A Series of Hybrid Multifunctional Interfaces as Artificial SEI Layer for Realizing Dendrite Free, and Long‐Life Sodium Metal Anodes

Abstract

Sodium metal (Na) anodes are considered the most promising anode for high‐energy‐density sodium batteries because of their high capacity and low electrochemical potential. However, Na metal anode undergoes uncontrolled Na dendrite growth, and unstable solid electrolyte interphase layer (SEI) formation during cycling, leading to poor coulombic efficiency, and shorter lifespan. Herein, a series of Na‐ion conductive alloy‐type protective interface (Na‐In, Na‐Bi, Na‐Zn, Na‐Sn) is studied as an artificial SEI layer to address the issues. The hybrid Na‐ion conducting SEI components over the Na‐alloy can facilitate uniform Na deposition by regulating Na‐ion flux with low overpotential. Furthermore, density functional study reveals that the lower surface energy of protective alloys relative to bare Na is the key factor for facilitating facile ion diffusion across the interface. Na metal with interface layer facilitates a highly reversible Na plating/stripping for ≈790 h, higher than pristine Na metal (100 h). The hybrid self‐regulating protective layers exhibit a high mechanical flexibility to promote dendrite free Na plating even at high current density (5 mA cm−2), high capacity (10 mAh cm−2), and good performance with Na3V2(PO4)3 cathode. The current study opens a new insight for designing dendrite Na metal anode for next generation energy storage devices.

Synergy of Cu-foam/Sb2O3/rGO for stable potassium anodes of high-rate and low-temperature potassium metal batteries

“…S25a†). 52 These results indicate that the inorganic composition can significantly contribute to the stability of the SEI layer. The synergistic effect of both inorganic and organic SEI layers can enhance the cycling stability of the cell at elevated current and capacity levels.…”

“…Although Cu@Cu 2 Sb is able to cycle at −20 °C, when the temperature rose back to −10 °C a steep drop in voltage polarization can occur, which is due to the instability of the voltage polarization caused by the un-protected unstable Sb alloy sites in the SEI film. 52 Furthermore, a long cycling test at −20 °C shows that Cu@Sb 2 O 3 @rGO can still be stably cycled for more than 6000 minutes at −20 °C and maintain a stable voltage polarization (Fig. 5b–c).…”

Wide-temperature-range sodium-metal batteries: from fundamentals and obstacles to optimization

“…22a describes the diffusion-path simulation of Na + in the (100) crystal planes of NaSn 2 , NaIn and NaBi, respectively. 519 Green represents the Na + diffusion path between different adsorption sites. Specifically, the activation barriers of different pathways were calculated, as shown in Fig.…”

3D mixed ion/electron-conducting scaffolds for stable sodium metal anodes

“…Currently, researchers are engaged in exploring three main strategies to solve the aforementioned issues: (I) the optimization of electrolyte composition and additives; 23–25 (II) the development of artificial SEIs; 26–30 (III) the utilization of three-dimensional (3D) conductive scaffolds for fabricating composite Na–scaffold anodes (CSSAs). 31–36 However, the first two strategies can only sustain the prolonged cycling life of Na metal anodes at low current densities and low areal capacities, but are unable to withstand the extreme volume change and mechanical deformation induced by the Na metal during long-term cycling at high current densities required for commercial applications, which leads to the repeated rupture of the SEI film and uncontrolled dendrite growth, posing a severe threat to the reversibility and safety of Na metal anodes.…”