Constructing Ionic Gradient and Lithiophilic Interphase for High-Rate Li-Metal Anode

Li metal is the optimal choice as an anode due to its high theoretical capacity, but it suffers from severe dendrite growth, especially at high current rates. Here, an ionic gradient and lithiophilic inter-phase film is developed, which promises to produce a durable and high-rate Li-metal anode. The film, containing an ionic-conductive Li0.33La0.56TiO3 nanofiber (NF) layer on the top and a thin lithiophilic Al2O3 NF layer on the bottom, is fabricated with a sol-gel electrospinning method followed by sintering. During cycling, the top layer forms a spatially homogenous ionic field distribution over the anode, while the bottom layer reduces the driving force of Li-dendrite formation by decreasing the nucleation barrier, enabling dendrite-free plating-stripping behavior over 1000 h at a high current density of 5 mA cm(-2). Remarkably, full cells of Li//LiNi0.8Co0.15Al0.05O2 exhibit a high capacity of 133.3 mA h g(-1) at 5 C over 150 cycles, contributing a step forward for high-rate Li-metal anodes.