editors

Perla B. Balbuena Yixuan Wang

University of South Carolina

Lithium-Ion Batteries Solid-Electrolyte Interphase

Imperial College Press

CONTENTS

Preface xiii

Chapter 1. SEI on lithium, graphite, disordered carbons and tin-based alloys 1 Emanuel Peled and Diana Golodnitsky

1. Introduction 1 2. SEI formation 3

2.1 The main principles and routes of the SEI formation 3 2.2 Structure of the SEI 5

3. Chemical composition and properties of the SEI on inert Substrate and on lithium 7 3.1 Inert metal Substrate 7 3.2 Lithium covered by a native film 10 3.3 SEI formation in solid polymer and gel electrolytes 11

4. Carbonaceous electrodes 13 4.1 Principles of SEI formation 13 4.2 SEI composition and morphology 16

4.2.1 HOPG 16 4.2.2 SLX20 28 4.2.3 Disordered carbons 32 4.2.4 Overview of SEI composition and properties in

different carbon/non-aqueous electrolyte Systems 45 4.2.5 Effect ofcarbonmodificationon SEI formation 49

5. SEI formation on lithium-tin alloys 53 6. Conclusions 59

Chapter 2. Identification of surface films on electrodes in non-aqueous electrolyte Solutions: spectroscopic, electronic and morphological studies 70 Doron Aurbach and Yaron S. Cohen

1. Introduction " 70 la. Passivation of surface films: a general phenomenon 70

VI Lithium-Ion Batteries: Solid-Electrolyte Interphase

Ib. Modes of growth of surface film phenomena, and their transport properties 72

lc. On the effect of the electrolyte Solutions 73 Id. The role of the cation in surface phenomena in

non-aqueous electrolyte Solutions 74 le. On the impact of the electrode's material 75 lf. Some comments on applications 76

2. Methods for identification of surface films on electrodes 77 2a. Introductory remarks 77 2b. Fast Fourier Transform Infrared Spectroscopy (FTIR) 78 2c. Raman spectroscopy 80 2d. Ultraviolet, Visible Light (UV-Vis) 81 2e. Extended X-ray Absorption Fine Structure (EXAFS),

X-ray Absorption Near-Edge Structure (XANES) 82 2f. X-ray Photoelectron Spectroscopy (XPS) and Auger (AES)

Electron Spectroscopy 82 2g. Energy Dispersive Analysisof X-rays (ED AX) 82 2h. Secondary Ion Mass Spectrometry (SIMS) 83 2i. Electrochemical Quarte Crystal Microbalance (EQCM) 83 2j. X-ray Diffractometry (XRD) 85 2k. NMR, ESR spectroscopy 86 21. Scanning Probe Microscopies (AFM, STM) 86 2m. The use of UHV Systems for identification of surface films

formed on lithium 87 3. The general structure of surface films on reactive surfaces 87

3a. Introduction 87 3b. Surface film formation on active metals 88 3c. Surface film formation on non-reactive metal and carbon

electrodes 90 3d. On transport properties of surface films 93

4. Impedance spectroscopy of electrodes covered by surface films 93 4a. Introductory remarks 93 4b. Active metal electrodes 94

4b. 1 Lithium 94 4b.2 Mg electrodes 95

4c. Non-active metal electrodes polarized to low potentials 97 5. Identification of surface films formed on lithium and non-active

electrodes polarized to low potentials in Li salt Solutions 100

Contents vn

5a. The preparation of a library of FTIR spectra 100 5b. Identification of surface films formed on Li electrodes in

ether Solutions 102 5c. Identification of surface films formed on Li and non-active

electrodes at low potentials in ester Solutions 105 5d. Identification of surface films formed on Li and non-active

metals at low potentials in alkyl carbonate Solutions 107 5e. The impact of salt anions and contaminant reactions on the

surface chemistry of lithium and noble metal electrodes in non-aqueous Li salt Solutions 111

5f. On surface films formed on Li electrodes in polymeric electrolytes 116

6. Surface films on lithiated carbon electrodes 116 6a. Introductory remarks: surface film formation on carbon

electrodes, the influence of the type of carbon, and the impact of the surface films on Li insertion processes 116

6b. On the identification of surface films formed on lithiated graphite electrodes 117

6c. On the correlation between the Performance of lithiated graphite anodes and their surface chemistry 120

7. Surface studies of lithium and lithiated carbon electrodes by scanning probe microscopy 124 7a. Imaging of Li electrodes byAFM 124 7b. Graphite electrodes 126

8. About surface film formation on transition metal oxide cathodes in non-aqueous salt Solutions 128

9. Identification of surface films on calcium and magnesium electrodes 129

10. Concluding remarks 131

Chapter 3. Spectroscopy studies of solid-electrolyte interphase on positive and negative electrodes for lithium ion batteries 140 Zhaoxiang Wang, Xuejie Huang andLiquan Chen

1. Introduction 140 2. SEI on tin oxide anode in various electrolytes 141

2.1 Sample preparation and instrumental 143 2.2 Capacity loss and electrolyte decomposition in first cycle 144

Vll l Lithium-Ion Batteries: Solid-Electrolyte Interphase

2.3 HRTEM study of SEI structure on nano-SnO surface 145 2.4 Identification ofLi2C03 and ROC02Li on nano-SnO anodes 146 2.5 Formation ofLi2C03 and ROC02Li on nano-SnO anodes 150 2.6 Question: What is the reduction sequence of SnO and

electrolyte? 152 2.7 Electrolyte-dependent SEI composition 154 2.8 Conclusion 157

3. Surface enhanced Raman scattering (SERS) on rough electrodes 157 3.1 Normal Raman scattering and SERS studies on battery

materials 158 3.2 Experimental 159 3.3 Electrochemical Performance ofAgelectrode 160 3.4 SERS study of passivating film on Ag electrode in lithium

batteries 160 3.5 Prospects and conclusions on Raman scattering in SEI

investigation 166 4. Infrared absorption and X-ray photelectron spectroscopic

investigation on Performance improvement of surface-modified LiCo02 cathode materials 167 4.1 Sample preparation 170 4.2 Comparison of EC adsorbed on different Substrates 172 4.3 IR spectraofECon electrodes chargedto different voltages 180 4.4 XPS study on evolution of electronic structure of cathode

materials with charge voltages 185 4.5 Conclusions 189

5. Summary and comments 190 6. Acknowledgements 190

Chapter 4. Scanning probe microscopy analysis of the SEI formation on graphite anodes 198 Minoru Inaba and Zempachi Ogumi

1. Introduction 198 2. Charge and discharge characteristics of graphite anode in EC-

and PC-based solutions 201 3. Morphology changes of HOPG basal planes in the initial stage of

solvent decomposition 203 4. SEI formation in EC-based solutions 206

Contents ix

5. Effect of co-solvent on solvent co-intercalation in EC-based Solutions 211

6. Additives in PC-based Solutions 214 6.1 Roles of VC, FEC, and ES as additives 216 6.2 Roles ofother additives in PC-based Solutions 220

7. Summary and outlook 221

Chapter 5. Theoretical insights into the SEI composition and formation mechanism: density functional theory studies 227 Yixuan WangandPerlaß. Balbuena

1. Introduction 227 2. Theoretical modeis and computational details 229 3. Initial reduction of Li+(EC), Li+(PC), and Li+(VC) 231 4. Comparison of reductive decomposition between EC and PC:

Li+(EC)n and Li+(PC)n (n = 2, 3) 232 4.1 Reduction potentials and ring opening barriers of EC

and PC 233 4.2 Decomposition products of EC and PC: Li+(EC)2 and

Li+(PC)2 235 The effect of VC on the reductive decomposition of EC and 5. PC: (S)nLi+(VC) (S = EC and PC; n = 1 and 2) Clusters 238

5.1 Initial reduction 238 5.2 Terminationreactionofradicalanions 241 5.3 Summary of reductive decomposition of solvents in

the presence of VC 246 6. Associations of lithium alkyl dicarbonates through

0~»»«Li+»»»0~ bridges 247 6.1 Geometries and energetics 247 6.2 Vibrational frequencies 255

7. Adsorption and two-dimensional association of lithium alkyl dicarbonates on graphite surfaces through 0~"»»»Li+»»»»7t (arene) interactions 260 7.1 - H-truncated Cluster modeis 261 7.2 Adsorption of lithium alkyl dicarbonates on the basal plane

ofthe neutral graphite surface 262 7.3 Adsorption of lithium alkyl dicarbonates on the basal plane

of negatively charged Gr54" and edge plane of Gr78^ 267

X Lithium-Ion Batteries: Solid-Electrolyte Interphase

7.4 Two-dimensional association of lithium alkyl dicarbonates on the basal plane of the graphite surface (Gr96) 269

7.5 Summary about adsorptions of LVD, LED and LPD on anode surface 271

8. Remarks on the failure of PC and the efficiency of VC for the SEI layer formation in EC/PC-based Solutions 272

Chapter 6. Continuum and Statistical mechanics-based modeis for solid-electrolyte interphases in lithium-ion batteries 276 Harry J. Ploehn, Premanand Ramadass, Ralph E. White, Diego Altomare andPerla B. Balbuena

1. Introduction 276 2. Continuum modeis for SEI growth 277

2.1 Overview ofprevious macroscopic modeis 277 2.2 Elements of continuum mechanics 280

2.2.1 Kinematics 282 2.2.2 Conservationofmass 285

2.3 Dynamic continuum modeis for SEI formation and growth 287 2.3.1 Growth limited by SEI electronic conductivity 288 2.3.2 Growth limited by solvent diffusion 291

3. Statistical mechanics-based model 296 3.1 Description of the lattice-gas model 297

3.1.1 Implementation of the model 299 3.2 Results and discussions 299 3.3 Remarks with respect to the lattice model 305

Chapter 7. Development of new anodes for rechargeable lithium batteries and their SEI characterization by Raman and NEXAFS spectroscopy 308 Giselle Saudi

1. Introduction 308 2. Carbon as a host in lithium ion cells 310 3. Alternative anode materials 319 4. UV Raman spectroscopy oftemplated-disorderedcarbons 321 5. SEI characterization by NEXAFS 323

Contents XI

1. 2.

3. 4. 5.

Background LiMn204

2.1 XPSanalysis 2.2 Elevated temperature effects for LiMn204

LiCo02, LiNi02 and LiNio.8Co0.202

LiFeP04

Summary

6. Conclusions 331 7. Acknowledgements 331

Chapter 8. The cathode-electrolyte interface in a Li-ion battery 337 Kristina Edström, Torbjörn Gustafsson and Josh Thomas

337 338 340 344 353 358 360

Chapter 9. Theoretical studies on the solvent structure and association properties, and on the Li-ion solvation: implications for SEI layer phenomena 365 Yixuan Wang andPerla B. Balbuena

1. Introduction 365 2. Computational details 367 3. Geometrie structures of various cyclic/linear carbonates, and

effective additives and co-solvents to PC-based Solutions 368 4. Seif and cross associations of cyclic/linear carbonates via

C-H»«»0 interactions 373 4.1 Geometrie and energetic properties 374 4.2 C-H bond lengths and vibrational frequencies 380 4.3 C=0 bond lengths and vibrational frequencies 384 4.4 Characteristics of C-H»»»0 interactions using AIM 384

5. Li+ solvation from alkyl carbonates 387 5.1 Interactions between Li+ and organic solvents 387 5.2 Solvation mumberofLi+ 390

6. Conclusion: Implications for SEI layer phenomena 393

Index 398