Chapter 1: Advanced Electrode Materials for High-Performance Energy Storage: Fundamentals, Design Principles, and Future Perspectives

The pursuit of efficient and sustainable energy storage technologies has positioned supercapacitors at the forefront of modern electrochemical energy storage due to their outstanding power density, extended cycle life, quick charge-discharge capabilities, and operational stability. Nevertheless, additional progress in terms of achieving higher energy densities and more efficient electrodes is critical for addressing the ever-growing needs of electric vehicles, portable devices, and renewable energy sources. This chapter gives a detailed insight into the fundamental aspects of designing and developing novel electrode materials for supercapacitors. First, basic principles of electrochemical energy storage and mechanisms of charge storage in electrical double-layer capacitors, pseudocapacitors, and hybrid supercapacitors will be provided. Next, an overview of electrode materials development history will be presented, highlighting their structure, properties, and performance characteristics. Specifically, carbonaceous materials, transition metal oxides, transition metal sulfides, conducting polymers, and hybrid nanocomposites will be covered. In addition, key approaches to materials engineering, such as nanostructure engineering, morphology control, elemental doping, defect engineering, interfacial engineering, and hierarchical architecture design, will be discussed. Additionally, this chapter describes synthesis pathways that are commonly used, modern methods of characterization, and electrochemical performance assessment techniques which demonstrate clearly defined relationships between the material structures and their device behaviour. Lastly, future research directions such as sustainable material development, scale-up fabrication processes, computational material design, and materials discovery using artificial intelligence are discussed to provide a vision of future advancements in developing advanced supercapacitors and novel materials described in the subsequent chapters of this book.