Oriented wrinkle textures of free-standing graphene nanosheets: application as a high-performance lithium-ion battery anode

Morphology control of a graphene nanosheet (GNS) is important for graphene-based battery electrodes to exhibit the increased practical surface area and the enhanced ion diffusion into the nanosheets. Nevertheless, it is very difficult to minutely control the shape of graphene nanosheets based on the conventional GNS suspension methods. In this work, we fabricated wrinkle textures of free-standing GNS for large area using Langmuir-Schaefer technique. The wrinkles are oriented vertically to the direction of the monolayer compression. The textured structure of GNS was obtained by cross-deposition of each layer with controlling the orientation of the wrinkle direction. These wrinkles can cause Li-ion to diffuse into the voids created by them and raise the specific surface area between the GNSs. Consequently, as a prospective anode for Li-ion battery, the wrinkled GNS multilayer, exhibits the high specific capacity of similar to 740 mAh g(-1)at 100 mA g(-1)and the great power capability with similar to 404 mAh g(-1)being delivered even at 2 A g(-1). Furthermore, outstanding cycle performance of the wrinkled GNS multilayer is achieved over 200 cycles at 300 mA g(-1)with high Coulombic efficiency of similar to 96%.

Automated summary

In this study, wrinkle textures were fabricated on large area free-standing graphene nanosheets using Langmuir-Schaefer technique, which can improve the specific surface area between graphene nanosheets and facilitate Li-ion diffusion. The wrinkled GNS multilayer exhibits high specific capacity and great power capability in Li-ion batteries, with excellent cycle performance achieved over 200 cycles at 300 mA g(-1) and high Coulombic efficiency around 96%.