A Dielectric MXene‐Induced Self‐Built Electric Field in Polymer Electrolyte Triggering Fast Lithium‐Ion Transport and High‐Voltage Cycling Stability

, leading to a small polarization of approximately 25 mV for Li//Li symmetric cell after 6000 h. Furthermore, it enables a prolonged cycle life at a high voltage of up to 4.6 V. Overall, this work not only broadens the application of MXene for QPE but also inspires the great potential of the self-built electric field in QPE-based high-voltage batteries.