title: Non-destructive monitoring of charge-discharge cycles on lithium ion batteries using ⁷Li stray-field imaging.
abstract: Magnetic resonance imaging provides a noninvasive method for in situ monitoring of electrochemical processes involved in charge/discharge cycling of batteries. Determining how the electrochemical processes become irreversible, ultimately resulting in degraded battery performance, will aid in developing new battery materials and designing better batteries. Here we introduce the use of an alternative in situ diagnostic tool to monitor the electrochemical processes. Utilizing a very large field-gradient in the fringe field of a magnet, stray-field-imaging (STRAFI) technique significantly improves the image resolution. These STRAFI images enable the real time monitoring of the electrodes at a micron level. It is demonstrated by two prototype half-cells, graphite∥Li and LiFePO₄∥Li, that the high-resolution (7)Li STRAFI profiles allow one to visualize in situ Li-ions transfer between the electrodes during charge/discharge cyclings as well as the formation and changes of irreversible microstructures of the Li components, and particularly reveal a non-uniform Li-ion distribution in the graphite.
authors.affiliation: National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Tang
authors.forename: Sneha
authors.initials: S
authors.lastname: Dugar
authors.forename: Guiming
authors.initials: G
authors.lastname: Zhong
authors.forename: Naresh S
authors.initials: NS
authors.lastname: Dalal
authors.forename: Jim P
authors.initials: JP
authors.lastname: Zheng
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Riqiang
authors.initials: R
authors.lastname: Fu
mesh_terms: D011211:Electric Power Supplies; D004735:Energy Transfer; D019544:Equipment Failure Analysis / Q000379:methods*; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D060306:Magnetometry / Q000379:methods*
chemical_list: D007477:Ions; D008094:Lithium