Page 516 - Handbook of Battery Materials

16.2 SEI Formation, Chemical Composition, and Morphology 489

Table 16.1 A compilation of specific bimolecular rate con-
stants (k e ) for the reaction of hydrated electrons with Li bat-
tery related materials [59, 60].

◦
Reactant pH Rate constant, k e at 15–25 C
−1
(L mol −1 s )
− 9
AsF 6 7 9 × 10
BF 4 5.8 <2.3 × 10 5
7 7.7 × 10 9
CO 2
2− – <3.9 × 10 6
CO 3
ClO 4 – <10 6
2 10
CrO 4 13 5.4 × 10
H + – 2.5 × 10 10
HF – 6 × 10 7
MnO 4 7 4.4 × 10 10
− – 8.2 × 10 9
NO 3
O 2 7 1.9 × 10 9
− 6.7 7.7 × 10 6
H 2 PO 4
2− 7 <10 6
SO 4
2− 10
S 2 O 8 7 1 × 10
SF 6 7 1.6 × 10 10
Acetone 7 6 × 10 9
Acetonitrile – 4 × 10 7
Acetophenone – 2.4 × 10 10
Acrylamide – 2.2 × 10 10
Acrylate ion 9.2 5.3 × 10 9
Acrylonitrile – 1.3 × 10 10
Carbon disulfide – 3.1 × 10 10
Cyclopentanone – 7.4 × 10 9
Ethyl acrylate 11 8.7 × 10 9
Cyclohexene 11 <10 6
Diethyl ether – <10 7
Dimethyl fumarate 9.2 3.3 × 10 10
Dimethyl oxalate – 2 × 10 10
Ethyl acetate 6.5 5.9 × 10 7
Furan 8 3 × 10 6
Propylene glycol carbonate – 7.2 × 10 7
[CH 2 CH(CH 3 )OCOO]
Naphthalene 11 5.4 × 10 9
Styrene 12.7 1.1 × 10 10
α, α, α-Trifluorotoluene 11 1.8 × 10 9

2− − 2− −
like O 2 ,CrO 4 ,MnO ,and S 2 O 8 are diffusion-controlled. AsF 6 and CO 2 ,
4
which are good SEI precursors [13, 14, 22, 23] have values of k e that approach
those for diffusion-controlled reactions. There is good correlation between the SEI
−
composition and the reactivity of electrolyte components toward e . For example,
aq
LiF and As–F–O species are found in the SEI formed in electrolytes containing
LiAsF 6 [7, 20, 24–26]. Also, when CO 2 is added to the electrolyte, more Li 2 CO 3