Graphene nanobuds as a novel anode design paradigm with superior Li-ion storage capacity and rate capability

Abstract

This work reports the growth of graphene nanobuds (GNB) on Cu foil by chemical vapor deposition and its direct application as an electrode in lithium-ion batteries. The obtained novel GNB anode exhibited a superhigh specific capacity of 2813 mAh g−1 at a current rate of 4 A g−1 with a reversible coulombic efficiency of 78% in the first cycle. The most important advantage of using GNB as an anode was its outstanding cycled performance, maintaining a stable capacity of 1600 mAh g−1 at 8 A g−1 for at least 330 charge/discharge cycles with a coulombic efficiency of 99%. More significantly, the cell still maintained a retention capacity of 870 mAh g−1 when cycled at the very high current rate of 40 A g−1. The exceptional electrochemical performance in storage capacity and rate capability of GNB can be mainly attributed to the nanobuds having more loose space in their adjacent walls and hollow spaces; and to the intrinsic nano-oriented structure of few-layered graphene. This unique structure enables better Li-ion diffusion and higher Li-ion storage capacity. The outstanding electrochemical performance of the GNB as an anode places it as one of the most promising advanced carbon materials for next-generation lithium-ion batteries.