Metal-organic framework formation by [Fe4S4] clusters offers promising electrochemical performance

[Display omitted] •Application of [Fe4S4] to metal-ion batteries is studied using DFT calculations.•Embedding [Fe4S4]2+ clusters in metal–organic frameworks generates high voltage.•The electrochemical performance is based on an intercalation mechanism.•Among the screened material pairs, Zn2+-BMOF shows the highest efficiency. [Fe4S4] clusters have served as molecular batteries and charge transfer centers in many biosystems. However, their potential as electrode materials has been overlooked amidst the ever-increasing studies on various materials in the search for efficient battery compositions. To evaluate their electrochemical efficiency as electrode materials, we focused on the use of two important oxidation states, [Fe4S4]2+ and [Fe4S4]⁰, in a series of Li-, Na-, K-, Mg-, Ca-, and Zn-ion batteries. We also assessed the effect of metal–organic framework (MOF) formation on their performance by studying [Fe4S4]2+-1,4-benzenedithiolate MOF (BMOF) and its carboxylate-based counterpart (CMOF). Our model-based Density Functional Theory (DFT) calculations indicated that oxidation of the cluster to [Fe4S4]2+ and MOF formation significantly improve the electrochemical efficiency of the cluster. Among the studied electrode materials and metals, the BMOF combination with Mg0 and Zn2+ presented the best electrochemical performance. Notably, our periodic calculations indicated an open circuit voltage of 4.32 V for the Zn2+-BMOF system, suggesting a promising performance for BMOF compared to other cathode/negative electrode materials. Our atomic and electronic structure analyses indicated that intercalation is the underlying electrochemical mechanism.