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Title: The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries

Abstract

Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and the use of redox mediator additives, in an attempt to lower the large electrochemical overpotentials associated with the charge reaction. However, the stabilizing or catalytic effect of these materials can become complicated due to the presence of major side-reactions observed during dis(charge). Here, we isolate the charge reaction from the discharge by utilizing electrodes prefilled with commercial lithium peroxide with a crystallite size of about 200-800 nm. Using a combination of S/TEM, online mass spectrometry, XPS, and electrochemical methods to probe the nature of surface films on carbon and conductive Ti-based nanoparticles, we show that oxygen evolution from lithium peroxide is strongly dependent on their surface properties. Insulating TiO2 surface layers on TiC and TiN - even as thin as 3 nm*can completely inhibit the charge reaction under these conditions. On the other hand, TiC, which lacks this oxide film, readily facilitates oxidation of the bulk Li2O2 crystallites, at a much lower overpotential relative to carbon. Since oxidation of lithium oxygen battery cathodes is inevitable in these systems, precise control of the surface chemistry at the nanoscale becomes ofmore » upmost importance.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1188909
Report Number(s):
PNNL-SA-108401
KC0208010
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Nano, 8(12):124831-12493
Additional Journal Information:
Journal Name: ACS Nano, 8(12):124831-12493
Country of Publication:
United States
Language:
English

Citation Formats

Adams, Brian D., Black, Robert, Radtke, Claudio, Williams, Zach, Mehdi, Beata L., Browning, Nigel D., and Nazar, Linda F. The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries. United States: N. p., 2014. Web. doi:10.1021/nn505337p.
Adams, Brian D., Black, Robert, Radtke, Claudio, Williams, Zach, Mehdi, Beata L., Browning, Nigel D., & Nazar, Linda F. The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries. United States. https://doi.org/10.1021/nn505337p
Adams, Brian D., Black, Robert, Radtke, Claudio, Williams, Zach, Mehdi, Beata L., Browning, Nigel D., and Nazar, Linda F. Tue . "The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries". United States. https://doi.org/10.1021/nn505337p.
@article{osti_1188909,
title = {The Importance of Nanometric Passivating Films on Cathodes forLi - Air Batteries},
author = {Adams, Brian D. and Black, Robert and Radtke, Claudio and Williams, Zach and Mehdi, Beata L. and Browning, Nigel D. and Nazar, Linda F.},
abstractNote = {Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and the use of redox mediator additives, in an attempt to lower the large electrochemical overpotentials associated with the charge reaction. However, the stabilizing or catalytic effect of these materials can become complicated due to the presence of major side-reactions observed during dis(charge). Here, we isolate the charge reaction from the discharge by utilizing electrodes prefilled with commercial lithium peroxide with a crystallite size of about 200-800 nm. Using a combination of S/TEM, online mass spectrometry, XPS, and electrochemical methods to probe the nature of surface films on carbon and conductive Ti-based nanoparticles, we show that oxygen evolution from lithium peroxide is strongly dependent on their surface properties. Insulating TiO2 surface layers on TiC and TiN - even as thin as 3 nm*can completely inhibit the charge reaction under these conditions. On the other hand, TiC, which lacks this oxide film, readily facilitates oxidation of the bulk Li2O2 crystallites, at a much lower overpotential relative to carbon. Since oxidation of lithium oxygen battery cathodes is inevitable in these systems, precise control of the surface chemistry at the nanoscale becomes of upmost importance.},
doi = {10.1021/nn505337p},
url = {https://www.osti.gov/biblio/1188909}, journal = {ACS Nano, 8(12):124831-12493},
number = ,
volume = ,
place = {United States},
year = {2014},
month = {12}
}