Lithium-ion Batteries Enabled by Silicon Anodes

Description

Deploying lithium-ion (Li-ion) batteries depends on cost-effective electrode materials with high energy and power density to facilitate lower weight and volume. Si-based anode materials theoretically offer superior lithium storage capacity. Replacing a graphite anode with high-capacity materials such as silicon will further improve the energy density. Durable, low-cost, and high-energy-density materials are vital to developing plug-in electric vehicles as affordable and convenient as gasoline-powered ones, while reducing carbon emissions. This reference presents the knowledge gained over recent decades in the materials science and chemistry of silicon and its derivates as anode materials for Li-ion batteries, and provides insights into developing Si-based anode materials for next-generation batteries. Coverage includes the structure and chemistry of silicon, electrolytes and chemistry of Si anodes, nanostructure and binder additives for Si anodes, surface modification and mechanical properties. Researchers in academia and industry will find this detailed reference a highly useful resource. Cover Contents List of figures List of tables About the editors Foreword 1 Overview of the development of silicon anodes for lithium-ion batteries 1.1 Introduction 1.1.1 Siilicon-based Li-anode materials 1.1.2 Conventional graphite anodes 1.1.3 Why Si? 1.2 Electrochemical insertion of Li in Si 1.3 Si-based materials design 1.3.1 Li15Si4 suppression 1.3.2 Fracture suppression 1.3.2.1 Si-transition metal (Si-M) alloys 1.3.2.2 SiO 1.3.2.3 Si-C 1.4 Electrolyte additives 1.5 Binders 1.5.1 Electrochemically active binders 1.5.2 Electrochemically inactive binders 1.6 Implementation of Si alloys in Li-ion cells References 2 Application of Zintl–Klemm rules to silicon-based LIB anodes 2.1 Energy storage 2.2 Zintl–Klemm rules 2.3 Structural considerations 2.4 Binary Zintl phase reactivity 2.5 Ternary Zintl phases 2.6 Electrochemical characterization of the Si-based Zintl phase compounds 2.7 Conclusions Acknowledgements References 3 Electrochemistry of silicon 3.1 Introduction 3.2 High-temperature Li−Si phases 3.3 Room-temperature electrochemical (de)lithiation of Si and corresponding phase changes 3.3.1 Difference between room- and high-temperature Si electrochemistry 3.3.2 Structural evolution during the first lithiation and delithiation 3.4 Anisotropic expansion of Si during lithiation 3.5 Lithiation mechanism in Si 3.5.1 Atomic mechanism of Li insertion into crystalline Si 3.5.2 Atomic mechanism of Li insertion into amorphous Si 3.5.3 Localized phase transformation during lithiation and delithiation 3.5.3.1 Possible lithium silicide phases and their characteristics 3.5.3.2 Phase transformation during first lithiation 3.5.3.3 Phase transformation during first delithiation 3.5.3.4 Phase transformation during second and following lithiation 3.5.3.5 Phase transformation during delithiation of intermediate lithiated phases 3.5.4 Effect of surface oxide on electrochemical reactions 3.5.5 Species evolution during lithiation/delithiation of Si 3.6 Outlook References 4 Electrolytes used in silicon anodes 4.1 Electrolytes based on aprotic solutions 4.1.1 Lithium salts 4.1.2 Aprotic organic solvents 4.1.2.1 Carbonates 4.1.2.2 Ethers 4.1.2.3 Other aprotic solvents 4.1.3 Electrolyte additives 4.2 Electrolytes based on ionic liquid solutions 4.3 Solid-state electrolytes 4.3.1 Ceramic-based SSEs 4.3.2 Polymer-based SSEs or solid-state polymer electrolytes 4.3.3 Gel polymer electrolyte 4.3.4 Materials other than electrolytes used 4.4 Perspective References 5 Interfacial chemistry on silicon anode 5.1 Introduction 5.2 SEI formation mechanisms 5.3 The effect of electrolyte solvent and salt on Si SEI formation 5.3.1 Reduction of solvent molecules 5.3.1.1 Reduction of the cyclic carbonate—ethylene carbonate 5.3.1.2 Reduction of linear carbonates 5.3.2 Reduction of lithium salt 5.4 The effect of electrolyte additives on Si SEI formation 5.4.1 Carbonate solvent additive—FEC 5.4.2 Carbonate solvent additive—VC 5.5 SEI characterization techniques 5.5.1 Morphological methods 5.5.1.1 Optical microscopy 5.5.1.2 Electron microscopy 5.5.1.3 Scanning probe microscopy 5.5.2 Surface chemistry 5.5.2.1 Infrared spectroscopy 5.5.2.2 Confocal microscope Raman spectroscopy 5.5.2.3 X-ray photoelectron spectroscopy 5.5.2.4 Time-of-flight secondary ion mass spectrometry 5.6 Summary 5.6.1 Silicon SEI models 5.6.2 Outlook Acknowledgment References 6 Computational studies for understanding and developing silicon anodes 6.1 Introduction 6.2 Brief review of computational methodology 6.3 Si anode properties characterized by computational methods 6.3.1 Si anode lithiation 6.3.2 Si clusters: stability, lithiation, and interaction with electrolyte components at low degrees of lithiation 6.3.3 Effect of higher lithiation and surface facet structure on the reductive decomposition of solvents, additives, and salts of electrolyte solutions 6.3.4 Effects of Si crystallinity and oxidation degrees on the SEI reactions 6.3.5 Allotropes of silicon and implications for the SEI layer formation 6.4 Consequences of volume expansion and potential solutions 6.4.1 Mechanical stresses and particle cracking 6.4.2 Artificial SEI layers and other anode protection strategies 6.5 Conclusions and future work References 7 Nanostructure silicon for Li-ion batteries 7.1 Introduction 7.2 Opportunities and challenges for Si anodes 7.3 Synthesis and nanoeffect of nanostructured Si anodes 7.3.1 0D Si nanostructure 7.3.2 1D Si nanostructure 7.3.3 2D Si nanostructure 7.3.4 3D Si nanostructure 7.4 Synthesis and nanoeffect of nanostructured Si-based composite anodes 7.4.1 Si/amorphous carbon composites 7.4.2 Si/graphitic carbon composites 7.4.3 Si/conductive polymer composites 7.4.4 Si/metal or oxide composites 7.5 Si-based nanostructure anodes for high-energy full cells 7.5.1 Si-based anode paired with LMO cathode 7.5.2 Si-based anode paired with sulfur-based cathode 7.6 Summary and outlook References 8 Binder additive for silicon anodes 8.1 Introduction 8.2 The functionality of binders in a composite electrode 8.2.1 Fundamentals of adhesion 8.2.2 The battery electrode as a unique polymer composite 8.3 Surfaces of Si materials 8.4 Commercial binders: PVDF and CMC/SBR 8.5 New functional binders 8.5.1 Design principles for Si electrode binders 8.5.2 Development of adhesive binders 8.5.3 Development of elastic binders 8.5.4 Development of conductive binders 8.5 Development of water-soluble or dispersible binders 8.6 Additional considerations References 9 Surface modification for silicon anodes 9.1 Introduction 9.2 Materials and techniques for surface modification 9.2.1 Carbonaceous material coatings 9.2.1.1 Carbon coatings via pyrolysis of polymers 9.2.1.2 Carbon coating via chemical vapor deposition 9.2.1.3 Effects of carbon coating on conductivity and SEI composition 9.2.2 Si-metal alloy modification 9.2.2.1 Si-metal as a Li-active material 9.2.2.2 Si as a Li-active material 9.2.3 Surface modification via ALD and MLD 9.2.3.1 Introduction 9.2.3.2 Surface modifications via MLD on Si-based anodes 9.2.4 In situ Li–M–Si phase formation using additional salt References 10 Mechanical characterization of silicon-based electrodes 10.1 Nanoindentation 10.1.1 Instrumented nanoindentation technique 10.1.2 Mechanical property evolution of LixSi alloys during electrochemical cycling 10.1.3 Mechanical property evolution of Si composite electrodes 10.2 Scratch tests 10.3 Peel tests 10.4 In situ stress measurements 10.4.1 Multi-beam optical stress sensor (MOSS) 10.4.2 In situ curvature measurements of cantilever electrodes 10.5 Fracture behavior of Si-based electrodes 10.5.1 Si wafer electrodes 10.5.2 Si thin film electrodes 10.5.3 Si composite electrodes 10.6 Summary Acknowledgments References 11 Practical implementation of silicon-based negative electrodes in lithium-ion full-cells—challenges and solutions 11.1 Introduction 11.1.1 Lessons learned from commercialized battery cells based on lithium-alloying anodes 11.1.2 Can we directly transform the knowledge gained from graphite anodes to Si anodes? 11.2 Impact of Si-addition to lithium-ion cells: performance and application 11.2.1 Key metrics for practical Si anode-based lithium-ion cells 11.2.1.1 Cycle and calendar life 11.2.1.2 Efficiencies of redox reactions: impact on cycle life and power (rate capability) 11.2.1.3 Specific energy and energy density 11.2.1.4 Cost: from material cost to cell cost 11.2.1.5 Safety 11.2.2 Impact of Si-addition on the performance characteristics of lithium-ion cells 11.2.3 Silicon in commercial LIB cells: state of the art and markets for Si-based cells 11.3 Challenges for practical implementation of Si-based negative electrodes in lithium-ion battery full-cells 11.3.1 Studies of Si-based materials in Li metal cells: opportunities, pitfalls, and lessons learned 11.3.2 Studies of Si-based materials in lithium-ion full-cells: considerations for anode/cathode capacity balancing and challenges with respect to active lithium losses 11.3.3 Challenges for implementation Si-based materials in practical lithium-ion cell formats: electrolyte drying-out and electrode swelling 11.4 Strategies for the development of advanced Si-based lithium-ion full-cells 11.4.1 Material concepts toward practical usage of Si-based anodes 11.4.1.1 Silicon/graphite blends as anode material 11.4.1.2 Major recent results on Si-based LIB full-cells 11.4.2 Electrode formulation and binder development 11.4.3 Pre-treatment and pre-lithiation strategies for Si-based negative electrodes 11.4.4 Electrolyte development 11.4.4.1 Salt anions 11.4.4.2 Electrolyte additives 11.5 Conclusion and future perspectives References 12 A silicon future References Index Back cover