  We present the derivation of an ab-initio and parameter free effective
electron-electron interaction that goes beyond the screened RPA and accounts
for superconducting pairing driven by spin-fluctuations. The construction is
based on many body perturbation theory and relies on the approximation of the
exchange-correlation part of the electronic self-energy within time dependent
density functional theory. This effective interaction is included in an
exchange correlation kernel for superconducting density functional theory, in
order to achieve a completely parameter free superconducting gap equation.
First results from applying the new functional to a simplified two-band
electron gas model are consistent with experiments.
