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Dive into the research topics where Brandon R. Long is active.

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Featured researches published by Brandon R. Long.


Journal of the American Chemical Society | 2015

Re-entrant Lithium Local Environments and Defect Driven Electrochemistry of Li- and Mn-Rich Li-Ion Battery Cathodes

Fulya Dogan; Brandon R. Long; Jason R. Croy; Kevin G. Gallagher; Hakim Iddir; John T. Russell; Mahalingam Balasubramanian; Baris Key

Direct observations of structure-electrochemical activity relationships continue to be a key challenge in secondary battery research. (6)Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is the only structural probe currently available that can quantitatively characterize local lithium environments on the subnanometer scale that dominates the free energy for site occupation in lithium-ion (Li-ion) intercalation materials. In the present study, we use this local probe to gain new insights into the complex electrochemical behavior of activated 0.5(6)Li2MnO3·0.5(6)LiMn(0.5)Ni(0.5)O2, lithium- and manganese-rich transition-metal (TM) oxide intercalation electrodes. We show direct evidence of path-dependent lithium site occupation, correlated to structural reorganization of the metal oxide and the electrochemical hysteresis, during lithium insertion and extraction. We report new (6)Li resonances centered at ∼1600 ppm that are assigned to LiMn6-TM(tet) sites, specifically, a hyperfine shift related to a small fraction of re-entrant tetrahedral TMs (Mn(tet)), located above or below lithium layers, coordinated to LiMn6 units. The intensity of the TM layer lithium sites correlated with tetrahedral TMs loses intensity after cycling, indicating limited reversibility of TM migrations upon cycling. These findings reveal that defect sites, even in dilute concentrations, can have a profound effect on the overall electrochemical behavior.


Journal of Materials Chemistry | 2015

Pristine-state structure of lithium-ion-battery cathode material Li1.2Mn0.4Co0.4O2 derived from NMR bond pathway analysis

Hakim Iddir; Baris Key; Fulya Dogan; John T. Russell; Brandon R. Long; Javier Bareño; Jason R. Croy; R. Benedek

Layered lithium ion battery cathode materials have been extensively investigated, of which layered–layered composites xLi2MnO3·(1 − x)LiMO2 (M = Mn, Co, Ni) are of particular interest, owing to their high energy density. Before the structural transformations that occur in these materials with cycling can be understood, the structure of the pristine material must be established. In this work, NMR spectra are measured for the model layered–layered system xLi2MnO3·(1 − x)LiCoO2 and Bond-Pathway-model analysis is applied to elucidate the atomic arrangement and domain structure of this material in its pristine state, before electrochemical cycling. The simplest structural element of an Li2MnO3 domain consists of a stripe of composition LiMn2 parallel to a crystallographic axis in a metal layer of the composite. A simple model of the composite structure may be constructed by a superposition of such stripes in an LiCoO2 background. We show that such a model can account for most of the features of the observed NMR spectra.


Applied Physics Letters | 2013

X-ray diffraction microscopy of lithiated silicon microstructures

Tim T. Fister; Jason L. Goldman; Brandon R. Long; Ralph G. Nuzzo; Andrew A. Gewirth; Paul Fenter

Optically patterned silicon microstructures show great promise as lithium ion battery electrodes as they can balance the high intrinsic charge capacity of silicon with its large volume changes during repeated cycling. Previous scanning electron microscopy showed that lithiation initially occurs at (110)-oriented facets, but was not directly sensitive to the amount of crystalline silicon within the core of each microstructure. Here, we image the extent of the lithiation and the degree of residual crystallinity in individual silicon micro-posts directly using full-field x-ray reflection interfacial microscopy (XRIM). Images of the silicon posts are interpreted using a straightforward model relevant for XRIM images obtained from large scale topological features. This approach should be widely applicable to a broad range of battery materials and for probing the liquid/solid interfaces of complex heterostructures during lithiation reactions.


Sustainable Energy and Fuels | 2018

The quest for manganese-rich electrodes for lithium batteries: strategic design and electrochemical behavior

Michael M. Thackeray; Jason R. Croy; Eungje Lee; A. Gutierrez; Meinan He; Joong Sun Park; Bryan T Yonemoto; Brandon R. Long; Joel D. Blauwkamp; Christopher S. Johnson; Youngho Shin; W. I. F. David

Manganese oxides, notably γ-MnO2 and modified derivatives, have played a major role in electrochemical energy storage for well over a century. They have been used as the positive electrode in primary (single discharge) Leclanche dry cells and alkaline cells, as well as in primary and secondary (rechargeable) lithium cells with non-aqueous electrolytes. Lithiated manganese oxides, such as LiMn2O4 (spinel) and layered lithium–nickel–manganese–cobalt (NMC) oxide systems, are playing an increasing role in the development of advanced rechargeable lithium-ion batteries. These manganese-rich electrodes have both cost and environmental advantages over their nickel counterpart, NiOOH, the dominant cathode material for rechargeable nickel–cadmium and nickel–metal hydride batteries, and their cobalt counterpart, LiCoO2, the dominant cathode material in lithium-ion batteries that power cell phones. An additional benefit is that tetravalent manganese can be used as a redox-active and/or stabilizing ‘spectator’ ion in lithiated mixed-metal oxide electrodes. This paper provides an overview of the historical development of manganese-based oxide electrode materials and structures, leading to advanced systems for lithium-ion battery technology; it updates a twenty-year old review of manganese oxides for lithium batteries. The narrative emanates largely from strategies used to design manganese oxide electrode structures at the Council for Scientific and Industrial Research, South Africa (1980–1994), Oxford University, UK (1981–1982), and Argonne National Laboratory, USA (1994–2017); it highlights the worldwide evolution of ideas and recent trends to improve the design, stability, and electrochemical capacity of structurally integrated, manganese-rich electrode materials.


Advanced Functional Materials | 2011

Strain Anisotropies and Self-Limiting Capacities in Single-Crystalline 3D Silicon Microstructures: Models for High Energy Density Lithium-Ion Battery Anodes

Jason L. Goldman; Brandon R. Long; Andrew A. Gewirth; Ralph G. Nuzzo


Journal of The Electrochemical Society | 2014

Quantifying Hysteresis and Voltage Fade in xLi2MnO3●(1-x)LiMn0.5Ni0.5O2 Electrodes as a Function of Li2MnO3 Content

Jason R. Croy; Kevin G. Gallagher; Mahalingam Balasubramanian; Brandon R. Long; Michael M. Thackeray


Journal of The Electrochemical Society | 2016

Optimizing Areal Capacities through Understanding the Limitations of Lithium-Ion Electrodes

Kevin G. Gallagher; Stephen E. Trask; Christoph Bauer; Thomas Woehrle; Simon F. Lux; Matthias Tschech; Peter Lamp; Bryant J. Polzin; Seungbum Ha; Brandon R. Long; Qingliu Wu; Wenquan Lu; Dennis W. Dees; Andrew N. Jansen


Journal of Physical Chemistry C | 2011

Dopant Modulated Li Insertion in Si for Battery Anodes: Theory and Experiment

Brandon R. Long; Maria K. Y. Chan; Jeffrey Greeley; Andrew A. Gewirth


Journal of Physical Chemistry Letters | 2011

The First-Cycle Electrochemical Lithiation of Crystalline Ge: Dopant and Orientation Dependence and Comparison with Si

Maria K. Y. Chan; Brandon R. Long; Andrew A. Gewirth; Jeffrey Greeley


Journal of The Electrochemical Society | 2014

Advances in Stabilizing ‘Layered-Layered’ xLi2MnO3·(1-x)LiMO2 (M=Mn, Ni, Co) Electrodes with a Spinel Component

Brandon R. Long; Jason R. Croy; Joong Sun Park; Jianguo Wen; Dean J. Miller; Michael M. Thackeray

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Jason R. Croy

University of Central Florida

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Kevin G. Gallagher

Argonne National Laboratory

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Baris Key

Argonne National Laboratory

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Fulya Dogan

Stony Brook University

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Joong Sun Park

Argonne National Laboratory

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Paul Fenter

Argonne National Laboratory

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Bing Shi

Argonne National Laboratory

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Hakim Iddir

Argonne National Laboratory

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