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Exhaustive research of phase engineering of two-dimensional molybdenum disulfide (2D-MoS2) is currently ongoing to develop numerous applications, including optoelectronic devices, spintronics, and new platforms for the study of unconventional quantum phenomena. Therefore, it is urgently needed to achieve phase-controlled synthesis of MoS2 with a high quality and large area. However, the metallic phase MoS2 (1T-MoS2) synthesized by conventional chemical vapor deposition (CVD) is randomly distributed in the semiconductor phase (2H-MoS2) domain, and the position-controlled synthesis of the phase is not achieved. In this study, we achieved the controlled synthesis of the 1T-MoS2 domain in the 2H main phase. Salt-assisted CVD was used to induce V-atom doping at the right time by controlling the concentration of vanadium ions. The synthesis benefitted from 1D vapor–liquid–solid (VLS) growth and 2D vapor–solid (VS) edge expansion. The results of the growth controlled by regulating the NaCl concentration showed that the 1T phase was located at the three vertex domains of the MoS2 triangle. The distribution domains of 1T phase MoS2 can be confirmed by Raman mapping, X-ray photoelectron spectroscopy, and transmission electron microscopy. Furthermore, we calculated the doping rate of V atoms in VLS and VS modes based on the two-dimensional diffusion model and observed that the doping rate of V atoms in the VLS mode was approximately three times higher than that in the VS mode, which was consistent with the experimental results. The controllable phase-domain synthesis of 2D-MoS2 is beneficial to the preparation of nano-electronic devices and provides a platform for the study of physicochemical properties. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable lithium-ion batteries (ARLBs) are regarded as a competitive challenger for large-scale energy storage systems because of their high safety, modest cost, and green nature. A kind of modified composite material composed of H 2 V 3 O 8 nanorods and graphene sheets (HVO/G) has been effectively made by a one-step hydrothermal method and following calcination at 523 K. XRD, SEM, TEM, and TG are used to determine the phase structures and morphologies of the composite materials. Owing to the advantage of the layered structure of H 2 V 3 O 8 nanorods, the excellent conductivity of the graphene sheets, and the 3D network structure of the modified composite, the ARLBs with HVO/G can deliver an adequate specific capacity of 271 mA h g -1 at 200 mA g -1 and have a retention rate of 73.4% after 50 cycles. The average discharge capacity of ARLB with HVO/G as anode has a considerable improvement over that of HVO/CNTs and HVO, whatever the current rate used. Moreover, we find that the diffusion coefficient of lithium-ion increases by an order of magnitude through the theoretical calculation for HVO/G ARLB. The new ARLB with HVO/G electrode is a potential energy storage system with great advantages, such as simple preparation, easy assembly process, excellent safety and low-cost environmental protection., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)