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Electrolyte stability determines scaling limits for solid-state 3D Li ion batteries

Nano Letters

Ruzmetov, Dmitry; Oleshko, Vladimir P.; Haney, Paul M.; Lezec, Henri J.; Karki, Khim; Baloch, Kamal H.; Agrawal, Amit K.; Davydov, Albert V.; Krylyuk, Sergiy; Liu, Yang; Huang, Jian Y.; Tanase, Mihaela; Cumings, John; Talin, A.A.

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. © 2011 American Chemical Society.

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TYPE Journal Article YEAR 2012
ScopusOSTI

In situ atomic-scale imaging of electrochemical lithiation in silicon

Nature Nanotechnology

Liu, Xiaohua L.; Wang, Jiang W.; Huang, Jian Y.; Fan, Feifei; Huang, Jian Y.; Liu, Yang; Krylyuk, Sergiy; Yoo, Jinkyoung; Dayeh, Shadi A.; Davydov, Albert V.; Mao, Scott X.; Picraux, S.T.; Zhang, Sulin; Li, Ju; Zhu, Ting; Huang, Jian Y.

In lithium-ion batteries, the electrochemical reaction between the electrodes and lithium is a critical process that controls the capacity, cyclability and reliability of the battery. Despite intensive study, the atomistic mechanism of the electrochemical reactions occurring in these solid-state electrodes remains unclear. Here, we show that in situ transmission electron microscopy can be used to study the dynamic lithiation process of single-crystal silicon with atomic resolution. We observe a sharp interface (∼1 μnm thick) between the crystalline silicon and an amorphous Li x Si alloy. The lithiation kinetics are controlled by the migration of the interface, which occurs through a ledge mechanism involving the lateral movement of ledges on the close-packed {111} atomic planes. Such ledge flow processes produce the amorphous Li x Si alloy through layer-by-layer peeling of the {111} atomic facets, resulting in the orientation-dependent mobility of the interfaces. © 2012 Macmillan Publishers Limited. All rights reserved.

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TYPE Journal Article YEAR 2012
ScopusOSTIDOI

Real-time studies of battery electrochemical reactions inside a transmission electron microscope

Sullivan, John P.; Huang, Jian Y.; Leung, Kevin L.; Fan, Hongyou F.; Liu, Xiaohua L.; Hudak, Nicholas H.

We report the development of new experimental capabilities and ab initio modeling for real-time studies of Li-ion battery electrochemical reactions. We developed three capabilities for in-situ transmission electron microscopy (TEM) studies: a capability that uses a nanomanipulator inside the TEM to assemble electrochemical cells with ionic liquid or solid state electrolytes, a capability that uses on-chip assembly of battery components on to TEM-compatible multi-electrode arrays, and a capability that uses a TEM-compatible sealed electrochemical cell that we developed for performing in-situ TEM using volatile battery electrolytes. These capabilities were used to understand lithiation mechanisms in nanoscale battery materials, including SnO{sub 2}, Si, Ge, Al, ZnO, and MnO{sub 2}. The modeling approaches used ab initio molecular dynamics to understand early stages of ethylene carbonate reduction on lithiated-graphite and lithium surfaces and constrained density functional theory to understand ethylene carbonate reduction on passivated electrode surfaces.

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TYPE SAND Report YEAR 2012
OSTIDOI
Results 1–25 of 95
Results 1–25 of 95