Nanocrystalline (between 30 and 40 nm) LiCoO2 and LiCo1-xGaxO2 (0 <= x <= 0.15) powders have been prepared by using a standard microwave furnace. Depending on the power and irradiation time, nanosized LT-LiCo1-xGa5O2 (cubic) or HT-LiCo1-xGaxO2 (hexagonal) (0 <= x <= 0.15) materials have been obtained and studied by means of X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical characterization and magnetic behaviour of the electrochemical active polymorphs (HT-phases) have also been investigated. (C) 2010 Elsevier B.V. All rights reserved.