Ni₃N Nanocrystals Decorated Reduced Graphene Oxide with High Ionic Conductivity for Stable Lithium Metal Anode

Lithium (Li) metal is the ultimate choice of anode material for high energy density rechargeable Li batteries, yet its practical application has been seriously hindered due to fast capacity decay, infinite volume expansion, and uncontrolled dendrite formation. Herein, we report the utilization of Ni3N nanocrystals decorated nitrogen doped reduced graphene oxide (Ni3N@N-RGO) coated Cu as a stable host for the lithium metal anode. The uniformly distributed Ni3N nanocrystals can be in situ converted into Li3N, which leads to high ionic conductivity and homogeneous Li-ion flux distribution of the 3D N-RGO matrix. As a result, the Ni3N@N-RGO/Cu electrode presents a stable Li plating/strapping for 1400 h at 1 mA cm–2 with a small overpotential of ∼30 mV. The improved electrochemical stability is demonstrated as the smooth and dense surfaces of the plated metallic Li on Ni3N@N-RGO/Cu electrode over 300 cycles. The Li||LiFePO4 full cells with Li/Ni3N@N-RGO/Cu anode present improved rate and cycling performances. These results indicate that improving the ionic conductivity of 3D graphene based hosts with uniformly distributed Ni3N nanocrystals is a feasible approach for a stable Li metal anode.