SE2ND is a joint experimental and theoretical effort. SE2ND strives to develop a highly efficient and continuous solid-state source of spatially separated spin-entangled electrons. A source of this kind, integrated with other electronic elements, will be of great importance in future quantum processors, where they provide, for example, entanglement distribution required to synchronize quantum circuits, and enable secure communication. The project will exploit entangled electron pairs that naturally occur in the ground state of a superconductor. The key target device of SE2ND is an electron-pair splitter with two defining key functions: 1) it ensures that pairs are emitted one by one, and 2) the two electrons of the pair are spatially separated by directing them into two different output channels, while maintaining their entanglement. Both objectives can be realized in carefully tuned double quantum dots. Hybrid double quantum dots will be realized in high-quality low-dimensional materials (semiconducting nanowires, carbon nanotubes and graphene) and integrated together with superconducting injectors, serving as sources of the electron pairs, ferromagnetic elements and microwave cavities in order to assess the degree of pair splitting and electron entanglement. SE2ND will explore the relevant material and fabrication parameters, optimize the splitting efficiency, assess the spin relaxation rate, coherence and the degree of entanglement to provide an optimized source with near to unity efficiency. SE2ND will extensively develop hybrid nanodevices which exploit the unique properties of quantum dots in proximity to superconductors and ferromagnetic materials, thereby providing a novel toolbox for electron-based quantum information technology, helping to maintain Europe at the forefront of this rapidly evolving field.