A comparative analysis of the electrochemical behavior and Li+ transport characteristics of thin-layer LiNi0.5Mn1.5O4 intercalation electrodes comprised of micro- or nano-sized particles in standard Li salt solutions, was carried out and is reported herein. These electrodes were free of any conductive additives and polymeric binder in order to avoid their complex impact on the electrochemical response of the active mass. It was clearly established that the electrodes prepared from nanoparticles of the active mass show faster kinetics and a more reversible electrochemical behavior compared to the electrodes comprising microparticles. The response of the nanoparticles to electrochemical techniques such as linear sweep voltammetry and potentiostatic intermittent titration (PITT) is characterized by high resolution. Thus D versus E could be calculated very precisely. It was encouraging to realize the good performance of the electrodes comprising nano-LiMn1.5Ni0.5O4, in spite of their high surface area and their high operating voltage.