Recent
theoretical and experimental studies have shown that the
formation of Li2O2, the main discharge product
of nonaqueous Li–O2 batteries, is a complex multistep
reaction process. The formation, nucleation, and adsorption of Li
x
O
y
(x and y = 0, 1, and 2) and (Li2O2)
n
clusters with n =
1–4 on the surface of carbon nanotubes (CNTs) were investigated
by periodic density functional theory calculation. The results showed
that both Li2O2 and Li2O on CNT electrodes
are preferentially generated by lithiation reaction rather than disproportionation
reaction. The free energy profiles demonstrate that the discharge
potentials of 2.54 and 1.29 V are the threshold values of spontaneous
nucleation of (Li2O2)2 and (Li2O)2 on a CNT surface, respectively. The electronic
structure indicates that Li2O2 is a p-type semiconductor, while Li2O exhibits the
properties of an insulator. Interestingly, once Li2O2 molecules condense into large clusters, they will be repelled
away from the CNT surface and continue to grow into large-sized Li2O2. Our results provide insights into the full
understanding of the electrochemical reaction mechanism and product
formation processes of lithium oxides in the cathodes of Li–O2 batteries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.