Silk, particularly fibroin, has gained attention as a potential material for energy storage devices owing to its unique properties, such as excellent mechanical strength, high ionic conductivity, and the ability to be modified into various forms. The high tensile strength, elastic modulus, and strain percentage at break of fibroin make it an ideal candidate for use in energy storage systems. The polar functional groups of the material, including C=O and N–H in its β-sheet structures, provide high ionic conductivity, which is essential for improving the performance of supercapacitors, Li-ion batteries, Li-metal batteries, and Li–S batteries. The carbonization of fibroin further enhances its properties, allowing for the development of high-quality hard carbon that can improve the energy density and performance of secondary batteries. In addition, the hierarchical porous structure and nitrogen doping of fibroin-based carbon materials enable enhanced ion diffusion and electrochemical stability. Despite these advancements, further research is required to explore the full potential of silk for energy storage applications, such as its use as electrolytes, binders, and dry electrodes. Overall, fibroin and sericin offer significant promise for the development of sustainable, high-performance energy storage devices, contributing to the development of next-generation energy solutions.