We present here a multi-length scale integration of compositionally tailored NaSICON-based Na⁺ conductors to create a high Na⁺ conductivity system resistant to chemical attack in strongly alkaline aqueous environments. Using the Pourbaix Atlas as a generalized guide to chemical stability, we identify NaHf₂P₃O₁₂ (NHP) as a candidate NaSICON material for enhanced chemical stability at pH > 12, and demonstrate the stability of NHP powders under accelerated aging conditions of 80 °C and pH = 13–15 for a variety of alkali metal cations. To compensate for the relatively low ionic conductivity of NHP, we develop a new low temperature (775 °C) alkoxide-based solution deposition chemistry to apply dense NHP thin films onto both platinized silicon wafers and bulk, high Na⁺ conductivity Na₃Zr₂Si₂PO₁₂ (NZSP) pellets. These NHP films display Na⁺ conductivities of 1.35 × 10⁻⁵ S cm⁻¹ at 200 °C and an activation energy of 0.53 eV, similar to literature reports for bulk NHP pellets. Under aggressive conditions of 10 M KOH at 80 °C, NHP thin films successfully served as an alkaline-resistant barrier, extending the lifetime of NZSP pellets from 4.26 to 36.0 h. This integration of compositionally distinct Na⁺ conductors across disparate length scales (nm, mm) and processing techniques (chemically-derived, traditional powder) represents a promising new avenue by which Na⁺ conducting systems may be utilized in alkaline environments previously thought incompatible with ceramic Na⁺ conductors.

中文翻译：

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ha取代的NaSICON离子导体中增强的碱稳定性†

在这里，我们介绍了基于成分定制的NaSICON的Na ⁺导体的多长度尺度集成，以创建高Na ⁺电导率系统，以抵抗强碱性水溶液环境中的化学侵蚀。使用Pourbaix Atlas作为化学稳定性的通用指南，我们确定了NaHf ₂ P ₃ O ₁₂（NHP）作为NaSICON候选材料，可增强pH> 12时的化学稳定性，并证明了NHP粉末在80°C和pH = 13–15的加速老化条件下对各种碱金属阳离子的稳定性。为了补偿NHP相对较低的离子电导率，我们开发了一种新的基于低温（775°C）醇盐的溶液沉积化学方法，将致密的NHP薄膜应用于镀铂硅晶片和块状高Na ⁺电导率Na ₃ Zr ₂ Si ₂ PO ₁₂（NZSP）颗粒。这些NHP膜显示的Na ⁺电导率为1.35×10 ^-5 S cm ^-1在200°C下的活化能为0.53 eV，类似于散装NHP颗粒的文献报道。在80°C的10 M KOH的苛刻条件下，NHP薄膜成功地充当了耐碱性的屏障，将NZSP颗粒的使用寿命从4.26 h延长至36.0 h。跨不同长度尺度（nm，mm）的成分不同的Na ⁺导体和加工技术（化学衍生的传统粉末）的这种集成代表了一种有前途的新途径，通过该途径，可以将Na ⁺导电体系用于以前认为与陶瓷不兼容的碱性环境中Na ⁺导体。