Metal nitride heterostructures capsulated in carbon nanospheres to accommodate lithium metal for constructing a stable composite anode

Abstract

Although various hosts have been proposed to accommodate the Lithium (Li) metal to solve the uneven Li deposition and infinite volume change, the pulverization of the host or lithiophilic modification layer easily leads to structural damage and the poor cycling stability of the composite anode. Herein, we design a host of metal nitrides (Mo2N and WN heterostructures) nanoparticles capsulated in the hollow carbon nanospheres, which can accommodate Li metal to form a stable composite anode. The lithiophilic Mo2N guides uniform infusion and reduces the nucleation barriers of Li metal during electrochemical process. Note that the rigid WN matrix is uniformly composited with Mo2N, which can suppress the pulverization of Mo2N during the repeat Li plating/stripping, ensuring the stability of regulated deposition during long cycling. High mechanical strength, uniform surface potential distribution and good electrolyte wettability of the Li metal-based composite anode guarantee the rapid Li plating/stripping kinetics. Thus, the obtained composite anode can stably cycle 1400 h at 1 mA cm-2 and 1 mA h cm-2 in the symmetric battery. The assembled full cells with LiNi0.8Mn0.1Co0.1O2 (NCM811) also deliver high capacity retention under the high loading (8.6 mg cm-2) or lean electrolyte (2 μL mg-1) condition. This work suggests a promising host structure design to construct a highly stable lithium metal anode for practical applications.