Studies of Ozone-Sensitized Low- and High-Temperature Oxidations of Diethyl Carbonate

Diethyl carbonate (DEC) oxidation with different levels of O-3 addition was performed in an atmospheric laminar flow reactor from 400 to 850 K. Experimental results showed that, without O-3 addition, the oxidation of DEC began from 650 K with no low-temperature reactivity, while with O-3 addition the low-temperature chemistry of DEC was observed from 450 K. A DEC/O-3 kinetic model was developed, and the model predictions agreed with the experimental data reasonably well with a slight overprediction of DEC oxidation between 550 and 750 K. The low-temperature chemistry of DEC with O-3 addition was described in the reaction pathway of DEC. It was found that O-3 assisted the low-temperature oxidation of DEC mainly through the production of the active O: atom instead of the direct reaction with the fuel molecule. The present work indicated that the Li-ion battery degradation at 400-500 K might result from the low-temperature chemistry of DEC with active oxygen supplies from the cathode metal oxide materials or from singlet O-2 during the battery discharge process. This article used O-3 to mimic the oxidizing environment in the Li-ion battery by providing active atomic oxygen. It provided insights into the chemically sensitized gas-phase low-temperature chemistry of DEC and explained the mechanism of battery degradation involving the low-temperature oxidation at the electrolyte solvent and the cathode interface from 400 to 500 K.

Automated summary

Experimental results showed that, with O-3 addition, the low-temperature chemistry of DEC started from 450K, mainly through the production of active O: atom to facilitate the oxidation of DEC.