Electronic structure of the electrode/electrolyte interface: Large-scale tight-binding quantum chemical simulation

Recently, we have succeeded in the development of new tight-binding quantum chemical molecular dynamics code "Colors", based on our original tight-binding theory. It realizes 5000 times acceleration compared to the conventional first-principles molecular dynamics method and enables us to simulate huge simulation models. Hence, in the present study we applied our new tight-binding quantum chemical molecular dynamics method to the investigation of the electronic structure of the interface of the Li_0.5CoO ₂ electrode and the ethylene carbonate (EC) electrolyte along with LiPF₆. Our electronic structure calculations for the Li _0.5CoO₂/EC+LiPF₆ interface suggest that the EC+LiPF₆ electrolyte significantly stabilizes the instability of the Li_0.5CoO₂ surface. Moreover, the detailed analyses for the electronic structure of the electrode/electrolyte interface were also performed. These analyses cannot be realized by the conventional first-principles approach, since it requests huge computational time for such large and complicated system. Hence, we confirmed the effectiveness of our tight-binding quantum chemical molecular dynamics approach to the investigation of the electrode/electrolyte interface on electronic- and atomic-level.