Previous studies have shown that mixture of hydrogenated Ti and thermally expanded graphite (TEG) can be used as a material for cathodes of thermophotoemission energy converters and allows reducing significantly the temperature of the start of electron emission. In the present work, the changes in the structural state and electronic properties of nanostructured material based on hydrogenated Ti with 0.53 wt.% TEG during the vacuum annealings of it at different temperatures in a furnace are studied. By comparing the experimental and theoretical values of electrical conductivity for different densities of the powder material, it is shown that the hydrogenated Ti–TEG mixture can form a composite. The reason for this is the important role of interfaces between the components of the composite as well as the charge transfer through these interfaces. As found, the short-term increase of temperature changes significantly and irreversibly the structure of each component of the composite and its electrical conductivity, but the composite does not show significant irreversible changes during such heating. As shown, the long-term (1.5 h) annealing of the material in a vacuum furnace at $\cong$ 700 K and 900 K leads to the loss of above-mentioned thermal stability of composite. As established, the specific electroconductivity of the composite is increased after long-term vacuum annealing at a temperature of 700 K, and, when the annealing temperature is near 900 K, it is decreased compared to the previous case. According to the results of the specific electroconductivity temperature dependences’ analysis, activation energies of electrokinetic phenomena in the studied material are established and, for the first time, the important role of electronic subsystem in investigated composite formation and in changes of its properties under various thermal influences is proved experimentally that is important to create ‘cold’ emitters of electrons.