D. Aurbach et al., A COMPARATIVE-STUDY OF SYNTHETIC GRAPHITE AND LI ELECTRODES IN ELECTROLYTE-SOLUTIONS BASED ON ETHYLENE CARBONATE DIMETHYL CARBONATE MIXTURES, Journal of the Electrochemical Society, 143(12), 1996, pp. 3809-3820
This work entails a comparative study of both Li and synthetic graphit
e electrodes in electrolyte solutions based on ethylene and dimethyl c
arbonates (EC-DMC) and the impact of the salt used [from the LiAsF6, L
iClO4, LiPF6, LiBF4, and LiN(SO2CF3)(2) list]. The presence of some ad
ditives in solutions (e.g., Li2CO3, CO2, tributylamine) and the effect
of the particle size of the carbon on the electrode's behavior were i
nvestigated. The correlation between the surface chemistry, the morpho
logy, and the performance of Li and graphite electrodes was explored u
sing surface sensitive Fourier transform infrared and x-ray and photoe
lectron spectroscopies, impedance spectroscopy, x-ray diffraction and
scanning electron microscopy in conjunction with standard electrochemi
cal techniques. Synthetic graphite anodes could be cycled (Li intercal
ation-deintercalation) hundreds of times at a capacity close to the op
timal (x --> 1 in LixC6) in EC-DMC solutions due to the formation of h
ighly stable and passivating surface films in which EC reduction produ
cts such as (CH2OCO2Li)(2) are the major constituents. The cycling eff
iciency of Li metal anodes in these solutions, however, is lower than
that obtained in ethereal solutions and seems to be too low for Li-met
al liquid electrolyte, rechargeable battery application. The connectio
n between the solution composition and the electrode's performance is
discussed.