MXenes suffer from severe restacking and oxidative degradation, which may cause the loss of functional properties and hamper further applications in aqueous energy storage devices. It has been proven that MXenes' physical/electrochemical properties are strongly dependent on surface terminations. Establishing the relationship between the molecular configuration, electronic structure of surface modifier and the chemical/electrochemical properties is critical for designing MXene-based aqueous energy storage devices. Herein, a cyclocrosslinked polyphosphazene modified MXene (MXene/PZS) is fabricated by forming the Ti−O−P covalent bond through nucleophilic addition and successive condensation reaction. The MXene/PZS enables faster ion transport, enhanced ion accessibility and stronger oxidation resistance through the combined pillar, steric, and electronic effects provided by the cyclocrosslinked polyphosphazene, leading to pseudocapacitance of 380 F g⁻¹ with superb rate performance. Moreover, the fabricated quasi-solid-state flexible symmetric supercapacitor shows an ultrahigh energy density of 12.26 Wh kg⁻¹ at 0.125 kW kg⁻¹, displaying remarkable flexibility and integrability. Our findings provide a holistic understanding of how the MXenes' physical/electrochemical properties influenced by the surface modifier, thus promoting the design of MXene-based aqueous energy devices.

MXenes 遭受严重的重新堆叠和氧化降解，这可能导致功能特性的丧失并阻碍在水性储能设备中的进一步应用。已经证明，MXenes 的物理/电化学性质在很大程度上取决于表面终端。建立表面改性剂的分子构型、电子结构与化学/电化学性质之间的关系对于设计基于 MXene 的水系储能装置至关重要。在此，通过亲核加成和连续缩合反应形成 Ti-O-P 共价键，制备了环交联聚磷腈改性的 MXene (MXene/PZS)。MXene/PZS 通过组合柱、空间、⁻¹具有极好的速率性能。此外，所制造的准固态柔性对称超级电容器在0.125 kW kg ^{-1时显示出12.26 Wh kg -1}的超高能量密度，显示出卓越的灵活性和可集成性。我们的研究结果提供了对 MXenes 的物理/电化学性质如何受表面改性剂影响的整体理解，从而促进了基于 MXene 的水能源设备的设计。