In the next decades, in order to address climate change, the electricity generation sector needs to definitely abandon fossil fuels and rely on sustainable and carbon-free energy sources. In view of this, fusion energy represents, in the long-term, a clean and predictable energy source, useful to handle and balance the well-known intermittency of the wind and solar electricity production. In the framework of the European roadmap for the realization of fusion energy, a key step is the realization of the EU DEMO fusion reactor, the first fusion device to produce electricity and to exploit a closed-fuel cycle, demonstrating tritium self-sufficiency. To produce the tritium fuel needed for the fusion reactions, DEMO will be the first fusion reactor to have a Breeding Blanket (BB); the BB, in fact, contains lithium-based materials (called breeding materials) which, interacting with the neutron flux coming from the plasma, produce the tritium needed to sustain the fusion reactions.