Preparation and Application of Li4Ti5O12 anode Material in Lithium-Ion Battery

Abstract

This research is focusing on preparing the Li4Ti5O12 anode material by a spray-drying method. Normally, we use graphite carbon as an anode material. The formation of dendrites on the graphite electrode surface may cause short circuits during high-rate charging or long-term cycling, and it possibly leads to thermal runaway of the battery. So, we use the Li4Ti5O12 anode material to solve its safety problem for lithium ion battery. However, the Li4Ti5O12 anode material cannot form a SEI film on the electrode surface; the electrolyte will decompose and even generate some gases (e.g., CO2, H2, CO, etc.). Therefore, the surface of the Li4Ti5O12 anode material is coated with aluminum phosphate (AlPO4); it can prevent that the Li4Ti5O12 anode material contact with the electrolyte directly. Moreover, LiAlPO4F solid ionic conductor might be formed on the surface to improve ionic conducting properties and reduce electrolyte decomposition. Systematical investigations including crystal structure analysis, micro-Raman spectroscopy, morphology characterization, and dynamic light scattering, were carried out. The electrochemical performance on half cells (2032 type coin cells) with Li/Li4Ti5O12 (LTO) electrode was tested. Electrochemical tests of the coin cells were conducted over the voltage range of 1.0–2.5V at a current density from 0.1C to 10C. The results of characterization properties demonstrated that LTO-P25-750oC sample possesses several notable results, such as: small particle size, spherical morphology, and better ionic conductivity, etc. The specific capacities of LTO-P25-750oC batteries at 0.1, 1, 5, and 10C were found to be 167, 160, 154, and 148 mAh g-1, respectively. In order to verify the performance in practical battery applications, LiNi0.5Mn1.5O4 (LNMO) material is chosen as the cathode material and assembled into LNMO/LTO full cell for performance study. It was found that the specific capacity was 136 mAh g-1 at a charge/discharge rate of 0.1 C/0.1 C. Moreover, the specific capacity at different rates (0.2/0.2C, 0.5C/0.5C, 1C/1C, 3C/3C, 5C/5C) were 123, 111, 96, 50, and 5 mAh g-1, respectively. It was found that the specific capacity still maintains around 122 mAh g-1 when the rate returned to the charge/discharge rate of 0.2C/0.2C. In conclusion, the our as-prepared LTO anode composite show excellent rate performance, good long-term cycling performance. It might be a potential anode material for Lithium-ion battery. Keywords: Lithium titanium oxide (Li4Ti5O12), Titanium dioxide (TiO2, type P25), Spray-drying method, Lithium-ion battery (LIB), Aluminum phosphate (AlPO4)