Finite-bias molecular dynamics simulations of water at the electrified graphene surface

A fundamental understanding of the electrified electrochemical interfaces in atomic scale holds critical implications for the development of advanced energy storage and conversion devices. For this purpose, first-principles characterizations based on the approach combining density functional theory (DFT) and non-equilibrium Green’s function (NEGF) have been utilized with much successes. However, due to the requirement of semi-infinite electrodes, the DFT-NEGF approach so far could not be adopted to graphene-based electrified electrochemical interface models. In this presentation, taking the advantage of the multi-space constrained-search DFT (MS-DFT) formalism [1-3] that can handle the electrified two-dimensional electrodes, we firstly investigate the non-equilibrium energetics of water clusters connected through hydrogen bond network on the electrified graphene electrode surface. Next, by carrying out non-equilibrium molecular dynamics (MD) simulations based on MS-DFT, we study the bias-dependent configurations of few-layer water on the electrified graphene interfaces. Drastic difference between the interfacial water properties on graphene electrode with those on normal metal electrodes will be revealed.

[1] J. Lee et al. Proc. Natl. Acad. Sci. U.S.A., 117, 10142 (2020)

[2] J. Lee et al. Adv. Sci., 7, 2001038 (2020)

[3] T.H. Kim et al., Npj Comput. Mater. 8, 50 (2022)