Defect Evolution in Graphene upon Electrochemical Lithiation

Journal Article · Thu Oct 09 00:00:00 EDT 2014 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/am503715g· OSTI ID:1391901

Jaber-Ansari, Laila ^[1]; Puntambekar, Kanan P. ^[1]; Tavassol, Hadi ^[2]; Yildirim, Handan ^[3]; Kinaci, Alper ^[4]; Kumar, Rajan ^[1]; Saldaña, Spencer J. ^[5]; Gewirth, Andrew A. ^[2]; Greeley, Jeffrey P. ^[3]; Chan, Maria K. Y. ^[4]; Hersam, Mark C. ^[6]

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1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
2. Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
3. School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
4. Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
5. Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
6. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States; Department of Medicine, Northwestern University, Chicago, Illinois 60611, United States

Despite rapidly growing interest in the application of graphene in lithium ion batteries, the interaction of the graphene with lithium ions and electrolyte species during electrochemical cycling is not fully understood. In this work, we use Raman spectroscopy in a model system of monolayer graphene transferred on a Si(111) substrate and density functional theory (DFT) to investigate defect formation as a function of lithiation. This model system enables the early stages of defect formation to be probed in a manner previously not possible with commonly used reduced graphene oxide or multilayer graphene substrates. Using ex situ and Ar-atmosphere Raman spectroscopy, we detected a rapid increase in graphene defect level for small increments in the number of lithiation/delithiation cycles until the I(D)/I(G) ratio reaches ~1.5–2.0 and the 2D peak intensity drops by ~50%, after which the Raman spectra show minimal changes upon further cycling. Using DFT, the interplay between graphene topological defects and chemical functionalization is explored, thus providing insight into the experimental results. In particular, the DFT results show that defects can act as active sites for species that are present in the electrochemical environment such as Li, O, and F. Furthermore, chemical functionalization with these species lowers subsequent defect formation energies, thus accelerating graphene degradation upon cycling. This positive feedback loop continues until the defect concentration reaches a level where lithium diffusion through the graphene can occur in a relatively unimpeded manner, with minimal further degradation upon extended cycling. Overall, this study provides mechanistic insight into graphene defect formation during lithiation, thus informing ongoing efforts to employ graphene in lithium ion battery technology.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1391901
• Journal Information: ACS Applied Materials and Interfaces, Vol. 6, Issue 20; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
lithium ion battery
Raman spectroscopy
defects
density functional theory
graphene
silicon