Phase transformations in CVD diamond wear tracks revealed by NEXAFS mapping
2004 (English)In: Nordtrib 2004, Tromsö, Norway, 2004Conference paper (Refereed)
The origin of the different Li+ intercalation behavior of raw and jet-milled natural graphite has been investigated. Jet-milled graphite is found to cycle reversibly in equal solvent mixture of propylene carbonate (PC) and etylene carbonate (EC), whereas raw graphite does not. Using both Al Ka and synchrotron radiation (SR) Photoelectron Spectroscopy, new insight is obtained inti the formation of the solid electrolyte interphase (SEI) on the two different graphite materials during electrochemical cycling in 1 M LiPF6 in either PC:EC (1:1) or in PC with 5% vinylene carbonate (VC) as additive. Solvent reduction products are found at the surface of both raw and jat-milled graphite cycled in PC:EC (1:1), but differed in composition. The addition of VC reduces primarily the quantities of salt reaction products (LiF and LixPFy compounds) and produces a mainly organic SEI layer. Electron diffraction from the edges for raw and jet-milled graphite particles shows a physical barrier hindering PC co-intercalation and faciltating the formation of a stable SEI layer.
Place, publisher, year, edition, pages
natural graphite, photoelectron spectroscopy, propylene carbonate, vinylene carbonate, solid electrolyte interphase
IdentifiersURN: urn:nbn:se:uu:diva-70390OAI: oai:DiVA.org:uu-70390DiVA: diva2:98301