High temperature investigation of electrochemical lithium insertion into Li4Ti5O12

Li₄Ti₅O₁₂ was synthesized via a solid state reaction and lithiated at 400 °C in a custom built galvanostatic cell consisting of a molten LiCl-KCl electrolyte and Li-Al alloy wires as counter and reference electrodes. The material exhibits decreased rate capability at 400 °C compared to the room temperature behavior. Electrochemical lithiation at C/20 exhibits a discharge profile with both a sloping curve and flat plateau, which is indicative of a solid solution behavior before reaching a two phase region. This electrochemical behavior is shown to be correlated with reversible formation of the cubic Li₂TiO₃ phase.