Synergistic Mo/V‐Implanted 2D M 3 X 2 MXene Nanoarchitectures for Enhanced Structural Stability and Ultrahigh Proton Storage Performance

ABSTRACT 2D MXenes are promising materials for supercapacitors in managing smart grid peak‐valley demand and integrating renewable energy, due to their excellent electrical conductivity, optimal interlayer spacing, and abundant active sites. However, commonly used M 3 X 2 MXene, such as Ti 3 C 2, still face practical issues including structural instability and insufficient pseudo‐capacitance, which hinder the broader application. Herein, we propose an atomic‐scale strategy to construct a medium‐entropy TiVMoC 2 MXene nanoarchitecture by implanting Mo and V into the Ti 3 C 2 skeleton, thereby enabling the simultaneous enhancement of structural robustness and electrochemical activity. Mo improves M─C bond covalency and oxidation resistance, while V introduces multivalent redox centers to boost pseudo‐capacitance. Therefore, the TiVMoC 2 electrode delivers the outstanding gravimetric and volumetric capacitances of 1081.6 F g −1 and 3125.0 F cm −3 at 5 mV s −1 . Moreover, it maintains 90.8% capacity after 30,000 cycles, demonstrating remarkable electrochemical stability. Further in situ and ex situ electrochemical tests, along with theoretical analyses, confirm that TiVMoC 2 demonstrates reversible proton storage properties, pseudocapacitive behavior, excellent structural stability, and a lower ion diffusion barrier. Therefore, this work customizes stable MXene electrodes with ultrahigh capacitance, providing an innovative solution to achieve both gravimetric and volumetric capacitance in energy storage devices.