High‐Performance Silicon–Air Batteries Enabled by MIL Materials Covering Si Anodes With a Screening Function

ABSTRACT Silicon–air (Si–air) batteries have received significant attention owing to their high theoretical energy density and safety profile. However, the actual energy density of the Si–air battery remains significantly lower than the theoretical value, primarily due to corrosion issues and passivation. This study used various metal–organic framework (MOF) materials, such as MIL‐53(Al), MIL‐88(Fe), and MIL‐101(Cr), to modify Si anodes. The MOFs were fabricated to have different morphologies, particle sizes, and pore sizes by altering their central metal nodes and ligands. This approach aimed to modulate the adsorption behavior of H 2 O, SiO 2 , and OH − , thereby mitigating corrosion and passivation reactions. Under a constant current of 150 μA, Si–air batteries with MIL‐53(Al)@Si, MIL‐88(Fe)@Si, and MIL‐101(Cr)@Si as anodes demonstrated lifetimes of 293, 412, and 336 h, respectively, surpassing the 276 h observed with pristine silicon anodes. Among these composite anodes, MIL‐88(Fe)@Si displayed the best performance due to its superior hydrophobicity and optimal pore size, which enhance OH − migration. This study offers a promising strategy for enhancing Si–air battery performance by developing an anodic protective layer with selective screening properties.