Ti₃C₂T_x MXene with two-dimensional (2D)-layered structure shows potential application in various fields owing to its superb metallic conductivity and excellent solution processability. However, a fundamental challenge limiting the implementation of Ti₃C₂T_x in practical applications is its susceptibility to oxidation in either humid or aqueous environments only within a few days, which results in the disassembly of the 2D-layered structure and severely deteriorates the functional properties including electrical conductivity, mechanical strength and EMI shielding performance. Herein, we firstly demonstrate a robust procedure to protect sensitive Ti₃C₂T_x from degradation by modification with imidazolium-based inion liquid (IL), which remarkably improves the chemical stability of Ti₃C₂T_x in aqueous and significantly increases the mechanical strength of assembled freestanding Ti₃C₂T_x film (IL-MXene). The crystalline structure of IL-MXene sheet remains intact up to 30 days and preserves the 2D-layered structure as long as 8 months in aqueous, meanwhile, the tensile strength of freestanding IL-MXene film is as high as 75.9 ± 4.9 MPa and the increment is up to 84% when compared to that of untreated MXene film (41.2 ± 4.5 MPa). A novel mechanism for improved chemical stability of MXene sheet was proposed and elucidated based on the radical-scavenging ability of IL and the surface chemistry of MXene sheet. This study provides a new strategy to achieve chemically stable Ti₃C₂T_x and improved mechanical strength of assembled MXene film, which is also available for other type of MXenes.

具有二维（2D）层结构的Ti ₃ C ₂ T _x MXene由于其极好的金属导电性和出色的固溶加工性而显示出在各种领域中的潜在应用。然而，在实际应用中限制Ti ₃ C ₂ T _x实施的一个基本挑战是其仅在几天之内在潮湿或水性环境中对氧化的敏感性，这导致2D层结构的分解并严重破坏了3D层的结构。功能特性包括电导率，机械强度和EMI屏蔽性能。在这里，我们首先展示了一种保护敏感的Ti ₃ C的鲁棒程序。通过使用咪唑鎓离子液体（IL）进行改性而降解而产生的₂ T _x，可显着提高Ti ₃ C ₂ T _x在水中的化学稳定性，并显着提高组装的独立式Ti ₃ C ₂ T _x的机械强度胶卷（IL-MXene）。IL-MXene片的晶体结构可保持长达30天的完整状态，并在水中保持2D层结构长达8个月，同时，独立的IL-MXene膜的拉伸强度高达75.9±4.9 MPa，且与未经处理的MXene膜（41.2±4.5 MPa）相比，其增量高达84％。基于IL的自由基清除能力和MXene片材的表面化学性质，提出并阐明了提高MXene片材化学稳定性的新机理。这项研究为获得化学稳定的Ti ₃ C ₂ T _x和提高组装的MXene膜的机械强度提供了一种新策略，该方法也可用于其他类型的MXene。