Continuous Synthesis of Carbon-Coated Na₃V₂(PO₄)₃ by Segmented Flow Tubular Reactor

Scaling-up the synthesis of materials via hydrothermal and solvothermal routes is a long process and usually involves time- and cost-intensive parameter optimization. The solution to this challenge is continuous synthetic approaches. In this study, we present an easily scalable, continuous synthesis approach for the sodium ion battery cathode material Na₃V₂(PO₄)₃ (NVP) using a segmented flow tubular reactor (SFTR) following a polyol synthesis route, followed by a high-temperature treatment to form a carbon coated active material. We investigate the phase formation of the SFTR-derived material during high-temperature treatment through in situ XRD. We investigate the material morphology-structure-performance relationship to understand the consequences of this synthesis and processing methodology in comparison to conventional hydrothermal synthesis methods. Finally, the electrochemical evaluation in half-cell configurations demonstrates that the SFTR-derived NVP exhibits excellent performance, with a low capacity fading of 0.016% per cycle at 1C and excellent high-rate capability up to 10C. The presented synthesis methodology is readily transferable to other phosphate-based chemistries. Furthermore, these results underscore the potential of continuous synthesis methods to accelerate the scalable production of high-performance battery materials.