The role of defects on the electronic structure of a graphite surface

Graphene Nano-Blister in Graphite for Future Cathode in Dual-Ion Batteries: Fundamentals, Advances, and Prospects

The intercalating of anions into cost-effective graphite electrode provides a high operating voltage, therefore, the dual-ion batteries (DIBs) as novel energy storage device has attracted much attention recently. The "graphene in graphite" has always existed in the graphite cathode of DIBs, but has rarely been researched. It is foreseeable that the graphene blisters with the intact lattice structure in the shell can utilize its ultra-high elastic stiffness and reversible lattice expansion for increasing the storage capacity of anions in the batteries. This review proposes an expected "blister model" by introducing the high elasticity of graphene blisters and its possible formation mechanism. The unique blisters composed of multilayer graphene that do not fall off on the graphite surface may become indispensable in nanotechnology in the future development of cathode materials for DIBs.

Multi-oriented moiré superstructures of graphene on Ir(111): experimental observations and theoretical models

Six types of moiré superstructures of graphene on Ir(111) with different orientations (labeled as R0, R14, R19, R23, R26 and R30) are investigated by low-energy electron diffraction, scanning tunneling microscopy and first-principles calculations. The moiré superstructure of R0 graphene has remarkable diffraction spots and deeper corrugation than that of the other superstructures. A high-order commensurate (HOC) method is applied to produce a list of all possible graphene moiré superstructures on Ir(111). Several useful structural data including the precise matrices of the moiré patterns are revealed. Density functional theory based first-principles calculations that include van der Waals interactions reveal the differences of the geometric environment and electronic structures of carbon atoms with respect to the underlying Ir(111) lattices for all the observed moiré patterns. The further calculations of electronic properties at the graphene-Ir interfaces show that the electron transfers for all superstructures are small and of the same order of magnitude, which demonstrates a weak interaction between graphene and the Ir(111) substrate, leading to the coexistence of multi-oriented moiré superstructures.