Uniform Distribution of Alloying/Dealloying Stress for High Structural Stability of an Al Anode in High‐Areal‐Density Lithium‐Ion Batteries

Aluminum (Al) is one of the most attractive anode materials for lithium-ion batteries (LIBs) due to its high theoretical specific capacity, excellent conductivity, abundance, and especially low cost. However, the large volume expansion, originating from the uneven alloying/dealloying reactions in the charge/discharge process, causes structural stress and electrode pulverization, which has long hindered its practical application, especially when assembled with a high-areal-density cathode. Here, an inactive (Cu) and active (Al) co-deposition strategy is reported to homogeneously distribute the alloying sites and disperse the stress of volume expansion, which is beneficial to obtain the structural stability of the Al anode. Owing to the homogeneous reaction and uniform distribution of stress during the charge/discharge process, the assembled full battery (LiFePO₄ cathode with a high areal density of ≈7.4 mg cm^-2 ) with the Cu-Al@Al anode, achieves a high capacity retention of ≈88% over 200 cycles, suggesting the feasibility of the interfacial design to optimize the structural stability of alloying metal anodes for high-performance LIBs.