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3D MoS 2 –Graphene Microspheres Consisting of Multiple Nanospheres with Superior Sodium Ion Storage Properties
Author(s) -
Choi Seung Ho,
Ko You Na,
Lee JungKul,
Kang Yun Chan
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201402428
Subject(s) - materials science , graphene , anode , composite number , stacking , faraday efficiency , current density , chemical engineering , ion , nanotechnology , composite material , electrode , organic chemistry , chemistry , physics , quantum mechanics , engineering
A novel anode material for sodium‐ion batteries consisting of 3D graphene microspheres divided into several tens of uniform nanospheres coated with few‐layered MoS 2 by a one‐pot spray pyrolysis process is prepared. The first discharge/charge capacities of the composite microspheres are 797 and 573 mA h g −1 at a current density of 0.2 A g −1 . The 600th discharge capacity of the composite microspheres at a current density of 1.5 A g −1 is 322 mA h g −1 . The Coulombic efficiency during the 600 cycles is as high as 99.98%. The outstanding Na ion storage properties of the 3D MoS 2 –graphene composite microspheres may be attributed to the reduced stacking of the MoS 2 layers and to the 3D structure of the porous graphene microspheres. The reduced stacking of the MoS 2 layers relaxes the strain and lowers the barrier for Na + insertion. The empty nanospheres of the graphene offer voids for volume expansion and pathways for fast electron transfer during repeated cycling.