Development of Electrochemical Cell for Lithium Dendrite Formation using Atomic Force Microscopy
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Date
2019-12
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The Ohio State University
Abstract
Due to a rapidly growing use of portable electronics in daily life, there has been increasing
demand for developing next-generation lithium-ion (Li-ion) batteries having a longer lasting
battery life and lower safety risk. To meet the demand, many research efforts have been directed
toward studying lithium dendrite formation. Lithium dendrite are lithium metal that is plated on
the surface of anode during lithiation cycle. This phenomenon poses safety concern because Lidendrite can gradually grow on a surface during repeated charging/discharging and short-circuit
battery cells. This not only leads to a premature cell failure but triggers thermal runaway of
batteries. Plus, active lithium ions are consumed to form lithium dendrite, thereby reducing the
capacity of batteries overtime.
To address this issue, it is important to understand the mechanism of Li-dendrite growth while
operating Li-ion battery cells. Many research groups have studied the Li-dendrite growth by using
ex-situ characterization methods. On the other hand, by using in-situ characterization technique,
one can collect live data on the evolution of the Li-dendrite while its growth rate would be
controlled under various experimental parameters. The resulting data will provide a critical
insight on the formation mechanism of the Li-dendrite and even an opportunity to find an
approach to suppress it.
In this regard, this study aims to characterize the Li-dendrite by using in-situ Atomic Force
Microscopy (AFM) in conjunction with an Electrochemistry Cell (EC cell). First, a unit cell was
made using a copper foil as anode and NMC (Lithium Nickel Manganese Oxide) as cathode. All
the cell assembling process was performed in an argon-filled glove box to avoid encapsulating
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moisture or air in the cell. Next, the assembled EC cell was transferred to an AFM chamber and
an in-situ AFM characterization was performed while it was charged/discharged under various
current densities. AFM scans of the Li-dendrite growth on copper were taken in a set time interval
to monitor evolutions of topography and mechanical properties. Results from this study will
advance our fundamental understanding by filling a knowledge gap on the mechanical behavior
of Li-dendrite growth.
Description
Keywords
Li-ion Battery, Lithium Dendrite, AFM