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Gas analysis of Li O2 cells with Vulcan Carbon and ATO based cathodes

To compare and validate the novel coupled Baratron/OEMS system, the first measurement is performed with Li-O2 cells containing Vulcan Carbon cathodes. During the discharge in the O2 atmosphere (upper panel left side until SOC #1), the O2 pressure measured by Baratron decreases linearly (middle panel left side). In the subsequent charge under the Ar atmosphere, an almost linear increase of the O2 signal (m/z = 32) can be determined by OEMS. The continuous consumption and evolution of O2 correspond well to the observed voltage plateaus during discharge and charge. Oxygen evolution ceases as the potential rises above 4.5 V toward the end of the charge, and a significant amount of CO2 is detected (see SOC #2 in the upper panel). The voltage plateau around 4.7 V after completion of the charging process is attributed to electrolyte decomposition, accompanied by the formation of H2. The gas consumption and evolution measurements by a pressure transducer and OEMS are used to calculate current-normalized gas evolution rates. This allows us to distinguish between the cell's different reduction and oxidation processes. Taking Faraday's constant (96485 As/mol), an oxygen consumption/evolution rate of 5.18 μmol/(As) corresponds to the formation/decomposition of Li2O2 in a two-electron process. Similarly, an oxygen consumption/evolution rate of 2.59 μmol/(As) equals a four-electron process such as the formation/decomposition of Li2O or Li2CO3: The latter can be distinguished by an additional consumption/release of CO2, whereby consumed CO2 does not have to be present in the gas phase but rather originates from the simultaneous oxidation of the electrolyte and the carbon support. If you are looking for high quality, high purity, and cost-effective ATO, or if you require the latest price of ATO, please feel free to email contact mis-asia.

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