Ni@Li2O co-axial nanowire based reticular anode: Tuning electric field distribution for homogeneous lithium deposition

Abstract

The employment of three-dimensional (3D) conductive scaffolds can improve safety level of metallic anodes at high rates, since they can lower down the average current density per electrode area, and thus suppress/delay the formation of metal dendrites. However, metal dendrites would still preferentially grow in the anode areas which are near to cathode, due to the more concentrated electric field strength. Here, we demonstrate that in-situ forming Li2O nano-layer on the surface of 3D Ni nanowire scaffold can not only facilitate Li+ transportation, but also render more homogenous electric field strength distribution throughout the entire anode. We observed a very low voltage hysteresis (~55 mV during 200 cycles) with enhanced cycling stability of more than 150 cycles at 3 mA cm−2. When coupling with LiFePO4 cathode, the as-assembled full cell can stably run for over 300 cycles with minimal capacity degradation and an average Columbic efficiency of 99.9% at 1 C, showing significant improvement of battery cycling stability. This work may represent a key step towards scalable production of highly safe metal anodes using electric field theory.