title: Surface-Sensitive NMR Detection of the Solid Electrolyte Interphase Layer on Reduced Graphene Oxide.
abstract: Forming a stable solid electrolyte interphase (SEI) is critical for rechargeable batteries' performance and lifetime. Understanding its formation requires analytical techniques that provide molecular-level insight. Here, dynamic nuclear polarization (DNP) is utilized for the first time to enhance the sensitivity of solid-state NMR (ssNMR) spectroscopy to the SEI. The approach is demonstrated on reduced graphene oxide (rGO) cycled in Li-ion cells in natural abundance and13C-enriched electrolyte solvents. Our results indicate that DNP enhances the signal of outer SEI layers, enabling detection of natural abundance13C spectra from this component of the SEI on reasonable time frames. Furthermore,13C-enriched electrolyte measurements at 100 K provide ample sensitivity without DNP due to the vast amount of SEI filling the rGO pores, thereby allowing differentiation of the inner and outer SEI layer composition. Developing this approach further will benefit the study of many electrode materials, equipping ssNMR with the necessary sensitivity to probe the SEI efficiently.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovot, 76100 Israel.
authors.forename: Michal
authors.identifier: http://orcid.org/0000-0002-7172-9689
authors.initials: M
authors.lastname: Leskes
authors.affiliation: Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.|Cambridge Graphene Centre, University of Cambridge , Cambridge CB3 0FA, United Kingdom.
authors.forename: Gunwoo
authors.initials: G
authors.lastname: Kim
authors.affiliation: Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Michan
authors.affiliation: Bruker BioSpin , 34 rue de l'Industrie BP 10002, 67166 Wissembourg Cedex, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Aussenac
authors.affiliation: Bruker BioSpin , 34 rue de l'Industrie BP 10002, 67166 Wissembourg Cedex, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Dorffer
authors.affiliation: DNP MAS NMR Facility, Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Subhradip
authors.initials: S
authors.lastname: Paul
authors.affiliation: Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Clare P
authors.initials: CP
authors.lastname: Grey