One of the important challenges in advancing aqueous zinc-ion batteries is the separator, which is crucial for promoting stable electrode-electrolyte interface and energy density of the battery. Herein, this study introduces a metal ion-activated air-laid paper (ALP Act) as an alternative for traditional glass fiber separators with big thickness and weight. Notably, the sustainable release of metal ions facilitates in situ interface engineering, thus creating a surface layer with high zinc affinity to promote the uniform migration and depositio...