  We investigate the transport properties of LixCoO2 thin films whose
resistivities are nearly an order of magnitude lower than those of the bulk
polycrystals. A metal-nonmetal transition occurs at ~0.8 in a biphasic domain,
and the Seebeck coefficient (S) is drastically increased at ~140 K (= T*) with
increasing the Li concentration to show a peak of magnitude ~120 \muV/K in the
S-T curve of x = 0.87. We show that T* corresponds to a crossover temperature
in the conduction, most likely reflecting the correlation-induced temperature
dependence in the low-energy excitations.
