Crafting high-performance polymer-integrated solid electrolyte for solid state sodium ion batteries

The development of modern solid-state batteries with high energy density has provided the reliable and durable solution needed for over-the-air network connectivity devices. In this study, a NASICON-type Na₃Zr₂Si₂PO₁₂ (NZSP) ceramic filler was prepared using the sol-gel method and then a polymer-integrated solid electrolyte consisting of polyethylene oxide (PEO), NZSP, and sodium perborate (SPB) was prepared by Stokes' solution casting process. Through physico-chemical and electrochemical characterization techniques, the morphology, electrochemical, and thermal properties of the prepared solid electrolyte sample were carefully studied. The PEO/NZSP/SPB electrolyte developed for all-solid-state sodium-ion batteries (ASSSBs) exhibited a strong ionic conductivity, a large window for electrochemical stability, and was effective in controlling the growth of sodium dendrites. Furthermore, the polymer-integrated solid electrolyte showed impressive rate capability, high discharge capacity (73.2 mAh g⁻¹) at 0.1 mA cm⁻², and good faradaic efficiency (98%) even after 100 cycles. These results reveal that the PEO/NZSP/SPB electrolyte is a potential and inevitable candidate for the evolution of high-performance rechargeable ASSSBs.