Graphite Fluoride Prepared at Mild Temperature for High Energy/High Power Density Lithium Batteries
作者:
R. Yazami,
P. Hany,
P. Masset,
A. Hamwi,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 1998)
卷期:
Volume 310,
issue 1
页码: 397-402
ISSN:1058-725X
年代: 1998
DOI:10.1080/10587259808045368
出版商: Taylor & Francis Group
关键词: Carbon fluoride;lithium batteries;high rate capability
数据来源: Taylor
摘要:
We used a two-step fluorination of natural or synthetic graphites, the one at the ambient temperature in the presence of F2+ IF5+ HF and the second in the temperature range of 100 – 350°C in F2atmosphere. This led to graphite fluorides characterized by the planarity of the carbon hexagons (sp2hybridization), by the iono-covalent character of the C-F bondings and by the high F/C ratio, close to unity. These graphite fluorides were compared to conventional, highly covalent CFx(sp3hybridization) in their electrochemical performances in lithium batteries, especially regarding the high rate discharge capability. We found a large advantage with the iono-covalent CFxthat is they sustain a 5 C rate discharge where the covalent ones failed to discharge under 4 C. The difference is tentatively related to the internal structure and to the higher electrical conductivity of iono-covalent CFx.
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