Improving Na|NaSICON solid electrolyte interfaces by powder aerosol deposited interlayers

Titelangaben

Sozak, Mutlucan ; Wiedemann, Kim Bennet ; Hämmerle, Martin ; Kalyk, Fariza ; Vargas-Barbosa, Nella M. ; Bianchini, Matteo ; Moos, Ralf:
Improving Na|NaSICON solid electrolyte interfaces by powder aerosol deposited interlayers.
2026
Veranstaltung: Advanced Battery Power 2026 , 14th - 16th April 2026 , Münster, Germany.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Poster )

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Abstract

Solid-state sodium batteries (SSSBs) are promising candidates for next-generation energy storage because they enable the direct use of high-capacity sodium metal anodes while eliminating flammable liquid electrolytes. Beyond enhanced safety, SSSBs benefit from the cost-effective and abundant raw materials of sodium compared to lithium-ion systems, making them particularly attractive for large-scale energy storage. Among solid electrolytes, the NaSICON-type material Na₃Zr₂Si₂PO₁₂ (NZSP) exhibits high room-temperature ionic conductivity and good chemical stability. However, practical implementation is limited by high interfacial resistance and poor cycling stability at the Na|NZSP interface. In this work, CuO was investigated as a conversion-type interlayer to stabilize and homogenize sodium plating and stripping at the Na|NZSP interface. Dense, well-adhering CuO films were deposited on NZSP substrates using powder aerosol deposition (PAD), a binder- and solvent-free technique that enables the fabrication of thin to thick ceramic coatings directly from powders at room temperature. Electrochemical impedance spectroscopy and critical current density measurements were employed to evaluate the interfacial properties and electrochemical performance. The introduction of CuO interlayers substantially reduced interfacial resistance and enabled higher critical current densities compared to bare NZSP. Additional thermal post-treatment of the CuO layers further lowered interfacial resistance and significantly improved long-term cycling stability. These improvements are attributed to the formation of a porous, ionically and electronically conductive Cu/Na₂O interphase, which facilitates uniform sodium plating and stripping while mitigating contact loss during cycling. Overall, these results demonstrate that CuO is a highly promising interlayer material for enhancing the Na|NZSP interface in SSSBs, enabling more stable and efficient sodium metal cycling. Furthermore, this study highlights PAD as a versatile and effective room-temperature approach for fabricating functional interlayers on solid electrolyte interfaces.