Premium
Mesoporous Carbon Nanofibers Embedded with MoS 2 Nanocrystals for Extraordinary Li‐Ion Storage
Author(s) -
Hu Shan,
Chen Wen,
Uchaker Evan,
Zhou Jing,
Cao Guozhong
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503356
Subject(s) - materials science , nanofiber , mesoporous material , carbon nanofiber , crystallinity , electrospinning , chemical engineering , specific surface area , nanocrystal , nanotechnology , composite material , carbon nanotube , catalysis , chemistry , polymer , organic chemistry , engineering
MoS 2 nanocrystals embedded in mesoporous carbon nanofibers are synthesized through an electrospinning process followed by calcination. The resultant nanofibers are 100–150 nm in diameter and constructed from MoS 2 nanocrystals with a lateral diameter of around 7 nm with specific surface areas of 135.9 m 2 g −1 . The MoS 2 @C nanofibers are treated at 450 °C in H 2 and comparison samples annealed at 800 °C in N 2 . The heat treatments are designed to achieve good crystallinity and desired mesoporous microstructure, resulting in enhanced electrochemical performance. The small amount of oxygen in the nanofibers annealed in H 2 contributes to obtaining a lower internal resistance, and thus, improving the conductivity. The results show that the nanofibers obtained at 450 °C in H 2 deliver an extraordinary capacity of 1022 mA h g −1 and improved cyclic stability, with only 2.3 % capacity loss after 165 cycles at a current density of 100 mA g −1 , as well as an outstanding rate capability. The greatly improved kinetics and cycling stability of the mesoporous MoS 2 @C nanofibers can be attributed to the crosslinked conductive carbon nanofibers, the large specific surface area, the good crystallinity of MoS 2 , and the robust mesoporous microstructure. The resulting nanofiber electrodes, with short mass‐ and charge‐transport pathways, improved electrical conductivity, and large contact area exposed to electrolyte, permitting fast diffusional flux of Li ions, explains the improved kinetics of the interfacial charge‐transfer reaction and the diffusivity of the MoS 2 @C mesoporous nanofibers. It is believed that the integration of MoS 2 nanocrystals and mesoporous carbon nanofibers may have a synergistic effect, giving a promising anode, and widening the applicability range into high performance and mass production in the Li‐ion battery market.