Studies on 3D printing of Na3Zr2Si2PO12 ceramic solid electrolyte through Fused Filament Fabrication

Solid-state batteries are considered being the next step in battery technology to achieve higher energy densities and potentially safer batteries. As there is no organic liquid, the risk of flammability is drastically reduced. Nevertheless, there are numerous challenges associated with the realization of all-solid-state batteries, such as improving slow kinetics, contact interface issues between battery components and cell integration among others. 3D printing holds the potential to address these issues as it  allows to improve kinetics by structuring the battery components and the possibility of a customized cell integration. A structured surface of the electrolyte can in principle also enhance interface effects with the metal electrode. To contribute in this regard, composite filaments with Na3Zr2Si2PO12 were fabricated and 3D printed. Subsequent sintering of the printed parts after removal of the polymer components led to the required densification of the fully ceramic electrolyte. The parts were microstructurally and electrochemically characterized and showed a reasonable performance with an ionic conductivity of (3.02 ± 0.14) · 10-4 S·cm-1 at 20 °C. Critical current density testing revealed stable cycling up to 200 mA·cm-2, with cell failure occurring at a current density of 750 mA·cm-2, demonstrating the application potential of 3D printed full ceramic solid electrolytes.