Metal‐organic frameworks (MOFs) are of quite a significance in the field of inorganic‐organic hybrid crystals. Especially, MOFs have attracted increasing attention in recent years due to their large specific surface area, desirable electrical conductivity, controllable porosity, tunable geometric structure, and excellent thermal/chemical stability. Some recent studies have shown that carbon materials prepared by MOFs as precursors can retain the privileged structure of MOFs, such as large specific surface area and porous structure and, in contrast, realize in situ doping with heteroatoms (eg, N, S, P, and B). Moreover, by selecting appropriate MOF precursors, the composition and morphology of the carbon products can be easily adjusted. These remarkable structural advantages enable the great potential of MOF‐derived carbon as high‐performance energy materials, which to date have been applied in the fields of energy storage and conversion systems. In this review, we summarize the latest advances in MOF‐derived carbon materials for energy storage applications. We first introduce the compositions, structures, and synthesis methods of MOF‐derived carbon materials, and then discuss their applications and potentials in energy storage systems, including rechargeable lithium/sodium‐ion batteries, lithium‐sulfur batteries, supercapacitors, and so forth, in detail. Finally, we put forward our own perspectives on the future development of MOF‐derived carbon materials.

The capacity degredation in layered Ni-rich LiNi x Co y Mn z O2 (x ≥ 0.8) cathode largely originated from drastic surface reactions and intergranular cracks in polycrystalline particles. Herein, we report a highly stable single-crystal LiNi0.83Co0.12Mn0.05O2 cathode material, which can deliver a high specific capacity (∼209 mAh g–1 at 0.1 C, 2.8–4.3 V) and meanwhile display excellent cycling stability (>96% retention for 100 cycles and >93% for 200 cycles). By a combination of in situ X-ray diffraction and in situ pair distribution function analysis, an intermediate monoclinic distortion and irregular H3 stack are revealed in the single crystals upon charging–discharging processes. These structural changes might be driven by unique Li-intercalation kinetics in single crystals, which enables an additional strain buffer to reduce the cracks and thereby ensure the high cycling stability.

The correlation between structure and function lies at the heart of materials science and engineering. Especially, modern functional materials usually contain inhomogeneities at an atomic level, endowing them with interesting properties regarding electrons, phonons, and magnetic moments. Over the past few decades, many of the key developments in functional materials have been driven by the rapid advances in short‐range crystallographic techniques. Among them, pair distribution function (PDF) technique, capable of utilizing the entire Bragg and diffuse scattering signals, stands out as a powerful tool for detecting local structure away from average. With the advent of synchrotron X‐rays, spallation neutrons, and advanced computing power, the PDF can quantitatively encode a local structure and in turn guide atomic‐scale engineering in the functional materials. Here, the PDF investigations in a range of functional materials are reviewed, including ferroelectrics/thermoelectrics, colossal magnetoresistance (CMR) magnets, high‐temperature superconductors (HTSC), quantum dots (QDs), nano‐catalysts, and energy storage materials, where the links between functions and structural inhomogeneities are prominent. For each application, a brief description of the structure‐function coupling will be given, followed by selected cases of PDF investigations. Before that, an overview of the theory, methodology, and unique power of the PDF method will be also presented.

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Low-cost Pt-CoP hollow polyhedra exhibited prominent performance for the HER in both basic and neutral solutions.

Ternary NiCo 2 O 4 has attracted tremendous interest as a type of prospective electrochemical energy storage material. Hence, a facile and economical preparation method for N-doped carbon-coated NiCo 2 O 4 (NiCo 2 O 4 @NC) nanowire array electrodes is reported by simply dipping the NiCo 2 O 4 nanowire arrays grown on Ni foam substrate into a dopamine aqueous solution followed by annealing in an argon atmosphere. The hybrid NiCo 2 O 4 @NC nanowire arrays grown on a Ni foam substrate is directly employed as a 3D-structure porous electrode without adhesive. Compared with the original NiCo 2 O 4 nanowire array electrode, the hierarchical hybrid NiCo 2 O 4 @NC nanowire array electrode delivers a higher capacitance, better rate performance, and excellent stability (final capacity remains 91.3% at 10 A g −1 after 5000 test cycles). An asymmetric supercapacitor based on NiCo 2 O 4 @NC//active carbon is designed and achieves a high energy density of 29.4 Wh kg −1 at a power density of 349 W kg −1 with superior capacitance retention of 97.3% at 5 A g −1 after 15,000 cycles. The improvement of the electrochemical energy storage property demonstrates the potential of the hierarchical NiCo 2 O 4 @NC nanowire array electrode in the electrochemical energy field.

Rechargeable lithium-ion and sodium-ion batteries (SIB) have dominated the energy storage fields such as electric vehicles and portable electronics due to their high energy density, long cycle life, and environmental friendliness. However, the critical bottleneck hindering the further improvement of their electrochemical performance is the unsatisfactory cathode materials, typically exhibiting inherent drawbacks such as low reversible capacity, initial capacity loss, fast capacity decay, and poor rate performance. These issues are mainly attributed to changes in the internal structure of cathode materials, such as irreversible transformation of particle morphology, evolution of crystal structure, and undesired physicochemical interfacial reactions during the electrochemical process. To address above obstacles, abundant research efforts have been devoted to stabilizing the structural evolution of cathode materials and enhancing their electrochemical performance. Herein, we reviewed the research progress on the cathode materials for lithium-ion and SIBs. The typical cathodes and their structural characteristics, electrochemical behaviors, reaction mechanisms, and strategies for electrochemical performance optimization were summarized. This review aims to promote the understanding of the structure-performance relationship in the cathode materials and provide some guidance for the design of advanced cathode materials for lithium-ion and SIBs from the perspective of crystal structure.