Titanato de litio como material de ánodo de baterías de ion-litio: síntesis, post-tratamiento y su respuesta electroquímica

SUSANA CHAUQUE; FABIANA Y. OLIVA; DANIEL BARRACO; EZEQUIEL P.M LEIVA ; OSVALDO R. CÁMARA

Congreso; Congreso Internacional de Metalurgia y Materiales 16º SAM-CONAMET; 2016

The use of portable electronic devices has been made feasible thanks to the technology of lithium-ion batteries (LIBs). These were first commercialized by Sony in 1991, and consisted of a graphite anode and a layer oxide cathode. LIBs have the advantage of lower weight, higher energy density and faster charge and discharge rates, compared to other similar technologies. The lithium titanate Li4Ti5O12 (LTO) is currently one of the best candidates for anode materials of safer LIB for various reasons: the lithium insertion process takes place at a higher potential than graphite, thereby minimizing the decomposition of the solvent employed and consequently avoiding the formation of a solid electrolyte interface. Also, LTO is a ?zero-strain? material with only a 0.2% of change in unit cell volume when Li+ ions are intercalated or de-intercalated and has a prolonged lifetime in charge/discharge cycling [1]. In the present work, therelationship between the structure and crystallinity of LTO, at different synthesis post-treatment conditions on the lithium-ion storage capacity is discussed. Li4Ti5O12 was synthesized by solid-state reaction at a high temperature and time [2], and the resulting material was post-treated with a ball milling process at different times. The materials were structurally and morphologically characterized by XRD and SEM techniques. To study the effect of ball milling time on the lithium-ion storage capacity, electrochemical experiments of galvanostatic charge-discharge cycling, cyclic voltammetry, and rate capability experiments were performed. The application of high-energy milling at different times showed that the specific capacity increased with particle size reduction, as long as the crystallinity degree of the material remained high. The LTO with the smallest particle size but with a poorly defined crystalline state demonstrated a lower specific capacity. To conclude, an optimal post-treatment requires the management of particle size, crystallinity and the inter-particle conductivity.