Spinel LiMn2O4 active material with high capacity retention

Heating the mixture of LiMn2O4 and NiO at 650 degrees C was employed to enhance the cyclability of spinel LiMn2O4. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy analyses implied that a LiNixMn2-xO4 solid solution was formed on the surface of LiMn2O4 particles. And charge-discharge tests showed that the enhancement of the capacity retention of modified LiMn2O4 is significant, maintained 97.2% of the maximum capacity after 100 cycles at charge and discharge rate of C/2, while the pure one only 75.2%. The modified LiMn2O4 also results in a distinct improvement in rate capability, even at the rate of 12C. The improvement of electrochemical cycling stability is greatly attributed to the suppression of Jahn-Teller distortion at the surface of spinel LiMn2O4 particles. (c) 2007 Published by Elsevier B.V.