Porous single-crystalline hematite (R-Fe 2 O 3 ) nanorod array has been synthesized on large-area Ti foil via a facile hydrothermal method followed by a simple annealing treatment in Ar gas at 450 °C. The nanorods attained from 6 h hydrothermal reaction are average 30 nm in diameter and 450 nm in length. When used directly as additive-free anode for lithium ion batteries (LIBs), the R-Fe 2 O 3 nanorod array demonstrates excellent cycling performance up to 50 times (∼562 mAh g -1 retained at C/5) and good rate capability, in distinct contrast to R-Fe 2 O 3 nanorod powder-based electrode. The improved electrochemical performance could be ascribed to the enhanced electron transport and Li + diffusion that result from the well-defined array architecture and the porous nature of the single-crystalline nanorods. Fe 3 O 4 and C/R-Fe 2 O 3 nanorod arrays are further prepared to improve the lithium storage property. Our work represents a successful example of fabricating iron oxide 1D nanostructure arrays directly on nonreactive current collector. Once optimized, the array electrode may hold great promise in thin-film LIBs and other microelectronic systems.

Owing to the fascinating properties of graphene, fulfilling the promising characteristics of graphene in applications has ignited enormous scientific and industrial interest. Chemical vapor deposition (CVD) growth of graphene on metal substrates provides tantalizing opportunities for the large‐area synthesis of graphene in a controllable manner. However, the tedious transfer of graphene from metal substrates onto desired substrates remains inevitable, and cracks of graphene membrane, transfer‐induced doping, wrinkles as well as surface contamination can be incurred during the transfer, which highly degrade the performance of graphene. Furthermore, new issues can arise when moving to large‐scale transfer at an industrial scale, thus cost‐efficient and environment‐friendly transfer techniques also become imperative. The aim of this review is to provide a comprehensive understanding of transfer‐related issues and the corresponding experimental solutions and to provide an outlook for future transfer techniques of CVD graphene films on an industrial scale.

The epitaxial growth of single-crystal thin films relies on the availability of a single-crystal substrate and a strong interaction between epilayer and substrate. Previous studies have reported the roles of the substrate (e.g., symmetry and lattice constant) in determining the orientations of chemical vapor deposition (CVD)-grown graphene, and Cu( 111) is considered as the most promising substrate for epitaxial growth of graphene single crystals. However, the roles of gas-phase reactants and graphene−substrate interaction in determining the graphene orientation are still unclear. Here, we find that trace amounts of oxygen is capable of enhancing the interaction between graphene edges and Cu(111) substrate and, therefore, eliminating the misoriented graphene domains in the nucleation stage. A modified anomalous grain growth method is developed to improve the size of the as-obtained Cu(111) single crystal, relying on strongly textured polycrystalline Cu foils. The batch-to-batch production of A3-size (∼0.42 × 0.3 m 2 ) single-crystal graphene films is achieved on Cu(111) foils relying on a self-designed pilot-scale CVD system. The as-grown graphene exhibits ultrahigh carrier mobilities of 68 000 cm 2 V −1 s −1 at room temperature and 210 000 cm 2 V −1 s −1 at 2.2 K. The findings and strategies provided in our work would accelerate the mass production of high-quality misorientation-free graphene films.