In-Situ Monitoring of Charge Storage Mechanism from Ti₃C₂T_xMXene Nanostructures via Ionic Liquid Etching and Intercalation

MXenes are promising materials for energy storage due to their high electrical conductivity and unique layered structure. This study demonstrates the dual role of 1-Butyl-3-methylimidazolium tetrafluoroborate (BMImBF₄) as both an etching agent and an intercalation medium for synthesizing Ti₃C₂T_x MXene with enhanced electrochemical performance. In-situ Raman and XRD analyses show that BMIm⁺ ions intercalate between MXene layers, stabilizing the nanoscale (002) interlayer spacing, preventing restacking and improving ion transport. When tested in the H₂SO₄–BMImBF₄ hybrid electrolyte, the Ti₃C₂T_x MXene delivers a capacitance of 228.7 F g^–1 at a scan rate of 1 mV s^–1, compared to 179.9 F g^–1 in pure H₂SO₄, measured on the same batch of materials. This demonstrates that incorporating BMImBF₄ into H₂SO₄ significantly enhances the charge storage capability of Ti₃C₂T_x MXene. These findings highlight the effectiveness of BMImBF₄ in optimizing charge storage and reinforce the potential of ionic liquids for advanced MXene-based energy storage systems.