Therefore, the computational and experimental results demonstrate that a higher content of [Fe(CN)6] 4-anion vacancy can favor K + intercalation from both thermodynamic and kinetics effects; thus, compared with KFe60, K + intercalation is maximized in KFeRT, leading to a Kdominated intercalation and a higher capacity in the NIB cell. We finally illustrate in Figure the benefits of [Fe(CN)6] 4-anion vacancy in KFeFe-PBAs used as NIB cathode materials. In the case of an anion vacancy-free KFeFe-PBA framework (KFeVF, Figure ), the computational and experimental results indicate a slow K + diffusion.