The influence of several processing conditions on the phase formation and electrochemical performance of LiNi0.5Mn0.5O2 powders, obtained by freeze drying method, is studied. Thermal processing in pellets at maximum heating rate promotes better crystallographic ordering of hexagonal LiNi0.5Mn0.5O2 and maximum capacity values irrespectively of chemical composition of the precursor. Instead, intense mechanical processing of precursors exerts considerable negative effect on the electrochemical performance. Cathode materials containing superstoichiometric amount of lithium (Li1.3Mn0.5Ni0.5O2+δ) demonstrate reversible capacity values up to 190mAh/g between 2.5 and 4.6V.