A MOLECULAR DYAMICS STUDY OF OXIDATION- AND REDUCTION-INDUCED SOLVENT DECOMPOSITION REACTIONS IN MODEL BATTERY ELECTROLYTES

摘要

The choice of solvent/anion/additive mixtures in developing high performing electrolytes has important implications in the nature and formation of the resulting degradation products generated by Li- based cells employing linear and cyclic carbonate based electrolyte mixtures. The degradation mechanism for carbonate based electrolytes mixed with fluorinated Li salts was found to be initiated by lithium methoxide. Insight into the electrolyte decomposition reaction pathways taking place at the electrolyte and passivation layer interface is gained from studying the mechanism of gas evolution in lithium-ion batteries through storage tests and tests on initial charging, where several gas species have been detected (CO2, CO, H2, C2H4, and C2H6. The gas-evolution behavior upon initial charge showed that C2H4 was exclusively formed from EC, while C2H6 derived from DEC. EC and nonsolvent components were found to be the source of CO emission.