Electrochemical properties of nanocrystalline LiCu _xMn _2-xO ₄ (x = 0.2-0.6) particles prepared by ultrasonic spray pyrolysis method

The nanocrystalline LiCu _xMn _2-xO ₄ (x = 0.2-0.6) particles were prepared by ultrasonic spray pyrolysis method using lithium nitrate, manganese nitrate and copper nitrate salts at 800 °C in air atmosphere. Particle properties were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. Besides, voltammetric and galvanostatic tests were performed to investigate the effects of the copper substituted on electrochemical behavior. Particle characterization studies showed that low copper substituted nanocrystalline particles had single spinel structure, and increasing amount caused tendency of second spinel phase formation. Particles, ranging between 250 nm and 1.5 μm size, were formed by aggregation of nanoparticles. The cumulative discharge capacities of LiCu _0.2Mn _1.8O ₄ were determined as 122, 105 and 87 mAh g ^-1 at 0.5, 1 and 2 C rates, respectively between 4.8 and 3 V potential range. The capacity fade is 44% of initial capacity after 50 cycles at 0.5C rate. Results showed that electrochemical properties of LiCu _xMn _2-xO ₄ (x = 0.2-0.6) particles were impaired by increasing Cu substitute due to the second phase formation and ionic displacement in the lattice.