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In this study, the electrochemical performances of anthraquinone (C14H8O2) without modification, anthraquinone‐1‐sulfonic acid sodium (C14H7NaO5S) and anthraquinone‐1,5‐disulfonic acid disodium salts (C14H6Na2O8S2) as organic cathode materials for sodium‐ion batteries are reported for the first time. Ionizable sodium sulfonate functional groups lead to a significant enhancement of the structural stability of C14H8O2, yielding excellent cycle and rate performance. The C14H6Na2O8S2 and C14H7NaO5S electrodes exhibit initial discharge capacities of 195 and 209 mAh g−1, which are maintained at 131 and 93 mAh g−1, respectively, after 100 cycles at a current density of 30 mA g−1. Even at a high rate of 480 mA g−1, the initial discharge capacity of C14H6Na2O8S2 is 114 mAh g−1, indicating a high rate capability. Also, the results show that the carbonyl group is the Na+ storage location during charge/discharge. Owing to their superior electrochemical performance, these organic cathode materials demonstrate promise for use in environmentally friendly, sustainable sodium‐ion batteries. The electrochemical performances of anthraquinone (AQ) and the sodium and disodium salts (AQS and AQDS) as organic cathode materials for sodium‐ion batteries are studied. Ionizable sodium sulfonate functional groups lead to a significant enhancement of the structural stability of AQ, yielding excellent cycle and rate performances. [ABSTRACT FROM AUTHOR]

Abstract: Different dimensions of carbon materials with various features have captured numerous interests due to their applications on the tremendous fields. Restricted by the raw materials and devices, the controlling of their morphology is a major challenge. Utilizing the catalytic features of the intermediates from the low‐cost salts and polymerization of 0D carbon quantum dots (CQDs), 0D CQDs are expected to self‐assemble into 1/2/3D carbon structures with the assistance of temperature‐induced intermediates (e.g., ZnO, Ni, and Cu) from the salts (ZnCl2, NiCl2, and CuCl). The formation mechanisms are illustrated as follows: 1) the “orient induction” to evoke “vine style” growth mechanism of ZnO; 2) the “dissolution–precipitation” of Ni; and 3) the “surface adsorption self‐limited” of Cu. Subsequently, the degree of graphitization, interlayer distance, and special surface area are investigated in detail. 1D structure from 700 °C as anode displays a high Na‐storage capacity of 301.2 mAh g−1 at 0.1 A g−1 after 200 cycles and 107 mAh g−1 at 5.0 A g−1 after 5000 cycles. Quantitative kinetics analysis confirms the fundamentals of the enhanced rate capacity and the potential region of Na‐insertion/extraction. This elaborate work opens up an avenue toward the design of carbon with multidimensions and in‐depth understanding of their sodium‐storage features. [ABSTRACT FROM AUTHOR]

Room temperature sodium–sulfur batteries have emerged as promising candidate for application in energy storage. However, the electrodes are usually obtained through infusing elemental sulfur into various carbon sources, and the precipitation of insoluble and irreversible sulfide species on the surface of carbon and sodium readily leads to continuous capacity degradation. Here, a novel strategy is demonstrated to prepare a covalent sulfur–carbon complex (SC‐BDSA) with high covalent‐sulfur concentration (40.1%) that relies on SO3H (Benzenedisulfonic acid, BDSA) and SO42− as the sulfur source rather than elemental sulfur. Most of the sulfur is exists in the form of OS/CS bridge‐bonds (short/long‐chain) whose features ensure sufficient interfacial contact and maintain high ionic/electronic conductivities of the sulfur–carbon cathode. Meanwhile, the carbon mesopores resulting from the thermal‐treated salt bath can confine a certain amount of sulfur and localize the diffluent polysulfides. Furthermore, the CSxC bridges can be electrochemically broken at lower potential (<0.6 V vs Na/Na+) and then function as a capacity sponsor. And the R‐SO units can anchor the initially generated Sx2− to form insoluble surface‐bound intermediates. Thus SC‐BDSA exhibits a specific capacity of 696 mAh g−1 at 2500 mA g−1 and excellent cycling stability for 1000 cycles with 0.035% capacity decay per cycle. The covalent sulfur–carbon complex SC‐BDSA (S, 40.1%) with different chain lengths is prepared. The short‐chain bridges can be electrochemically broken at potential <0.6 V (Na/Na+) and then worked together with the long‐chain units as a capacity sponsor. The R‐SO parts anchor Sx2− to form insoluble surface‐bound intermediates, leading to a special capacity of ≈750 mAh g−1 over 200 cycles. [ABSTRACT FROM AUTHOR]

As a result of its high‐energy density, metal–selenides have demanded attention as a potential energy‐storage material. But they suffer from volume expansion, dissolved poly‐selenides and sluggish kinetics. Herein, utilizing' thermal selenization via the Kirkendall effect, microspheres of NiSe2 confined by carbon are successfully obtained from the self‐assembly of Ni‐precursor/PPy. The derived hierarchical hollow architecture increases the active defects for sodium storage, while the existing double N‐doped carbon layers significantly alleviate the volume swelling. As a result, it shows ultrafast rate capability, delivering a stable capacity of 374 mAh g−1, even after 3000 loops at 10.0 A g−1. These remarkable results may be ascribed to the NiOC bonds on the interface of NiSe2 and the carbon film, which leads to the faster transfer of ions, the effective trapping of poly‐selenide, and the highly reversible conversion reaction. The kinetic analysis of cyclic voltammetry (CV) demonstrates that the electrochemical process is mainly dominated by pseudocapacitive behaviors. Supported by the results of electrochemical impedance spectroscopy (EIS), it is confirmed that the solid–electrolyte interface films are reversibly formed/decomposed during cycling. Given this, this elaborate work might open up a potential avenue for the rational design of metal‐sulfur/selenide anodes for advanced battery systems. Hierarchial hollow‐structured NiSe2/N‐C with double carbon films are designed from the self‐assembled clew‐like Ni‐Pr by the Kirkendall effect. And it is found that incorporation of NiOC into the carbon layers enables tailoring of the interfacial traits, inducing the fascinating electrochemical behaviors. This elaborate work might open up a potential avenue for these rational TMDs anodes designs for advanced battery storage systems. [ABSTRACT FROM AUTHOR]