High performance NASICON ceramic electrolytes produced by tape-casting and low temperature hot-pressing: Towards sustainable all-solid-state sodium batteries operating at room temperature

In this work, we propose a processing methodology, based on the combination of tape-casting and low tem-perature hot-pressing, to develop ceramic NASICON electrolytes with formula Na3.16Zr1.84Y0.16Si2PO12 towards the attainment of solid-state sodium batteries operating at room temperature. Solid-state NASICON electrolytes with very good mechanical properties and high ionic conductivity are successfully tested in terms of electro-chemical behavior by using the cell configuration: Na/NASICON/FePO4. Following charge-discharge cycles, an unusual redox pair of FePO4 is found, indicating that the all-solid-state battery with the Na metal anode may be effectively operated at room temperature. At a charge/discharge current density of C/20, the solid-state battery has an initial reversible discharge capacity of 85 mAh/g. Because of its relatively high ionic conductivity and thermostability, when in contact with the Na anode and the FePO4 cathode, the NASICON ceramic electrolyte is a viable option for attaining reliable, safer and sustainable all-solid-state batteries operating at room temperature.

Automated summary

In this work, a processing methodology combining tape-casting and low temperature hot-pressing is proposed to develop ceramic NASICON electrolytes for solid-state sodium batteries at room temperature. The electrolytes show good mechanical properties and high ionic conductivity, and are successfully tested in a Na/NASICON/FePO4 cell configuration. Charge-discharge cycles reveal an unusual redox pair of FePO4, indicating the effectiveness of the all-solid-state battery with Na metal anode at room temperature. The NASICON ceramic electrolyte is a viable option for reliable and safe all-solid-state batteries, thanks to its high ionic conductivity and thermostability.