The present invention provides a solid-state sodium-based secondary cell (or rechargeable battery). While the secondary cell can include any suitable component, in some cases, the secondary cell comprises a solid sodium metal negative electrode that is disposed in a non-aqueous negative electrolyte solution that includes an ionic liquid. Additionally, the cell comprises a positive electrode that is disposed in a positive electrolyte solution. In order to separate the negative electrode and the negative electrolyte solution from the positive electrolyte solution, the cell includes a sodium ion conductive electrolyte membrane. Because the cell's negative electrode is in a solid state as the cell functions, the cell may operate at room temperature. Additionally, where the negative electrolyte solution contains the ionic liquid, the ionic liquid may impede dendrite formation on the surface of the negative electrode as the cell is recharged and sodium ions are reduced onto the negative electrode.