Structural Cement‐Based Supercapacitors with Multifunctional Robustness for Energy Storage

The rapid deployment of renewable energy demands cost-effective and scalable energy storage solutions. While cement-based supercapacitors offer transformative potential, their development is hindered by charge storage capacity, mechanical strength, and environmental stability. Herein, a breakthrough carbon cement supercapacitor (CCS) with exceptional electrochemical performance and excellent robustness is engineered. The porous carbon cement (CC) electrode, characterized by high strength, extremely low resistance, and high-connectivity conductive hydrogel electrolyte, is prepared by thermomechanical consolidation at 90 °C. Through in situ polymerization around sodium dodecyl sulfate (SDS)-mediated carbon black (CB) surfaces, a CB-hydrogel network is built inside the multiscale pore structure of the carbon-cement electrode. The CCS exhibits a leading areal capacitance (1708 mF cm^- ²), over 83% capacitance retention after 10 000 cycles, high strength (>8 MPa), 92.2% capacitance retention under extreme loading conditions, a wide operating temperature range from -20 to 80 °C with less than 9% capacitance fluctuation, and incombustibility. This new device exhibits potential to revolutionize energy-storage systems.