  We investigate the surface spot activity of the rapidly rotating,
lithium-rich active single K-giant DI Psc to measure the surface differential
rotation and understand the mechanisms behind the Li-enrichment. Doppler
imaging was applied to recover the surface temperature distribution of DI Psc
in two subsequent rotational cycles using the individual mapping lines Ca I
6439, Fe I 6430, Fe I 6421 and Li I 6708. Surface differential rotation was
derived by cross-correlation of the subsequent maps. Difference maps are
produced to study the uniformity of Li-enrichment on the surface. These maps
are compared with the rotational modulation of the Li I 6708 line equivalent
width. Doppler images obtained for the Ca and Fe mapping lines agree well and
reveal strong polar spottedness, as well as cool features at lower latitudes.
Cross-correlating the consecutive maps yields antisolar differential rotation
with shear coefficient -0.083 +- 0.021. The difference of the average and the
Li maps indicates that the lithium abundance is non-activity related. There is
also a significant rotational modulation of the Li equivalent width.
