Sodium metal has gain recent attention as a high capacity anode material for sodium rechargeable battery because of its abundance as well as high energy density with low-working potential. Unfortunately, low Coulombic efficiency and dendrite formation of sodium metal anode during cycling are key hurdles to be utilized for practical application. In this work, we have investigated the electrochemical properties of sodium metal interphase with highly concentrated Na⁺-conductive inorganic electrolyte by various analytical techniques and electrochemical measurements. We found the morphological stability of sodium metal anode with NaAlCl₄-2SO₂ inorganic electrolyte, forming dendrite-free polygonal sodium deposition. By adopting a highly stable electrolyte for sodium metal, the electrochemical characteristics of sodium metal anode showed significant improvement compared to the conventional Na ion conducting organic electrolyte, encouraging the development of room-temperature sodium metal-based rechargeable batteries. More details of electrochemical performance of sodium metal anode will be discussed on this presentation.