Subnanometric Stacking of Two-Dimensional Nanomaterials: Insights from the Nanotexture Evolution of Dense Reduced Graphene Oxide Membranes

Assembling two-dimensional (2D) nanomaterials into laminar membranes with a subnanometer (subnm) interlayer spacing provides a material platform for studying a range of nanoconfinement effects and exploring the techno-logical applications related to the transport of electrons, ions and molecules. However, the strong tendency for 2D nanoma-terials to restack to their bulk crystalline-like structure makes it challenging to control their spacing at the subnm scale. It is thus necessary to understand what nanotextures can be formed at the subnm scale and how they can be engineered experimentally. In this work, with dense reduced graphene oxide membranes as a model system, we combine synchrotron -based X-ray scattering and ionic electrosorption analysis to reveal that their subnanometric stacking can result in a hybrid nanostructure of subnm channels and graphitized clusters. We demonstrate that the ratio of these two structural units, their sizes and connectivity can be engineered by stacking kinetics through the reduction temperature to allow the realization of high-performance compact capacitive energy storage. This work highlights the great complexity of subnm stacking of 2D nanomaterials and provides potential methods to engineer their nanotextures at will.

Automated summary

Assembling two-dimensional (2D) nanomaterials into laminar membranes with a subnanometer (subnm) interlayer spacing provides a material platform for studying nanoconfinement effects and exploring technological applications related to the transport of electrons, ions, and molecules. This study reveals that dense reduced graphene oxide membranes exhibit a hybrid nanostructure of subnm channels and graphitized clusters, which can be engineered by controlling stacking kinetics and reduction temperature. The optimized nanotextures enable high-performance compact capacitive energy storage.