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Alloying‐type antimony (Sb) with high theoretical capacity is a promising anode candidate for both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Given the larger radius of Na+ (1.02 Å) than Li+ (0.76 Å), it was generally believed that the Sb anode would experience even worse capacity degradation in SIBs due to more substantial volumetric variations during cycling when compared to LIBs. However, the Sb anode in SIBs unexpectedly exhibited both better electrochemical and structural stability than in LIBs, and the mechanistic reasons that underlie this performance discrepancy remain undiscovered. Here, using substantial in situ transmission electron microscopy, X‐ray diffraction, and Raman techniques complemented by theoretical simulations, we explicitly reveal that compared to the lithiation/delithiation process, sodiation/desodiation process of Sb anode displays a previously unexplored two‐stage alloying/dealloying mechanism with polycrystalline and amorphous phases as the intermediates featuring improved resilience to mechanical damage, contributing to superior cycling stability in SIBs. Additionally, the better mechanical properties and weaker atomic interaction of Na−Sb alloys than Li−Sb alloys favor enabling mitigated mechanical stress, accounting for enhanced structural stability as unveiled by theoretical simulations. Our finding delineates the mechanistic origins of enhanced cycling stability of Sb anode in SIBs with potential implications for other large‐volume‐change electrode materials. [ABSTRACT FROM AUTHOR]

Developing high‐capacity conversion‐type anodes with superior durability substituting conventional graphite anodes is urgently desired to improve the energy density of lithium‐ion batteries (LIBs). However, fatal capacity decay during cycling of the conversion‐type anodes, which is primarily due to their inevitable structural degradation and continuous solid‐electrolyte interphase reformation induced by drastic volume change, has highly restricted their commercialization. And, the interrelated effects of phase transformation, structural evolution, and electrochemical characteristics of the conversion‐type anodes during cycling remain poorly understood. Herein, the findings on the fabrication and understanding of a previously unexplored entropy‐stabilized spinel oxide, (Co0.2Mn0.2V0.2Fe0.2Zn0.2)3O4 as a promising conversion anode for LIBs, exhibiting not only moderate volume change character but also highly reversible capacities of ≈900 mAh g−1 for 500 cycles at 0.2 A g−1 and ≈500 mAh g−1 for 2000 cycles at 3 A g−1, respectively, are reported. Evidenced by in situ transmission electron microscopy coupled with theoretical calculations, its underlying mechanism underpinning highly reversible Li storage is explicitly revealed, which originates from reversible phase transformation and domain reconstruction during cycling. Moreover, the origin of small volume change is also clearly clarified. This work provides renewed mechanistic insights into designing high‐capacity and durable conversion‐type electrode materials for high‐performance LIBs. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)‐based materials merit high theoretical volumetric specific capacity (3800 mAh mL⁻1) but suffer from huge volume variations and sluggish reaction kinetics during cycling. Herein, the optimal framework of Bi/Bi2O3 nanodots enriched in suitable outer amorphous carbon sheets (Bi/Bi2O3 NDs@CSs) is first proposed to alleviate volume variations and accelerate stable charge transport to boost K+ storage performance. The introduction of proper Bi2O3 not only provides an efficient K+ adsorption path, but also effectively buffers volume changes via conversion reaction. Accordingly, the as‐prepared anode exhibits a remarkable rate capability (149.3 mAh g−1 at 60 A g−1, 42% capacity retention with a 120‐fold current‐density increase) and extraordinary durability (1800 cycles at 5.0 A g−1, 95% capacity retention), among the best rate and cycling performance to date in potassium ion batteries (PIBs) anodes. Theoretical calculations reveal the feasible structures of Bi/Bi2O3 NDs@CSs with double protection of carbon sheets and Bi2O3 are conducive to enhance charge transfer and efficiency of electrochemical reaction. Substantial in situ/ex situ characterizations and finite element simulation further unveil high reversibility and robust mechanical behavior of Bi/Bi2O3 NDs@CSs, favorable for the reinforcement of structural stability. This study provides new insights into developing high‐performance and durable Bi‐based anodes for PIBs. [ABSTRACT FROM AUTHOR]

N‐doped carbons, as promising anode materials for energy storage, are generally modified by the additional heteroatoms (B, P, and S) doping to further promote the electrochemical performance. However, the promotion mechanism by such additional doping, especially its interplay with N‐containing species, remains unclear. Herein, by adopting N/S co‐doped carbon as a model system, it is found that S‐doping can significantly improve the content of pyridinic‐N, i.e., the most energetically favorable N type for K+ storage. Theoretical calculations reveal that such S‐induced pyridinic‐N improvement possibly originates from its catalytic effect that can facilitate the transition from edge quaternary‐N to pyridinic‐N. The resultant high content of pyridinic‐N, together with the additional S species, ensures abundant active sites for K+ storage. Accordingly, the N/S co‐doped carbon anode delivers both a high reversible capacity (422.9 mA h g−1 at 0.05 A g−1) and an impressive cyclic stability (249.6 mA h g−1 at 1 A g−1 over 4000 cycles). Moreover, in/ex situ characterizations further verify the merits of N/S co‐doped carbon from the perspective of compositional evolution and structural stability. This study unravels the origin of enhanced K+ storage by N/S co‐doping, which also helps to understand the synergistic effects of other heteroatoms co‐doping systems. [ABSTRACT FROM AUTHOR]

Zinc ion batteries (ZIBs) have been gradually developed in recent years due to their abundant resources, low cost, and environmental friendliness. Therefore, ZIBs have received a great deal of attention from researchers, which are considered as the next generation of portable energy storage systems. However, poor overall performance of ZIBs restricts their development, which is attributed to zinc dendrites and a series of side reactions. Constructing 3D zinc anodes has proven to be an effective way to significantly improve their electrochemical performance. In this review, the challenges of zinc anodes in ZIBs, including zinc dendrites, hydrogen evolution and corrosion, as well as passivation, are comprehensively summarized and the energy storage mechanisms of the zinc anodes and 3D zinc anodes are discussed. 3D zinc anodes with different structures including fiberous, porous, ridge‐like structures, plated zinc anodes on different substrates and other 3D zinc anodes, are subsequently discussed in detail. Finally, emerging opportunities and perspectives on the material design of 3D zinc anodes are highlighted and challenges that need to be solved in future practical applications are discussed, hopefully illuminating the way forward for the development of ZIBs. [ABSTRACT FROM AUTHOR]

The application of alloying‐typed red phosphorus (red P) anode in potassium‐ion batteries (KIBs) with ultra‐high theoretical capacity is hindered by the limited capacity and fast capacity decay due to poor electronic conductivity and huge volume change. Herein, a facile and efficient strategy of fluorine (F) doping is innovatively developed to modulate the pore structure of carbon matrix (F‐CNS) to encapsulate red P with enhanced potassium storage capability. Theoretical calculations reveal that F doping induces additional defects within the carbon layer, which facilitates P4 molecules embedding into the F‐doping‐induced micropores, enhances the adsorption ability toward K atoms and P4 molecules, and improves electrochemical kinetics assisted with more charge transfer obtained from the electron density difference, thus enabling robust potassium storage capability for such unique Red P@F‐CNS anode. Accordingly, the Red P@F‐CNS anode demonstrates outstanding cycling stability (90% capacity retention after 800 cycles at 2A g−1), and the potassium‐ion full cell (Red P@F‐CNS//KFeHCF) exhibits exceptional long‐term cycling performance (129 mAh g−1 after 2500 cycles at 5 A g−1 with only 0.014% decay per cycle). In situ characterizations confirm the superior structural integrity of the carbon‐based matrix. This study offers a rational design principle for engineering high‐performance carbon‐supported alloying‐typed anodes for KIBs. [ABSTRACT FROM AUTHOR]

Anthracite-derived soft carbon rich in closed nanopores and significantly suppressed graphitization is synthesized through a kinetically controlled flash sintering strategy. This advancement has achieved a grealty extended low-voltage plateau for soft carbon, exhibiting a high Na+-ion storage capacity of 309 mAh g−1 at 0.1 C. This work promotes the large-scale preparation and commercial application of low-cost soft carbon anodes for future sodium-ion batteries. [Display omitted] • Anthracite-derived soft carbon is synthesized through a flash sintering strategy. • Anthracite-derived soft carbon is rich in closed nanopores and reduced graphitization. • The soft carbon exhibits a significantly-extended low-voltage plateau below 0.1 V. • The soft carbon demonstrates a high Na+-ion storage capacity of 309 mAh g−1 at 0.1 C. • Our work promotes the commercial application of high-capacity soft carbon anodes. Soft carbon, characterized by its abundant reserves, low cost, and high carbon yield, should have been an important choice for anode materials in sodium-ion batteries (SIBs), similar to hard carbon. However, traditional high-temperature synthesis tends to graphitize soft carbon, which is extremely detrimental to the adsorption and intercalation of Na+ ions. This raises a highly challenging scientific question: whether it is possible to suppress the graphitization of soft carbon and transform it towards closed nanopores favorable for Na+ storage during high-temperature treatment. Herein, we introduce flash Joule heating (FJH) technology to treat anthracite with rapid heating and quenching, obtaining metastable soft carbon (anthracite-FJH) containing a large number of short-range ordered graphitic microdomains and their assembled closed nanopores. Benefiting from the abundant closed nanopores, this kinetically-controlled soft carbon exhibits a significantly enhanced Na+ adsorption and pore-filling capacity of 309 mAh g−1 at 0.1 C, dominantly contributed by the low-voltage plateau. Moreover, a reversible specific capacity of 256.2 mAh g−1 is maintained at 0.5 C with a capacity retention of 93.2 % after 200 cycles. We experimentally and theoretically explicitly disclose the "carbon microstructure regulation-Na+ storage mechanism" relationship. This work paves the way for the disruptive synthesis of high-capacity soft carbon SIB anodes based on anthracite. [ABSTRACT FROM AUTHOR]