A 3D conductive scaffold with lithiophilic modification for stable lithium metal batteries

In this study, a non-lithiophilic nickel foam (NF) was transformed into a 3D lithiophilic N-doped graphene/nickel foam (NGNF) scaffold by a simple hydrothermal method. This scaffold can increase the area for Li deposition, improve the poor lithiophilicity of NF, and decrease the overpotential for Li deposition, leading to uniform Li plating/stripping. Thus, the average coulombic efficiency for Li deposition on the NGNF electrode can remain as high as 98.3% over 200 cycles and 98.0% over 100 cycles at current densities of 2 mA cm-2and 4 mA cm-2, respectively. Even when the Li deposition capacity is increased to as high as 10 mA h cm-2, the cells with NGNF electrodes still exhibit stable cycling performance with a high coulombic efficiency of 98.9% after 84 cycles. Density functional theory (DFT) calculations were performed to achieve a deeper understanding of the interaction between Li atoms and the designed scaffold. In addition, the potential application of the scaffold is further demonstrated by the superior electrochemical performance of an assembled LiFePO4/Li-NGNF full cell under room-temperature and low-temperature conditions.