Inherently multifunctional geopolymeric cementitious composite as electrical energy storage and self-sensing structural material
By Saafi, M.; Gullane, A.; Huang, B.; Sadeghi, H.; Ye, J.; Sadeghi, F.
Published in Composite Structures
2018
Abstract
In this paper, we demonstrate for the first time that potassium-geopolymeric (KGP) cementitious composites can be tuned to store and deliver energy, and sense themselves without adding any functional additives or physical sensors, thus creating intelligent concrete structures with built-in capacitors for electrical storage and sensors for structural health monitoring. Density function theory (DFT)-based simulations were performed to determine the electronic properties of the KGP cementitious composite and understand its conduction mechanism. Experimental characterization was also conducted to determine the structure, chemical composition, conduction mechanism, energy storage and sensing capabilities of the KGP cementitious composite. The DFT simulations suggested that the KGP cementitious composite relies on the diffusion of potassium (K+) ions to store electrical energy and sense mechanical stresses. The geopolymeric cementitious composite exhibited a good room temperature ionic conductivity in the range of 12 (10?2 S/m) and an activation energy as high as 0.97 eV. The maximum power density of the KGP capacitors is about 0.33 kW/m2 with a discharge life of about 2 h. The KGP stress sensors showed high sensitivity to compressive stress: 11 ?/MPa based on impedance measurement and 0.55 deg/MPa based on phase measurement. With further development and characterization, the KGP cementitious composite can be an integral part of concrete structures in the form of a battery to store and deliver power, and sensors to monitor the structural integrity of urban infrastructure such as bridges, buildings and roads.