发表机构
Federal Institute for Materials Research and Testing (BAM); Humboldt-Universität zu Berlin（联邦材料研究与测试研究所 (BAM); 柏林洪堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过调控煅烧温度实现非反应性烧结，提高NASICON电解质的致密度和离子电导率，并解决磷损失问题，实现高临界电流密度和长期稳定循环。
AI 中文摘要
NASICON材料是室温钠固态电池中很有前景的固体电解质，通常通过固态反应合成。虽然烧结已被广泛研究，但煅烧对电解质性能的影响仍知之甚少。在本工作中，确定了Na3Zr2Si2PO12和Na3.4Zr2Si2.4P0.6O12中NASICON相形成的温度。然后，在900 °C至1200 °C之间改变煅烧温度，以获得在烧结前具有不同反应程度的粉末。在相同的烧结条件下，煅烧粉末中较高的NASICON相含量被证明能产生更致密的电解质。非反应性烧结还改善了晶界电导率，对Na3.4Zr2Si2.4P0.6O12而言，晶界电导率提高了130%，并且对于分别在900 °C和1200 °C煅烧的粉末，总电导率从1.60 mS/cm提高到2.95 mS/cm。最后，研究表明，加工过程中的磷损失会损害对Na金属电极的循环稳定性，而添加非化学计量比的磷可解决此问题，同时达到5.0 mA/cm^2的临界电流密度和3.82 mS/cm的室温电导率，并实现超过400小时的稳定循环。总体而言，这些发现直接将合成和加工条件与NASICON固体电解质的最终材料性能和电化学性能联系起来。
英文摘要
NASICON materials are promising solid electrolytes for room-temperature sodium solid-state batteries and are typically synthesized via solid-state reaction. While sintering has been extensively studied, the effect of calcination on electrolyte properties remains poorly understood. In this work, the temperatures at which the NASICON phase forms in Na3Zr2Si2PO12 and Na3.4Zr2Si2.4P0.6O12 are identified. Calcination temperature is then varied between 900 °C and 1200 °C to obtain powders with different degrees of reaction prior to sintering. Under identical sintering conditions, higher NASICON phase content in the calcined powder is shown to yield denser electrolytes. Non-reactive sintering also improves grain boundary conductivity, increasing it by 130% for Na3.4Zr2Si2.4P0.6O12 and raising total conductivity from 1.60 to 2.95 mS/cm for powders calcined at 900 °C and 1200 °C, respectively. Finally, it is shown that phosphorus loss during processing compromises cycling stability against Na metal electrodes, and that adding off-stoichiometric phosphorus resolves this issue, while reaching a critical current density of 5.0 mA/cm^2 and a room-temperature conductivity of 3.82 mS/cm with over 400 hours of stable cycling. Overall, these findings directly relate synthesis and processing conditions to the final material properties and electrochemical performance of NASICON solid electrolytes.
