One-step generation and characterization of perfluorohexanone emulsions via modified Tessari method for sodium...

Lithium-ion battery fires pose significant risks due to high heat release and rapid propagation, making effective fire suppression critical. Perfluorohexanone (PFH) is a promising fire-fighting agent but suffers from high volatility and short release duration, which can be mitigated by sodium alginate (SA)-based microcapsules. However, formulating stable PFH emulsions (essential for microcapsules) using SA solutions remains challenging due to the high interfacial energy of PFH. This study proposes a modified Tessari method, which uses two syringes to prepare a stable PFH emulsion in one step, for the manufacture of PFH@SA microcapsules. We systematically compared the emulsion stability between the modified Tessari method and classical stirring method, and investigated the effects of key parameters (viscosity, surface tension, PFH-to-water ratio, flow velocity, voltage, frequency) on emulsion stability, jetting modes, microcapsule size, and encapsulation efficiency. The results showed that the modified Tessari method exhibited superior efficiency and emulsion stability. Viscosity dominated the dripping-to-cone-jet transition of jetting modes (surface tension secondary), a moderate flow rate (2.5 mL/min) favored microcapsule formation, and a suitable core-to-shell ratio (1:4) ensured high encapsulation efficiency. The battery thermal runaway suppression tests further indicated the fire suppression potential of the resultant microcapsules. This study offers theoretical guidance for high-performance PFH microcapsule fabrication.