title: Electrolyte stability determines scaling limits for solid-state 3D Li ion batteries.
abstract: Rechargeable, all-solid-state Li ion batteries (LIBs) with high specific capacity and small footprint are highly desirable to power an emerging class of miniature, autonomous microsystems that operate without a hardwire for power or communications. A variety of three-dimensional (3D) LIB architectures that maximize areal energy density has been proposed to address this need. The success of all of these designs depends on an ultrathin, conformal electrolyte layer to electrically isolate the anode and cathode while allowing Li ions to pass through. However, we find that a substantial reduction in the electrolyte thickness, into the nanometer regime, can lead to rapid self-discharge of the battery even when the electrolyte layer is conformal and pinhole free. We demonstrate this by fabricating individual, solid-state nanowire core-multishell LIBs (NWLIBs) and cycling these inside a transmission electron microscope. For nanobatteries with the thinnest electrolyte, ≈110 nm, we observe rapid self-discharge, along with void formation at the electrode/electrolyte interface, indicating electrical and chemical breakdown. With electrolyte thickness increased to 180 nm, the self-discharge rate is reduced substantially, and the NWLIBs maintain a potential above 2 V for over 2 h. Analysis of the nanobatteries' electrical characteristics reveals space-charge limited electronic conduction, which effectively shorts the anode and cathode electrodes directly through the electrolyte. Our study illustrates that, at these nanoscale dimensions, the increased electric field can lead to large electronic current in the electrolyte, effectively shorting the battery. The scaling of this phenomenon provides useful guidelines for the future design of 3D LIBs.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Ruzmetov
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Oleshko
authors.forename: Paul M
authors.initials: PM
authors.lastname: Haney
authors.forename: Henri J
authors.initials: HJ
authors.lastname: Lezec
authors.forename: Khim
authors.initials: K
authors.lastname: Karki
authors.forename: Kamal H
authors.initials: KH
authors.lastname: Baloch
authors.forename: Amit K
authors.initials: AK
authors.lastname: Agrawal
authors.forename: Albert V
authors.initials: AV
authors.lastname: Davydov
authors.forename: Sergiy
authors.initials: S
authors.lastname: Krylyuk
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Jiany
authors.initials: J
authors.lastname: Huang
authors.forename: Mihaela
authors.initials: M
authors.lastname: Tanase
authors.forename: John
authors.initials: J
authors.lastname: Cumings
authors.forename: A Alec
authors.initials: AA
authors.lastname: Talin
mesh_terms: D011211:Electric Power Supplies; D004573:Electrolytes / Q000737:chemistry*; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008094:Lithium / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation*; D010316:Particle Size
chemical_list: D004573:Electrolytes; D008094:Lithium