Precise engineering of bismuth oxychloride for enhanced anion sequestration in capacitive deionization

Abstract This study presents a solvent-mediated strategy for engineering BiOCl-based electrode architectures. By implementing a precisely tuned ethylene glycol/water solvent system during hydrothermal synthesis, we have effectively mitigated the structural deficiencies of conventional BiOCl materials, particularly addressing challenges related to nanosheet aggregation and suboptimal active site exposure. The optimized BiOCl electrode demonstrates a high performance in capacitive deionization, including a desalination capacity of 72.29 mg g−1 at an applied current of 0.15 mA. This exceptional performance originates from the synergistic effects of a hierarchically porous architecture with significantly expanded specific surface area, enabling superior electrolyte accessibility. The developed solvent-regulation protocol establishes a generalizable paradigm for designing high-performance electrode materials for energy-efficient desalination technologies.