Synthesis of Nanoscale Cesium Dihydrogen Phosphate Particles via Bead Milling for Advanced Electrode Composites

This work presents an optimized bead-milling approach for producing monodisperse cesium dihydrogen phosphate nanoparticles (100–200 nm), while preserving their P21/m crystal structure, as confirmed by X-ray diffraction and particle size characterized by scanning electron microscopy and Rietveld refinement (125 ± 10 nm crystallites). The obtained nanoparticles demonstrated high proton conductivity (∼1.8 × 10–2 S cm–1 at 240°C) due to the bulk transport mechanism predominance, which allowed them to be successfully applied in the first tests in fuel cell electrodes (OCV 0.96 V, current density ∼120 mA/cm2 at 235°C). The developed mechanical processing method enables precise particle size control, facilitating the fabrication of electrode materials with enhanced three-phase boundary characteristics for improved fuel cell performance.