MXenes are an emerging class of materials used in various applications such as sensors, catalysis, and energy storage devices. Chemical synthesis poses a major obstacle to their industrial application, requiring the direct use of HF as a leaching agent. Developing alternative synthetic routes that utilize in situ generation of HF is the primary strategy to overcome this limitation. This study compares four different leaching methods based on the use of NH4HF2, NaF HCl, HBF4, and NaBF4 HCl to produce Ti3C2Tx from Ti3AlC2. Three of these leaching methods are already reported in the literature, while one is introduced here for the first time. Structural analysis of the obtained products relies on X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), and X-ray photoelectron spectroscopy (XPS).

All materials were tested in half-cells against metallic Na; charge/discharge profiles and C-rate tests were discussed and correlated with specific structural characteristics. Overall, the results reveal that the MXene obtained using the leaching agent HBF4 is comparable both in structure and functional properties to the reference material, i.e., the MXene produced using 5% HF concentration. In fact, the MXene synthesized with HBF4 exhibits low average voltage and low potential hysteresis, while demonstrating the highest coulombic efficiency in the first cycle (69.7%), surpassing the performance of the MXene produced with 5% HF (67%). This study demonstrates the feasibility of producing MXene using a more sustainable method.