Electrochemical Properties of Dispersed Micron Carbon Sheets on Electrolytes for Portland Cement-Based Capacitors

Abstract

With high compressive strength and volumetric specific capacitance, Portland cement-based capacitors can be used as building energy storage alone or as a large energy storage device used in conjunction with new energy sources. In this work, inexpensive micron carbon sheets and barium chloride (BaCl₂) solution are dispersed into Portland cement as the conductive and ionic phases of the electrolyte, and the comprehensive performance of the electrolyte compressive strength and ionic conductivity of Portland cement is controlled by adjusting the amount of micron carbon sheets dispersion. It was found that when the dispersion amount of micron carbon sheets dispersed in Portland cement is 10 wt.%, its ionic conductivity is 10.18 mS/cm, which is 2.90 times higher than that of the Portland cement without micron carbon sheets(3.51 mS/cm). When the Portland cement with 10 wt.% dispersion of micron carbon sheets is used as electrolyte and copper mesh electrode to assemble individual capacitor, the volumetric specific capacitance can reach 418.89 mF/cm³, the efficiency can reach 99.97%, the average of Galvanostatic charge and discharge efficiency can reach 99.17% for 100 long-term cycles and the capacity decay is only 0.40%/cycle at 1 mA/cm² current density. Portland cement-based capacitor is under a wide application prospect in terms of performance and cost.