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Sodium is a promising candidate for stationary storage applications, especially when the demand for lithium-ion batteries increases due to electromobility applications. Even though its energy density is lower, Na-ion technology is estimated to lead to a cost reduction of 30% compared to Li-ion technology. To improve safety as well as energy density, Na-based all-solid-state-batteries featuring solid electrolytes such as beta-alumina and sodium superionic conductors and cathode materials such as Na₃V₂(PO4)₃ and NaₓCoO₂ have been developed over the past years. However, the biggest challenge are mixed cathodes with highly conductive interfaces, especially when co-sintering the materials. For example, a promising sodium superionic conductor type Na₃Zr₂Si₂PO₁₂ electrolyte sinters at 1,250°C, whereas the corresponding Na₃V₂PO₁₂ cathode decomposes at temperatures higher than 900°C, posing a bottleneck. Thus in this paper, we synthesized Na₀.₆₂ [Ni₀.₁₀Fe₀.₁₀Mn₀.₈₀]O₂ as cathode material for all-solid-state sodium-ion batteries via a relatively cheap and easy solution-assisted solid state reaction processing route. The thermal investigations of the pure cathode material found no degradation up to 1,260°C, making it a perfect match for Na₃.₄Zr₂Si₂.₄P₀.₆O₁₂ electrolyte. In our aim to produce a co-sintered mixed cathode, electron microscopy investigation showed a highly dense microstructure and the elemental mapping performed via energy dispersive X-ray spectroscopy and secondary ion mass spectrometry confirm that Na₃.₄Zr₂Si₂.₄P₀.₆O₁₂ and Na₀.₆₂ [Ni₀.₁₀Fe₀.₁₀Mn₀.₈₀]O₂ do not react during sintering. However, the active cathode material forms a sodium rich and a sodium deficient phase which needs further investigation to understand the origin and its impact on the electrochemical performance. CA Extern |
