Introduction
A lot of researches of sodium/sulfur battery have been performed for last several decades, because it had high theoretical energy density (760Wh/kg) and low material cost[1]. The sodium/sulfur battery could be applied for the electric storage system, electric vehicles and so on[2]. One of severe problems of the sodium/sulfur battery was high operating temperature above 250oC, which could induce the explosion and corrosion because of molten sodium, sulfur and polysulfides. In order to decrease operating temperature, the sodium ion type batteries have been studied[3]. However, the energy densities of the sodium ion batteries were much lower than high temperature sodium/sulfur cell. Recently, lithium/sulfur battery has been studied extensively because of high energy density[4]. However there was no study on the sodium/sulfur battery operated at room temperature. In this study, we constructed the sodium/sulfur cell, which can operate at room temperature using solid sodium, solid sulfur electrode and organic electrolyte. The discharge and cycling properties of sodium sulfur cell were studied.
