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Sodium‐metal batteries (SMBs) are considered as a promising route to realize a high energy density battery, showing potential for applications in large‐scale energy storage. However, the cycling stability and reversibility of the Na‐metal anode suffer from significant challenges because of the growth of Na dendrites. This study reports an active/inactive Co‐Sn alloy interface to suppress the growth of Na dendrites under harsh test conditions. In this interface, Sn provides abundant nucleation sites and Co plays a synergistic role in alleviating volume variation of Sn nanoparticles and increasing the interaction between Na and substrate, significantly promoting the uniform Na deposition and preventing the Na plating from the root of the deposited Na. Under High‐current‐density (12 mA cm−2) with a high depth of discharge (DOD, 66.67%), Na||Na can achieve stable cycling for over 4200 h at 4 mA h cm−2. When paired with a high‐loading NaTi2(PO4)3 cathode (10 mg cm−2), SMB delivers an excellent performance (800 cycles) at a negative‐to‐positive electrode capacity (N/P) ratio up to 2. [ABSTRACT FROM AUTHOR]

Sodium metal batteries are recognized as promising candidates for next‐generation energy storage devices, as a result of their high energy density, low redox potential, and cheap material price. Na metal anodes, however, generally exhibit notorious problems, including progressively thickened interfaces with active Na loss and Na metal dendrite growth with safety hazards. Herein, a lightweight aerogel consisting of MgF2 nanocrystals grown on a reduced graphene oxide (RGO) aerogel matrix (MgF2@RGO) is rationally designed as a multifunctional host material for Na metal anodes. The MgF2 nanocrystals can be electrochemically converted in situ into Mg and NaF nanograins during the first Na plating process, in which the Mg works as sodiophilic nucleation seeds for Na plating and NaF plays a key role in suppressing Na dendrite growth. Significantly, the Na metal anodes with the MgF2@RGO aerogel host deliver significantly enhanced Coulombic efficiency and dramatically improved cycling stability for more than 1600 h. The morphology evolution confirms the advantages of the Na metal anode with the MgF2@RGO host, which exhibits dense and flat interfaces. By pairing with the Na3V2(PO4)3 cathode, the Na metal batteries achieve stable cycling and good rate capability, suggesting the potential of the Na/MgF2@RGO anode for practical applications. [ABSTRACT FROM AUTHOR]

The undesirable Li dendrite growth and other knock‐on issues have significantly plagued the application of Li metal anodes (LMAs). Herein, we report that the synergistic regulation of double interfaces adjacent to the metallic Li anode can effectively prevent the dendritic Li growth, significantly improving the cycling performance of LMAs under harsh conditions including high current density and high depth of discharge. Thorough comparison of electrolytes demonstrated that 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2‐dimethoxyethane (DME) can yield a robust and lithiophobic LiF‐rich upper interface (solid electrolyte interphase). Besides, the Sb‐based buffer layer forms a lithiophilic lower interface on current collector. The synergy of the upper and lower interfacial engineering plays an important role for outstanding cyclability of LMAs. Consequently, the plating/stripping of Li can be stably repeated for 835 and 329 cycles with an average Coulombic efficiency (CE) above 99% at 1 and 3 mA h cm−2, respectively. Surprisingly, the Li||Li symmetric cell can even withstand the baptism of current density up to 20 mA cm−2. The excellent performance validates that the facile synergistic regulating of interfaces adjacent to the metallic Li anode provides an effective pathway to stabilize LMAs. [ABSTRACT FROM AUTHOR]

Sodium metal is an ideal anode material for metal rechargeable batteries, owing to its high theoretical capacity (1166 mAh g−1), low cost, and earth‐abundance. However, the dendritic growth upon Na plating, stemming from unstable solid electrolyte interphase (SEI) film, is a major and most notable problem. Here, a sodium benzenedithiolate (PhS2Na2)‐rich protection layer is synthesized in situ on sodium by a facile method that effectively prevents dendrite growth in the carbonate electrolyte, leading to stabilized sodium metal electrodeposition for 400 cycles (800 h) of repeated plating/stripping at a current density of 1 mA cm−2. The organic salt, PhS2Na2, is found to be a critical component in the protection layer. This finding opens up a new and promising avenue, based on organic sodium slats, to stabilize sodium metals with a protection layer. [ABSTRACT FROM AUTHOR]

• A novel anionic nanosheet electrolyte additive was proposed in aqueous Zn batteries. • High reversibility, evidenced by a high average CE as high as 99.6%, is achieved. • Long-term cycling, reflected by Zn plating/stripping over 3700 h, is attained. Metallic Zinc (Zn) has attracted great attention as a promising anode for aqueous batteries owing to its high theoretical capacity, low cost, and high natural abundance. However, Zn anode suffers from a crucial challenge, namely the growth of Zn dendrites, which brings not only a short life span but also severe safety concerns. In this work, we report that anionic tin sulfide nanosheets (TS-Ns) server as electrolyte additive to mitigate the dendrite growth. The negatively charge TS-Ns can attract the positive Zn2+ from the electrolyte through electrostatic interaction and increase the local concentration of Zn2+. Moreover, TS-Ns can co-deposit with Zn2+ at the initial deposition stage and then form an interfacial protection layer around the Zn surface, guiding the uniform deposition of Zn on cycling. The TS-Ns additive endow the Zn anode with excellent performance, reflected by stable cycling for 3700 h in a symmetric cell with a capacity of 0.2 mAh /cm2 and for 500 cycles in an asymmetric cell with an average coulombic efficiency of 99.6%. These merits bring high capacity and low polarization in Zn||MnO 2 full cells. We believe that TS-Ns additive provides a new pathway to achieve high-performance Zn metal anodes in aqueous electrolytes. [ABSTRACT FROM AUTHOR]