Particle morphology and battery properties of lithium manganate synthesized by ultrsonic spray pyrolysis

摘要

Spherical LiMn_2O_4 fine powders with two different morphologies were prepared by ultrasonic spray pyrolysis. Scanning and transmission microscope observations showed that the type of starting solution influenced the particle morphology. The particle structure derived from nitrate precursor solutioni was porous, while the powders from acetate precursor solution invovled a lot of hollow particles. X-ray diffraction revealed that as-prepared powders were well crystallized to a spinel structure with a Fd3m space group. Atomic absortion spectrometry analysis showed that the chemical composition of LiMn_2O_4 was in agreement with that of the starting solution. The first charge/discharge capacity of LiMn_2O_4 obtained from metal nitrate and acetate was 120-130 mAh/g, respectively. The discharge capacity of LiMn_2O_4 decreased with increasing cycle number. The cycle performance of LiMn_2O_4 obtained from metal nitrate was superior to that of LiMn_2O_4 obtained from metal acetate. It was found that the cycle performance was influenced by the morphology and microstructure of LiMn_2O_4 particles.