Effect of conductive additives on the structural and electrochemical properties of Li4Ti5O12 spinel

Abstract

The effect of a conductive agent on the structural and electrochemical properties of Li4Ti5O12(LTO) spinel was investigated through neutron diffraction during Li intercalation and electrochemical measurements. The charging process of LTO is known as transformation of the white (Li3)8a[LiTi5] 16dO12 into a dark-colored (Li3-X) 8a[LiX+Y]16c[LiTi5] 16dO12 by incorporating the inserted Li into octahedral 16c sites, and the Li in tetrahedral 8a sites shifted to 16c sites. The occupancy of the tetrahedral 8a site varied with the existence of carbon in the electrode. Without carbon, the lattice parameter and cell volume of LTO decreased more notably than in the carbon-containing LTO electrode during Li insertion process. These phenomena might be attributed that the Li occupancy of the tetrahedral 8a of the LTO electrode without carbon was less than that of the carboncontaining LTO electrode.