Beyond Materials: The Interface as a Design Paradigm in Structural Supercapacitors

Structural supercapacitors (SSCs) are poised to revolutionize energy storage in lightweight systems by integrating mechanical load-bearing and electrochemical functionality into a single device. However, a core challenge remains unresolved: simultaneously achieving a high mechanical stiffness and robust electrochemical performance. This Perspective presents a focused viewpoint on interface-dominated mechanisms that dictate the multifunctionality in SSCs. Advancements in carbon fiber surface activation, polymer electrolyte design, and nanomaterial interlayers are identified as promising pathways to decouple the mechanical electrochemical trade-off. Recent literature and experimental insights demonstrate that interface engineering at the fiber/electrolyte and electrode/separator interfaces governs ion transport, stress distribution, and energy retention. A strategic roadmap for scalable fabrication and performance optimization is outlined, positioning interface control as the linchpin of next-generation SSC technologies.