Carbon materials such as graphene, nanotubes and even aromatic compounds1-3
are being widely considered as active electrode materials in Li-ion batteries owing to their light weight and low cost. The functionalization of carbon appears to be the key to enabling faradaic electrochemical activity. We are investigating the possibility of bromine-functionalized carbon materials as redox active with Li ions. We have shown that carbon functionalized with oxygen groups can undergo redox reaction with Li at a range of potentials, including some that are sufficiently high for such structures to be appropriate for use at cathodes.4
Some such structures may also be able to catalyze the oxygen reduction reaction in Li (Li-ORR). Furthermore we are carrying out density functional theory calculations coupled with electrochemical modeling to investigate the redox properties of bromine-functionalized carbon moieties. We find that under-coordinated carbon atoms can form certain stable brominated structures that can undergo redox reaction with Li. Local chemical environments plays an important role in efficient electrochemical reactivity of the carbon structures.5, 6
Our results provides insights at the atomic scale on the functionalizations required for activating carbon for these important electrochemical reactions.
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