Electrochemical energy storage (EES) is increasingly critical for development and applications of numerous technologies or new products, such as portable electronics, electric vehicles, and large-scale energy storage systems. The expanding market of EES requires products that are low cost, environmentally friendly, and with high energy density. Natural proteins are abundant bio-macromolecules and possess numerous useful functional groups through millions of years of evolution. By the rational control of the protein molecular architectures, we can effectively develop important component materials with functionalities for energy storage systems via appropriately utilizing the functional groups of proteins. Therefore, tremendous research efforts on application of natural proteins for enhancing the performance of EES have been reported. In this book, advanced strategies for adopting various natural proteins to development of the components of EES are comprehensively summarized, such as protein-derived active materials, separators, binders, electrolytes, and more. The advantages and challenges of the various strategies are discussed in detail. Finally, future perspectives of the protein-based strategies toward high-performance EES are proposed.