Preparation of Li 4 Ti 5 O 12 Yolk–Shell Powders by Spray Pyrolysis and their Electrochemical Properties

We have reported for the first time the preparation of yolk–shell‐structured Li 4 Ti 5 O 12 powders for use as anode materials in lithium‐ion batteries. One Li 4 Ti 5 O 12 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 Li 4 Ti 5 O 12 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 Li 4 Ti 5 O 12 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 %).