RESUMEN
We simulated the discharge process of Li-O2 batteries and the growth of Li2O2 thin films at the mesoscale with a novel kinetic Monte Carlo model, which combined a stochastic description of mass transport and detailed elementary reaction kinetics. The simulation results show that the ordering of the Li2O2 thin film is determined by the interplay between diffusion and reaction kinetics. Due to the fast reaction kinetics on the catalyst, the Li2O2 formed in the presence of catalyst (cat-CNF) shows a low degree of ordering and is more likely to be amorphous. Moreover, the mobility of the LiO2 ion pair, which depends largely on the nature of the electrolyte, also impacts the homogeneity of the compactness of the Li2O2 thin film. These results are of high importance for understanding the role of the catalyst and reaction kinetics in Li-O2 batteries.
RESUMEN
We report a comprehensive multiscale model describing charge processes of Li-O2 batteries. On the basis of a continuum approach, the present model combines mathematical descriptions of mass transport of soluble species (O2, Li+, LiO2) and elementary reaction kinetics, which are assumed to be dependent on the morphology of the Li2O2 formed during discharge. The simulated charge curves are in agreement with previously reported experimental studies. The model along with the assumed reaction mechanisms provides physical explanations for the two-step charge profiles. Furthermore, it suggests that these charge profiles depend on the size of the Li2O2 particles, which are determined by the applied current density during discharge. Therefore, the model underlines the strong link between discharge and charge processes.
RESUMEN
The title compound, C(22)H(16)N(2)O(4), was obtained unintentionally as the product of an attempted synthesis of a new phthalocyanine. The dihedral angles formed by the central benzene ring with the aromatic rings of the meth-oxy-phen-oxy groups are 85.39â (5) and 64.19â (5)°.
RESUMEN
In the title compound, C(11)H(12)O(2)S, the C and S atoms of the central thio-phene and the methyl groups, and the two carbonyl groups of the cyclo-hepta-nedione are almost coplanar [maximum deviation from the mean plane = 0.221â (2)â Å]. The packing is stabilized by π-π inter-actions between the conjugated thio-phenes, the shortest centroid-centroid distance between thio-phene rings being 3.9759â (10)â Å.