Effect of Primary Particle Size upon Polarization and Cycling Stability of 5-V Lithium Insertion Material of Li[Ni[sub 1∕2]Mn[sub 3∕2]]O[sub 4]

The lithium insertion materials of having different primary particle sizes were prepared by the two-step solid-state reaction at several temperatures and characterized by Fourier transform infrared, X-ray diffraction, and scanning electron microscopy. The primary particle size of depends on the heating temperature. High temperature synthesis gives highly crystallized having large particle sizes with smooth {111} facets of octahedra characteristic of spinel. The steady-state polarization measurements were carried out by applying the sinusoidal voltage of peak amplitude of at to the cell consisting of and . The well-developed primary particles prepared at were superior to the small primary particles prepared at temperatures lower than that value in terms of polarization together with cycling stability.