We present in this paper a study on the peculiar supergiant HD 172481 .
Its spectral type ( F2Ia ) , high galactic latitude ( b = - 10 \aas@@fstack { \circ } 37 ) , circumstellar dust , high radial velocity and moderate metal deficiency ( [ Fe/H ] = - 0.55 ) confirm the post-AGB character of this object .
A detailed chemical analysis shows slight but real s-process overabundances , however no CNO-enhancement was detected .
Furthermore , the spectral energy distribution and the TiO bands in the red part of the spectrum reveal a red luminous companion .
The luminosity ratio of the hot F type component and this cool M type companion L _ { F } /L _ { M } is derived for a reddening of E ( B-V ) = 0.44 ( L _ { F } /L _ { M } \sim 1.8 ) and indicates that the companion must also be strongly evolved and probably evolving along the AGB .
Neither our photometric data-set , nor our radial velocity monitoring show evidence for orbital variability which may indicate that the period is too large for direct binary interaction .
Most interestingly , a strong lithium resonance line is detected , which yields an abundance of \log \epsilon ( { Li } ) = 3.6 .
Several explanations for this large lithium content are explored .