Oriented TiO2 nanotubes as a lithium metal storage medium

A new strategy for suppressing dendritic lithium growth in rechargeable lithium metal batteries is introduced, in which TiO2 nanotube (NT) array electrodes prepared by anodization are used as a metallic lithium storage medium. During the first charge process, lithium ions are inserted into the crystal structure of the TiO2 NT arrays, and then, lithium metal is deposited on the surfaces of the NT arrays, i.e., in the NT pores and between NT walls. From the second cycle onward, the TiO2 material is used as lithium ion pathways, which results in the effective current distribution for lithium deposition and prevents disintegration of the deposited metallic lithium. Compared to a Li(Cu foil)–LiCoO2 cell, the Li(TiO2 NT)–LiCoO2 cell exhibits enhanced cycling efficiency. This new concept will enable other 3D structured negative active materials to be used as lithium metal storage media for lithium metal batteries.