Electrodes for Li-ion Batteries: Materials, Mechanisms and Performance

By Laure Monconduit, Laurence Croguennec and Rémi Dedryvère

The electrochemical energy storage is a means to conserve electrical energy in chemical form. This form of storage benefits from the fact that these two energies share the same vector, the electron. This advantage allows us to limit the losses related to the conversion of energy from one form to another.  The RS2E focuses its research on rechargeable electrochemical devices (or electrochemical storage) batteries and supercapacitors.

The materials used in the electrodes are key components of lithium-ion batteries. Their nature depend battery performance in terms of mass and volume capacity, energy density, power, durability, safety, etc. This book deals with current and future positive and negative electrode materials covering aspects related to research new and better materials for future applications (related to renewable energy storage and transportation in particular), bringing light on the mechanisms of operation, aging and failure.

• Language: English
• Publisher: Wiley
• Release date: Jun 2, 2015
• ISBN: 9781119007388

Book preview

Table of Contents

Cover

Title

Copyright

Acknowledgments

Preface

Introduction

1: Negative Electrodes

1.1. Preamble

1.2. Classic materials: insertion mechanism

1.3. Toward other materials and other mechanisms

1.4. Summary on negative electrodes

2: Positive Electrodes

2.1. Preamble

2.2. Layered transition metal oxides as positive electrode materials for Li-ion batteries: from LiCoO2 to Li1+xM1−xO2

2.3. Alternatives to layered oxides

Conclusion

Bibliography

Index

End User License Agreement

List of Tables

Introduction

Table I.1. The conditions that constitutive active materials (AM) of positive and negative electrodes should meet in order to create a Li-ion battery

List of Illustrations

Introduction

Figure I.1. Representation of the energy and potential of the electrodes and the electrolyte in a Li-ion battery, making apparent the necessity of passivating the negative electrode’s surface. (Adapted from [GOO 10] with permission. Copyright 2010 American Chemical Society)

1: Negative Electrodes

Figure 1.1. Negative electrode materials put forward as alternatives to carbon graphite, a comparison of their respective capacities and potential. From [ZHE 95]

Figure 1.2. Electrochemical mechanisms of different negative electrode materials, of insertion-type (above), or alloys and conversion-type (below). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 1.3. a) Diagram of stages of graphite intercalated by lithium, b) galvanostatic curve for a battery Cgr//Li making the correspondence between plateaux of potential and stages formed. (Adapted from [ZHE 95] with permission. Copyright 1995 American Physical Society)

Figure 1.4. Graphite exfoliation process resulting from the co-intercalation of the solvent between the graphene sheets (above). Protective role of the passivation layer (SEI) which blocks the exfoliation (below). (Adapted from [VET 05] with permission. Copyright 2005 Elsevier)

Figure 1.5. Vinylene carbonate (VC) and fluoroethylene carbonate (FEC): two electrolyte additives for SEI formation currently used in Li-ion batteries

Figure 1.6 Diagram off the structure Li4Ti5O12 ([Li]8a[Li1/3Ti5/3]16dO4, described in the space group Fd-3m), the te trahedra LiO4 are in light gray and the octahhedra are in dark gray (Li/Ti)O6. For a color version of thee figure, see www.iste.co.uk/deedryvere/electroodes.zip

Figure 1.7 Image of a Li4Ti5O12 parrticle with AlF3 coating, obtainned from transmmission electro n microscopy (TEM). Performmance during cycling of LiMn2O4//Li4Ti5O12 batteries with and without coating. (Adapted from [ZHE 09] with permission. Copyright 2014 Elsevier)

Figure 1.8 Diagram of TiO2 structures a) rutile described in space P42/mnm, b) anatase described in space group I4/amd and c) bronze (B) described in space group C²/m For a color version of the figure www.iste.co.uk/dedryvere/electrodes.zip

Figure 1.9. First galvanostatic discharges of anatase samples: two commercial samples showing two particle sizes (200 and 5–10 nm) and a nanoporous sample. (Reprinted from [SHI 11] with permission. Copyright 2011 WILEY-VCH Verlag GmbH & Co)

Figure 1.10. Gravimetric and volumetric capacities of different LiX alloys, X being an element from columns 12 to 15 of the periodic table. (Reprinted from [LAR 07] with permission. Copyright 2007 the Royal Society of Chemistry)

Figure 1.11. Galvanostatic curve of a composite Si electrode [Si/Cb/CMC] [70/18/12] cycled in the electrolyte LiPF6 in EC:PC:3DMC (+1% FEC)

Figure 1.12. Failure mechanism controlled by the evolution of porosity within the Si electrode. Appearance of large-scale pores (10 cycles). Progressive filling of these pores by products resulting from the electrolyte degradation, making it increasingly difficult for Li+ ions to percolate. (Reprinted from [PHI 13a] with permission. Copyright 2014. The Owner Societies). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 1.13. Phase transformations and special reactivity of silicon particles' surface involving the native SiO2 oxide layer. Formation of Li2O and Li4SiO4 phases at the first lithiation. Fluoration of the surface (SiOxFy) and disappearance of Li2O during cycling following the reaction with HF present in the electrolyte. (Adapted from [IDO 97] with permission. Copyright 2013 American Chemical Society)

Figure 1.14. Diagram of electrochemical reactions during Sn lithiation/delithiation. (Reprinted from [LI 14c] with permission. Copyright 2014 American Chemical Society)

Figure 1.15. Illustration of fissures formed in tin grains during the first cycle: a) potential curve as a function of time with points where b) the in situ X-ray transmission microscopy images were recorded. (Adapted from [CHA 10] with permission. Copyright 2010 Elsevier). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 1.16. Performances of the TiSnSb composite electrode (CMC/CB+VGCF) at different cycling rates (4C and C) compared to an electrode prepared without CMC binder

2: Positive Electrodes

Figure 2.1. Main positive electrode material families, compared on a graph, potential versus gravimetric capacity. Graphite, the usual negative electrode material, is also shown. (Adapted from [TAR 01] with permission. Copyright 2001 Nature Publishing Group). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.2. Layered oxides: a wide variety of compositions and cationic distributions between the slabs and the interslab spaces. Depending on the composition, cationic orders can be observed in the slabs

Figure 2.3. Structural description of LiCoO2 using a rock salt structure

Figure 2.4. The Li/Co stoichiometry’s impact on the structure, morphology and electrochemical signature of LiCoO2. (Adapted from [SAT 15] with permission. Copyright 1999 the Royal Society of Chemistry). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.5. Influence of Li/Ni stoichiometry on Li1-zNi1+zO2 (z ≤ 1)’s electrochemical performances in Li//Li1-zNi1+zO2 batteries. (Adapted from [PÉR 96] with permission. Copyright 1996 Elsevier). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.6. Phase transformations and cationic reorganizations associated with the thermal degradation of deintercalated layered oxides LixMO2. The Li ions are not shown for the layered and spinel structure phases for reasons of simplicity. (Adapted from [AMA 01] and [LEE 13] with permission. Copyright 2010 American Chemical Society). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.7. (Top) Representation of a lithium-layered oxide particle containing a concentration gradient, the nickel concentration decreases from the core toward the surface, whereas the manganese concentration increases. (Bottom) Comparison of the cycling performance of lithium batteries using: first a material displaying a concentration gradient at the positive, a second with a composition identical to that at the core and a third with a composition identical to that at the surface. Their cycling was carried out between 2.7 and 4.5 V versus Li+/Li at the rate C/5 (~44 mA/g). (Adapted from [ZHA 13] with permission. Copyright 2012 Nature Publishing Group). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.8. Influence of the potential reached by the material NMC at the end of charge on the dissolution of metals (found in the electrolyte) at ambient temperature more than four weeks. (Reprinted from [ZHE 12] with permission. Copyright 2012 Elsevier)

Figure 2.9. Scheme showing cations, issued from the positive electrode material dissolution, migrating toward the negative electrode during charge, and at the origin of an SEI degradation. (Adapted from [SEG 99] with permission. Copyright 2005 Elsevier). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.10. Interfacial degradation mechanisms of Li(Ni1-xCox)O2 electrodes in contact with a standard LiPF6/carbonates electrolyte during cycling. Structural modifications of the active material’s surface and the formation of a passivation layer. (Reprinted from [SEG 99] with permission. Copyright 2005 Elsevier). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.11. Electron microscopy image (TEM) of an LiCoO2 particle covered with a coating of Al2O3. Comparison of cycling performances up to 4.5 V versus Li+/Li for LiCoO2 nanoparticles, with and without a coating. (Adapted from [PAD 97b] with permission. Copyright 2011 American Chemical Society). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.12. Comparison of charge and discharge curves obtained for Li//Li1.20Ni0.13Mn0.54Co0.13O2 batteries and evolution of the reversible discharge capacity (left arrow), as well as the average discharge potential (right arrow), as a function of the number of cycles. (Adapted from [VAN 09b] with permission. Copyright 2013 Elsevier). For a color version of the figure, see www.iste.co.uk/dedryvere/electrodes.zip

Figure 2.13. Representation of the densities of states (DOS) of Li2RuO3, Li2MnO3 and Li2-xRu1/2Mn1/2O3 for which the Fermi level (Ef) is represented by a horizontal dashed line. It shows that the more electronegative the transition metal element (Ru vs. Mn), the greater the hybridization of transition metals nd levels and oxygen 2p levels. The electronic levels involved in the redox processes are thus Ru⁴+(t2g) from x = 2 to1.5, then O(2p) from x = 1.5 to 1.0. (Adapted from [WAG 09] with permission. Copyright 2013 Nature Publishing Group). For a color