Morphology and texture of spheroidized natural and synthetic graphites

Mundszinger, Manuel; Farsi, Sarvenaz; Rapp, Manfred; Golla‐Schindler, Ute; Kaiser, Ute; Wachtler, Mario

doi:10.1016/j.carbon.2016.10.060

Cited by 53 publications

(55 citation statements)

References 17 publications

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“…In fact, for obtaining such spherical particle shape (also referred to as "potato shape"), the originally ake-like NG particles and the frequently randomly shaped SG particles have to be subjected to an additional mechanical treatment aer the mining process, the spheroidization. 227 This process aims at homogenizing the particle size (ideally, 8-30 mm) and morphology and, thus, improving the packing density in the electrode coating layer for enhanced volumetric capacities. In case of NG, this modication of the particle morphology allows moreover for avoiding the parallel-to-the-current-collector orientation of the ake-like material, which would hinder rapid lithium cation de-/intercalation.…”

Section: Natural Vs Synthetic Graphitementioning

confidence: 99%

The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites

Asenbauer

Eisenmann

Kuenzel

et al. 2020

Sustainable Energy Fuels

849

569

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Section: Natural Vs Synthetic Graphitementioning

confidence: 99%

The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites

Asenbauer

Eisenmann

Kuenzel

et al. 2020

Sustainable Energy Fuels

849

569

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show abstract

“…The second anode material investigated in this work, SNG, is prepared from natural graphite flakes using a labtype mechanical spheroidization process. [34,35] For comparison, we also characterized the SEI formation on the binder-free and binder-containing graphite powder film electrodes in LP30 electrolyte. SEI formation was first characterized by cyclic voltammetry measurements, following the current evolution upon repeated potential cycling.…”

Section: Introductionmentioning

confidence: 99%

“…Two types of graphite were studied: the first one, MAGE, is an artificial graphite produced by Hitachi Chemical Co., Ltd. which is used as anode material in high‐energy LIBs. The second anode material investigated in this work, SNG, is prepared from natural graphite flakes using a lab‐type mechanical spheroidization process [34,35] . For comparison, we also characterized the SEI formation on the binder‐free and binder‐containing graphite powder film electrodes in LP30 electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Model Studies on Solid Electrolyte Interphase Formation on Graphite Electrodes in Ethylene Carbonate and Dimethyl Carbonate II: Graphite Powder Electrodes

et al. 2020

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As part of a systematic study on the formation and composition of the solid electrolyte interphase (SEI) in lithium-ion batteries (LIBs), going stepwise from highly idealized electrodes such as highly oriented pyrolytic graphite and conditions such as ultrahigh vacuum conditions to more realistic materials and reaction conditions, we investigated the decomposition of simplified electrolytes (ethylene carbonate (EC) + 1 M LiPF 6 and dimethyl carbonate (DMC) + 1 M LiPF 6) at binder-free graphite powder model electrodes. The results obtained from cyclic voltammetry and ex situ X-ray photoelectron spectroscopy halfcell measurements-in particular on the effect of cycling rate, solvent and electrode-are explained in terms of a mechanistic model where electrolyte decomposition occurs at the SEI j electrode interface and where transport of solvent and salt species through the growing SEI plays an important role for explaining the observed change from preferential salt decomposition to solvent decomposition with increasing cycling rate.

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“…This indicates that the (002) planes in graphite are preferentially aligned parallel to the current collector, which is expected from previous investigations using SEM and X-ray tomographic microscopy and can be explained by the alignment of graphite particles with their major axes parallel to the current collector during fabrication. 6,10 Deconvoluting particle orientation and grain orientation within particles.-In porous electrodes containing polycrystalline particles, the measured orientation distribution f (α) is a convolution of the particle orientation distribution p(α) and the grain orientation distribution within a single particle g(α p ). Here, α p is the elevation angle relative to the particle plane (Figure 2a).…”

Section: Methodsmentioning

confidence: 99%

“…9 The two-dimensional nature of graphite is also reflected in the shape of graphite particles: they are naturally platelet-shaped. 10 Earlier work has shown that non-spherical particles align during porous electrode fabrication, leading to large tortuosity of the pore-phase, reducing effective transport of lithium in the electrolyte. 6 Tortuosity can be somewhat reduced by using spherical graphites, which often exhibit complex grain distributions depending on the manufacturing process.…”

mentioning

confidence: 99%

Rapid, Non-Invasive Method for Quantifying Particle Orientation Distributions in Graphite Anodes

Baade

Ebner

Wood

2017

J. Electrochem. Soc.

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For materials with 1D or 2D lithiation pathways and non-spherical particle shapes, knowledge of the crystallographic grain orientation in the particle and the active particle orientation in the porous electrode is important for quantifying battery performance. Here we study graphite anodes and show how X-ray diffraction based texture measurements can be used to quantify both the particle orientation, which develops during the coating and calendaring process, and the grain orientation within a specific type of graphite. This lab-based, non-invasive approach to study electrode structure and active particles can assist in engineering improved lithium ion batteries. © The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.1291712jes] All rights reserved.Manuscript submitted June 23, 2017; revised manuscript received August 14, 2017. Published September 8, 2017 In order to optimize a lithium ion battery, it is important to understand the lithiation pathways within the active material 1-5 as well as the lithium transport through the pore space of the electrode, which is governed by the shape and orientation distribution of particles in the electrode.6,7 Here, we present X-ray diffraction (XRD)-based texture measurements as a quantitative, non-invasive method to characterize the crystallographic grain orientation of particles and the orientation of these particles within lithium ion battery porous electrodes.The importance of this structural information is highlighted in the case of graphite, which is the most widely used active material for negative lithium ion battery electrodes. The two-dimensional structure of graphite is responsible for the anisotropy of its electronic, ionic, and thermal conductivity as well as its mechanical properties. 8(De)lithiation occurs along the (002) planes, causing directional volumetric expansion in the [001] direction, which can also translate to directional changes in electrode porosity as the graphite particles swell into the pore space during lithiation. 9 The two-dimensional nature of graphite is also reflected in the shape of graphite particles: they are naturally platelet-shaped. 10 Earlier work has shown that non-spherical particles align during porous electrode fabrication, leading to large tortuosity of the pore-phase, reducing effective transport of lithium in the electrolyte.6 Tortuosity can be somewhat reduced by using spherical graphites, which often exhibit complex grain distributions depending on the manufacturing process. 10For graphite anodes, the electronic and ionic conductivity of the graphite particles does not limit cell performance, 11,12 so most efforts have focused on quantifying and reducing tortuosity, which limits the fast charging of high energy dense cells. 13,14 To determine tortuosity of an e...

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Morphology and texture of spheroidized natural and synthetic graphites

Cited by 53 publications

References 17 publications

The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites

The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites

Model Studies on Solid Electrolyte Interphase Formation on Graphite Electrodes in Ethylene Carbonate and Dimethyl Carbonate II: Graphite Powder Electrodes

Rapid, Non-Invasive Method for Quantifying Particle Orientation Distributions in Graphite Anodes

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