Influence of the synthesis method on the electrochemical properties of the Li4Ti5O12 spinel in Li-half and Li-ion full-cells. A systematic comparison

Abstract

To study the influence of the synthesis method on the electrochemical performances of the Li4Ti5O12 spinel (LTO) several samples have been prepared by three different synthesis procedures (sol¿gel, self-combustion and solid-state). The use of the same Ti-source (TiCl4) and strictly the same experimental conditions has allowed performing a meaningful comparison analysis. The structural characterization by X-ray diffraction shown that cubic spinels, with similar cell parameter (ac ~ 8.35A¿ ), were obtained for the three methods. The purity of the samples prepared by sol¿gel (LTO-SG) and combustion (LTO-CB) was very high, >96%. FE-SEM studies revealed that the particle size (ps) and the particle aggregation notably changed with the synthesis method. The ps-values grow up from 301 nm for LTO-SG to 1580 nm for the sample synthesized by solid-state (LTO-SS). The comparison of the galvanostatic results permitted to demonstrate that LTO-electrochemical performances (capacity, cycleability and rate capability) strongly depend on the synthesis method. The LTO-SG sample exhibited the best electrochemical performances, with a discharge capacity of 146 mAh/g at 0.2 C, elevated cycleability and the highest rate capability. New formulation Li-ion full-cells with the synthesized LTO-samples as anode and LiCo2/3Ni1/6Mn1/6O2 as cathode have been assembled and studied. They have remarkable cycling performances with capacity retentions >90% after 50 cycles.