Sustainable Electrochemical Synthesis of High‐Quality MXenes: Mechanistic Insights, Applications, Challenges, and Technological Prospects

ABSTRACT

The emergence of two‐dimensional (2D) materials has revolutionized nanoscience by enabling atomic‐thickness systems with exceptional properties. Among them, MXenes exhibit metallic conductivity, hydrophilicity, chemical stability, and tunable surface chemistry. However, conventional hydrofluoric acid (HF) etching poses serious environmental and safety concerns and limits control over surface terminations. Electrochemical etching (E‐etching) has emerged as a sustainable alternative, using controlled potentials in aqueous, low‐fluorine, or fluorine‐free electrolytes to selectively remove the A‐layer from MAX phases while preserving the lattice structure, enabling larger flake sizes and programmable surface terminations (O/OH/Cl/F). This review systematically explores the evolution, mechanisms, and recent advances in E‐etched MXenes. Key synthesis parameters, applied potential, electrolyte composition, concentration, temperature, and etching time, are correlated with morphology, lateral size, defect density, surface chemistry, yield, and exfoliation behavior. A comparative assessment of fluoride‐free and low‐fluoride routes highlights trade‐offs in safety, scalability, and performance. Mechanistic insights into anodic dissolution, intercalation‐driven delamination, and carbide‐derived carbon (CDC) formation define optimal process windows. Emerging strategies, including pulsed techniques and advanced electrochemical configurations, are also discussed. Finally, this review critically outlines the applications (such as energy storage, catalysis, solid lubrication, environmental remediation, and sensing), challenges, and future prospects of green, scalable E‐etched MXenes.