Quantitative pre-intercalation of alkali metal ions enables precisely modulating Li+ storage of Mxenes

Ion intercalation is crucial for improving energy storage performance, but controlling the content of intercalated ions is challenging for two-dimensional (2D) electrode materials although it enables clarifying individual intercalation behaviors and thereof pinpointing the intercalation mechanism. Herein, the equal‐content alkali metal ions were successfully manipulated to intercalate into Mo₂CT_x MXene electrodes via an electrochemistry‐driven approach via the anti‐battery principle. Based on a variety of alkali metal ions pre‐intercalation into the Mo₂CT_x MXene (M⁺‐Mo₂CT_x) electrodes, the lithium storage performance was largely improved. Li⁺‐Mo₂CT_x electrode exhibits an outstanding capacity of 395.49 mAh g⁻¹ at 200 mA g⁻¹ after 100 cycles due to the enhanced redox activity induced by high-valence Mo and low-F interlayer exposed surface. Besides, the K⁺‐Mo₂CT_x electrode delivers excellent rate performance due to faster ion transfer kinetics originating from the pillaring effect of pre-intercalated K⁺ ions. In a broader sense, our study opens up a new route to accurately improve the electrochemical performance via precisely tuning the content of ions intercalated into 2D intercalation‐type materials.