Correlative Microscopy of Energy Materials

ARUN DEVARAJPHYSICAL AND COMPUTATIONAL SCIENCES DIRECTORATE (PCSD)

PACIFIC NORTHWEST NATIONAL LABORATORY,

RICHLAND, WA, USA, 99354

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Correlative microscopy: Motivation

Obtain all different pieces of information from the same sample volume:

structure, composition and chemical state information.

Beyond a single technique capability to achieve with high spatial

resolution.

Interrogate challenges and limitation of individual techniques:

quantification of what is real and what is an artifact in characterization

results.

Improve the analysis of results: Use information from complementary

imaging modalities to improve the analysis of results.

Correlative microscopy with APT

Many examples

TEM-APT direct correlation

STEM tomography-APT direct correlation

STEM Nanobeam diffraction-APT correlation

TEM-APT-STXM correlation

HRSTEM-APT

TKD-APT correlation

APT correlation with other

techniques.

M. Herbig et. al. PRL, 2014I. Arslan et. al. Ultramicroscopy, 2008

D. Schreiber et. al. Scripta Materialia, 2013

K. Kabinsky et. al. Ultramicroscopy, 2014

Dual-beam FIB for site-specific sample preparation

CAMECA LEAP 4000 XHR Atom Probe tomography

STXM imaging and

NEXAFS at ALS, LBNLAberration corrected Transmission

electron microscopy

STRUCTURE COMPOSITION CHEMICAL STATE

Multimodal chemical imaging

Level-set and FEM models

TEM-APT cross correlation: Ti-Al-Mo alloy

200nm

DF image at

-6oAlpha tilt

~106o

DF imageBF image

~106o

A. Devaraj et. al. Scripta Materialia, 69, 513-516, 2013.

~106o

50nm

20

0n

m Mo enriched

region: b

Ti enriched

region: a

Substantial partitioning of Mo while very limited partitioning of Al between a and b

On annealing at higher temperature a phase became enriched in Al as expected.

TEM-APT cross correlation

3

A. Devaraj et. al. Scripta Materialia, 69, 513-516, 2013.

Li-ion Battery Cathode material: Li1.2Ni0.2Mn0.6O2

TEM imaging, diffraction and EDS = structure + qualitative

composition understanding.

Ni segregates to surfaces and boundaries

Will Ni segregation impact the Li diffusivity?

Challenges

Accurate quantification of the compositional partitioning

across these different regions.

Understanding Li distribution in addition to Mn and Ni.

Gu et al, Nano Letters 12, 5186-5191 (2012)

Sample prep of single nanoparticles

Preparation of APT needle specimens of Li-ion battery cathode nanoparticles.

Li-ion Batteries: As-fabricated layered

Li1.2Ni0.2Mn0.6O2

Li segregate closer to Mn rich regions.

Ni segregate away from Mn rich regions

Spatially resolved compositional measurement of two regions within the layered LNMO cathode nanoparticles.

Segregation seems to be function of synthesis method.

A. Devaraj. et. al. Nature Communications, 6, 2015

Surface changes of cathode nanoparticles during cycling.

Structural characterization by HRSTEM.

Qualitative compositional and chemical state information by EDS and EELS.

Cycled layered Li1.2Ni0.2Mn0.6O2

P. Yang et. al. Nano Letters, 15, 514-522, 2015

Cycled layered Li1.2Ni0.2Mn0.6O2

Li, Mn, Ni segregating to independent regions.

Loss of Li quantified in cycled vs before cycling.

Postulated to be one reason for irreversible loss of capacity.

A. Devaraj. et. al. Nature Communications,6, 2015

Scanning Transmission X-ray Microscopy

STXM can provide ~30nm spatial resolved chemical state mapping of elements.

Beamlines 5.3.2 and 11.0.2 at advanced light source Berkeley.

Scanning Transmission X-ray Microscopy

STXM can spatially identify the origin of additional spectral features in O K edge NEXAFS spectra after cycling to be coming from surface region of the particles.

STXM mapping cannot pick up the compositional partitioning in the Li1.2Ni0.2Mn0.6O2.

600 nm

TEM-APT-STXM Direct Correlation

True multimodal chemical imaging to obtain nanoscale structure, composition,

and chemical state information of the same specimen

A. Devaraj et.al. Under preparation

Oxide thin films: Double Pervoskite Oxides

Multimodal characterization of the nanostructure in MBE grown oxide thin films

APT provides 3D quantitative measure of the nanoscale composition of MBE grown oxide

thin films, which can be correlated to the observed magnetic properties.

S. Spurgeon, A. Devaraj et. al. Chemistry of Materials, 2016

Direct Correlation of APT-STEM-FEM

Toward improved nanoscale chemical imaging of metal nanoparticles

embedded in oxides (e.g., catalysts, plasmonic materials) by combining

HRSTEM, APT, and computational simulations

Devaraj et al., Journal of Physical Chemistry Letters, 2014

Devaraj et. al., Journal of Physical Chemistry Letters, 2013

Featured in C&E News cover story, Oct 13, 2014

APT results: Metal-oxide interface

Change in sharpness of interface is evident from APT data

150nm

50nm70nm

CrCr

MgO MgO

70nm

15nm 15nm

Virgin 300 dpa

Cr

Mg

O

Composition change quantified perpendicular to interface using 10nm diameter cylindrical ROI

APT results: Metal-oxide (Cr/MgO) Depth profile

MgO Substrate

Cr

Interface width

~ 2nm

Virgin

MgO SubstrateCr

Cr diffusion up to 300nm

300 dpa

After the irradiation of 300 dpa, substantial Cr diffusion can be observed up to 300 nm. Interface sharpness has been significantly deteriorated

Correlative APT-STEM

Before APT After APT

APT- STEM correlation compared with level set simulations (100) Chromium single crystalline thin film grown on (100) single crystalline

MgO substrate

Correlative APT-STEM-Level set model

Direct Correlation of APT-STEM Level Set

Dynamic specimen shape evolution during field evaporation of complex

heterogeneous materials

Correlating experimental APT-TEM results with level set simulations

Xu et al., Computer and Physics 189, 106-113, 2015

Madaan et al., Applied Physics Letters, In press, 2015

Interesting undesirable observations!

C contamination build-up

Evaporation of APT needles in TEM?

MgO Nanowire growth under e beam

Au nanoparticle disappearance in STEM

Be very careful about beam damage in APT-TEM correlative microscopy experiments!

Conclusions

Correlative microscopy can provide you comprehensive understanding ofmaterials beyond what is achievable by any single technique.

For APT, correlating with TEM and other techniques can improve thereconstruction and interpretation of results.

Need to be careful about issues of beam damage and Carbon depositionespecially when using TEM/STEM to correlative with APT.

Acknowledgements

PNNLVineet Joshi, Curt Lavender

Chongmin Wang, Jason Zhang

Jie Bao, Zhijie Xu

Scott Chambers, Steven Spurgeon

CAMECADavid Larson

Brian Geiser

Ty Prosa

GPMFrancois Vurpillot

QEERIThevuthasan S

Illias Belharouak

UNTRajarshi Banerjee, Srinivasan

Srivilliputhur

Texas A&MAnkit Srivastava

Exon MobilRobert Colby

ALS, LBNLJinghua Guo, Wanli Yan, David Shuh

Apple Inc.Debasish Mohanty

Intel CorporationBaishakhi Mazumder

Funding

Chemical Imaging Initiative (CII), PNNL

Environmental Molecular Sciences Laboratory (EMSL), PNNL

JCESR

Advanced Light Source, Berkeley, LBNL

DOE OVT Propulsion materials program

Thank you

Contact: Arun Devaraj, Senior Research Scientist, Material Science, Physical and Computational Science Directorate, PNNLOffice: EMSL 2389, Arun.devaraj@pnnl.gov 509-371-6412https://www.emsl.pnl.gov/emslweb/people/arun-devaraj