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Title: In situ TEM observation of electrochemical lithiation of sulfur confined within inner cylindrical pores of carbon nanotubes

Lithium insertion into sulfur confined within 200 nm cylindrical inner pores of individual carbon nanotubes (CNTs) was monitored in-situ in a transmission electron microscope (TEM). This electrochemical reaction was initiated at one end of the S-filled CNTs. The material expansion during lithiation was accommodated by the expansion into the remaining empty pore volume and no fracture of the CNT walls was detected. A sharp interface between the initial and lithiated S was observed. The reaction front was flat, oriented perpendicular to the confined S cylinder and propagated along the cylinder length. Lithiation of S in the proximity of conductive carbon proceeded at the same rate as the one in the center of the pore, suggesting the presence of electron pathways at the Li 2S/S interface. Density of states (DOS) calculations further confirmed this hypothesis. In-situ electron diffraction showed a direct phase transformation of S into nanocrystalline Li 2S without detectable formation of any intermediates, such as polysulfides and LiS. These important insights may elucidate some of the reaction mechanisms and guide the improvements in the design of C-S nanocomposites for high specific energy Li-S batteries. As a result, the proposed use of conductive CNTs with tunable pore diameter as cylindricalmore » reaction vessels for in-situ TEM studies of electrochemical reactions proved to be highly advantageous and may help to resolve the on-going problems in battery technology.« less
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2]
  1. Georgia Inst. of Technology, Atlanta, GA (United States); Sila Nanotechnologies, Inc., Alameda CA (United States)
  2. Georgia Inst. of Technology, Atlanta, GA (United States)
  3. Purdue University, West Lafayette IN (United States)
  4. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1614-6832; 606209
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 5; Journal Issue: 24; Journal ID: ISSN 1614-6832
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
OSTI Identifier: