How Metal-Organic Frameworks Could Rewrite the Rules of Battery Anodes

Lithium-ion batteries have quietly powered two decades of portable electronics and electric vehicles, yet the material doing most of the heavy lifting on one side of the cell has barely changed. Graphite, the standard anode, stores lithium by slipping ions between its carbon layers, but its theoretical capacity tops out at just 372 milliampere-hours per gram. That ceiling is now a genuine bottleneck for anyone hoping to squeeze more range into an electric car or more runtime into a device. A comprehensive new review published in Frontiers in Batteries and Electrochemistry argues that a family of materials called metal-organic frameworks, or MOFs, may offer a way past it, provided scientists finally get a firm grip on exactly how these materials store lithium.

MOFs are crystalline, sponge-like compounds built from metal ions or clusters connected by organic linkers into porous, highly ordered networks. Their appeal to battery designers is obvious on paper: enormous internal surface area, tunable pore structures, and a wealth of chemically addressable sites where lithium ions can bind or react. They can also serve as sacrificial templates, transforming under heat or chemical treatment into metal oxides, sulfides, carbides, or porous carbon with intricate hollow architectures. The review, authored by Dongfang Shi of Shanghai Jiao Tong University’s Global College, systematically maps the lithium storage mechanisms operating across both pristine MOFs and their derived materials, aiming to close a knowledge gap that has limited rational electrode design even as publication numbers in the field have climbed steadily over the past decade.

In pristine MOFs, the review identifies two principal storage pathways. The first is ligand-centered intercalation, in which lithium ions insert into the organic components of the framework without destroying its crystal structure. A landmark demonstration came from work on a cobalt-based framework called Co-BDC, where spectroscopic analysis showed the cobalt ions remained electrochemically inert throughout cycling. Instead, lithium bound to deprotonated carboxylate groups through Coulombic attraction, while the aromatic rings of the ligand contributed additional capacity through cation-pi interactions with their delocalized electron clouds. That dual-site mechanism delivered a discharge capacity of 1963.6 mAh per gram, more than five times that of graphite, with a capacity retention of 70.7 percent after 100 cycles.

The second pathway puts the metal nodes themselves to work. Transition metals such as iron, cobalt, and nickel can access multiple oxidation states, and frameworks built around them can undergo reversible redox conversions during charging and discharging. In a lead-based framework, Pb-BTC, researchers tracked the metal center cycling between Pb2+ and metallic Pb, with higher Pb4+ states appearing during extended cycling to add further electron transfer. Bimetallic designs push the concept further. In a cobalt-iron framework nanosheet, both metal centers reduced reversibly to their metallic states, and the combination improved electronic conductivity and lithium diffusion relative to single-metal analogues, yielding an initial discharge capacity of 2050.3 mAh per gram. The most striking example is a cobalt framework called Co-NTTA, where ligand functional groups, aromatic rings, and cobalt centers together transfer 51 electrons per structural unit, producing a reversible capacity of 1390 mAh per gram.

MOF-derived materials take a different route entirely. When a MOF is heated or chemically transformed, it can yield metal oxides, sulfides, or selenides dispersed in a conductive carbon matrix inherited from the organic linkers. These derived compounds typically store lithium through conversion reactions, in which the metal compound is reduced to nanoscale metal clusters embedded in lithium oxide, or through alloying reactions with elements such as tin, zinc, antimony, and bismuth. Conversion reactions can store large quantities of lithium but inflict severe volume changes on the material, which is precisely where the MOF heritage pays off. Porous hollow structures and carbon coatings buffer the expansion, shorten ion transport distances, and prevent particles from pulverizing. A MOF-derived cobalt oxide hollow tetrahedron, for example, delivered 1196 mAh per gram, while carbon-wrapped iron sulfide composites retained 768.7 mAh per gram after 100 cycles.

The review also highlights a subtler kinetic phenomenon that may prove decisive for fast-charging applications: pseudocapacitance. Unlike conventional battery reactions, which depend on slow diffusion of ions deep into a bulk structure, pseudocapacitive charge storage arises from fast, reversible Faradaic reactions at or near the electrode surface. It is not a separate storage mechanism but a kinetic character that existing mechanisms can adopt, and it shows up in cyclic voltammetry as a current that scales more with sweep rate than diffusion would allow. Because MOFs and their derivatives expose abundant active sites on porous surfaces, they are unusually well suited to this behavior, and quantifying it has become central to explaining their exceptional rate capabilities.

The numbers involved are striking. Kinetic analysis of a bimetallic cobalt-iron framework attributed 96.62 percent of the charge storage to capacitive processes, compared with 70.27 percent for the cobalt-only and 39.63 percent for the iron-only versions. A tin-based framework reached an 85.39 percent capacitive contribution at high scan rates, and a nickel-based conductive MOF grown on reduced graphene oxide reached 67 percent while maintaining 880 mAh per gram after 500 cycles at 1 ampere per gram. Interestingly, the review notes a pattern: MOF-derived materials tend to show high capacitive contributions even at low scan rates thanks to their defects and nanoscale features, whereas pristine MOFs, with their more ordered frameworks, shift increasingly toward surface-controlled storage as scan rates rise.

None of these mechanisms can be confirmed by performance numbers alone, and the review devotes substantial attention to the diagnostic toolkit. X-ray photoelectron spectroscopy tracks oxidation-state changes that reveal whether metal centers or ligands are doing the redox work; infrared spectroscopy catches the formation and cleavage of bonds such as carbonyl-to-enolate conversions. Electron microscopy and elemental mapping document structural evolution and confirm uniform active-site distribution, while Raman spectroscopy can even show lithium inserting first at a framework’s boundaries before penetrating inward. Operando X-ray diffraction watches phase transitions in real time, distinguishing the gentle peak shifts of intercalation from the abrupt reconstruction of conversion reactions. Cyclic voltammetry, impedance spectroscopy, and galvanostatic intermittent titration quantify kinetics, and density functional theory calculations identify preferred lithium binding sites and diffusion barriers at the atomic scale.

The practical stakes are considerable. Anodes that combine multiple redox centers, hierarchical porosity, and pseudocapacitive kinetics could deliver capacities several times that of graphite while charging faster and lasting longer, addressing the twin demands of energy density and power that have constrained battery design for years. The review’s forward-looking agenda calls for multi-redox-active frameworks, engineered extra storage sites such as chemically varied aromatic rings, and, crucially, sustainability: avoiding toxic elements like the lead used in some high-performing frameworks, and pursuing green synthesis routes, including a cobalt-zinc MOF made from waste plastic in water that achieved a remarkable 2774 mAh per gram. If the field can convert mechanistic understanding into predictive design, MOF-based anodes may move from laboratory curiosity to the material foundation of the next battery generation.

Subject of Research: Lithium storage mechanisms and kinetics in MOF-based lithium-ion battery anodes

Article Title: Lithium storage mechanisms and kinetics in MOF-based anodes: from pristine frameworks to derived materials for high-performance lithium-ion batteries

Article References: Shi, D. (2026). Lithium storage mechanisms and kinetics in MOF-based anodes: from pristine frameworks to derived materials for high-performance lithium-ion batteries. Frontiers in Batteries and Electrochemistry, 5, Article 1836690. https://doi.org/10.3389/fbael.2026.1836690

Image Credits: AI Generated

DOI: 10.3389/fbael.2026.1836690

Keywords: metal-organic frameworks, lithium-ion batteries, anode materials, lithium storage mechanisms, pseudocapacitance, conversion reactions, alloying reactions, redox chemistry, MOF-derived materials, electrochemical kinetics, graphite anode, battery characterization