Optimal usage and consumption of designed fuel pellets in the inertial confinement fusion system (ICF) is one of the very important parameters. In this research, nuclear fusion in D/3Hey/6Lix mixtures is considered using a time dependent model based on nuclear reactions, including ion–electron collisions, bremsstrahlung losses and inverse Compton effects and mechanical expansion [1]. The effect of the initial lithium concentration on ignition temperature and energy gain is analyzed. It was found that with x = 0.37 (x: lithium content parameter) and ρR = 23 g cm−2 (ρR: areal density) and Ti = 32 keV (Ti : ignition temperature) we get the maximum energy gain.