Metal-organic frameworks (MOFs) are a class of porous materials with unprecedented chemical and structural tunability. Their synthetic versatility, long-range order, and rich host-guest chemistry make MOFs ideal platforms for identifying design features for advanced functional materials. This review addresses synthetic approaches to control MOF attributes for realizing material properties such as charge conductivity, stability, surface area, and flexibility. Along with an updated account on MOFs employed in batteries and supercapacitors, new directions are outlined for advancing MOF research in emergent technologies such as solid-state electrolytes and battery operation in extreme environments. G lobal demands for clean energy storage and delivery continue to push developing technology to its limits. Batteries and supercapacitors are among the most promising technologies for electrical energy storage owing to their portability and compact size for on-demand usage. Despite their promise, chemical and physical limitations of existing materials hinder performance and require new, creative solutions. For instance, polymers and conductive carbon materials are relatively inexpensive, scalable, and synthetically tunable but can lack physical and chemical stability for device implementation. On the other hand, solid inorganic materials, such as metal oxides and silicon, are used as electrode materials due to their robust structure and redox-active sites. However, sluggish ion diffusion of metal oxides limit charge/ discharge rate capabilities and large volumetric changes lead to mechanical instability. Drawbacks in these current platforms motivate the discovery and development of new materials for advanced energy storage devices. Metal-organic frameworks (MOFs) are attractive candidates to meet the needs of nextgeneration energy storage technologies. MOFs are a class of porous materials composed of metal nodes and organic linkers. Their modular nature allows for great synthetic tunability, affording both fine chemical and structural control. With creative synthetic design, properties such as porosity, stability, particle morphology, and conductivity can be tailored for specific applications. As the needs of each energy storage device are different, this synthetic versatility of MOFs provides a method to optimize materials properties to combat inherent electrochemical

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Lithium sulfur (Li−S) battery technology is one of the most promising candidates for next-generation energy storage devices; however, it is still hindered by limited capacity yield and poor long-term stability. The complexity of these devices has hindered efforts to study electrochemical determinants of battery performance, impeding advancement of the field. Due to the ease of functionalization, metal−organic frameworks (MOFs) are unique platforms to explore such reactions, where integration of defects into the crystalline structure provides a convenient method for introducing synthetic handles. In Zr-based MOFs such as UiO-66, the engineered defect sites contain acidic protons that can be replaced with lithium ions, transforming defected MOFs into a range of materials with tunable lithium content. Our results demonstrate the capability of this facile lithiation procedure to create novel cathode additives and evaluate their influence on Li−S battery performance. By improving ionic conductivity and dispersion of sulfur species, lithiated MOFs enhance both sulfur utilization and capacity retention at a variety of cycling rates compared to the as-synthesized MOFs. Our general synthetic strategy has the potential to be applied to technologies beyond MOFs, including polymeric and inorganic materials. Ultimately, we illustrate that defected MOFs can be used to systematically control lithiation, currently unprecedented in conventional inorganic materials, and provide a window to examine heterogeneous reactions relevant to energy conversion and storage.

In an age of rapid acceleration toward next-generation energy storage technologies, lithium–sulfur (Li–S) batteries offer the desirable combination of low weight and high specific energy. Metal–organic frameworks (MOFs) have been recently studied as functionalizable platforms to improve Li–S battery performance. However, many MOF-enabled Li–S technologies are hindered by low capacity retention and poor long-term performance due to low electronic conductivity. In this work, we combine the advantages of a Zr-based MOF-808 loaded with sulfur as the active material with a graphene/ethyl cellulose additive, leading to a high-density nanocomposite electrode requiring minimal carbon. Our electrochemical results indicate that the nanocomposites deliver enhanced specific capacity over conventionally used carbon/binder mixtures, and postsynthetic modification of the MOF with lithium thiophosphate results in further improvement. Furthermore, the dense form factor of the sulfur-loaded MOF–graphene nanocomposite electrodes provides high volumetric capacity compared to other works with significantly more carbon additives. Overall, we have demonstrated a proof-of-concept paradigm where graphene nanosheets facilitate improved charge transport because of enhanced interfacial contact with the active material. This materials engineering approach can likely be extended to other MOF systems, contributing to an emerging class of two-dimensional nanomaterial-enabled Li–S batteries.

An optical centrifuge pulse drives carbon dioxide molecules into ultrahigh rotational states with rotational frequencies of ω ≈ 32 THz based on the centrifuge frequency at the full width at half-maximum of the spectral chirp. High-resolution transient IR absorption spectroscopy is used to measure the time-evolution of translational and rotational energy for a number of states in the range of J = 0-100 at a sample pressure of 5-10 Torr. Transient Doppler profiles show that the products of super rotor collisions contain substantial amounts of translational energy, with J-dependent energies correlating to a range of ΔJ propensities. The transient population in J = 100 is short-lived, indicating rapid relaxation of high J states; populations in J = 36, 54, and 76 increase overall as the super rotor energy is redistributed. Transient line profiles for J = 0 and 36 are consistently narrower than the initial ambient sample temperature, showing that collision cross sections for super rotors increase with decreasing collision energy. Quantum scattering calculations on Ar-CO2(j) collisions are used to interpret the qualitative features of the experimental results. The results of this study provide the groundwork for developing a more complete understanding of super rotor dynamics.

Demands for energy storage and delivery continue to rise worldwide, making it imperative that reliable performance is achievable in diverse climates. Lithium−sulfur (Li−S) batteries offer a promising alternative to lithium-ion batteries owing to their substantially higher specific capacity and energy density. However, improvements to Li−S systems are still needed in low-temperature environments where polysulfide clustering and solubility limitations prohibit complete charge/discharge cycles. We address these issues by introducing thiophosphate-functionalized metal− organic frameworks (MOFs), capable of tethering polysulfides, into the cathode architecture. Compared to cells with the parent MOFs, cells containing the functionalized MOFs exhibit greater capacity delivery and decreased polarization for a range of temperatures down to −10 °C. We conduct thorough electrochemical analyses to ascertain the origins of performance differences and report an altered Li−S redox mechanism enabled by the thiophosphate moiety. This investigation is the first low-temperature Li−S study using MOF additives and represents a promising direction in enabling energy storage in extreme environments.

We report the synthesis of a set of 2D metal–organic frameworks (MOFs) constructed with organosilicon‐based linkers. These oligosilyl MOFs feature linear SinMe2n(C6H4CO2H)2 ligands (lin‐Sin, n=2, 4) connected by Cu paddlewheels. The stacking arrangement of the 2D sheets is dictated by van der Waals interactions and is tunable by solvent exchange, leading to reversible structural transformations between many crystalline and amorphous phases.

Lithium-sulfur (Li-S) batteries have great potential as next generation batteries. However, the redox chemistry mechanism involves the generation of solubilized lithium polysulfides, which can lead to leaching of the active...