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Title: Directing the lithium–sulfur reaction pathway via sparingly solvating electrolytes for high energy density batteries

The lithium–sulfur battery has long been seen as a potential next generation battery chemistry for electric vehicles owing to the high theoretical specific energy and low cost of sulfur. However, even state-of-the-art lithium–sulfur batteries suffer from short lifetimes due to the migration of highly soluble polysulfide intermediates and exhibit less than desired energy density due to the required excess electrolyte. The use of sparingly solvating electrolytes in lithium–sulfur batteries is a promising approach to decouple electrolyte quantity from reaction mechanism, thus creating a pathway toward high energy density that deviates from the current catholyte approach. Herein, we demonstrate that sparingly solvating electrolytes based on compact, polar molecules with a 2:1 ratio of a functional group to lithium salt can fundamentally redirect the lithium–sulfur reaction pathway by inhibiting the traditional mechanism that is based on fully solvated intermediates. In contrast to the standard catholyte sulfur electrochemistry, sparingly solvating electrolytes promote intermediate- and short-chain polysulfide formation during the first third of discharge, before disproportionation results in crystalline lithium sulfide and a restricted fraction of soluble polysulfides which are further reduced during the remaining discharge. Moreover, operation at intermediate temperatures ca. 50 °C allows for minimal overpotentials and high utilization of sulfur atmore » practical rates. Finally, this discovery opens the door to a new wave of scientific inquiry based on modifying the electrolyte local structure to tune and control the reaction pathway of many precipitation–dissolution chemistries, lithium–sulfur and beyond.« less
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [3] ; ORCiD logo [3] ;  [4] ;  [3] ; ORCiD logo [2] ;  [1]
  1. Joint Center for Energy Storage Research, Lemont, IL (United States); Argonne National Lab. (ANL), Lemont, IL (United States)
  2. Joint Center for Energy Storage Research, Lemont, IL (United States); Univ. of Waterloo, Waterloo, ON (Canada)
  3. Joint Center for Energy Storage Research, Lemont, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Joint Center for Energy Storage Research, Lemont, IL (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Published Article
Journal Name:
ACS Central Science
Additional Journal Information:
Journal Volume: 3; Journal Issue: 6; Journal ID: ISSN 2374-7943
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE
OSTI Identifier:
1358466
Alternate Identifier(s):
OSTI ID: 1368568; OSTI ID: 1372260