Vertically Grown Edge-Rich Graphene Nanosheets for Spatial Control of Li Nucleation

Inhomogeneous mass and charge transfers induce severe Li dendrite formation, impeding the service of Li metal anodes in rechargeable batteries. Various 3D hosts are proposed to address the related issues. To enable better progress, hybrid micro/nanostructures with the ability to realize spatial control of Li deposition over nucleation should be developed. Here, it is demonstrated that edge-rich graphene (ERG), which is vertically grown on a 3D carbon nanofiber (CNF) substrate via a simple chemical vapor deposition method, can serve as nanoseeds to reduce the nucleation overpotential of Li effectively and guide the Li deposition on the 3D CNF substrate uniformly, free from dendrites. Different from the case in other sp² carbon featuring interconnected graphitic structures such as planar graphene, the zero nucleation overpotential presented by ERG is attributed to its unique electron properties (i.e., the enhanced surface electronegativity) and its open architecture. Compared to the pristine CNF host, the ERG-hybridized one resolves the problems of the Li metal anode better, endowing a practical Li battery with a long lifespan of 1000 cycles with a Coulombic efficiency of 99.7%. The results present novel sights for developing next-generation Li-carbon anodes with high cycling stability.