Turning on Lithium–Sulfur Full Batteries at −10 °C

Abstract

Lithium–sulfur (Li–S) batteries using Li2S and Li-free anodes have emerged as a potential high-energy and safe battery technology. Although the operation of Li–S full batteries based on Li2S has been demonstrated at room temperature, their effective use at a subzero temperature has not been realized due to the low electrochemical utilization of Li2S. Here, ammonium nitrate (NH4NO3) is introduced as a functional additive that allows Li–S full batteries to operate at −10 °C. The polar N–H bonds in the additive alter the activation pathway of Li2S by inducing the dissolution of the Li2S surface. Then, Li2S with an amorphized surface layer undergoes the modified activation process, which consists of the disproportionation and direct conversion reaction, through which Li2S is efficiently converted into S8. The Li–S full battery using NH4NO3 delivers a reversible capacity and cycling stability over 400 cycles at −10 °C.

Making the Unfeasible Feasible: Synthesis of the Battery Material Lithium Sulfide via the Metathetic Reaction between Lithium Sulfate and Sodium Sulfide

“…However, the spans of these semicircles are quite different, with that of s-Li 2 S–Co 9 S 8 being much smaller than those of the other two. This phenomenon means that the s-Li 2 S–Co 9 S 8 cathode has smaller charge transfer resistance ( R CT ), which corresponds to more efficient charge transfer. − Likewise, as shown in Figure B, the CV plots for the first cycle of these three cells also present the superiority of s-Li 2 S–Co 9 S 8 . During the initial charging process, the oxidation peak of the c-Li 2 S cell starts to rise at 3.25 V and reach the summit at 3.59 V. For the s-Li 2 S cell, its onset potential is similar but its peak potential is higher at 3.27 V. Two reduction peaks of both cells occur at comparable positions.…”

Catalytic Effect of Ammonium Thiosulfate as a Bifunctional Electrolyte Additive for Regulating Redox Kinetics in Lithium–Sulfur Batteries by Altering the Reaction Pathway

“…The interaction between AMTS and Li 2 S molecules was further investigated by molecular electrostatic potential (MESP) Figure b shows the calculated MESP map of the independent AMTS and Li 2 S after relaxation.…”

“…The interaction between AMTS and Li 2 S molecules was further investigated by molecular electrostatic potential (MESP). 39 Figure 3b shows the calculated MESP map of the independent AMTS and Li 2 S after relaxation. The negative (blue) and positive (red) electrostatic potential regions indicate strong tendencies toward electrophilic and nucleophilic reactions, respectively.…”

Partially Ion‐Paired Solvation Structure Design for Lithium‐Sulfur Batteries under Extreme Operating Conditions

“…To enhance the compatibility of Li metal with carboxylate ester‐containing electrolytes, prior studies explored fluorinated additives to promote the formation of LiF‐rich solid electrolyte interphase (SEI) on the anode aiming to improve cycling performance at ambient conditions. Unfortunately, these merits fail to sustain at ultralow temperatures (<−30 °C) [5a,12a,13] . Achieving stable cycling of high areal loading of Li‐S batteries under both extreme temperatures poses a significant challenge because the electrolytes employed in such batteries need to meet multiple criteria simultaneously, including decent ionic conductivity, low flammability, and excellent compatibility with both lithium metal anodes and sulfur‐based cathodes across a wide range of operating temperatures.…”

“…Although increasing salt concentration can alleviate the shuttling effects, the increased viscosity renders sluggish kinetics and significant capacity decay, especially at subzero temperature conditions. [5] Recent works showed that typical ether-based electrolytes (e.g., DOL/DME system) encountered dendritic Li metal growth at subzero temperatures, probably due to the increased charge-transfer resistance at subzero temperatures. [6] Our previous work showed that monodentate ether (e.g., diethyl ether) can partially address this limitation by providing facile desolvation kinetics.…”