It was found that qCPA all approaches significantly improves

It was found that qCPA (all approaches) significantly improves the prediction of binary VLE and the correlation of LLE between CO2+n-alkane mixtures. A significantly smaller interaction parameter is needed to correlate the experimental data with qCPA compared to the CPA approaches. When it comes to CO2+associating mixtures very good correlations were obtained with qCPA when solvation was taken into account using the approach suggested by Kleiner and Sadowski [77] and a single small binary interaction parameter. The model was finally applied to two quadrupolar-quadrupolar mixtures, which illustrated that the model seem to have difficulties for quadrupolar mixtures of opposite sign such as CO2+acetylene. Overall explicitly accounting for the quadrupolar forces appears to offer significantly improved predictions, and better (smaller k) correlations, for CO2 containing mixtures compared to the two other CPA approaches. The performance of the qCPA approaches is similar with regards to the derivative properties of CO2 and for mixtures of CO2+self-associating compounds. For CO2+n-alkanes the four-parameter versions of qCPA both perform somewhat better than the three-parameter version. Nevertheless this modest improvement may not justify the increased model flexibility and uncertainty in the parameter estimation. Unless the primary focus is binary CO2+n-alkane mixtures the most promising approach is thus considered to be qCPA with three adjustable parameters.
Acknowledgements The authors gratefully acknowledge the Danish Research Council for Independent Research for funding this work as part of the project; ‘CO2 Hydrates – Challenges and Possibilities’.
Introduction Lithium-ion battery materials are still considered to be the most promising 6-Bnz-cAMP sodium salt converter/charger due to their excellent electrochemical parameters, and their industrial applications especially for power electronic devices are extremely important [1,2,3,4,5]. Moreover, outstanding commercial success of Li-ion cathode materials based on lithium cobaltate (LiCoO2) caused that they became materials for personal use, which in turn demands more efficient functional parameters such as high energy density, long life-cycle, light-weight and safety. In recent years, in order to have a deeper insight into electrochemical properties of Li-ion battery cathode materials, theoretical investigations based on DFT electronic band structure calculations have been undertaken in systematic way [6,7,8,9,10,11]. For instance, the impact of electronic structure features on the discharge curve in the series of compounds as AMO2 (A = Li, Na; M = Mn, Co, Ni, Fe) and their solid solutions, have been recently notified based on detailed experimental and theoretical investigations [11,13,14]. Also, the step-like vs. continuous-like character of the discharge curve have been interpreted in terms of correlations between electronic structure and electrochemical properties in selected Li- and Na-ion cathode materials, respectively. Quite recently, it was found that substitution of Ni by lower cost and more accessible elements such as Co and Mn in LiNiCoMnO2 cathode material, improved its electrochemical properties, namely crystal stability, initial capacity and life cycle [15,16,17,18]. The fact that experimentally investigated Li-ion battery materials commonly contain 3d transition metal elements (M = Mn, Fe, Co, Ni) directs attention to their possible magnetic properties. More precisely one can ask about local magnetic moments appearance in such materials and how magnetism can be affected when Li concentration changes.