Flexible Energy Conversion and Storage Devices

Chunyi Zhi, PhD, is Associate Professor in the Department of Physics and Materials Science at City University of Hong Kong, China. He has published more than 150 papers and his research field is mainly about synthesis and functionalization of boron nitride nanotubes/nanosheets, polymer composites, as well as flexible/wearable energy storage devices and sensors etc. Liming Dai, PhD, is Kent Hale Smith Professor in Department of Macromolecular Science and Engineering at Case Western Reserve University in Ohio.

• Preface xiii1 Flexible All-Solid-State Supercapacitors andMicro-Pattern Supercapacitors 1Yuqing Liu, Chen Zhao, Shayan Seyedin, Joselito Razal, and Jun Chen1.1 Introduction 11.2 Potential Components and Device Architecture for Flexible Supercapacitors 41.2.1 Flexible Electrode Materials 51.2.1.1 Carbon Materials 51.2.1.2 Conducting Polymers 61.2.1.3 Composite Materials 71.2.2 Solid-State Electrolytes 71.2.3 Device Architecture of Flexible Supercapacitor 81.3 Flexible Supercapacitor Devices with Sandwiched Structures 101.3.1 Freestanding Films Based Flexible Devices 101.3.2 Flexible Substrate Supported Electrodes Based Devices 141.4 Flexible Micro-Supercapacitor Devices with Interdigitated Architecture 181.4.1 In situ Synthesis of Active Materials on Pre-Patterned Surfaces 181.4.2 Direct Printing of Active Materials 211.4.3 Patterning ofWell-Developed Film Electrodes 241.5 Performance Evaluation and Potential Application of Flexible Supercapacitors 271.5.1 Performance Evaluation of Flexible Supercapacitors 281.5.2 Integration of Flexible Supercapacitors 291.6 Conclusions and Perspectives 32References 322 Fiber/Yarn-Based Flexible Supercapacitor 37Yang Huang and Chunyi Zhi2.1 Introduction 372.2 Supercapacitor with Intrinsic Conductive Fiber/Yarn 402.2.1 Carbolic Fiber/Yarn-Based Supercapacitor 412.2.2 Metallic Fiber/Yarn-Based Supercapacitor 442.2.3 Hybrid Conductive Fiber/Yarn-Based Supercapacitor 482.3 Supercapacitors with Intrinsic Nonconductive Fiber/Yarn 512.3.1 Fiber/Yarn Modified by Carbon Materials 522.3.2 Fiber/Yarn Modified by Metallic Materials 542.4 Integrated Electronic Textiles 572.5 Conclusion and Outlook 61References 623 Flexible Lithium Ion Batteries 67Xuli Chen and YingyingMa3.1 Overview of Lithium Ion Battery 673.1.1 General Principle 673.1.2 Cathode 703.1.2.1 LiCoO2 with Layered Structure 703.1.2.2 LiMn2O4 with a Spinel Structure 703.1.2.3 LiFePO4 with an Olivine Structure 703.1.3 Anode 713.1.3.1 Carbonaceous Anodes 713.1.3.2 Metal Alloy Anodes 713.1.4 Electrolyte 723.2 Planar-Shaped Flexible Lithium Ion Batteries 733.2.1 Bendable Planar Lithium Ion Batteries 733.2.1.1 Bendable Carbon-Based Planar Lithium Ion Battery 733.2.1.2 Thin Metal Material-Based Lithium Ion Battery 773.2.1.3 Polymer-Based Lithium Ion Battery 793.2.1.4 Special Structural Design-Based Flexible Lithium–Ion Battery 823.2.2 Stretchable Planar Flexible Lithium Ion Batteries 843.3 Fiber-Shaped Flexible Lithium Ion Batteries 873.3.1 Bendable Fiber-Shaped Lithium Ion Battery 873.3.2 Stretchable Fiber-Shaped Lithium Ion Battery 933.4 Perspective 94References 954 Flexible Sodium Ion Batteries: From Materials to Devices 97Shengyang Dong, Ping Nie, and Xiaogang Zhang4.1 Introduction to Flexible Sodium Ion Batteries (SIBs) 974.2 The Key Scientific Issues of Flexible SIBs 984.2.1 Design of Advanced Active-Materials 994.2.2 Design of Flexible Substrates and Electrodes 994.2.3 Developing Novel Processing Technologies 1014.3 Design of Advanced Materials for Flexible SIBs 1014.3.1 Inorganic Anode Materials for Flexible SIBs 1014.3.2 Inorganic Cathode Materials for Flexible SIBs 1104.3.3 Organic Materials for Flexible SIBs 1144.3.4 Other Major Components for Flexible SIBs (Electrolyte, Separators, etc.) 1154.4 Design of Full Cell for Flexible SIBs 1174.5 Summary and Outlook 121References 1235 1D and 2D Flexible Carbon Matrix Materials for Lithium–Sulfur Batteries 127TianyiWang, Yushu Liu, Dawei Su, and GuoxiuWang5.1 Introduction 1275.2 The Working Mechanism and Challenges of Li–S Batteries 1285.3 Flexible Cathode Hosts for Lithium–Sulfur Batteries 1295.4 Electrolyte Membranes for Flexible Li–S Batteries 1385.4.1 Solid Polymer Electrolytes for Flexible Li–S Batteries 1395.4.2 Gel Polymer Electrolytes for Flexible Li–S Batteries 1425.4.3 Composite Polymer Electrolytes for Flexible Li–S Batteries 1435.5 Separator for Flexible Li–S Batteries 1445.6 Summary 148References 1496 Flexible Electrodes for Lithium–Sulfur Batteries 155Jia-Qi Huang,Meng Zhao, Rui Xu, and Qiang Zhang6.1 Introduction 1556.2 Lithium–Sulfur Battery and Flexible Cathode 1566.2.1 Lithium–Sulfur Battery 1566.2.2 Flexible Cathode for Lithium–Sulfur Battery 1566.3 The Flexible Cathode of Lithium–Sulfur Battery 1576.3.1 Flexible Cathode Based on One-dimensional Materials 1576.3.1.1 Flexible Cathode Based on CNTs 1576.3.1.2 Flexible Cathode Based on Carbon Nanofibers 1636.3.1.3 Flexible Cathode Based on Polymer Fibers 1666.3.2 Flexible Cathode Based on Two-dimensional Materials 1676.3.2.1 Flexible Cathode Based on Graphene Paper 1676.3.2.2 Flexible Cathode Based on Graphene Foam 1696.3.3 Flexible Cathode Based on Three-dimensional Materials 1726.3.3.1 Flexible Cathode Based on Three-dimensional Carbon Foam Materials 1726.3.3.2 Flexible Cathode Based on Carbon/Binder Composites Materials 1746.3.3.3 Flexible Cathode Based on Three-dimensional Metal Materials 1766.4 Summary and Prospect 177References 1787 Flexible Lithium–Air Batteries 183Qing-Chao Liu, Zhi-Wen Chang, Kai Chen, and Xin-Bo Zhang7.1 Motivation for the Development of Flexible Lithium–Air Batteries 1837.2 State of the Art for Flexible Lithium–Air Batteries 1847.2.1 Overview of Flexible Energy Storage and Conversion Devices 1847.2.2 Overview of Flexible Lithium–Air Batteries 1857.2.2.1 Similarities between Coin Cell/Swagelok Batteries with Flexible Battery 1877.2.2.2 Differences between Coin Cell/Swagelok Batteries with Flexible Battery 1887.2.3 Current Status of Flexible Lithium–Air Battery 1907.2.3.1 Planar Battery 1907.2.3.2 Cable-type Battery 1997.2.3.3 Woven-type Battery Pack 2027.2.3.4 Battery Array Pack 2037.3 Challenges and FutureWork on Flexible Lithium–Air Batteries 2067.4 Concluding Remarks 207References 2088 Nanodielectric Elastomers for Flexible Generators 215Li-Juan Yin and Zhi-Min Dang8.1 Introduction 2158.2 Electro-Mechanical Principles 2168.2.1 Electro-Mechanical Conversion 2168.2.2 Equations of DE Generators 2178.3 Increasing the Performance of Dielectric Elastomers from the Materials Perspective 2188.3.1 Increasing the Relative Permittivity of DEs 2198.3.1.1 Elastomer Composites 2198.3.1.2 Elastomer Blends 2228.3.1.3 Chemical Modification 2238.3.2 Decreasing Young’s Modulus 2258.3.3 Complex Network Structure 2258.4 Circuits and Electro-Mechanical Coupling Methods 2278.5 Examples of Dielectric Elastomer Generators 2308.6 Conclusion and Outlook 231Acknowledgments 232References 2329 Flexible Dye-Sensitized Solar Cells 239Byung-Man Kim, Hyun-Gyu Han, Deok-Ho Roh, Junhyeok Park, KwangMin Kim, Un-Young Kim, and Tae-Hyuk Kwon9.1 Introduction 2399.2 Materials and Fabrication of Electrodes for FDSCs 2429.2.1 Photo-electrode 2429.2.1.1 Flexible Substrate for Photo-electrode 2429.2.1.2 Nanostructured-photoactive Film 2439.2.1.3 Fiber-type FDSCs 2499.2.2 Counter-electrode 2519.3 Sensitizers in FDSCs and Thin Photoactive Film DSCs 2549.3.1 State-of-the-Art Review of Sensitizers in FDSCs 2549.3.2 Sensitizers in Thin Photoactive Film DSCs 2589.4 Electrolyte and Hole-Transporting Materials for FDSCs 2709.5 Conclusion and Outlook 276References 27810 Self-assembly in Fabrication of Semitransparent and Meso–Planar Hybrid Perovskite Photovoltaic Devices 283Ravi K.Misra, Sigalit Aharon,Michael Layani, Shlomo Magdassi, and Lioz Etgar10.1 Introduction 28310.1.1 Semitransparent Perovskite Solar Cells Through Self-assembly of Perovskite in One Step 28510.1.1.1 Cell Architecture and Morphology 28610.1.1.2 Transparency and Photovoltaic Performance of the Cells 28810.1.1.3 Recombination Behavior of the Charges in Cells 29110.1.2 Mesoporous–Planar Hybrid Perovskite Devices Through Mesh-assisted Self-assembly of Mesoporous-TiO2 29210.1.2.1 Cell Architecture and Morphology 29310.1.2.2 Photovoltaic Performance of the Solar Cells 29710.1.2.3 Study of Recombination Behavior through Charge Extraction 30010.2 Summary and Future Perspective 302References 30211 Flexible Organic Solar Cells 305Lin Hu, Youyu Jiang, and Yinhua Zhou11.1 Introduction 30511.1.1 Working Principle 30611.1.2 Performance Characterization of OSCs 30711.1.3 Device Structure 30811.1.3.1 Conventional Device Structure 30811.1.3.2 Inverted Device Structure 30811.2 Active Layer 30811.2.1 Donor Materials 31011.2.1.1 Poly(Phenylenevinylene) (PPV) and Polythiophene (PT) Derivatives 31011.2.1.2 D–A Conjugated Polymers 31111.2.2 Acceptor Materials 31311.2.2.1 Fullerene Derivatives 31311.2.2.2 Non-fullerene Acceptors 31511.3 Flexible Electrode 31711.3.1 Conductive Polymer (PEDOT:PSS) 31711.3.2 Metal Nanowires and Grids 31811.3.3 Hybrid Carbon Material 31911.4 Interfacial Layer 32011.4.1 Hole Transporting Layer (HTL) 32011.4.2 Electron Transporting Layer (ETL) 32011.5 Tandem Organic Solar Cells 32111.5.1 Interconnecting Layer 32211.5.2 Low Bandgap Polymer Sub-cell 32411.6 Fabrication Technology for Flexible Organic Solar Cells 32611.7 Summary 328References 32912 Flexible Quantum Dot Sensitized Solar Cells 339Yueli Liu, Keqiang Chen, Zhuoyin Peng, andWen Chen12.1 Introduction 33912.2 Basic Concepts 34012.2.1 Quantum Dots (QDs) 34012.2.1.1 Quantum Size Effect 34112.2.1.2 Multiple Exciton Generation 34112.2.1.3 Ultrafast Electron Transfer 34212.2.1.4 Large Specific Surface Area 34312.2.2 Quantum Dots Sensitized Solar Cells (QDSSCs) 34412.2.2.1 Schematic of the Structure and Charge Circulation of QDSSCs 34412.2.2.2 Evaluation of the Photovoltaic Performances of QDSSCs 34512.3 Development of the Flexible QDSSCs 34712.3.1 Choosing of the Types of QDs 34712.3.1.1 Cd-based QDs 34712.3.1.2 Pb-based QDs 34812.3.1.3 Cu-based QDs 34912.3.2 Fabrication of the Flexible Photo-anode Films 35012.3.3 TiO2-Based Photo-anodes 35112.3.3.1 Photo-anodes of TiO2 Nanoparticles 35112.3.3.2 Photo-anodes of TiO2 Nanoarray Structures 35212.3.3.3 Designing of Novel TiO2 Architecture as Photo-anodes 35412.3.4 ZnO based Photo-anodes 35412.3.5 Other Metal Oxide Based Photo-anodes 35512.3.6 Development of the Sensitization Method 35512.3.6.1 In situ Sensitization Techniques 35612.3.6.2 Ex situ Techniques 35812.3.6.3 Co-sensitization Techniques 36012.3.7 Interfacial Engineering in QDSSCs 36012.3.7.1 Surface Passivation by Large-bandgap Semiconductors 36112.3.7.2 Surface Passivation by Metal Oxides 36112.3.7.3 Surface Passivation by Molecular Dipoles 36212.3.7.4 Surface Passivation by Dye Molecules 36212.3.7.5 Surface Passivation by Molecular Relays 36212.3.7.6 Combined Interfacial Engineering Methods 36312.3.8 Optimization of the Counter Electrodes 36312.3.8.1 Noble Metal Counter Electrodes 36512.3.8.2 Carbon Counter Electrodes 36512.3.8.3 Metallic Compound Counter Electrodes 36612.3.8.4 Polymer Counter Electrodes 37012.4 Conclusion and Future Outlook 370Acknowledgments 371References 37113 Flexible Triboelectric Nanogenerators 383Fang Yi, Yue Zhang, Qingliang Liao, Zheng Zhang, and Zhuo Kang13.1 Introduction 38313.1.1 Motivation for the Development of Flexible Triboelectric Nanogenerators 38313.1.2 Basic Working Mechanism and Working Modes of Flexible Triboelectric Nanogenerators 38513.2 Materials Used for Flexible Triboelectric Nanogenerators 38713.3 Flexible Triboelectric Nanogenerators for Harvesting Ambient Energy 38813.3.1 Harvesting Biomechanical Energy 38813.3.2 HarvestingWind Energy 39113.3.3 HarvestingWater Energy 39213.4 Flexible Triboelectric Nanogenerators for Self-Powered Sensors 39313.4.1 Self-Powered Touch/Pressure Sensors 39313.4.2 Self-Powered Motion Sensors 39713.4.2.1 Sensing Motion of Human Body 39713.4.2.2 Sensing Motion of Objects 39913.4.3 Self-Powered Acoustic Sensors 39913.4.4 Self-Powered Liquid/Gas Flow Sensors 40213.5 Flexible Triboelectric Nanogenerators for Self-Charging Power Units 40513.5.1 Self-Charging over a Period of Time to Power Electronics 40613.5.2 Sustainably Powering Electronics 40613.6 Flexible Triboelectric Nanogenerators for Hybrid Energy Cells 40913.7 Service Behavior of Triboelectric Nanogenerators 41113.8 Summary and Prospects 414References 41514 Flexible Thermoelectric Materials and Devices 425Radhika Prabhakar, Yu Zhang, and Je-Hyeong Bahk14.1 Introduction 42514.2 Thermoelectric Energy Conversion Basics 42614.3 Flexible Thermoelectric Materials 42914.3.1 Conducting Polymers 43114.3.2 Graphene and Carbon Nanotube Based TE Materials 43414.4 Flexible Thermoelectric Energy Harvesters 43514.4.1 Energy Management 43914.4.2 Architecture of Thermoelectric Modules 44014.5 Transverse TE Devices 44114.5.1 Simulations of Transverse TEG 44414.6 Thermoelectric Sensors 44614.7 Summary and Outlook 447References 44815 Carbon-based Electrocatalysts forWater-splitting 459Guoqiang Li and Weijia Zhou15.1 Introduction 45915.2 Nonmetal-doped Carbon for HER 46015.2.1 Nitrogen-doped Carbon-based Catalysts for HER 46015.2.2 Other Heteroatom (B, S)-doped Carbon-based Catalysts for HER 46215.2.3 Dual- or Treble-doped Carbons in Metal-free Catalysis 46315.2.4 Metal-doped Carbon for HER 46415.3 Metals Embedded in Carbon for HER 46615.3.1 Core–Shell Structure for Carbon Nanotube and Nanoparticle 46815.3.2 Metal Organic Frameworks for HER 47115.4 Electrochemistry 47415.4.1 Overpotential/Onset Potential and Calibration 47415.4.2 Current Density and Electrochemical Surface Area 47515.4.3 Tafel Plot and Exchange Current Density 47615.4.4 Electrochemical Impedance 47615.4.5 HER Durability and H2 Production 47715.4.6 Activation 47715.5 Outlook and Future Challenges 47915.5.1 HER Mechanism for Carbon-based Catalysts 47915.5.2 Electrochemistry, Especially for Activation Process 48015.5.3 OER in Acidic Electrolyte 480References 480Index 485