Understanding in-plane sliding of functionalized Ti3C2Tx MXene by in-situ microscale analysis of electrochemical actuation

• Main Authors: Harpreet Singh, Chen, Shaohua, Francius, Grégory, Liu, Liang, Lee, Pooi See, Etienne, Mathieu
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2025
• Subjects: Engineering; Deformation; Electrodes; Functionalization; Ions; Two dimensional materials
• Online Access: https://hdl.handle.net/10356/182297
• Institution: Nanyang Technological University

Electrochemical actuation is based on the deformation of electrodes upon applying a mild potential (usually in the range of ±5V in a single cell). In this work, in-situ local analysis of the electrochemical actuation of Ti3C2Tx (T = -O, -OH, -F) MXene at microscale is achieved by Raman spectroscopy, atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM) while applying potential in an electrochemical cell. First, Raman spectra recorded at steady state with different potentials confirm the intercalation/deintercalation of Li+ ions, resulting in the change of out-of-plane vibrations due to the interaction of Li+ with the -O and -OH surface group atoms of MXene. A methylcellulose functionalization of MXene films results in more freedom for in-plane vibrations. Second, SECM is applied to visualize the deformation of two-end-fixed MXene films both at steady state (0V vs. Ag/AgCl QRE) and at scanning potential. The results show a buckling-type actuation, which is more pronounced for methylcellulose-functionalized samples. Electrochemical AFM provided the evidence of a significant in-plane sliding of the MXene flakes. Out-of-plane changes appears to be negligible in the actuation mechanism, as supported by the AFM approach curve analysis. Overall, the methylcellulose-functionalized MXene shows better actuation performance, especially in the in-plane direction and at high frequency. The mechanism is then discussed.