Sodium-Sulfur Batteries Enabled by a Protected Inorganic/Organic Hybrid Solid Electrolyte

Sodium-sulfur batteries are promising energy-dense, cost-effective energy storage systems. However, a low-resistance solid electrolyte is necessary to stabilize the sodium anode. While sulfide-based solid electrolytes offer high ionic conductivity, they suffer from chemical reactivity when in contact with sodium metal and are mechanically brittle. This paper implements an in situ cross-linking reaction to embed sodium-ion-conducting sodium thioantimonate in a protective polymer host. The enhanced flexibility enables the formation of a thin but transferable hybrid electrolyte film (30 mu m in thickness, 65 ohm cm(2) room temperature resistance). Owing to the chemical bonding between sodium thioantimonate and the polymer, the hybrid electrolyte maintains a stable interface with sodium when cycling at a current density of 0.5 mA cm(-2). The hybrid solid electrolyte protects the sodium metal from corroding with polysulfide-containing liquid electrolyte and enables the stable operation of a sodium-sulfur battery using a nonencapsulated sulfur cathode for 90 cycles.