To understand such phenomena as ion and electron transfer at the semiconductor-electrolyte interface, it is important to model the atomic and electronic dynamics of the electrode. For many such problems, first-principles techniques are too computationally costly We have developed a self-consistent tight-binding model to address these questions related to the electrode-electrolyte interface. The model has been parameterized by a fit to first-principles results for a bulk oxide. The resulting model has been shown to be useful for describing surface and defect structures. Since our model has been developed to have a computational cost which scales linearly with the number of atoms, simulation of systems with 1000 ore more ions is now within reach. We will discuss application to metal-oxide interfaces.