POST-TEST ANALYSIS OF LITHIUM-ION BATTERY MATERIALS

J. BAREÑO, N. DIETZ-RAGO,I. BLOOM

K. FENTON, L. A. STEELE, J. LAMB, S. SPANGLER, C. GROSSO

D. WOOD, Z. DU, Y. SHENG, JIANLIN LI

DOE Annual Merit ReviewWashington, DC, June 5-9, 2017

PROJECT ID: ES166

This presentation does not contain any proprietary, confidential or otherwise restricted information

Project start: October 1, 2015 Project end: September 30, 2018

– 50% complete

Overview

TIMELINE

POST-TEST ANALYSIS OF LITHIUM-ION BATTERY MATERIALS

FY17: $850K FY16: $750K

BUDGET Oak Ridge National Laboratory Sandia National Laboratory NEAH Power

COLLABORATORS

OBJECTIVES Elucidate physical and chemical

response of constituent battery materials under battery abuse conditions Develop analysis procedures

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A THREE-LABORATORY CONSORTIUM

Argonne, Sandia and Oak Ridge teamed to leverage strengths and abilities at each site to study effects of processing and abuse response of two lithium-ion battery chemistries, high-Ni NMC and LiFePO4

What each site contributes– Argonne: Post-test Facility – ability to characterize battery materials under

inert atmosphere– Sandia: Battery Abuse Testing Lab (BATLab) – ability to thermally and

electrically abuse cells under controlled conditions– Oak Ridge: Battery Manufacturing R&D Facility – ability to make cells with

well-defined chemistries, as the project needs

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POST-TEST ANALYSIS OF LITHIUM-ION BATTERY MATERIALS

Science Issues

What are the underlying changes in cell components during an abuse event,such as overcharge? Are there effects from battery format? Chemistry? Howdo these effects manifest themselves?– In principle, we can use what we learn to mitigate the effect of abuse

What is the impact of processing methods on the performance of the cells? Thatis, what is the effect of type of binder and drying procedure on the SEI layer, cellimpedance, binder degradation, gases, and current collector corrosion?

Relevance

APPROACH

Changes in cell components during overcharge– Compare surface and bulk chemistry of electrodes before and after abuse

event– Expected outcome

• Understanding of the physical and chemical changes in the cell during abuse events

• Design rules to manage/eliminate abuse consequences, such as binders for a more-controlled overcharge response

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MILESTONESMilestone Due date Type Status

Report to DOE 12/31/15 Quarterly progress measure

Complete

Report to DOE 3/31/16 Quarterly progress measure

Complete

Report to DOE 6/30/16 Quarterly progress measure

Complete

Compare aqueous- and organic-processed electrode, elucidating differences.

9/30/16 Annual SMART milestone

Delayed. Initialcomparison showed a difference in reactivity

Report to DOE 12/31/16 Quarterly progress measure

Complete. 9/30milestone delayed due to XPS issues. Should be complete in January

Report to DOE 3/31/17 Quarterly progress measure

Complete. 9/30 milestone complete

Report to DOE 6/30/17 Quarterly progress measure

Compare pre- and post-abuse event cell materials, elucidating changes in electrode materials

9/30/17 Annual SMART milestone

Report to DOE 12/31/17 Quarterly progress measure

Report to DOE 3/31/18 Quarterly progress measure

Report to DOE 6/30/18 Quarterly progress measure

Compare pre- and post-abuse event cells. The cells were made at ORNL and will contain aqueous-processed, thick electrodes.

9/30/18 Annual SMART milestone

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TECHNICAL PROGRESS:

THE ADVANCED MANUFACTURING FACILITY AT ORNL MADE TWO SETS OF NCM/GRAPHITE CELLS, ONE USING PVDF BINDER AND AN NMP BASED PROCESS, ONE USING CMC BINDER AND AN AQUEOUS PROCESS

THE BATTERY ABUSE TESTING LABORATORY AT SNL TOOK EACH CELL IN EACH SET TO A DIFFERENT STATE OF OVERCHARGE, FROM 100% SOC (NO OVERCHARGE) TO FAILURE

THE CELLS WERE DISASSEMBLED AT ANL AND THEIR COMPONENTS CHARACTERIZED TO ELUCIDATE THE BINDER-DEPENDENT PHYSICOCHEMICAL CHANGES INDUCED BY THE ABUSE

NMP PROCESS CELL TEARDOWN10

0% S

OC

140%

SO

C18

0% S

OC

120%

SO

C16

0% S

OC

Failu

re

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AQUEOUS PROCESS CELL TEARDOWN10

0% S

OC

140%

SO

C18

0% S

OC

120%

SO

C16

0% S

OC

Failu

re

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ICPMS ANALYSIS:TM MIGRATION FROM CATHODE TO ANODE

More severe at higher SOC and in NMP process Follows stoichiometric ratio (Ni:Mn:Co ~ 5:3:2) for both electrode processes Additionally, more P incorporation on Aqueous process

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ppm

by

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%SOC

NMP Processing

Ni Co Mn P

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Aqueous Processing

Mn Co Ni P

NMP Aqueous

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NMP PROCESS ANODES

100% 120% 140%

160% 180% 250%

Dendrites start to appear at 120% SOC and increase in density with increasing SOC. The dendrites are organic/organometallic and become heavily coated with increasing SOC. Transition metals are detected starting at 120% SOC, associated with the dendrite coating.

C 72.20O 6.18F 19.64P 1.75Ni 0.07Cu 0.15Total 100.0

0

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SEM of 180% SOC NMP Processed Anode

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2

45

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Backscattered electron image

Area 1 2 3 4C 42.25 23.63 45.09 89.41O 32.48 14.44 32.48 5.57F 11.45 54.37 9.50 4.75P 2.06 6.06 1.65 0.21S 0.13 0.33 0.17Mn 0.96 0.37 1.20Co 3.76 0.25 3.33Ni 6.69 0.70 6.28Cu 0.05Total 100.00 100.00 100.00

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5

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5-collector

dendrites

graphite

Surface

Cracked smooth layer

Complex layers are observed on surface. Transition metals identified through the dendrite layer (#3). The backscattered electron image highlights the superficial distribution of transition metals on the surface.

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NMP PROCESS CATHODES

100% 120% 140%

250%160% 180%

Surface microstructure appears the same until 180% SOC. Amorphous material between particles has formed at 180% SOC. More topographic variation is present in 180% and 250% SOC suggesting a loss of binder.

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AQUEOUS PROCESS ANODES

100%

180%160%

140%120%

270%

Dendrites start to appear at 120% SOC and increase in density with increasing SOC. The dendrites are organic/organometallic and become coated with increasing SOC. Transition metals are detected starting at 160% and are associated mainly with the dendrite coating.

FOV 3.5kC 67.96O 15.54F 15.22Si 0.14P 0.56S 0.05

Mn 0.12Co 0.04Ni 0.14Cu 0.22

Total 100.00

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AQUEOUS PROCESS CATHODES

100%

180%160%

140%120%

270%

Surface appears unaltered until 180% SOC, surface aggregates appear along with cracking and discoloration. At 270% SOC, more discoloration and large areas of gouged out material, along with surface bubbling suggests binder breakdown.

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AQUEOUS PROCESS CATHODES

100%

180%160%

140%120%

270%

Surface microstructure appears the same until 180% SOC. More topographic variation is present in 180% and 270% SOC suggesting a loss of binder.

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EMERGENCE OF FLUORINATED C IN AQUEOUS CATHODELi REMAINING AT ANODE C FOR LOW OVERCHARGE

Anode Cathode

NM

PA

queo

us

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LiF DOMINANT AT ANODESLiF PRESENT AT AQUEOUS CATHODE AT HIGH OVERCHARGE

Anode Cathode

NM

PA

queo

us

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THINNER CEI AT NMP CATHODESMOX PRESENT IN NMP CATHODE (160% SOC)

Anode Cathode

NM

PA

queo

us

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MORE P INCORPORATION AT ANODESAnode Cathode

NM

PA

queo

us

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Al PRESENT IN AQUEOUS CATHODELi IN ANODE MORE DEPENDENT ON SOC FOR AQUEOUS

Anode Cathode

NM

PA

queo

us

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SUMMARY

Argonne, Oak Ridge and Sandia National Laboratories are collaborating to study the physical and chemical effects of overcharge on cells, and the influence of chemistry and binder Mechanical degradation of electrodes is evident and progressively worsens at

higher overcharge Transition metal dissolution from NMC cathodes and migration to anode also

worsens at higher overcharge, follows stoichiometric ratios, and is worse in the NMP process (pVdF binder) than in the Aqueous process (CMC binder) cells Dendrite formation is more severe, and occurs at lower overcharge, on NMP

process anodes than on Aqueous process anodes Stronger MOx signal (thinner surface layer) on NMP process cathode than on

Aqueous process cathode Al present in Aqueous process cathodes, suggesting current collector corrosion

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www.anl.gov

ACKNOWLEDGMENTS

This work has been produced under the auspices of the US Department of Energy, Office of Vehicle Technology, under contract numbers:• DE-AC02-06CH11357 (Argonne)• DE-AC04-94AL85000 (Sandia)• DE-AC05-00OR22725 (Oak Ridge)

The authors are grateful to P. Faguy and D. Howell (VTO/DOE) for their support

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