Charge/discharge behavior of plasma-fluorinated natural graphites in propylene carbonate-containing solvent
Abstract
Plasma-fluorination of natural graphite samples with average particle sizes of 5 μm, 10 μm and 15 μm (NG5μm, NG10μm and NG15μm) was performed using CF 4 and charge/discharge characteristics of surface-fluorinated samples were investigated in 1 mol dm -3 LiClO 4-ethylene carbonate (EC)/diethyl carbonate (DEC)/propylene carbonate (PC) (1:1:1, v/v/v). Fluorine contents obtained by elemental analysis were in the range of 0.3-0.6 at.% and surface fluorine concentrations determined by X-ray photoelectron microscopy (XPS) were 14.8-17.3 at.%. Plasma-fluorination increased surface disorder of natural graphite samples though reduced surface areas due to its surface etching effect. Electrochemical decomposition of PC was highly reduced on surface-fluorinated NG10μm and NG15μm with high disorder. First coulombic efficiencies of plasma-fluorinated NG10μm and NG15μm increased by 9.7 and 19.3% at 150 mA g -1, respectively.
- Publication:
-
Journal of Power Sources
- Pub Date:
- 2007
- DOI:
- 10.1016/j.jpowsour.2007.06.008
- Bibcode:
- 2007JPS...171..932A
- Keywords:
-
- Plasma-fluorination;
- Surface modification;
- Graphite anode;
- Lithium ion battery