Cured cements, cement slurries, and methods of making cured cement and methods of using cement slurries are provided. The method of making a modified cement slurry includes adding particles comprising carbon nanotube sponges disposed on sacrificial templates to a cement slurry to form the modified cement slurry and allowing the sacrificial templates to disintegrate, thereby leaving the carbon nanotube sponges dispersed throughout the modified cement slurry.