Sodium-Ion Capacitors Enables readers to quickly understand core issues and field development of sodium-ion capacitors Sodium-Ion Capacitors summarizes and outlines the dynamics and development of sodium-ion capacitors, covering key aspects of the technology including background, classification and configuration, key technologies, and more, allowing readers to gain an understanding of sodium-ion capacitors from the perspective of both industrial technology and electrochemistry. Sodium-Ion Capacitors includes information on: EDLC-type mechanism of SCs and battery-type mechanism of SIBs, definition and types of pseudocapacitance, and energy storage mechanism of pseudocapacitors Cathode materials for sodium-ion capacitors, covering EDLC cathode materials, carbon nanotubes, reduced graphene oxide, and hollow carbon microspheres Flexible battery-type anode and capacitive cathode SICs cell configurations, including flexible electrodes based on carbon nanofiber, graphene substrates, carbon cloth, MXenes, and metal foil Pre-sodiation technologies, covering operation with Li metal, usage of Li-based alternatives, and the sacrificial additives method Summarizing the development, directions, potential, and core issues of sodium-ion capacitors, Sodium-Ion Capacitors is an essential resource on the subject for materials scientists, solid-state chemists and electrochemists, and semiconductor physicists in both industry and academia.