Mechanically Resilient Graphene Assembly Microspheres with Interlocked N-Doped Graphene Nanostructures Grown In Situ for Highly Stable Lithium Metal Anodes

Li metal is considered the most attractive anode material for high-energy Li batteries. However, the uncontrollable growth of Li dendrites and severe volume changes during Li plating and stripping inhibit the practical application of Li metal anodes. Herein, a synergistic strategy is developed not only to suppress Li dendrite growth but also to withstand repeated volume changes during long-term cycling. Specifically, mechanically resilient graphene assembly microspheres with interlocked Ni/N-doped lithiophilic graphene nanostructures grown in situ are developed as stable 3D graphene hosts for Li-metal anodes. Importantly, the approach provides a novel strategy to control radial distribution of lithiophilic Ni nanocatalysts in the graphene assembly. These 3D graphene hosts can repeatedly guide the uniform deposition of Li owing to the high lithiophilicity of Ni nanocatalysts and the N-doped graphene nanostructures. Furthermore, graphene nanoshell forms in situ between the graphene layers in the inner part of the graphene assembly, creating strong contacts between rGO layers and providing the 3D graphene host with high structural integrity. Notably, the approach emphasizes mechanical resilience of the 3D graphene host, which retains its initial morphology after repeated Li plating/stripping cycles. Consequently, the 3D graphene host maintains a highly stable coulombic efficiency of 99% over 500 cycles.