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Designing highly active and durable electrocatalysts remain an ongoing challenge in the oxygen reduction reaction (ORR). Here, the reductive IL/Ti3C2Tx(FA) is produced in a water‐free mixture of formic acid (FA), ionic liquid (IL) and LiF, subsequently, the simultaneous reduction encapsulation trap the Pd nanocatalysts and IL within bilayer carbide‐derived carbon (CDC) to obtain Pd@IL/CDC(FA) with high metal loading up to 69.7%. Thereby, the featured active phases in Pd@IL/CDC(FA) impart potent chemical nanoconfinement to defend metals from dissolution and aggregation, boost mass and electron transfer, and mediate oxidation states and adsorption/desorption of metal Pd in the ORR. Instead of deactivation and Ostwald ripening, the catalytic performances of Pd@IL/CDC(FA) are gradually enhanced in an accelerated durability test up to 20 000 cycles. In a Zn–air battery, the Pd@IL/CDC(FA) cathode gives a specific capacity of 812.6 mAh gZn−1 and a voltage loss of only 41 mV in galvanostatic discharge for 1000 h. The work opens new venues in controllably preparing high activity and durable electrocatalysts from in‐situ generated CDCs. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene is regarded as a promising material in energy-related applications; however, the overscreening charge effect of the electric double layer on electrified interfaces, along with "inert" F terminations, limits the electrochemical operation efficiencies. Here, we developed a protocol to harvest a coupled conductor through confining in situ 1-ethyl-3-methylimidazolium ([Emim]+) ions into Ti3C2Tx interlayers. The ionic–electronic coupling does not require any external counterions, but activates terminal F and even sub-surface Ti, and endows the conductor with metal-like and ionophilic characteristics. Different from physically preintercalated or adsorbed ions, the resulting chemically confined [Emim]+ ions offer more accessible electroactive sites, faster electron transport in surface redox, and more efficient channels for ion transfer. Hence, the Ti3C2Tx electrodes present high gravimetric capacitance, rate performance and cycling stability. This work highlights the important roles of the coupling in the design and research of mixed ionic–electronic conductors with high electrochemical activity. [ABSTRACT FROM AUTHOR]