Preparation of Li4Ti5O12 yolk-shell powders by spray pyrolysis and their electrochemical properties.

We have reported for the first time the preparation of yolk-shell-structured Li4Ti5O12 powders for use as anode materials in lithium-ion batteries. One Li4Ti5O12 yolk-shell-particle powder is directly formed from each droplet containing lithium, titanium, and carbon components inside the hot wall reactor maintained at 900 °C. The precursor Li4Ti5O12 yolk-shell-particle powders, which are directly prepared by spray pyrolysis, have initial discharge and charge capacities of 155 and 122 mA h g(-1) , respectively, at a current density of 175 mA g(-1) . Post-treatment of the yolk-shell-particle powders at temperatures of 700 and 800 °C improves the initial discharge and charge capacities. The initial discharge capacities of the Li4Ti5O12 powders with a yolk-shell structure and a dense structure post-treated at 800 °C are 189 and 168 mA h g(-1) , respectively. After 100 cycles, the corresponding capacities are 172 and 152 mA h g(-1) , respectively (retentions of 91 and 90%).