The improved manufacturing technology and the results of the study of the emissive properties of metal-porous M-type cathodes modified with polyhedral fulleroid-type nanoparticles of toroidal shape - astralenes, in the refractory matrix and sulfoadduct of carbon nanoclusters - ugleron, in the active substance are presented. It is established that the cathode-grid knots and devices with ugleron-modified cathodes are characterized by increased durability due to the decrease in the evaporation rate of the active substance at the operating temperature of the cathode of 1050 ^oC. The mechanism of increasing the durability of the cathode is revealed by molecular-dynamic modeling using the density functional method. It is found that the layered carbon nanostructures effectively retain the components of the cathode active substance - Ba and BaO, with the adsorption energy of ~ 2-3 eV. Experimental studies have shown that the cathode material containing astralenes has a higher thermionic capacity in the space charge-limited mode compared to similar cathodes whose emitting material does not contain astralenes. Experimental studies of the operation of cathodes whose emitting materials are modified with ugleron and astralenes in various combinations have shown that their service life is 2-6 times longer than that of commercially used M-type cathodes. Keywords: metal-porous cathode, emission properties, nanocarbon, astralen, ugleron, density functional theory, molecular dynamics modeling.