| 研究実績の概要 |
In this year the extended DFT+U method (DFT+U with additional corrections of interactions between the electrons with opposite spins), formulated in the initial stages of this project has been applied for calculation of redox potentials of several important cathode materials. Important new result is a proposed computational procedure, which allows parameterisation of the extended DFT+U method, providing numerically determined values of a standard U parameter as well as additional U parameter, used for description of interactions between the electrons with opposite spins.
The calculations provided a very good agreement of theoretical values of redox potentials as compared to experimental measurements, fully avoiding fitting to previously found experimental results. It was also demonstrated that the standard method of Lichtenstein et al does not provide improvement in prediction of values of redox voltages, in spite of a formal inclusion of corrections of interactions between the electrons with opposite spins. Moreover, it has been shown that corrections of exchange interactions (setting J parameter) results only in a very minor change of calculated redox potentials.
Additionally, calculations of a full voltage profile of NaMnO2 material has been completed, also in a very good agreement with experiment and without recourse to measured data. Overall, it has been demonstrated that proposed extension of DFT+U method could be used for calculations of redox voltages of a wide range of cathode materials as well as for voltage profile evaluation.
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