  Fundamental understanding of the reactivity between coating material of
Li-ion battery cathode and electrolyte is important in order to obtain suitable
coating candidates. Herein, we study ethylene carbonate (EC) adsorption and
decomposition reactions on pristine, O vacancy- and Zn vacancy-defected ZnO
(10-10) by means of first-principles density functional theory (DFT)
calculations. Possible decomposition pathways via H-abstraction and EC
ring-opening reaction that leads to the generation of CO2 and C2H4 gases are
studied from the thermodynamic and kinetic aspects. Firstly, we find that
molecular EC preferably adsorbs on both pristine and defective ZnO (1010) via
the bonding between its carbonyl oxygen (OC) and surface Zn. Secondly,
subsequent decomposition reactions show large tendency of EC to decompose on
both pristine and defective ZnO (10-10). This tendency is indicated by the
large thermodynamic driving forces to decompose EC that range from -1.5 eV to
-2.5 eV on both pristine and defective ZnO (10-10) (calculated with respect to
EC gas phase). The large tendency of EC to decompose, however, is hindered by
the high activation barriers of the EC decomposition, shown by the lowest
activation barrier of 0.96 eV on Zn vacancy defected ZnO (10-10). Our results
thus indicate that EC decomposition on ZnO (10-10) is mainly hindered due to
its slow rate of decomposition instead of the thermodynamic factors.
