Stable Dendrite-Free Sodium–Sulfur Batteries Enabled by a Localized High-Concentration Electrolyte

Abstract

Ambient-temperature sodium–sulfur batteries are an appealing, sustainable, and low-cost alternative to lithium-ion batteries due to their high material abundance and specific energy of 1274 W h kg–1. However, their viability is hampered by Na polysulfide (NaPS) shuttling, Na loss due to side reactions with the electrolyte, and dendrite formation. Here, we demonstrate that a solid–electrolyte interphase rich in inorganic components can be realized at both the sulfur cathode and the Na anode by tweaking the solvation structure of the electrolyte. This transforms the sulfur redox process from conventional dissolution–precipitation chemistry into a quasi-solid-state reaction, which eliminates NaPS shuttling and facilitates dendrite-free Na-metal plating and stripping. With the solvated ionic liquid electrolyte structure, a high initial capacity of 922 mA h g–1 with a capacity fade of as low as 0.10% per cycle over 300 cycles was achieved. The scalability of this approach to pouch cells with practically necessary parameters demonstrates its potential for practical viability.

Electrocatalysis in Room Temperature Sodium‐Sulfur Batteries: Tunable Pathway of Sulfur Speciation

“…It can be seen that besides physical Reproduced with permission. [21,30,[46][47][48][49][50] Copyright 2016-2021, Wiley-VCH, Springer Nature, and American Chemical Society.…”

“…Furthermore, based on the research progress in the LiS battery system, Manthiram and co‐workers demonstrated that the quasi‐solid state conversion pathway of sulfur could be realized by tweaking the solvation structure of the electrolyte, and the challenges at both electrodes can be addressed simultaneously (NaPSs shuttling and facilitating dendrite‐free Na‐metal plating and stripping) in NaS batteries. [ 50 ] Herein, it demonstrated that a unique solventized structure was formed with the dimethoxyethane to sodium bis(fluorosulfonyl)imide (DME:NaFSI) molar ratio decreases. Then, galvanostatic charge–discharge test was employed to analyze the conversion pathway of sulfur electrodes in localized high concentration electrolytes (LHCE) (Figure 10i).…”

“…Reproduced with permission. [ 21,30,46–50 ] Copyright 2016–2021, Wiley‐VCH, Springer Nature, and American Chemical Society.…”

“…Figure 2. Development timeline and schematic diagrams of strategies for tuning the sulfur conversion pathway of RT NaS batteries in recent years.Reproduced with permission [21,30,[46][47][48][49][50]. Copyright 2016-2021, Wiley-VCH, Springer Nature, and American Chemical Society.…”

“…l) The top-surface morphology. Reproduced with permission [50]. Copyright 2021, American Chemical Society.…”