Trifluoropropylene Carbonate‐Induced Solid‐Electrolyte Interphases Enable High‐Rate and Robust Alkali‐Metal Ion Storage in MXenes

ABSTRACT MXenes are featured by nanoscale interlayer spacing and prominent electronic conductivity, making them highly suitable as anodes for high‐rate storage of alkali metal ions (such as Li + ). However, the structural stability of MXenes faces significant challenges during long‐term ion insertion/extraction processes, primarily due to interlayer restacking and solid electrolyte interphase (SEI) accretion caused by electrolyte side reactions. Herein, we for the first time propose the introduction of a functional cosolvent, trifluoropropylene carbonate (TFPC), to form an ultrathin yet robust LiF‐rich SEI layer on the interlayer surfaces of MXenes. This strategy not only effectively suppresses interlayer restacking but also preserves the structural stability of fast ion‐transport channels, thereby significantly enhancing the cycling stability and rate capability of MXene electrodes. Benefiting from TFPC addition, the Ti 3 C 2 F electrode delivers a high capacity of 386.2 mAh g −1 at 200 mA g −1 , and sustains a stable capacity of 116.7 mAh g −1 over 3950 cycles even under the extreme current density of 10 A g −1 , nearly twice that of unmodified Ti 3 C 2 F electrodes. More encouragingly, TFPC demonstrates excellent universality across different MXene materials (e.g., Nb 2 CF and V 2 CF), and its performance‐enhancing effect can be extended to durable sodium/potassium‐ion storage in MXenes as well as to LiFePO 4 ||Ti 3 C 2 F full cells.