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SUMMARY:Chemical Engineering Seminar - Li-ion and Li-air battery electroch
 emistry: harnessing oxygen redox and understanding interfacial reactivity 
 in high energy batteries
DTSTART:20190205T150000
DTEND:20190205T160000
DTSTAMP:20260501T055917Z
UID:4985999c1fb2d480fe0ce3fca8e27e1176d7540b702d6a8929babd99
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Bryan McCloskey\, Department of Chemical and Biomolecul
 ar Engineering\, University of California\, Berkeley\, USA\nMultiple dire
 ctions in battery research are now being pursued with the goal of advancin
 g beyond the specific energy limits imposed by current Li-ion batteries. 
  When considering the design of new high-energy storage systems\, new mate
 rials\, processes\, or chemistries are introduced that are inherently more
  unstable than conventional Li-ion battery materials\, resulting in limite
 d battery cycle life and safety.  Two such examples of high energy batter
 y chemistries\, high voltage operation of Ni-rich Li[Ni\, Mn\, Co]O2 Li+ i
 nsertion electrodes (Ni-rich NMC) and Li-O2 electrochemistry\, will be dis
 cussed in this presentation. Previous observations of high-voltage instabi
 lities include NMC surface reconstruction\, transition metal dissolution\,
  electrolyte decomposition\, and formation of solid surface species. Howev
 er\, the picture of these processes is still incomplete\, with the depende
 nce on electrolyte and NMC composition not yet fully understood.  I will 
 present results in which isotopic labeling of 18O in Ni-rich NMCs is combi
 ned with quantitative gas evolution analysis to identify key contributions
  to these high voltage instabilities\, including instabilities related to 
 solid-state anionic (oxygen) redox and the surprising impact of residual s
 olid lithium carbonate (Li2CO3) on electrolyte and electrode degradation. 
 These results are reminiscent of similar issues with Li2CO3 formation duri
 ng Li-O2 battery operation\, where large overpotentials are observed durin
 g battery charging as a result of parasitic interfacial carbonate formatio
 n.  This presentation will emphasize the need to accurately quantify thes
 e minor parasitic side reactions to fully understand their large influence
  on battery performance.
LOCATION:BCH 2201 https://plan.epfl.ch/?room==BCH%202201
STATUS:CONFIRMED
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