Carbon black and alkali-activated slag composites for structural supercapacitors

To tackle the challenges of intermittency and instability of clean energy sources and high manufacturing costs of conventional storage materials, this study develops cost-effective structural supercapacitors (SSCs) by combining carbon black (CB) and alkali-activated slag (AAS), as an affordable and scalable energy storage solution. Two CB dispersion methods—Method A (dry mixing followed by wet mixing) and Method B (ultrasonic dispersion followed by wet mixing)—are systematically compared regarding their impact on the microstructure and energy storage performance of the innovative CB-AAS composites through mechanical, structural, and electrochemical characterizations. Results indicate that Method B significantly improves CB dispersion and ion conductivity, leading to greater hardness (HV=3.9) and higher coulombic efficiency (79 %), while Method A achieves higher specific capacitance (95 mF/cm 2 ) at high CB content but suffers from reduced efficiency and structural deformation due to excessive mesopores. This study provides theoretical insights and technical guidance for the development of low-cost, high-performance energy storage building materials, advancing the integration of structure and functionality in buildings and infrastructure. • Low-cost CB-AAS SSCs enable energy storage in building materials. • Dispersion methods impact CB-AAS microstructure and electrochemical properties. • Macropores boost Coulombic efficiency, and mesopores enhance specific capacitance.