Applied Science and Convergence Technology 2011; 20(3): 205-210
Published online May 1, 2011
Copyright © The Korean Vacuum Society.
J. H. Lee,K. J. Kim
Structural and electrochemical properties of spinel oxide LiMn₂O₄ thin films prepared by using a sol-gel method on Pt/Ti/SiO₂/Si substrates were investigated. When Li/Mn molar ratio of the film was smaller than 0.5, Mn₂O₃ phase was found to coexist with LiMn₂O₄. Half-cell batteries fabricated using the LiMn₂O₄ films as the cathode were put into chargedischarge (C-D) cycles and the change in structural properties of the cathode after the cycles was examined by X-ray diffraction and Raman spectroscopy. As the C-D cycle number increases, the discharge capacity of pure LiMn₂O₄ battery gradually decreases, being reduced to 72% of the initial capacity at 300 cycles. Such capacity fading is attributable to the decrease in the number of Li? ions that return to the tetrahedral sites of the spinel structure during the discharge step and the resultant increase in Mn⁴? density in the film. Also, Mn₂O₃ phase gradually appeared in the film as the cycle number increases.
Keywords: LiMn₂O₄,졸-겔,산화물,박막,2차 전지,구조적 성질,Sol-gel,Oxide,Thin film,Rechargeable battery,Structural properties