TY - JOUR
T1 - Stability of lithium superoxide LiO2 in the gas phase
T2 - Computational study of dimerization and disproportionation reactions
AU - Bryantsev, Vyacheslav S.
AU - Blanco, Mario
AU - Faglioni, Francesco
PY - 2010/8/12
Y1 - 2010/8/12
N2 - Knowledge of the precise molecular mechanisms during the discharge and recharge processes in the lithium-air battery is critical for achieving desired improvements in specific capacity, current density, and cyclability. The initial oxygen reduction product formed in the presence of Li+ ions is lithium superoxide LiO2. In this study, we report the computed structures and thermodynamic parameters of LiO2 dimerization in the gas phase, which enables us to provide a baseline for the reaction free energy profile of the subsequent disproportionation of (LiO2)2 to lithium peroxide Li2O2 and O2. Our calculations identified several low-lying (LiO2)2 dimers, with the singlet bipyramidal structure giving IR bands that are consistent with the characteristic IR vibration frequencies of (LiO2)2 in the oxygen matrix at T = 15-40 K. The activation barrier for (LiO 2)2 = Li2O2+O2 is 10.9 kcal/mol at the UCCSD(T)/CBS level (T = 298 K), suggesting that in the gas phase LiO2 and its aggregates could only be observed at low temperatures.
AB - Knowledge of the precise molecular mechanisms during the discharge and recharge processes in the lithium-air battery is critical for achieving desired improvements in specific capacity, current density, and cyclability. The initial oxygen reduction product formed in the presence of Li+ ions is lithium superoxide LiO2. In this study, we report the computed structures and thermodynamic parameters of LiO2 dimerization in the gas phase, which enables us to provide a baseline for the reaction free energy profile of the subsequent disproportionation of (LiO2)2 to lithium peroxide Li2O2 and O2. Our calculations identified several low-lying (LiO2)2 dimers, with the singlet bipyramidal structure giving IR bands that are consistent with the characteristic IR vibration frequencies of (LiO2)2 in the oxygen matrix at T = 15-40 K. The activation barrier for (LiO 2)2 = Li2O2+O2 is 10.9 kcal/mol at the UCCSD(T)/CBS level (T = 298 K), suggesting that in the gas phase LiO2 and its aggregates could only be observed at low temperatures.
UR - http://www.scopus.com/inward/record.url?scp=77955683390&partnerID=8YFLogxK
U2 - 10.1021/jp1047584
DO - 10.1021/jp1047584
M3 - Article
AN - SCOPUS:77955683390
SN - 1089-5639
VL - 114
SP - 8165
EP - 8169
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 31
ER -