Investigation on effects of LiCl, KCl and polyethylene oxide on electrochemical properties of cement-based capacitors

In this paper, cement-based capacitors fabricated using cement, nickel foam electrodes, and additives were investigated to achieve the integration of mechanical performance and energy storage capacity. The effects of the additives, including polyethylene oxide (PEO), lithium chloride (LiCl), and potassium chloride (KCl), on the cement hydration process were characterized, and the micromorphology of the cement-based capacitors was examined. The compressive strength, ionic conductivity, and impedance of the cement-based capacitors were assessed. An in-depth analysis of electrochemical properties of the cement-based capacitors was conducted. The results show that both the mechanical and electrochemical properties of the cement-based capacitors were enhanced by the addition of 2 mol/L KCl solution. Although LiCl improves electrochemical performance, its positive effect may weaken when its concentration exceeds a certain threshold. Moreover, the microstructure analysis also reveals a denser structure of the cement-based capacitor with 2 mol/L KCl. Additionally, the incorporation of 10 % PEO enhances specific capacitance, but fails to increase the ionic conductivity or compressive strength. These findings indicate the high potential of cement-based capacitors for developing energy storage capacity for self-powering, sustainable, and smart civil infrastructure. • The addition of PEO makes the microstructure of the cement matrix loose. • 2 mol/L potassium chloride demonstrated the best compressive strength and ionic conductivity. • There is an optimal additive concentration for each additive for the optimal specific capacitance. • Capacitive behavior is confirmed by the relationship between capacitance and impedance.