  We study the process of single ionization of Li in collisions with H$^+$ and
O$^{8+}$ projectile ions at 6 MeV and 1.5-MeV/amu impact energies,
respectively. Using the frameworks of the independent-electron model and the
impact parameter picture, fully (FDCS) and doubly (DDCS) differential cross
sections are evaluated in the continuum distorted-wave with eikonal
initial-state approximation. Comparisons are made with the recent measurements
of LaForge \textit{et al} [J. Phys. B \textbf{46} 031001 (2013)] for the DDCS
and Hubele \textit{et al} [Phys. Rev. Lett. \textbf{110} 133201 (2013)] for the
FDCS, respectively. For O$^{8+}$ impact inclusion of the heavy particle (NN)
interaction in the calculations is crucial and effects of polarization due to
the presence of the projectile ion have also to be taken into account for
getting very good agreement with the measured data. Our calculation reproduces
the satellite peak structure seen in the FDCS for the Li(2s) measurement, which
we explain as being formed by a combination of the binary and NN interactions.
