Electrochemically\nIntercalated Ti<sub>3</sub>C<sub>2</sub> MXene Bulk for Expanding\nInterlayer Spacing and Enhancing\nSupercapacitor Performance

Tuning the interlayer spacing of\n2D MXenes bulk mainly\nfocuses\non hydrothermal intercalation, physiotherapy intercalation, and ion\nexchange intercalation. Nevertheless, the feasibility of electrochemical\nintercalation technology for expanding the interlayer spacing of Ti<sub>3</sub>C<sub>2</sub> MXene bulk is not yet clear, and further research\nis required to advance it. Here, we employed an electrochemical intercalation\ntechnology to successfully embed metal cations (K<sup>+</sup> and\nNa<sup>+</sup>) into the interlayer structure of Ti<sub>3</sub>C<sub>2</sub> MXene bulk, expanding the interlayer spacing from ∼10.50\nto ∼13.10 Å by K<sup>+</sup> intercalation, which can\nbroaden electron/ion transport channels and enhance supercapacitor\nperformance. Compared to the pristine Ti<sub>3</sub>C<sub>2</sub> MXene\nbulk, the specific capacitance value increased by a factor of 2.8.\nMoreover, the intercalated MXene also exhibits excellent rate capability,\nwith an increase from 47.32 to 70.20%. This work opens up a new path\nfor the modification of Ti<sub>3</sub>C<sub>2</sub> MXene bulk.