Cathode having high rate performance for a secondary Li-ion cell surface-modified by aluminum oxide nanoparticles

In order to enhance the electrochemical properties, the spinel LiMn2O4 electrode surface was modified with amorphous Al2O3 nanoparticle as heterogeneous phase. LiMn2O4 was in preparation based on a conventional solid-state reaction. The LiMn2O4 Procedure was soaked in aluminum tri 2-propoxide solution. The LiMn2O4 whose surface was modified by aluminum oxide was obtained through the heat treatment at 400 degrees C for 4 h. The Al2O3-modified LiMn2O4 electrode exhibits a capacity higher than that of the unmodified LiMn2O4 electrode. On the other hand, no variation was shown with open circuit potential and apparent chemical diffusion coefficient of Li ion for LiMn2O4 before and after the surface modification. The charge-transfer resistance of Al2O3-modified LiMn2O4 decreased significantly in comparison with the unmodified LiMn2O4. The improved charge-transfer kinetics was largely attributed to Al2O3 which plays an important role of increasing the chemical potential at the electrode/electrolyte interface. (C) 2008 Elsevier B.V. All rights reserved.