A room-temperature sodium–sulfur battery with high capacity and stable cycling performance

Abstract

High-temperature sodium–sulfur batteries operating at 300–350 °C have been commercially applied for large-scale energy storage and conversion. However, the safety concerns greatly inhibit their widespread adoption. Herein, we report a room-temperature sodium–sulfur battery with high electrochemical performances and enhanced safety by employing a “cocktail optimized” electrolyte system, containing propylene carbonate and fluoroethylene carbonate as co-solvents, highly concentrated sodium salt, and indium triiodide as an additive. As verified by first-principle calculation and experimental characterization, the fluoroethylene carbonate solvent and high salt concentration not only dramatically reduce the solubility of sodium polysulfides, but also construct a robust solid-electrolyte interface on the sodium anode upon cycling. Indium triiodide as redox mediator simultaneously increases the kinetic transformation of sodium sulfide on the cathode and forms a passivating indium layer on the anode to prevent it from polysulfide corrosion. The as-developed sodium–sulfur batteries deliver high capacity and long cycling stability.

Design and Construction of Sodium Polysulfides Defense System for Room‐Temperature Na–S Battery

“…[35] Meanwhile, S 2p 3/2 and S 2p 1/2 of elemental sulfur (S 8 ) correspond to two double peaks at 162.1 and 165.5 eV in the spectrum of the HCS/ MoS 2 composite. [6] At 0.9 V, the peaks of the Raman spectra at 470 cm −1 correspond to Na 2 S 4 . [6] At 0.9 V, the peaks of the Raman spectra at 470 cm −1 correspond to Na 2 S 4 .…”

“…[6] At 0.9 V, the peaks of the Raman spectra at 470 cm −1 correspond to Na 2 S 4 . [6] In addition, the peak at around 168 eV in Figure 5d-f corresponds to the S 2 O 3 2− . Furthermore, after the battery is discharged to 0.5 V, characteristic peaks appeared in the Raman spectra at 188 and 210 cm −1 , indicating that Na 2 S is generated.…”

“…2019, 6,1901557 nonpolar carbon-based materials have weak interaction with polar polysulfides, which cannot effectively limit the diffusion of NaPSs. The Adv.…”

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popularization and application of this technology can not only reduce the environmental pollution caused by burning fossil fuels, but also address the issue of the intermittency of green energy resources including wind and solar energy, providing convenience for the life and development of human society. [4][5][6][7] These advantages make the room-temperature Na-S battery have broad application prospects in large-scale power grid equipment.However, there are still some burning questions that need to be solved in room-temperature Na-S battery: first, the active S has poor conductivity, resulting in slow electrochemical reaction kinetics and low utilization. [1][2][3] Recently, room-temperature Na-S batteries have attracted much attention because of their high theoretical specific capacity (1675 mAh g −1 ) and energy density (1274 Wh kg −1 ) as well as abundant Na and S resources in the Earth's crust.

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Rational Design of Binders for Stable Li‐S and Na‐S Batteries

“…[108] CMC molecules acquired high binding energy with Na polysulfide by forming strong SO bonds with Na polysulfide, which preventing the dissolution of Na polysulfide into the electrolyte (Figure 5A). Not until very recently did the researcher report the bifunctional binder to solve the notorious Na polysulfide shuttling, which is the main reason for the poor stability in Na-S batteries.…”