Rapid Lithium Diffusion in Order@Disorder Pathways for Fast‐Charging Graphite Anodes

Rapid charging of Li-ion batteries is limited by lithium plating on graphite anodes, whereby Li+ ions are reduced to Li metal on the graphite particle surface instead of inserting between graphitic layers. Plated Li metal not only poses a safety risk due to dendrite formation, but also contributes to capacity loss due to the low reversibility of the Li plating/stripping process. Understanding when Li plating occurs and how much Li has plated is therefore vital to remedying these issues. We demonstrate a titration technique with a minimum detection limit of 20 nmol (5×10-4 mAh) Li which is used to quantify inactive Li that remains on the graphite electrode after fast charging. Additionally, the titration is extended to quantify the total amount of solid carbonate species and lithium acetylide (Li2C2) within the solid electrolyte interphase (SEI). Finally, electrochemical modeling is combined with experimental data to determine the Li plating exchange current density (10 A/m2) and stripping efficiency (65%) of plated Li metal on graphite. These techniques provide a highly accurate measure of Li plating onset and quantitative insight into graphite SEI evolution during fast charge.

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Underpotential lithium plating on graphite anodes caused by temperature heterogeneity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2009221117 ◽

2020 ◽

Vol 117 (47) ◽

pp. 29453-29461

Author(s):

Hansen Wang ◽

Yangying Zhu ◽

Sang Cheol Kim ◽

Allen Pei ◽

Yanbin Li ◽

...

Keyword(s):

Short Circuit ◽

Equilibrium Potential ◽

Li Ion Batteries ◽

Li Ion Battery ◽

Slow Kinetics ◽

Battery Capacity ◽

Fast Charging ◽

Graphite Intercalation ◽

Graphite Anodes ◽

Li Ion

Rechargeability and operational safety of commercial lithium (Li)-ion batteries demand further improvement. Plating of metallic Li on graphite anodes is a critical reason for Li-ion battery capacity decay and short circuit. It is generally believed that Li plating is caused by the slow kinetics of graphite intercalation, but in this paper, we demonstrate that thermodynamics also serves a crucial role. We show that a nonuniform temperature distribution within the battery can make local plating of Li above 0 V vs. Li0/Li+(room temperature) thermodynamically favorable. This phenomenon is caused by temperature-dependent shifts of the equilibrium potential of Li0/Li+. Supported by simulation results, we confirm the likelihood of this failure mechanism during commercial Li-ion battery operation, including both slow and fast charging conditions. This work furthers the understanding of nonuniform Li plating and will inspire future studies to prolong the cycling lifetime of Li-ion batteries.

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Improved fast charging capability of graphite anodes via amorphous Al2O3 coating for high power lithium ion batteries

Journal of Power Sources ◽

10.1016/j.jpowsour.2019.03.027 ◽

2019 ◽

Vol 422 ◽

pp. 18-24 ◽

Cited By ~ 22

Author(s):

Dae Sik Kim ◽

Yeong Eun Kim ◽

Hansu Kim

Keyword(s):

Lithium Ion Batteries ◽

High Power ◽

Lithium Ion ◽

Al2o3 Coating ◽

Fast Charging ◽

Graphite Anodes ◽

Amorphous Al2o3

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EIS Study on the Electrode-Separator Interface Lamination

Batteries ◽

10.3390/batteries5040071 ◽

2019 ◽

Vol 5 (4) ◽

pp. 71 ◽

Cited By ~ 5

Author(s):

Martin Frankenberger ◽

Madhav Singh ◽

Alexander Dinter ◽

Karl-Heinz Pettinger

Keyword(s):

Solid Electrolyte ◽

Lithium Ion Batteries ◽

Surface Resistance ◽

Lithium Ion ◽

Capacity Fade ◽

Aging Effects ◽

Fast Charging ◽

Initial Decrease ◽

Graphite Anodes ◽

Comprehensive Study

This paper presents a comprehensive study of the influences of lamination at both electrode-separator interfaces of lithium-ion batteries consisting of LiNi1/3Mn1/3Co1/3O2 cathodes and graphite anodes. Typically, electrode-separator lamination shows a reduced capacity fade at fast-charging cycles. To study this behavior in detail, the anode and cathode were laminated separately to the separator and compared to the fully laminated and non-laminated state in single-cell format. The impedance of the cells was measured at different states of charge and during the cycling test up to 1500 fast-charging cycles. Lamination on the cathode interface clearly shows an initial decrease in the surface resistance with no correlation to aging effects along cycling, while lamination on both electrode-separator interfaces reduces the growth of the surface resistance along cycling. Lamination only on the anode-separator interface shows up to be sufficient to maintain the enhanced fast-charging capability for 1500 cycles, what we prove to arise from a significant reduction in growth of the solid electrolyte interface.

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3D Detection of Lithiation and Lithium Plating in Graphite Anodes during Fast Charging

ACS Nano ◽

10.1021/acsnano.1c02942 ◽

2021 ◽

Author(s):

Alec S. Ho ◽

Dilworth Y. Parkinson ◽

Donal P. Finegan ◽

Stephen E. Trask ◽

Andrew N. Jansen ◽

...

Keyword(s):

Fast Charging ◽

Graphite Anodes

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A Study of Diffusion in Lithium-ion Electrodes Under Fast Charging Using Electrochemical Impedance Spectroscopy

MRS Advances ◽

10.1557/adv.2017.451 ◽

2017 ◽

Vol 2 (54) ◽

pp. 3309-3315 ◽

Cited By ~ 2

Author(s):

Kazi Ahmed ◽

Jeffrey Bell ◽

Rachel Ye ◽

Bo Dong ◽

Yige Li ◽

...

Keyword(s):

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Equivalent Circuit ◽

Electrochemical Impedance ◽

Solid Phase ◽

Equivalent Circuit Model ◽

Lithium Ion ◽

Phase Diffusion ◽

Fast Charging ◽

Lithium Diffusion

ABSTRACTAn in-depth look at diffusion mechanics within lithium-ion electrodes under fast charging conditions is presented. Electrochemical impedance spectroscopy is used as the primary technique to investigate lithium diffusion within electrode material and in electrolyte near the electrode-electrolyte interface. Half-cells of silicon are charged under varying galvanostatic rates while obtaining impedance data. Collected data is analyzed with the help of an electrical equivalent circuit model that provides mechanical and electrochemical parameters for each instance. The novelty of this equivalent circuit partly lies in its ability to resolve between solid-phase diffusion and liquid-phase diffusion, both of which occur during cycling of a lithium-ion electrode. Observed patterns in the parameters of this circuit provide insight into impact of fast charging on mechanics of lithium diffusion, both inside the electrode matrix and within electrolyte.

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