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7747313 
Journal Article 
Hydrolysis of Ethylene Carbonate with Water and Hydroxide under Battery Operating Conditions 
Metzger, M; Strehle, B; Solchenbach, S; Gasteiger, HA 
2016 
1 
Journal of Electrochemical Society
ISSN: 0013-4651
EISSN: 1945-7111 
Electrochemical Society Inc. 
PENNINGTON 
163 
7 
A1219-A1225 
English 
WOS:000377412900011 
This study deals with the decomposition of ethylene carbonate (EC) by H2O in the absence and presence of catalytically active hydroxide ions (OH- ) at reaction conditions close to lithium-ion battery operation. We use On-line Electrochemical Mass Spectrometry (OEMS) to quantify the CO2 evolved by these reactions, referred to as H2O-driven and OH-driven EC hydrolysis. By examining both reactions at various temperatures (10 -80°C) and water concentrations (<20 ppm or 200, 1000, and 5000 ppm H2O) with or without catalytically active OH-ions in EC with 1.5 M LiClO4, we determine an Arrhenius relationship between the CO2 evolution rate and the cell temperature. While the apparent activation energy for the base electrolyte (<20 ppm H2O) is very large (app. Ea ≈153 kJ/mol), substantially lower values are obtained in the presence of H2O (app. Ea ≈99 ± 3 kJ/mol), which are even further decreased in the presence of catalytically active OH-(app. Ea ≈43 ± 5 kJ/mol). Our data show that OH--driven EC hydrolysis is relevant already at room temperature, whereas H2O-driven EC hydrolysis (i.e., without catalytically active OH-) is only relevant at elevated temperature (≥40°C), as is the case for the base electrolyte. Thus, catalytic quantities of OH-, e.g., from hydroxide contaminants on the surface of transition metal oxide based active materials, would be expected to lead to considerable CO2 gassing in lithium-ion cells. © 2016 The Electrochemical Society.