Test of reaction kinetics using both differential scanning and accelerating rate calorimetries as applied to the reaction of LixCoO2 in non-aqueous electrolyte
Dd. Macneil et Jr. Dahn, Test of reaction kinetics using both differential scanning and accelerating rate calorimetries as applied to the reaction of LixCoO2 in non-aqueous electrolyte, J PHYS CH A, 105(18), 2001, pp. 4430-4439
Extracting reliable reaction kinetics from nonisothermal calorimetric resul
ts can be difficult. The reaction model, activation energy, and frequency f
actor make up a "kinetic triplet" for a particular reaction and define the
reaction kinetics. One expects a good correlation between data and the pred
ictions of the reaction model for a variety of experiments, provided the re
action tripler has been well determined. Such a correlation is expected for
the results of accelerating rate calorimeter (ARC) and differential scanni
ng calorimeter (DSC) experiments. As an example, the reaction of LixCoO2 in
nonaqueous electrolyte (as is important in Li-ion battery safety) has been
studied with both DSC and ARC. Comparing the shape of ARC profiles to thos
e predicted theoretically limits the choice of reaction model. The activati
on energy is determined from the shift of the DSC profile with heating rate
or from the change in the initial self-heating rate of ARC samples as a fu
nction of temperature. The frequency factor is then chosen to give the corr
ect DSC peak temperature and correct self-heating rate. Calculated DSC and
ARC curves fit experiment well for several related reaction models.