Pushing Lithium–Sulfur Batteries towards Practical Working Conditions through a Cathode–Electrolyte Synergy

Abstract

The commercialization of lithium–sulfur (Li−S) batteries is still hindered by the unsatisfactory cell performance under practical working conditions, which is mainly caused by the sluggish cathode redox kinetics, severe polysulfide shuttling, and poor Li stripping/plating reversibility. Herein, we report an effective strategy by combining Se‐doped S hosted in an ordered macroporous framework with a highly fluorinated ether (HFE)‐based electrolyte to simultaneously address the aforementioned issues in both cathode and anode. A reversible and stable high areal capacity of >5.4 mAh cm−2 with high Coulombic efficiency >99.2 % can be achieved under high areal Se/S loading (5.8 mg cm−2), while the underlying mechanism was further revealed through synchrotron X‐ray probes and Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS). The practical application potential was further evaluated at low (0 °C) and high (55 °C) temperatures under high areal Se/S loading (>5.0 mg cm−2) and thin Li metal (40 μm).

Insights into the solvation chemistry in liquid electrolytes for lithium-based rechargeable batteries

“…LSBs using (ACN) 2 –TFSI–HFE showed negligible capacity fading under optimized test protocols. 239 Besides HFE, 240–243 BTFE, 244 TTE, 245–247 TFEE, 248 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane (F-EPE), 249 hexa-fuoroisopropyl methyl ether (HFME), 250 OTE, ETE, 251 OFE, 252 fluorobenzene (FB), 105,253 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TFTFE), 254 and other partially fluorinated solvent, 255–258 have been also adopted as non-polar co-solvents in LSBs.…”

High-performance all-solid-state Li2S batteries using an interfacial redox mediator

“…[10][11][12][13][14] However, the fabrication of all-solidstate Li-S batteries necessitates the construction of efficient charge transfer pathways within the cathode due to the poor electronic (e À ) and ionic (Li + ) conductivities of the sulfur and Li 2 S redox-end members. [15][16][17][18] Forming sulfur composites with high surface area carbon 11,15 or substituting sulfur with other elements such as Se 19 and Al 20 can improve the cathode's electronic conductivity. However -unlike a conventional Li-S cell where the flowable liquid electrolyte can easily infiltrate the pores of the S/C composite -in a solid state configuration there are only very limited contact points that constitute a triple phase boundary (active material, electron conduit, and solidstate electrolyte (SSE)) where there is simultaneous electronic and ionic conductivity (Fig.…”

A three-in-one C60-integrated PEO-based solid polymer electrolyte enables superior all-solid-state lithium–sulfur batteries

“…1 Nonetheless, several technical challenges still limit the commercialization of Li–S batteries. 2 Typically, Li–S batteries with common liquid ether-based electrolytes have the risk of leakage and combustion of flammable organic electrolytes. 3 The complicated stepwise chemical reaction and multiphase transformation of lithium polysulfides (LiPSs) intermediates with strong solvation ( x S + 2e − ↔ S x 2− , S 8 ↔ LiPSs ↔ Li 2 S 2 /Li 2 S) render a profound shuttle effect, in which LiPSs dissolve in the electrolyte and migrate from cathode to anode along with fast capacity decay and poor cyclability.…”