Diffusion-Controlled Electrochemical Kinetics of Ti3C2Tx MXene through HF Etching Optimization ​

The structural and electrochemical performance of Ti3C2Tx MXene are greatly influenced by the etching conditions during the synthesis process. Herein, Ti₃C₂Tₓ MXene was synthesized by employing different HF concentrations (20–40%) to study the effect of etching conditions on its structural and electrochemical properties. XRD results confirmed the increase in interlayer spacing and successful exfoliation after HF etching, with MX_20 showing the highest d-spacing and defect density. FE-SEM analysis revealed the characteristic accordion-like morphology of Ti₃C₂Tₓ MXene, with MX_20 exhibiting the highest degree of exfoliation uniformity. EDAX and elemental mapping confirmed the successful formation of MXene samples which is in accordance with XRD inference. Raman and FT-IR studies further confirmed structural disorder and surface functionalization of the MXene sheets. Electrochemical measurements in 1 M KOH electrolyte revealed the pseudocapacitive nature with a peak specific capacitance of 150.8 F/g at 1 A/g due to enhanced ion diffusion in the optimised sample. Warburg diffusion analysis confirmed the dominance of diffusion-controlled electrochemical kinetics with a K+ ion diffusion coefficient of 1.92 × 10-10 cm2/s, indicating efficient ionic transport through the MXene interlayers. The optimized HF etching conditions significantly enhanced ionic diffusion and electrochemical kinetics.