An asymmetric bilayer polymer-ceramic solid electrolyte for high-performance sodium metal batteries

Manufacturing an excellent solid electrolyte compatible with a high-voltage cathode is viewed as a critical tactic for improving the energy density of solid-state sodium-ion batteries (SSIBs). A novel asymmetric bilayer solid electrolyte of the PEO-SN-NaClO4|NZSP-NSO with an anti-reduction PEO-SN-NaClO4 layer close to the Na side is constructed by solution casting. The ionic conductivity is enhanced by using succinonitrile (SN) in polyethylene oxide (PEO) polymer electrolyte. The anti-oxidation layer of Na3Zr2Si2PO12 with Na2SiO3 (NZSP-NSO) is served as the support of the membrane on the cathode, which could improve the interface compatibility and electrochemical performance of SSIBs. The asymmetric bilayer solid electrolyte simultaneously features a wide electrochemical stability window (4.65 V vs. Na+/Na) and a high conductivity (2.68 x 10-4 S cm-1). Furthermore, the solid electrolyte demonstrates stable Na plating/stripping over 700 h and remarkably improves cycling stability in Na/Na3V2(PO4)3 batteries with an ultra-high capacity retention of 99.6% after 100 cycles at 50 degrees C and 0.5 C. This study provides an effective strategy for designing asymmetric high sodium ion conductivity solid-state electrolytes for high-performance SSIBs. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Manufacturing an excellent solid electrolyte compatible with a high-voltage cathode is crucial for improving the energy density of solid-state sodium-ion batteries (SSIBs). A novel asymmetric bilayer solid electrolyte has been developed with a wide electrochemical stability window and high conductivity, providing an effective strategy for designing high-performance SSIBs.