This new battery type—an initially anode-free sodium-ion battery—is a leading candidate for powering future electric vehicles or storing energy in the electrical grid. Typically, batteries are made up of two electrodes—an anode (negative side) and a cathode (positive side)—as well as a liquid electrolyte. Conversely, when an electrolyte contains multiple solvent molecules, controlling their interactions and behavior is challenging. "In this way, the electrolyte mixture would ideally behave like an anode-stable solvent at the anode, and like a cathode-stable solvent at the cathode." They used all-atom molecular dynamics simulations to predict the composition of solvent molecules near sodium ions and determine whether those ions "preferred" one solvent over the other.