미래를 창조하는 포스텍 화학공학과
High concentration liquid electrolytes, such as water-in-salt electrolytes and ionic liquids, as well as solid state polymer electrolytes are rapidly emerging materials to replace the flammable organic electrolytes widely used in industrial lithium ion batteries. Molecular dynamics (MD) simulation of these systems is challenging due to a number of reasons, including lack of predictive force fields, complex polarization effects occurring both in electrolytes and on electrodes, highly correlated ion motion due to high concentration and strong electrostatic interactions, to name a few.
In this talk, I’ll present our ongoing efforts to enable predictive molecular simulations of these highly charged systems. Two major advances will be highlighted – the development of predictive multi-scale force field for ILs and polymers based entirely on first-principle calculations, and the development of simulation algorithms to treat surface polarization and proper thermal equilibrium in polarizable MD simulations. New physical insights gained from the new simulation model and simulation algorithms will be discussed, which includes polarization effects on the ion adsorption at air/water and water/electrode interfaces, ion correlation in organic electrolytes, formation of ionic liquid crystals, as well as conformational dynamics in IL-polymer mixtures.
Another important study investigates the molecular response to the internal charge transfer events occurring in a trans-membrane protein, representing complex interfacial systems abundant in biology. I’ll cover both the development of new simulation methods and the applications of the methods toward energy storage materials and biomolecular systems, illustrating the versatile utility of understanding the underlying physics for fundamental questions.