Written by leading experts on various critical issues in this emerging field, this book reviews the recent progresses on flexible energy conversion and storage devices, such as batteries, supercapacitors, solar cells, and fuel cells. It introduces not only the basic principles and strategies to make a device flexible, but also the applicable materials and technologies, such as polymers, carbon materials, nanotechnologies and textile technologies. It also discusses the perspectives for different devices.
Flexible Energy Conversion and Storage Devices contains chapters, which are all written by top researchers who have been actively working in the field to deliver recent advances in areas from materials syntheses, through fundamental principles, to device applications. It covers flexible all-solid state supercapacitors; fiber/yarn based flexible supercapacitors; flexible lithium and sodium ion batteries; flexible diversified and zinc ion batteries; flexible Mg, alkaline, silver-zinc, and lithium sulfur batteries; flexible fuel cells; flexible nanodielectric materials with high permittivity for power energy storage; flexible dye sensitized solar cells; flexible perovskite solar cells; flexible organic solar cells; flexible quantum dot-sensitized solar cells; flexible triboelectric nanogenerators; flexible thermoelectric devices; and flexible electrodes for water-splitting.
-Covers the timely and innovative field of flexible devices which are regarded as the next generation of electronic devices
-Provides a highly application-oriented approach that covers various flexible devices used for energy conversion and storage
-Fosters an understanding of the scientific basis of flexible energy devices, and extends this knowledge to the development, construction, and application of functional energy systems
-Stimulates and advances the research and development of this intriguing field
Flexible Energy Conversion and Storage Devices is an excellent book for scientists, electrochemists, solid state chemists, solid state physicists, polymer chemists, and electronics engineers.
Table of Contents
Preface xiii
1 Flexible All-Solid-State Supercapacitors andMicro-Pattern Supercapacitors 1
Yuqing Liu, Chen Zhao, Shayan Seyedin, Joselito Razal, and Jun Chen
1.1 Introduction 1
1.2 Potential Components and Device Architecture for Flexible Supercapacitors 4
1.2.1 Flexible Electrode Materials 5
1.2.1.1 Carbon Materials 5
1.2.1.2 Conducting Polymers 6
1.2.1.3 Composite Materials 7
1.2.2 Solid-State Electrolytes 7
1.2.3 Device Architecture of Flexible Supercapacitor 8
1.3 Flexible Supercapacitor Devices with Sandwiched Structures 10
1.3.1 Freestanding Films Based Flexible Devices 10
1.3.2 Flexible Substrate Supported Electrodes Based Devices 14
1.4 Flexible Micro-Supercapacitor Devices with Interdigitated Architecture 18
1.4.1 In situ Synthesis of Active Materials on Pre-Patterned Surfaces 18
1.4.2 Direct Printing of Active Materials 21
1.4.3 Patterning ofWell-Developed Film Electrodes 24
1.5 Performance Evaluation and Potential Application of Flexible Supercapacitors 27
1.5.1 Performance Evaluation of Flexible Supercapacitors 28
1.5.2 Integration of Flexible Supercapacitors 29
1.6 Conclusions and Perspectives 32
References 32
2 Fiber/Yarn-Based Flexible Supercapacitor 37
Yang Huang and Chunyi Zhi
2.1 Introduction 37
2.2 Supercapacitor with Intrinsic Conductive Fiber/Yarn 40
2.2.1 Carbolic Fiber/Yarn-Based Supercapacitor 41
2.2.2 Metallic Fiber/Yarn-Based Supercapacitor 44
2.2.3 Hybrid Conductive Fiber/Yarn-Based Supercapacitor 48
2.3 Supercapacitors with Intrinsic Nonconductive Fiber/Yarn 51
2.3.1 Fiber/Yarn Modified by Carbon Materials 52
2.3.2 Fiber/Yarn Modified by Metallic Materials 54
2.4 Integrated Electronic Textiles 57
2.5 Conclusion and Outlook 61
References 62
3 Flexible Lithium Ion Batteries 67
Xuli Chen and YingyingMa
3.1 Overview of Lithium Ion Battery 67
3.1.1 General Principle 67
3.1.2 Cathode 70
3.1.2.1 LiCoO2 with Layered Structure 70
3.1.2.2 LiMn2O4 with a Spinel Structure 70
3.1.2.3 LiFePO4 with an Olivine Structure 70
3.1.3 Anode 71
3.1.3.1 Carbonaceous Anodes 71
3.1.3.2 Metal Alloy Anodes 71
3.1.4 Electrolyte 72
3.2 Planar-Shaped Flexible Lithium Ion Batteries 73
3.2.1 Bendable Planar Lithium Ion Batteries 73
3.2.1.1 Bendable Carbon-Based Planar Lithium Ion Battery 73
3.2.1.2 Thin Metal Material-Based Lithium Ion Battery 77
3.2.1.3 Polymer-Based Lithium Ion Battery 79
3.2.1.4 Special Structural Design-Based Flexible Lithium-Ion Battery 82
3.2.2 Stretchable Planar Flexible Lithium Ion Batteries 84
3.3 Fiber-Shaped Flexible Lithium Ion Batteries 87
3.3.1 Bendable Fiber-Shaped Lithium Ion Battery 87
3.3.2 Stretchable Fiber-Shaped Lithium Ion Battery 93
3.4 Perspective 94
References 95
4 Flexible Sodium Ion Batteries: From Materials to Devices 97
Shengyang Dong, Ping Nie, and Xiaogang Zhang
4.1 Introduction to Flexible Sodium Ion Batteries (SIBs) 97
4.2 The Key Scientific Issues of Flexible SIBs 98
4.2.1 Design of Advanced Active-Materials 99
4.2.2 Design of Flexible Substrates and Electrodes 99
4.2.3 Developing Novel Processing Technologies 101
4.3 Design of Advanced Materials for Flexible SIBs 101
4.3.1 Inorganic Anode Materials for Flexible SIBs 101
4.3.2 Inorganic Cathode Materials for Flexible SIBs 110
4.3.3 Organic Materials for Flexible SIBs 114
4.3.4 Other Major Components for Flexible SIBs (Electrolyte, Separators, etc.) 115
4.4 Design of Full Cell for Flexible SIBs 117
4.5 Summary and Outlook 121
References 123
5 1D and 2D Flexible Carbon Matrix Materials for Lithium-Sulfur Batteries 127
TianyiWang, Yushu Liu, Dawei Su, and GuoxiuWang
5.1 Introduction 127
5.2 The Working Mechanism and Challenges of Li-S Batteries 128
5.3 Flexible Cathode Hosts for Lithium-Sulfur Batteries 129
5.4 Electrolyte Membranes for Flexible Li-S Batteries 138
5.4.1 Solid Polymer Electrolytes for Flexible Li-S Batteries 139
5.4.2 Gel Polymer Electrolytes for Flexible Li-S Batteries 142
5.4.3 Composite Polymer Electrolytes for Flexible Li-S Batteries 143
5.5 Separator for Flexible Li-S Batteries 144
5.6 Summary 148
References 149
6 Flexible Electrodes for Lithium-Sulfur Batteries 155
Jia-Qi Huang,Meng Zhao, Rui Xu, and Qiang Zhang
6.1 Introduction 155
6.2 Lithium-Sulfur Battery and Flexible Cathode 156
6.2.1 Lithium-Sulfur Battery 156
6.2.2 Flexible Cathode for Lithium-Sulfur Battery 156
6.3 The Flexible Cathode of Lithium-Sulfur Battery 157
6.3.1 Flexible Cathode Based on One-dimensional Materials 157
6.3.1.1 Flexible Cathode Based on CNTs 157
6.3.1.2 Flexible Cathode Based on Carbon Nanofibers 163
6.3.1.3 Flexible Cathode Based on Polymer Fibers 166
6.3.2 Flexible Cathode Based on Two-dimensional Materials 167
6.3.2.1 Flexible Cathode Based on Graphene Paper 167
6.3.2.2 Flexible Cathode Based on Graphene Foam 169
6.3.3 Flexible Cathode Based on Three-dimensional Materials 172
6.3.3.1 Flexible Cathode Based on Three-dimensional Carbon Foam Materials 172
6.3.3.2 Flexible Cathode Based on Carbon/Binder Composites Materials 174
6.3.3.3 Flexible Cathode Based on Three-dimensional Metal Materials 176
6.4 Summary and Prospect 177
References 178
7 Flexible Lithium-Air Batteries 183
Qing-Chao Liu, Zhi-Wen Chang, Kai Chen, and Xin-Bo Zhang
7.1 Motivation for the Development of Flexible Lithium-Air Batteries 183
7.2 State of the Art for Flexible Lithium-Air Batteries 184
7.2.1 Overview of Flexible Energy Storage and Conversion Devices 184
7.2.2 Overview of Flexible Lithium-Air Batteries 185
7.2.2.1 Similarities between Coin Cell/Swagelok Batteries with Flexible Battery 187
7.2.2.2 Differences between Coin Cell/Swagelok Batteries with Flexible Battery 188
7.2.3 Current Status of Flexible Lithium-Air Battery 190
7.2.3.1 Planar Battery 190
7.2.3.2 Cable-type Battery 199
7.2.3.3 Woven-type Battery Pack 202
7.2.3.4 Battery Array Pack 203
7.3 Challenges and FutureWork on Flexible Lithium-Air Batteries 206
7.4 Concluding Remarks 207
References 208
8 Nanodielectric Elastomers for Flexible Generators 215
Li-Juan Yin and Zhi-Min Dang
8.1 Introduction 215
8.2 Electro-Mechanical Principles 216
8.2.1 Electro-Mechanical Conversion 216
8.2.2 Equations of DE Generators 217
8.3 Increasing the Performance of Dielectric Elastomers from the Materials Perspective 218
8.3.1 Increasing the Relative Permittivity of DEs 219
8.3.1.1 Elastomer Composites 219
8.3.1.2 Elastomer Blends 222
8.3.1.3 Chemical Modification 223
8.3.2 Decreasing Young’s Modulus 225
8.3.3 Complex Network Structure 225
8.4 Circuits and Electro-Mechanical Coupling Methods 227
8.5 Examples of Dielectric Elastomer Generators 230
8.6 Conclusion and Outlook 231
Acknowledgments 232
References 232
9 Flexible Dye-Sensitized Solar Cells 239
Byung-Man Kim, Hyun-Gyu Han, Deok-Ho Roh, Junhyeok Park, KwangMin Kim, Un-Young Kim, and Tae-Hyuk Kwon
9.1 Introduction 239
9.2 Materials and Fabrication of Electrodes for FDSCs 242
9.2.1 Photo-electrode 242
9.2.1.1 Flexible Substrate for Photo-electrode 242
9.2.1.2 Nanostructured-photoactive Film 243
9.2.1.3 Fiber-type FDSCs 249
9.2.2 Counter-electrode 251
9.3 Sensitizers in FDSCs and Thin Photoactive Film DSCs 254
9.3.1 State-of-the-Art Review of Sensitizers in FDSCs 254
9.3.2 Sensitizers in Thin Photoactive Film DSCs 258
9.4 Electrolyte and Hole-Transporting Materials for FDSCs 270
9.5 Conclusion and Outlook 276
References 278
10 Self-assembly in Fabrication of Semitransparent and Meso-Planar Hybrid Perovskite Photovoltaic Devices 283
Ravi K.Misra, Sigalit Aharon,Michael Layani, Shlomo Magdassi, and Lioz Etgar
10.1 Introduction 283
10.1.1 Semitransparent Perovskite Solar Cells Through Self-assembly of Perovskite in One Step 285
10.1.1.1 Cell Architecture and Morphology 286
10.1.1.2 Transparency and Photovoltaic Performance of the Cells 288
10.1.1.3 Recombination Behavior of the Charges in Cells 291
10.1.2 Mesoporous-Planar Hybrid Perovskite Devices Through Mesh-assisted Self-assembly of Mesoporous-TiO2 292
10.1.2.1 Cell Architecture and Morphology 293
10.1.2.2 Photovoltaic Performance of the Solar Cells 297
10.1.2.3 Study of Recombination Behavior through Charge Extraction 300
10.2 Summary and Future Perspective 302
References 302
11 Flexible Organic Solar Cells 305
Lin Hu, Youyu Jiang, and Yinhua Zhou
11.1 Introduction 305
11.1.1 Working Principle 306
11.1.2 Performance Characterization of OSCs 307
11.1.3 Device Structure 308
11.1.3.1 Conventional Device Structure 308
11.1.3.2 Inverted Device Structure 308
11.2 Active Layer 308
11.2.1 Donor Materials 310
11.2.1.1 Poly(Phenylenevinylene) (PPV) and Polythiophene (PT) Derivatives 310
11.2.1.2 D-A Conjugated Polymers 311
11.2.2 Acceptor Materials 313
11.2.2.1 Fullerene Derivatives 313
11.2.2.2 Non-fullerene Acceptors 315
11.3 Flexible Electrode 317
11.3.1 Conductive Polymer (PEDOT:PSS) 317
11.3.2 Metal Nanowires and Grids 318
11.3.3 Hybrid Carbon Material 319
11.4 Interfacial Layer 320
11.4.1 Hole Transporting Layer (HTL) 320
11.4.2 Electron Transporting Layer (ETL) 320
11.5 Tandem Organic Solar Cells 321
11.5.1 Interconnecting Layer 322
11.5.2 Low Bandgap Polymer Sub-cell 324
11.6 Fabrication Technology for Flexible Organic Solar Cells 326
11.7 Summary 328
References 329
12 Flexible Quantum Dot Sensitized Solar Cells 339
Yueli Liu, Keqiang Chen, Zhuoyin Peng, andWen Chen
12.1 Introduction 339
12.2 Basic Concepts 340
12.2.1 Quantum Dots (QDs) 340
12.2.1.1 Quantum Size Effect 341
12.2.1.2 Multiple Exciton Generation 341
12.2.1.3 Ultrafast Electron Transfer 342
12.2.1.4 Large Specific Surface Area 343
12.2.2 Quantum Dots Sensitized Solar Cells (QDSSCs) 344
12.2.2.1 Schematic of the Structure and Charge Circulation of QDSSCs 344
12.2.2.2 Evaluation of the Photovoltaic Performances of QDSSCs 345
12.3 Development of the Flexible QDSSCs 347
12.3.1 Choosing of the Types of QDs 347
12.3.1.1 Cd-based QDs 347
12.3.1.2 Pb-based QDs 348
12.3.1.3 Cu-based QDs 349
12.3.2 Fabrication of the Flexible Photo-anode Films 350
12.3.3 TiO2-Based Photo-anodes 351
12.3.3.1 Photo-anodes of TiO2 Nanoparticles 351
12.3.3.2 Photo-anodes of TiO2 Nanoarray Structures 352
12.3.3.3 Designing of Novel TiO2 Architecture as Photo-anodes 354
12.3.4 ZnO based Photo-anodes 354
12.3.5 Other Metal Oxide Based Photo-anodes 355
12.3.6 Development of the Sensitization Method 355
12.3.6.1 In situ Sensitization Techniques 356
12.3.6.2 Ex situ Techniques 358
12.3.6.3 Co-sensitization Techniques 360
12.3.7 Interfacial Engineering in QDSSCs 360
12.3.7.1 Surface Passivation by Large-bandgap Semiconductors 361
12.3.7.2 Surface Passivation by Metal Oxides 361
12.3.7.3 Surface Passivation by Molecular Dipoles 362
12.3.7.4 Surface Passivation by Dye Molecules 362
12.3.7.5 Surface Passivation by Molecular Relays 362
12.3.7.6 Combined Interfacial Engineering Methods 363
12.3.8 Optimization of the Counter Electrodes 363
12.3.8.1 Noble Metal Counter Electrodes 365
12.3.8.2 Carbon Counter Electrodes 365
12.3.8.3 Metallic Compound Counter Electrodes 366
12.3.8.4 Polymer Counter Electrodes 370
12.4 Conclusion and Future Outlook 370
Acknowledgments 371
References 371
13 Flexible Triboelectric Nanogenerators 383
Fang Yi, Yue Zhang, Qingliang Liao, Zheng Zhang, and Zhuo Kang
13.1 Introduction 383
13.1.1 Motivation for the Development of Flexible Triboelectric Nanogenerators 383
13.1.2 Basic Working Mechanism and Working Modes of Flexible Triboelectric Nanogenerators 385
13.2 Materials Used for Flexible Triboelectric Nanogenerators 387
13.3 Flexible Triboelectric Nanogenerators for Harvesting Ambient Energy 388
13.3.1 Harvesting Biomechanical Energy 388
13.3.2 HarvestingWind Energy 391
13.3.3 HarvestingWater Energy 392
13.4 Flexible Triboelectric Nanogenerators for Self-Powered Sensors 393
13.4.1 Self-Powered Touch/Pressure Sensors 393
13.4.2 Self-Powered Motion Sensors 397
13.4.2.1 Sensing Motion of Human Body 397
13.4.2.2 Sensing Motion of Objects 399
13.4.3 Self-Powered Acoustic Sensors 399
13.4.4 Self-Powered Liquid/Gas Flow Sensors 402
13.5 Flexible Triboelectric Nanogenerators for Self-Charging Power Units 405
13.5.1 Self-Charging over a Period of Time to Power Electronics 406
13.5.2 Sustainably Powering Electronics 406
13.6 Flexible Triboelectric Nanogenerators for Hybrid Energy Cells 409
13.7 Service Behavior of Triboelectric Nanogenerators 411
13.8 Summary and Prospects 414
References 415
14 Flexible Thermoelectric Materials and Devices 425
Radhika Prabhakar, Yu Zhang, and Je-Hyeong Bahk
14.1 Introduction 425
14.2 Thermoelectric Energy Conversion Basics 426
14.3 Flexible Thermoelectric Materials 429
14.3.1 Conducting Polymers 431
14.3.2 Graphene and Carbon Nanotube Based TE Materials 434
14.4 Flexible Thermoelectric Energy Harvesters 435
14.4.1 Energy Management 439
14.4.2 Architecture of Thermoelectric Modules 440
14.5 Transverse TE Devices 441
14.5.1 Simulations of Transverse TEG 444
14.6 Thermoelectric Sensors 446
14.7 Summary and Outlook 447
References 448
15 Carbon-based Electrocatalysts forWater-splitting 459
Guoqiang Li and Weijia Zhou
15.1 Introduction 459
15.2 Nonmetal-doped Carbon for HER 460
15.2.1 Nitrogen-doped Carbon-based Catalysts for HER 460
15.2.2 Other Heteroatom (B, S)-doped Carbon-based Catalysts for HER 462
15.2.3 Dual- or Treble-doped Carbons in Metal-free Catalysis 463
15.2.4 Metal-doped Carbon for HER 464
15.3 Metals Embedded in Carbon for HER 466
15.3.1 Core-Shell Structure for Carbon Nanotube and Nanoparticle 468
15.3.2 Metal Organic Frameworks for HER 471
15.4 Electrochemistry 474
15.4.1 Overpotential/Onset Potential and Calibration 474
15.4.2 Current Density and Electrochemical Surface Area 475
15.4.3 Tafel Plot and Exchange Current Density 476
15.4.4 Electrochemical Impedance 476
15.4.5 HER Durability and H2 Production 477
15.4.6 Activation 477
15.5 Outlook and Future Challenges 479
15.5.1 HER Mechanism for Carbon-based Catalysts 479
15.5.2 Electrochemistry, Especially for Activation Process 480
15.5.3 OER in Acidic Electrolyte 480
References 480
Index 485
