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Title: Interfacial reaction dependent performance of hollow carbon nanosphere - sulfur composite as a cathode for Li-S battery

Lithium-sulfur (Li-S) battery is a promising energy storage system due to its high energy density, cost effectiveness and environmental friendliness of sulfur. However, there are still a number of challenges, such as low Coulombic efficiency and poor long-term cycling stability, impeding the commercialization of Li-S battery. The electrochemical performance of Li-S battery is closely related with the interfacial reactions occurring between hosting substrate and active sulfur species which are poorly conducting at fully oxidized and reduced states. Here, we correlate the relationship between the performance and interfacial reactions in the Li-S battery system, using a hollow carbon nanosphere (HCNS) with highly graphitic character as hosting substrate for sulfur. With an appropriate amount of sulfur loading, HCNS/S composite exhibits excellent electrochemical performance because of the fast interfacial reactions between HCNS and the polysulfides. However, further increase of sulfur loading leads to increased formation of highly resistive insoluble reaction products (Li2S2/Li2S) which limits the reversibility of the interfacial reactions and results in poor electrochemical performance. In conclusion, these findings demonstrate the importance of the interfacial reaction reversibility in the whole electrode system on achieving high capacity and long cycle life of sulfur cathode for Li-S batteries.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. George Washington Univ., Washington, DC (United States)
Publication Date:
OSTI Identifier:
1221498
Report Number(s):
PNNL--SA-107585
Journal ID: ISSN 2296-598X; 48146; VT1201000
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Frontiers in Energy Research
Additional Journal Information:
Journal Volume: 3; Journal ID: ISSN 2296-598X
Publisher:
Frontiers Research Foundation
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 77 NANOSCIENCE AND NANOTECHNOLOGY Environmental Molecular Sciences Laboratory; sulfur composite; interfacial reaction; sulfur utilization; cycling stability; rate capability; Li-S battery