High‐Voltage MXene‐Based Supercapacitors: Present Status and Future Perspectives

Abstract As an emerging class of 2D materials, MXene exhibits broad prospects in the field of supercapacitors (SCs). However, the working voltage of MXene‐based SCs is relatively limited (typically ≤ 0.6 V) due to the oxidation of MXene electrode and the decomposition of electrolyte, ultimately leading to low energy density of the device. To solve this issue, high‐voltage MXene‐based electrodes and corresponding matchable electrolytes are developed urgently to extend the voltage window of MXene‐based SCs. Herein, a comprehensive overview and systematic discussion regarding the effects of electrolytes (aqueous, organic, and ionic liquid electrolytes), asymmetric device configuration, and material modification on the operating voltage of MXene‐based SCs, is presented. A deep dive is taken into the latest advances in electrolyte design, structure regulation, and high‐voltage mechanism of MXene‐based SCs. Last, the future perspectives on high‐voltage MXene‐based SCs and their possible development directions are outlined and discussed in depth, providing new insights for the rational design and realization of advanced next‐generation MXene‐based electrodes and high‐voltage electrolytes.