Room-Temperature Solid-State Sodium∕Sulfur Battery

Solid-state sodium∕sulfur batteries using polyvinylidene-fluoride-hexafluoropropene (PVDF) polymer electrolyte were prepared and tested at room temperature. Solid sodium∕sulfur batteries may be composed of solid-composite-type sulfur electrodes, sodium metal electrodes, and PVDF gel polymer electrolyte. The PVDF gel polymer electrolyte with tetraglyme plasticizer and salt had a high sodium ion conductivity of at . During the first discharge, the sodium∕sulfur battery showed two plateau potentials of 2.27 and , respectively. The first discharge capacity was sulfur at room temperature, which was similar to the high temperature battery. The discharge capacity drastically decreased by repeated charge-discharge cycling, and remained at after .