Interfacial architectures based on a binary additive combination for high-performance Sn₄P₃ anodes in sodium-ion batteries

Abstract

Interfacial architectures based on the FEC + TMSP binary additive prevent the formation of Na15Sn4 with severe volume expansion and electrolyte decomposition.

Ultraconcentrated Sodium Bis(fluorosulfonyl)imide-Based Electrolytes for High-Performance Sodium Metal Batteries

“…This finding reveals that NaF formed by FEC decomposition acts as a resistive layer for Na plating/stripping in the ultraconcentrated 5 M NaFSI-DME electrolyte. 17,22 We surmise that minimal amount of free (uncoordinated) DME in the ultraconcentrated 5 M NaFSI-DME electrolyte minimizes the formation of a resistive SEI layer via interaction of the electrolyte components with reactive Na metal. The impact of ultraconcentrated 5 M NaFSI-DME on the cycling stability at high C rates is shown in Figure 12d.…”

“…[20][21][22][23][24][25][26][27] Nevertheless, the practical application of Na metal batteries is quite challenging because the high chemical and electrochemical reactivity of Na metal electrodes with organic liquid electrolytes leads to low Coulombic efficiencies and limited cycling performance. 20,[24][25][26] Severe electrolyte decomposition at the Na metal electrode results in the formation of a resistive and non-uniform surface film, leading to dendritic Na metal growth.…”

“…24,27 Using fluoroethylene carbonate (FEC) as an electrolyte additive for in situ formation of an artificial solid electrolyte interphase (SEI) layer could stabilize the anode-electrolyte interface ( Figure 2). 22,24,26 However, the FEC-derived SEI acted as a resistive layer, impeding the sodiation-desodiation process and reducing the reversible capacity of the anodes. 22 Finding new electrolyte systems that are stable at the Na metal electrode and possess high oxidation durability at high-voltage cathodes is necessary for the development of high-performance Na metal batteries.…”

“…It is obvious that the formulation of FEC with the ultraconcentrated 5 M NaFSI-DME electrolyte is detrimental to the cycling performance of Na/SS cells because of the resistive NaF formation by the FEC decomposition. 22 On the other hand, it is thought that 5 M NaFSI-DME without FEC produces a desirable interfacial structure, allowing highly reversible Na plating/stripping on the SS working electrode. This finding reveals that NaF formed by FEC decomposition acts as a resistive layer for Na plating/stripping in the ultraconcentrated 5 M NaFSI-DME electrolyte.…”

Electrochemical Na-insertion/Extraction Properties of Sn–P Anodes

“…[4][5][6] It has been recently reported that Sn 4 P 3 showed a synergistic Na-storage reaction where Sn and P atoms can react with Na to form Na 15 Sn 4 and Na 3 P, and that the resulting Na 15 Sn 4 alloy acts as a conducting pathway to activate the reversible Na-storage reaction of nonconductive Na 3 P particles while the well-dispersed Na 3 P phase provides a shield matrix to prevent the aggregation of the Na 15 Sn 4 / Sn nanoparticles.…”