Capacity‐Limited Na–M foil Anode: toward Practical Applications of Na Metal Anode

Abstract

The practical applications of Na metal anodes are severely plagued by unstable Na plating/stripping. Here the fabrication of Na‐rich Na–M (M = Au, Sn, and In) alloy anodes is reported as promising alternatives to address this issue. As compared to metallic Na foil anodes, the alloy foils exhibit improved electrolyte/electrode interface and provide abundant sodiophilic sites for efficient Na plating, while the self‐evolved porous Na‐M structures accommodate volume variation on cycling. Among three alloy foils, the Na–Au system shows the most promising performance. Under practical conditions such as capacity‐limited anodes (5 mAh cm−2) and large stripping/plating capacity (1.0 mAh cm−2), the Na0.9Au0.1 anodes demonstrate stable plating/stripping over 350 h. The proof‐of‐concept full cells assembled with hard carbon or Prussian blue materials and this thin Na0.9Au0.1 anode also have much elongated cycling life than for pristine Na metal anodes. These findings confirm that the rational design of Na–M alloy anodes can be a promising strategy to promote the development of Na metal batteries.

In Situ Construction of Sodiophilic Alloy Interface Enabled Homogenous Na Nucleation and Deposition for Sodium Metal Anode

“…Therefore, homogenous distribution of sodiophilic sites can uniform the nucleation and deposition of Na. In the choice of a variety of sodiophilic sites, alloying strategies (e.g., Na-Sn, Na-Au, Na-In, Na-Sb) [26][27][28][29] have recently been selected and studied by many researchers, and their effectiveness and extensive research prospects have been widely validated, even in other alkali metal anodes (Li@MnZnO/CNF, Zn@Cu). 30,31 Unfortunately, the sodiophilic alloying interfaces are often faced with complex fabrication methods or uneven distribution of sodiophilic sites.…”

Synergistic Manipulation of Na+ Flux and Surface‐Preferred Effect Enabling High‐Areal‐Capacity and Dendrite‐Free Sodium Metal Battery

“…The electrochemical impedance spectroscopy (EIS) displays that the Na/NaSn|Na/NaSn battery has a smaller diameter of half cycle than that of Na|Na battery, suggesting the improved charge transfer capability owing to the excellent sodiophilic property of Na–Sn alloy (Figure 2f ). [ 16 ] After 50 cycles, the diameter for Na/NaSn|Na/NaSn battery decreases, indicative of the reduced charge resistance, further demonstrating the outperformed cycling stability and low stripping/plating potential (Figure S9 , Supporting Information). The early stage of Na nucleation and growing process on the surface of electrodes were investigated by chronoamperometry method, as shown in Figure 2g .…”

Emerging Solutions to Enable the Efficient Use of Sodium Metal Anodes: Progress and Perspectives

“…[116] For instance, He et al report the preparation of a variety of Na-Au, Na-In, and Na-Sn alloys through with melting-rolling process (Figure 14a). [117] Among three alloy foils, the Na-Au system has the most prominent performance. The introduction of Au creates evolved sodipphilic porous structures for the subsequent Na plating.…”