Li4Ti5O12/hollow graphitized nano-carbon composites as anode materials for lithium ion battery

Abstract

Li₄Ti₅O₁₂/hollow graphitized nano-carbon composites (LTO/HGCs) have been synthesized by a hydrothermal reaction using hollow graphitized nano-carbon as a conductive agent, and the composites were calcined at 750 °C for 12 h. The as-prepared particles are highly-crystalline spinel-type Li₄Ti₅O₁₂ with a uniform particle size distribution, perfect crystal structure and small amounts of particle aggregation. The highly oriented hollow graphitized nano-carbon with a hexagonal carbon structure is uniformly distributed on the surface of Li₄Ti₅O₁₂ nanoparticles, effectively improved the contact of Li₄Ti₅O₁₂ nanoparticles. Electrochemical performance of the composites as anodes for lithium ion batteries is evaluated by galvanostatic discharge/charge, electrochemical impedance spectroscopy and cyclic voltammetry. The results show that the discharge capacity of composites with HGC (10.0 wt%) is 162.2 mA h g⁻¹ and 105.4 mA h g⁻¹ at the rate of 15 mA g⁻¹ and 1.5 A g⁻¹, respectively, and the discharge capacity retention rate after 500 cycles is 91.2% at 5C. The addition of hollow graphitized nano-carbon has improved the Li₄Ti₅O₁₂ performance in terms of rate capacity, cycling life and capacity retention due to the improvement of electrical conductivity and decrease of resistance and polarization. These facts suggest that LTO/HGCs are one of the promising anode materials for high rate lithium ion batteries.