Abstract: Due to increasing greenhouse gas emissions and the gradual depletion of fossil fuels, there is a growing concern in the world about environmental protection and global energy demands. For this reason, multifunctional composite energy storage technologies that reduce fuel and energy consumption have attracted much attention in recent years. Structural supercapacitors, which provide potential electrochemical energy storage and structural mechanical load carrying, enable the volume and mass of the overall system to be reduced because they display these features in a single structure. Thanks to this superior feature, structural supercapacitors have become an attractive option for electric vehicles, aerospace industry and portable devices. This book chapter provides an overview of the electrodes, electrolytes, and separators of structural supercapacitors with improved electrochemical and mechanical properties.