Physical and Electrochemical Characterization of Quaternary Li‐Mn‐V‐O Spinel as Positive Materials for Rechargeable Lithium Batteries

Abstract

Quaternary Li‐Mn‐V‐O spinels formed from heating mixtures of , and around 350° have been characterized by electrochemical measurement, x‐ray photoelectron spectroscopy, x‐ray diffractometry, , and magnetic susceptibility measurements. These results were compared with those for ternary Li‐Mn‐O spinels prepared at 350 and 850°C. The compositions of the quaternary and ternary spinels formed at 350°C were shown to be (x = 0.5 ∼ 1, y = 0 ∼ 0.4). The cubic a₀‐lattice parameter and specific density of the quaternary spinels increased with increasing vanadium content in the spinel structure. The measurements revealed that the quaternary spinels did not show any Knight shift, while the ternary Li‐Mn‐O spinels formed at 350 and 850°C had a large Knight shift of 490 ∼ 535 ppm in reference to LiCl. Furthermore, the measurement of the magnetic susceptibility indicated that the ternary and quaternary spinels formed at 350°C are paramagnetic and the ternary prepared at 850°C is antiferromagnetic.