Unveiling flow and mixing mechanism of a vortex microreactor and its use in preparing uniform layered oxide materials

Abstract Layered transition metal oxides (LTMOs, e.g., Na x Ni y Mn 1− y O 2 ) are critical cathode materials for sodium‐ion batteries (SIBs). However, they grapple with significant structural degradation during cycling, primarily caused by micro‐strain induced by TM heterogeneity during synthesis. Herein, we engineered a vortex microreactor to intensify fluid mixing during co‐precipitation processes, thereby achieving carbonate precursors with highly uniform elemental distribution. CFD simulations revealed fundamental microreactor hydrodynamics. Villermaux–Dushman experiments confirmed ≤0.62 ms molecular‐scale mixing, achieving near‐complete homogenization. The resulting precursors enabled exceptionally uniform TM distribution, yielding a P2‐type LTMO cathode with outstanding Ni/Mn homogeneity. Comparing with ball milling synthetics, this cathode exhibits superior rate capability, delivering an impressive 77.51 at 3000 mA g −1 while retaining 90% of the capacity measured at 150 mA g −1 . This work establishes micromixing engineering as a critical lever for inducing uniform TM distribution in LTMOs and provides a scalable platform for preparing SIBs cathode materials.