Search

Zn deposition with a surface‐preferred (002) crystal plane has attracted extensive attention due to its inhibited dendrite growth and side reactions. However, the nucleation and growth of the Zn(002) crystal plane are closely related to the interfacial properties. Herein, oriented growth of Zn(002) crystal plane is realized on Ag‐modified surface that is directly visualized by in situ atomic force microscopy. A solid solution HCP‐Zn (~1.10 at. % solubility of Ag, 30 °C) is formed on the Ag coated Zn foil (Zn@Ag) and possesses the same crystal structure as Zn to reduce its nucleation barrier caused by their lattice mismatch. It merits oriented Zn deposition and corrosion‐resistant surface, and presents long cycling stability in symmetric cells and full cells coupled with V2O5 cathode. This work provides insights into interfacial regulation of Zn anodes for high‐performance aqueous zinc metal batteries. [ABSTRACT FROM AUTHOR]

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]

Sodium dual‐ion batteries (Na‐DIBs) have attracted increasing attention due to their high operative voltages and low‐cost raw materials. However, the practical applications of Na‐DIBs are still hindered by the issues, such as low capacity and poor Coulombic efficiency, which is highly correlated with the compatibility between electrode and electrolyte but rarely investigated. Herein, fluoroethylene carbonate (FEC) is introduced into the electrolyte to regulate cation/anion solvation structure and the stability of cathode/anode‐electrolyte interphase of Na‐DIBs. The FEC modulates the environment of PF6− solvation sheath and facilitates the interaction of PF6− on graphite. In addition, the NaF‐rich interphase caused by the preferential decomposition of FEC effectively inhibits side reactions and pulverization of anodes with the electrolyte. Consequently, Sb||graphite full cells in FEC‐containing electrolyte achieve an improved capacity, cycling stability and Coulombic efficiency. This work elucidates the underlying mechanism of bifunctional FEC and provides an alternative strategy of building high‐performance dual ion batteries. [ABSTRACT FROM AUTHOR]

High‐voltage lithium‐ion batteries (LIBs) have attracted great attention due to their promising high energy density. However, severe capacity degradation is witnessed, which originated from the incompatible and unstable electrolyte‐electrode interphase at high voltage. Herein, a robust additive‐induced sulfur‐rich interphase is constructed by introducing an additive with ultrahigh S‐content (34.04 %, methylene methyl disulfonate, MMDS) in 4.6 V LiNi0.5Co0.2Mn0.3O2 (NCM523)||graphite pouch cell. The MMDS does not directly participate the inner Li+ sheath, but the strong interactions between MMDS and PF6− anions promote the preferential decomposition of MMDS and broaden the oxidation stability, facilitating the formation of an ultrathin but robust sulfur‐rich interfacial layer. The electrolyte consumption, gas production, phase transformation and dissolution of transition metal ions were effectively inhibited. As expected, the 4.6 V NCM523||graphite pouch cell delivers a high capacity retention of 87.99 % even after 800 cycles. This work shares new insight into the sulfur‐rich additive‐induced electrolyte‐electrode interphase for stable high‐voltage LIBs. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been regarded as promising cathode materials for alkali‐ion batteries owing to their high theoretical energy density and low cost. However, the high water and vacancy content of PBAs lower their energy density and bring safety issues, impeding their large‐scale application. Herein, a facile "potassium‐ions assisted" strategy is proposed to synthesize highly crystallized PBAs. By manipulating the dominant crystal plane and suppressing vacancies, the as‐prepared PBAs exhibit increased redox potential resulting in high energy density up to ≈450 Wh kg−1, which is at the same level of the well‐known LiFePO4 cathodes for lithium‐ion batteries. Remarkably, unconventional highly‐reversible phase evolution and redox‐active pairs were identified by multiple in situ techniques for the first time. The preferred guest‐ion storage sites and migration mechanism were systematically analysed through theoretical calculations. We believe these results could inspire the design of safe with high energy density. [ABSTRACT FROM AUTHOR]

Graphite shows great potential as an anode material for rechargeable metal‐ion batteries because of its high abundance and low cost. However, the electrochemical performance of graphite anode materials for rechargeable potassium‐ion batteries needs to be further improved. Reported herein is a natural graphite with superior rate performance and cycling stability obtained through a unique K+‐solvent co‐intercalation mechanism in a 1 m KCF3SO3 diethylene glycol dimethyl ether electrolyte. The co‐intercalation mechanism was demonstrated by ex situ Fourier transform infrared spectroscopy and in situ X‐ray diffraction. Moreover, the structure of the [K‐solvent]+ complexes intercalated with the graphite and the conditions for reversible K+‐solvent co‐intercalation into graphite are proposed based on the experimental results and first‐principles calculations. This work provides important insights into the design of natural graphite for high‐performance rechargeable potassium‐ion batteries. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) superlattices offer promising technological opportunities in tuning the intercalation chemistry of metal ions. Now, well‐ordered 2D superlattices of monolayer titania and carbon with tunable interlayer‐spacing are synthesized by a molecularly mediated thermally induced approach. The 2D superlattices are vertically encapsulated in hollow carbon nanospheres, which are embedded with TiO2 quantum dots, forming a 0D‐2D‐3D multi‐dimensional architecture. The multi‐dimensional architecture with the 2D superlattices encapsulated inside exhibits a near zero‐strain characteristic and enriched electrochemical reactivity, achieving a highly efficient Na+ storage performance with exceptional rate capability and superior long‐term cyclability. [ABSTRACT FROM AUTHOR]

Considering that the high capacity, long-term cycle life, and high-rate capability of anode materials for sodium-ion batteries (SIBs) is a bottleneck currently, a series of Co-doped FeS2 solid solutions with different Co contents were prepared by a facile solvothermal method, and for the first time their Na-storage properties were investigated. The optimized Co0.5Fe0.5S2 (Fe0.5) has discharge capacities of 0.220 Ah g−1 after 5000 cycles at 2 A g−1 and 0.172 Ah g−1 even at 20 A g−1 with compatible ether-based electrolyte in a voltage window of 0.8-2.9 V. The Fe0.5 sample transforms to layered Na xCo0.5Fe0.5S2 by initial activation, and the layered structure is maintained during following cycles. The redox reactions of Na xCo0.5Fe0.5S2 are dominated by pseudocapacitive behavior, leading to fast Na+ insertion/extraction and durable cycle life. A Na3V2(PO4)3/Fe0.5 full cell was assembled, delivering an initial capacity of 0.340 Ah g−1. [ABSTRACT FROM AUTHOR]