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Uniform Decoration of Vanadium Oxide Nanocrystals on Reduced Graphene‐Oxide Balls by an Aerosol Process for Lithium‐Ion Battery Cathode Material
Author(s) -
Choi Seung Ho,
Kang Yun Chan
Publication year - 2014
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.201400134
Subject(s) - graphene , materials science , oxide , composite number , faraday efficiency , thermogravimetric analysis , chemical engineering , graphene oxide paper , lithium (medication) , vanadium , composite material , electrochemistry , nanotechnology , electrode , metallurgy , chemistry , engineering , medicine , endocrinology
VO 2 ‐decorated reduced graphene balls were prepared by a one‐pot spray‐pyrolysis process from a colloidal spray solution of well‐dispersed graphene oxide and ammonium vanadate. The graphene–VO 2 composite powders prepared directly by spray pyrolysis had poor electrochemical properties. Therefore, the graphene–VO 2 composite powders were transformed into a reduced graphene ball (RGB)–V 2 O 5 (RGB) composite by post‐treatment at 300 °C in an air atmosphere. The TEM and dot‐mapping images showed a uniform distribution of V and C components, originating from V 2 O 5 and graphene, consisting the composite. The graphene content of the RGB–V 2 O 5 composite, measured by thermogravimetric analysis, was approximately 5 wt %. The initial discharge and charge capacities of RGB–V 2 O 5 composite were 282 and 280 mA h g −1 , respectively, and the corresponding Coulombic efficiency was approximately 100 %. On the other hand, the initial discharge and charge capacities of macroporous V 2 O 5 powders were 205 and 221 mA h g −1 , respectively, and the corresponding Coulombic efficiency was approximately 93 %. The RGB–V 2 O 5 composite showed a better rate performance than the macroporous V 2 O 5 powders.