Carbon nanotubes grown in situ on graphenenanosheets as superior anodes for Li-ion batteries

Abstract

Graphene and carbon nanotubes are intriguing alternative anode materials for lithium ion batteries. The prevention of graphene restacking and facilitation of lithium diffusion into CNTs with large aspect ratio are highly desirable for the performance enhancements including capacity, cycliability and rate capability. In this work, we demonstrated that a multilayered graphene-CNT hybrid nanostructure was able to hold such merits. GNS were separated and stabilized by CNTs grown in situ on GNS surface. The length of CNTs was found to be a key factor to the electrochemical performances. The GNS-CNT composite with the shortest CNT decoration displayed highly reversible capacities of 573 mAh g⁻¹ at a small current of 0.2C and 520 mAh g⁻¹ at a large current of 2C. The growth and lithium storage mechanism for graphene-CNT composite was also proposed.