As one of the most important structural complexities of PBAs, [Fe(CN)6] 4-anion vacancy has shown a significant role in various ion batteries. For instance, Komoba's group reported that size effect is not the primary factor, but introducing a suitable number of anion vacancy can enhance the KIB performance of K-PBA cathodes. For the case of NIBs, Regulating K + /Na + intercalation mechanism to realize the increase in intercalation voltage and energy density of hybrid NIBs can be strongly directed by the anion vacancy content in PBAs.