Hydrogen‐Bonding Crosslinking MXene to Highly Robust and Ultralight Aerogels for Strengthening Lithium Metal Anode

Li metal batteries offer the ultimate choice of high‐energy power source, but suffer the performance decay and safety risk originated from notorious dendrite problem and infinite volume change of Li metal anode. Herein, it is reported to strengthen the Li metal anode by ultralight but highly robust MXene aerogels (ULRMA) with build‐in strain‐resistant and molecular‐level lithiophilic properties. A hydrogen‐bonding crosslinking strategy is developed for rapidly assembling 2D MXene to ULRMA at ambient conditions with less sacrifice of intrinsic properties of MXene. The ULRMA with an ultralow density below 10 mg cm−3 are favorable to maximize the merit of Li metal in gravimetric energy density while offering exceptional stability of porous frameworks against mechanical strain of long‐term Li plating/stripping. The lithiophilic architecture with high conductivity and hierarchical porosity further largely reduces the potential polarization and guides the pattern of Li deposition. Uptaking Li metal into ULRMA leads to a stable Li metal anode with an ultralong lifetime of 1600 h with a high‐rate response up to 20 mA cm−2 and high coulombic efficiency. It yields a highly robust Li metal anode with high effectiveness in engineering stable Li‐ion and Li–S batteries even paring with commercial LiFePO4 or sulfur cathode without nanostructuring. A facile hydrogen‐bonding crosslinking strategy is developed for fast fabrication of ultralight but highly robust MXene aerogels (ULRMA). They allow for maximizing the gravimetric energy merit of Li metal while effectively strengthening Li metal anode. Uptaking Li metal into robust lithiophilic ULRMA yields stable Li metal anode for significantly enhancing the performance of Li‐ion and Li–S full cells.