Closo-borates and carba-closo-borates recently emerged as a promising class of solid electrolytes for all-solid-state batteries but are too expensive. Here, we introduce NaB₁₁H₁₄nido-borates as a new building block for solid electrolytes that can be synthesized via a cost-effective low-temperature method using cheap NaBH₄ as a chemical feedstock. We employ two-dimensional (2D) nuclear magnetic resonance techniques to analyze the structure of this new building block. High ionic conductivity of up to 4 mS/cm at 20 °C is achieved by combining nido-NaB₁₁H₁₄ with closo-Na₂B₁₂H₁₂ into cubic unit cells. Importantly, Na₂B₁₂H₁₂ can also be synthesized cost-effectively from NaBH₄. Crystal structures are solved and refined by synchrotron X-ray diffraction and density functional theory. Cyclic voltammetry reveals electrochemical stability from 0.15 to 2.6 V vs Na/Na⁺. Galvanostatic cycling in symmetrical cells with sodium metal electrodes shows only a small overpotential increase from 2 to 2.5 mV after 400 cycles at 50 μA/cm². We also discuss how our results can be translated to render lithium solid electrolytes economically viable.

中文翻译：

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全固态电池的Nido- Borate / Closo -Borate混合阴离子电解质

闭合碳-borates和carba-闭合碳-borates最近出现的一类有前景的固体电解质为全固态电池，但太贵了。在这里，我们介绍NaB ₁₁ H ₁₄氨基硼酸盐作为固体电解质的新组成部分，可以使用廉价的NaBH ₄作为化学原料，通过经济有效的低温方法合成。我们采用二维（2D）核磁共振技术来分析这种新构件的结构。高达4毫秒/厘米，在20℃下的高离子导电性，通过组合实现的巢-NaB ₁₁ ħ ₁₄与闭合碳-Na ₂乙₁₂ H ₁₂变成立方晶胞。重要的是，Na ₂ B ₁₂ H ₁₂也可以由NaBH ₄有效地合成。晶体结构通过同步加速器X射线衍射和密度泛函理论进行解析和精炼。循环伏安法显示相对于Na / Na ⁺在0.15至2.6 V范围内具有电化学稳定性。带有钠金属电极的对称电池中的恒电流循环显示，在50μA/ cm ^{2的条件下}经过400次循环后，过电位仅从2升高到2.5 mV 。我们还将讨论如何转换我们的结果以使锂固体电解质在经济上可行。