Fabricating Na/In/C Composite Anode with Natrophilic Na–In Alloy Enables Superior Na Ion Deposition in the EC/PC Electrolyte

Abstract

In conventional ethylene carbonate (EC)/propylene carbonate (PC) electrolyte, sodium metal reacts spontaneously and deleteriously with solvent molecules. This significantly limits the practical feasibility of high-voltage sodium metal batteries based on Na metal chemistry. Herein, we present a sodium metal alloy strategy via introducing NaIn and Na2In phases in a Na/In/C composite, aiming at boosting Na ion deposition stability in the common EC/PC electrolyte. Symmetric cells with Na/In/C electrodes achieve an impressive long-term cycling capability at 1 mA cm−2 (> 870 h) and 5 mA cm−2 (> 560 h), respectively, with a capacity of 1 mAh cm−2. In situ optical microscopy clearly unravels a stable Na ion dynamic deposition process on the Na/In/C composite electrode surface, attributing to a dendrite-free and smooth morphology. Furthermore, theoretical simulations reveal intrinsic mechanism for the reversible Na ion deposition behavior with the composite Na/In/C electrode. Upon pairing with a high-voltage NaVPOF cathode, Na/In/C anode illustrates a better suitability in SMBs. This work promises an alternative alloying strategy for enhancing Na metal interfacial stability in the common EC/PC electrolyte for their future applications.

Longevous Sodium Metal Anodes with High Areal Capacity Enabled by 3D-Printed Sodiophilic Monoliths

“…Notably, the F 1s signal of the Cu electrodes was very weak, possibly owing to the continuous destruction of SEI by a large number of agglomerated Na dendrites and "dead" sodium (Figure 4d and Figure 5a). 51 In comparison, the cycled 3DP rGO (Figure 6b) and 50% Ag/rGO electrodes (Figure 6c) show similar C 1s and O 1s spectra to those of the Cu foil, while the signal of F 1s more pronounced. Additionally, it is worth mentioning that the organic species content of the 3DP 50% Ag/rGO (Figure 6c) was greatly reduced and the content of favorable NaF was higher, indicating the superior interfacial stability of the 50% Ag/rGO electrode.…”

“…As evidenced in Figure a, the C 1s spectrum can be deconvoluted into two peaks with binding energies of 284.8 eV (C–C, C–H) and 289.4 eV (ROCO 2 Na), whereas the O 1s spectrum demonstrates two obvious peaks at 531.3 eV (CO) and 535.6 eV (C–O), which can be attributed to the main reduction products of diglyme. Notably, the F 1s signal of the Cu electrodes was very weak, possibly owing to the continuous destruction of SEI by a large number of agglomerated Na dendrites and “dead” sodium (Figure d and Figure a) . In comparison, the cycled 3DP rGO (Figure b) and 50% Ag/rGO electrodes (Figure c) show similar C 1s and O 1s spectra to those of the Cu foil, while the signal of F 1s more pronounced.…”

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

“…Some components of metal (In 0 ) and metal oxides (In 2 O 3 ) were also observed and could be formed during the sample handling process. [ 29 ] Moreover, the presence of Na‐rich SEI layer component (NaCl) over Na 1 In 1 alloy is evidenced by signals from the Cl 2p characteristic spectrum (Figure 1c) and the two peaks at 198.2 eV and 200.3 eV in the Cl 2p spectrum were assigned to Cl 2p 3/2 and Cl 2p 1/2 respectively. SEM images of Na, Na 1 In 1, Na 1 Bi 1 , Na 1 Zn 13 , and Na 1 Sn 2 alloy surface in (Figure 1d–h) show the formation of the new alloy layer over the Na metal after facile chemical solvent modification approach.…”

Stabilizing Metallic Na Anodes via Sodiophilicity Regulation: A Review

“…Similar to this strategy, Go et al also fabricated nanocrevasse-rich Li/Na metal polyacrylonitrile (PAN)-based carbon composites [52], but a step closer comparison with the former was that large-scale Li/Na metal carbon composites can be fabricated with a simple machine (Figure 5a). Aside from the studies mentioned above, it was widely reported that introducing alloy phases, metal oxide nanoparticles, functional groups, or heteroatom dopants could dramatically improve the sodiophilicity of CC, thereby significantly refining the stripping/plating behavior of Na metal anodes [53][54][55][56][57]. Recently, Wang et al utilized a simple Na/In liquid immersion in a CC scaffold and a subsequent condensation procedure to synthesize a Na/In/C composite (Figure 5b) [53].…”

“…Aside from the studies mentioned above, it was widely reported that introducing alloy phases, metal oxide nanoparticles, functional groups, or heteroatom dopants could dramatically improve the sodiophilicity of CC, thereby significantly refining the stripping/plating behavior of Na metal anodes [53][54][55][56][57]. Recently, Wang et al utilized a simple Na/In liquid immersion in a CC scaffold and a subsequent condensation procedure to synthesize a Na/In/C composite (Figure 5b) [53]. The existence of sodiophilic NaIn and Na 2 In phases on the Na/In/C composite electrode interface, as evidenced by experimental investigations and DFT simulations, is favorable to enhancing Na-ion deposition stability.…”