All-Solid-State Sodium Batteries with a Polyethylene Glycol Diacrylate–Na3Zr2Si2PO12 Composite Electrolyte

Abstract

A novel sodium-ion conducting polymer–ceramic solid-state composite electrolyte is developed for ambient-temperature sodium batteries. Polyethylene glycol diacrylate (PEGDA) is used as a polymeric matrix into which ceramic nanoparticles of NASICON-type Na3Zr2Si2PO12 are integrated. The PEGDA polymeric phase of the composite can maintain an amiable ionic interface between the solid-state electrolyte and electrodes. The Na3Zr2Si2PO12 ceramic phase not only enhances the sodium-ion conductivity of the composite but also can suppress the Na dendrites from penetrating through the electrolyte membrane. To optimize the Na+-ion conductivity, a succinonitrile (SCN) plasticizer is also incorporated. The composite solid electrolyte membranes are fabricated with an ultraviolet (UV) curing process. Through proper management of the composition, the PEGDA-SCN-Na3Zr2Si2PO12-NaClO4 composite solid electrolyte delivers an ionic conductivity of 4.5 × 10−4 S cm−1 at room temperature. All-solid-state Na cells with the PEGDA-SCN-NaClO4-Na3Zr2Si2PO12 composite electrolyte are fabricated by coupling a Na2MnFe(CN)6 positive electrode to a Na-metal negative electrode. The resulting Na ‖ PEGDA-SCN-NaClO4-Na3Zr2Si2PO12 ‖ Na2MnFe(CN)6 cells show remarkable cycling stability.