Metal–organic frameworks as electrode materials for post-lithium-ion batteries: Coordination chemistry, electrochemical behavior, and performance relationships

The growing demand for energy storage technology and various limitations of current Li-based batteries have driven research on post-lithium-ion batteries (post-LIBs), which use earth-abundant charge carriers, such as Na + , K + , Zn 2+ , Mg 2+ , Ca 2+ , and Al 3+ . Aside from several advantages of these systems, e.g., sustainability and high theoretical capacity, one of the main challenges to realizing post-LIBs is finding electrode materials that can reversibly insert large monovalent or multivalent guest ions. To facilitate solid-state ionic migration and to overcome slow diffusion kinetics due to strong electrostatic interactions and complex electronic charge redistribution, several criteria regarding the structural features of the host lattice should be met. Open porous structures with spacious crystallographic sites or adequately sized migration pathways have attracted significant attention for loading guest ions/charge-carrier species, facilitating mass transport, and accommodating mechanical strains. Metal organic frameworks (MOFs), a rapidly developing family of crystalline porous inorganic-organic hybrid materials assembled by metal ligand coordination bonds, have emerged as promising electrode materials, due to their tunable coordination environments and modular redox centers. In this review, the advantages as well as challenges of the development of post-LIBs are summarized. Possible solutions and approaches to overcome these technical hurdles in post-LIBs are also elucidated. From the metal–organic ligand coordination chemistry perspective, this review focuses exclusively on how fundamental parameters of MOFs, i.e., framework nature, redox origin, electronic structure and conductivity, and electrochemical stability, govern their electrochemical performance across post-LIB systems. MOFs reported for post-LIBs are systematically reviewed, with persistent issues, including poor electronic conductivity, framework degradation, and scalability, critically discussed alongside the future directions of MOFs as electrode materials.