We examine production of Li on the surface of a low-mass secondary in a black hole soft X-ray
transient (BHSXT) through the spallation of CNO nuclei
by neutrons which are ejected from a hot (> 10 MeV) advection-dominated accretion flow (ADAF) around
the black hole.
Using updated binary parameters, cross sections of neutron-induced spallation reactions,
and mass accretion rates in ADAF derived from the spectrum fitting of
multi-wavelength observations of quiescent BHSXTs,
we obtain the equilibrium abundances of Li by equating the production rate of Li
and the mass transfer rate through accretion to the black hole.
The resulting abundances are found to be
in good agreement with the observed values in seven BHSXTs.
We note that the abundances vary in a timescale longer than a few months in our model.
Moreover, the isotope ratio \nuc{Li}{6}/\nuc{Li}{7} is calculated to be about 0.7--0.8 on the secondaries, which is much higher than the ratio measured
in meteorites.
Detection of such a high value is favorable to the production of Li via spallation
and the existence of a hot accretion flow in quiescent BHSXT.
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