NaCrO₂ particles for high-rate sodium ion batteries were prepared on a multigram scale in segmented flow from chromium nitrate and sodium nitrate using a segregated flow water-in-oil emulsion drying process. Microfluidic processing is an environmentally friendly and rapid synthetic method, which can produce large-scale industrial implementation for the production of materials with superior properties. The reaction time for NaCrO₂ particles was reduced by almost one order of magnitude compared to a normal flask synthesis and by several orders of magntitude compared to a conventional solid-state reaction. In addition, it allows for an easy upscaling and was generalized for the synthesis of other layered oxides NaMO₂ (M = Cr, Fe, Co, Al). The automated water-in-oil emulsion approach circumvents the diffusion limits of solid-state reactions by allowing a rapid intermixing of the components at a molecular level in submicrometer-sized micelles. A combination of Raman and nuclear magnetic resonance spectroscopy (¹H, ²³Na), thermal analysis, X-ray diffraction and high resolution transmission electron microscopy provided insight into the formation mechanism of NaCrO₂ particles. The new synthesis method allows cathode materials of different types to be produced in a large scale, constant quality and in short reaction times in an automated manner.

中文翻译：

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分段流微流控合成高速钠离子电池用NaCrO2颗粒的广义合成

用于高倍率钠离子电池的NaCrO ₂颗粒采用分流油包水乳液干燥工艺，由硝酸铬和硝酸钠分流制备。微流控加工是一种环境友好、快速的合成方法，可以大规模工业化实施，用于生产性能优越的材料。_{与普通烧瓶合成相比，NaCrO 2}颗粒的反应时间减少了几乎一个数量级，与传统的固态反应相比，减少了几个数量级。此外，它易于放大并被推广用于其他层状氧化物 NaMO _2的合成（M = 铬、铁、钴、铝）。自动油包水乳液方法通过允许在亚微米大小的胶束中在分子水平上快速混合组分来规避固态反应的扩散限制。拉曼和核磁共振光谱 ( ¹ H, ²³ Na)、热分析、X 射线衍射和高分辨率透射电子显微镜的结合提供了对 NaCrO ₂颗粒形成机制的深入了解。新的合成方法允许以自动化的方式大规模、恒定质量和短反应时间生产不同类型的正极材料。