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Title: Hole Polaron Diffusion in the Final Discharge Product of Lithium–Sulfur Batteries

Poor electronic conductivity of bulk lithium sulfide (Li 2S) is a critical challenge for the debilitating performance of the lithium–sulfur battery. In this study we focus on investigating the thermodynamic and kinetic properties of native defects in Li 2S based on a first-principles approach. It is found that the hole polaron p + can form in Li 2S by removing a 3p electron from an S 2– anion. The p + diffusion barrier is only 90 meV, which is much lower than the Li vacancy (V Li ) diffusion barrier. Hence p + has the potential to serve as a charge carrier in the discharge product. Once the vacancy–polaron complex (V Li -––2p +) forms, the charge transport will be hindered due to the relatively higher diffusion barrier of the complex. Heteroatom dopants, which can decrease the p + formation energy and increase V Li formation energy, are expected to be introduced to the discharge product to improve the electronic conductivity.
Authors:
 [1] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Texas A & M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
  2. Texas A & M Univ., College Station, TX (United States). Dept. of Chemical Engineering
Publication Date:
Grant/Contract Number:
EE0006832
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 32; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Texas A & M Univ., College Station, TX (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1430631
Alternate Identifier(s):
OSTI ID: 1430595