Integration of zinc anode and cement: unlocking scalable energy storage

Abstract

The significant volume of existing buildings and ongoing annual construction of infrastructure underscore the vast potential for integrating large-scale energy storage solutions into these structures. Herein, we propose an innovative approach for developing structural and scalable energy storage systems by integrating safe and cost-effective zinc-ion hybrid supercapacitors into cement mortar, which is the predominant material used for structural purposes. By performing air entrainment and leveraging the adverse reaction of the ZnSO4 electrolyte, we can engineer an aerated cement mortar with a multiscale pore structure that exhibits dual functionality: effective ion conductivity in the form of a cell separator and a robust load-bearing capacity that contributes to structural integrity. Consequently, a hybrid supercapacitor building block consisting of a tailored cement mortar, zinc metal anode, and active carbon cathode demonstrates exceptional specific energy density (71.4 Wh kg−1 at 68.7 W kg−1), high areal energy density (2.0 Wh m−2 at 1.9 W m−2), favorable cycling stability (∼92% capacity retention after 1000 cycles), and exceptional safety (endurance in a 1-hour combustion test). By demonstrating the scalability of the structural energy storage system coupled with solar energy generation, this new device exhibits great potential to revolutionize energy storage systems.