and the global desire to avoid the most destructive consequences of climate change led to an exponential growth of research into alternative and sustainable battery technologies. [1][2][3][4] While transitionmetal-based inorganic compounds have been primarily used as cathodes, especially in Li-ion batteries (LIBs), the pace of the development of organic electrode materials continues to accelerate. [2] Organic compounds are considered to be more environment-friendly compared to their inorganic counterparts. They are also composed of light and naturally abundant elements (C, H, N, O, and S) eliminating the need for expensive and toxic metals, and can be prepared directly from renewable resources or synthesized from readily available small molecules. As a result, organic electrode materials could reduce energy consumption and CO 2 release during mass production, unlike materials containing transition metals which come from exhaustible mineral resources and require intensive mining, processing, and disposal. Small-molecule organic compounds can be rationally designed and synthesized with high precision to contain welldefined redox-active functional groups. Due to this unparalleled chemical and structural tunability, a large number of Organic electrode materials possess many advantages such as low toxicity, sustainability, and chemical/structural tunability toward high energy density. However, to compete with inorganic-based compounds, crucial aspects such as redox potential, capacity, cycling stability, and electronic conductivity need to be improved. Herein, a comprehensive strategy on the molecular design of small organic electron-acceptor-molecule-hexaazatrianthranylene (HATA) embedded quinone (HATAQ) is reported. By introducing conjugated quinone moieties into the electron-deficient hexaazatriphenylene-derivative core, HATAQ with highly extended π-conjugation can yield extra-high capacity for lithium storage, delivering a capacity of 426 mAh g −1 at 200 mA g −1 (0.4C). At an extremely high rate of 10 A g −1 (19C), a reversible capacity of 209 mAh g −1 corresponding to nearly 85% retention is obtained after 1000 cycles. A unique network of unconventional lockand-key hydrogen bonds in the solid-state facilitates favorable supramolecular 2D layered arrangement, enhancing cycling stability. To the best of the authors' knowledge, the capacity and rate capability of HATAQ are found to be the best ever reported for organic small-molecule-based cathodes. These results together with density functional theory studies provide proof-of-concept that the design strategy is promising for the development of organic electrodes with exceptionally high energy density, rate capability, and cycling stability.

A series of F‐substituted Na2/3Ni1/3Mn2/3O2−xFx (x = 0, 0.03, 0.05, 0.07) cathode materials have been synthesized and characterized by solid‐state 19F and 23Na NMR, X‐ray photoelectron spectroscopy, and neutron diffraction. The underlying charge compensation mechanism is systematically unraveled by X‐ray absorption spectroscopy and electron energy loss spectroscopy (EELS) techniques, revealing partial reduction from Mn4+ to Mn3+ upon F‐substitution. It is revealed that not only Ni but also Mn participates in the redox reaction process, which is confirmed for the first time by EELS techniques, contributing to an increase in discharge specific capacity. The detailed structural transformations are also revealed by operando X‐ray diffraction experiments during the intercalation and deintercalation process of Na+, demonstrating that the biphasic reaction is obviously suppressed in the low voltage region via F‐substitution. Hence, the optimized sample with 0.05 mol f.u.−1 fluorine substitution delivers an ultrahigh specific capacity of 61 mAh g−1 at 10 C after 2000 cycles at 30 °C, an extraordinary cycling stability with a capacity retention of 75.6% after 2000 cycles at 10 C and 55 °C, an outstanding full battery performance with 89.5% capacity retention after 300 cycles at 1 C. This research provides a crucial understanding of the influence of F‐substitution on the crystal structure of the P2‐type materials and opens a new avenue for sodium‐ion batteries.

Porous nickel/carbon (Ni/C) composite microspheres with diameters of ca. 1.2-1.5 μm were fabricated by a solvothermal method combined with carbon reduction. The pore size of the synthesized Ni/C composite microspheres ranged from several nanometers to 50 nm. The porous Ni/C composite microspheres exhibited a saturation magnetization (MS) of 53.5 emu g(-1) and a coercivity (HC) of 51.4 Oe. When tested as an electromagnetic (EM) wave absorption material, the epoxy resin composites containing 60% and 75% porous Ni/C microspheres provided high-performance EM wave absorption at thicknesses of 3.0-11.0 and 1.6-7.0 mm in the corresponding frequency ranges of 2.0-12 and 2.0-18 GHz, respectively. The superior EM wave absorption performances of porous Ni/C composite microspheres were derived from the synergy effects generated by the magnetic loss of nickel, the dielectric loss of carbon, and the porous structure.

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With the rapid development of energy storage systems in power supplies and electrical vehicles, the search for sustainable cathode materials to enhance the energy density of lithium‐ion batteries (LIBs) has become the focus in both academic and industrial studies. Currently, the widely utilized inorganic cathode materials suffer from drawbacks such as limited capacity, high energy consumption in production, safety hazards, and high‐cost raw materials. Therefore, it is necessary to develop green and sustainable cathode materials with higher specific capacity, better safety properties, and more abundant natural resources. As alternatives, organic cathode materials possess the advantages of high theoretical capacity, environmental friendliness, flexible structure design, systemic safety, and natural abundance, making them a promising class of energy storage materials. Herein, the development history of the organic cathode materials and recent research developments are reviewed, introducing several categories of typical organic compounds as cathode materials for LIBs, including conductive polymers, organosulfur compounds, radical compounds, carbonyl compounds, and imine compounds. The electrochemical performance, electrode reaction mechanism, and pros and cons of different organic cathode materials are comparatively analyzed to identify the challenges to be addressed. Finally, the future research and improvement directions of the organic cathode materials are also proposed.