Spinel LiMn2-xTixO4 (x=0.5, 0.8) with High Capacity and Enhanced Cycling Stability Synthesized by a Modified Sol-Gel Method

LiMn2-xTixO4 spinel-type compounds (x=0.5, 0.8) have been synthesized by a modified sol-gel process. The structural stability of the spinels is significantly improved by the partial substitution of Mn(IV) with Ti(IV) on octahedral sites. Compared to obvious structural changes for LiMn2O4, the spinel structure remains unchanged for LiMn1.2Ti0.8O4 after a deep discharge. The average fading rate of LiMn1.2Ti0.8O4 is similar to 0.1% for 100 cycles, subtracting the initial capacity loss of 5%, which is mainly due to the formation of a solid electrolyte interphase layer. In addition, the capacity retention of 90% is achieved with the LiMn1.2Ti0.8O4 electrode after 50 cycles between 2.0 and 4.8 V at 50 degrees C.