for lithium–sulfur batteries. As the polysulfides are physically entrapped by the carbon shells and chemically bound by the MnO2 nanosheets, this nanocomposite sulfur cathode displayed excellent specific/areal capacities and a good cycling stability.