Two dimensional nanoarchitectures are of great interest in lithium storage for energy-storage devices, in particular lithium-ion batteries, due to its shortened paths for fast lithium ion diffusion and large exposed surface offering more lithium-insertion channels. Their competitive lithium-storage features provide huge potentials to develop next-generation high-performance lithium-ion batteries. This review is devoted to the recent progress in the fabrication of innovative 2D structures with various synthetic strategies and their applications for lithium storage in lithium-ion batteries. These 2D architectures are categorized into six styles, i.e., nanoporous nanosheets, ultrathin nanosheets, flower-like structures assembled by nanosheets, sandwich-like nanosheets, corrugated nanosheets, and nanosheets with specific facets. Based on the lithium-storage manner, we further summerized their electrochemical performance for lithium storage with four classified themes including surface Li storage, zero or low-strain Li storage, volume-variation Li storage and synergic-effect Li storage. Finally, the outlook and perspective on 2D lithium-storage materials is concisely provided.

Two-dimensional nanoarchitectures for lithium storage.

The role of vacancy defects is demonstrated to be positive in various energy-related processes. However, introducing vacancy defects into single-crystalline nanostructures with given facets and studying their defect effect on electrocatalytic properties remains a great challenge. Here this study deliberately introduces oxygen defects into single-crystalline ultrathin Co3O4 nanosheets with O-terminated {111} facets by mild solvothermal reduction using ethylene glycol under alkaline condition. As-prepared defect-rich Co3O4 nanosheets show a low overpotential of 220 mV with a small Tafel slope of 49.1 mV dec−1 for the oxygen evolution reaction (OER), which is among the best Co-based OER catalysts to date and even more active than the state-of-the-art IrO2 catalyst. Such vacancy defects are formed by balancing with reducing environments under solvothermal conditions, but are surprisingly stable even after 1000 cycles of scanning under OER working conditions. Density functional theory plus U calculation attributes the enhanced performance to the oxygen vacancies and consequently exposed second-layered Co metal sites, which leads to the lowered OER activation energy of 2.26 eV and improved electrical conductivity. This mild solvothermal reduction concept opens a new door for the understanding and future designing of advanced defect-based electrocatalysts.

Single-Crystalline Ultrathin Co3O4 Nanosheets with Massive Vacancy Defects for Enhanced Electrocatalysis

First-principles thermodynamics from phonon and Debye model: Application to Ni and Ni3Al

We report on integration of GaAs nanowire-based light-emitting-diodes (NW-LEDs) on Si substrate by selective-area metalorganic vapor phase epitaxy. The vertically aligned GaAs/AlGaAs core-multishell nanowires with radial p-n junction and NW-LED array were directly fabricated on Si. The threshold current for electroluminescence (EL) was 0.5 mA (current density was approximately 0.4 A/cm2), and the EL intensity superlinearly increased with increasing current injections indicating superluminescence behavior. The technology described in this letter could help open new possibilities for monolithic- and on-chip integration of III−V NWs on Si.

GaAs/AlGaAs Core Multishell Nanowire-Based Light-Emitting Diodes on Si

Vertically aligned Ni(OH)2 and NiO single-crystalline nanoplatelet arrays were directly grown on the fluorine-doped tin oxide (FTO) substrate by a simple hydrothermal method. The effects of the hydrothermal parameters on the morphology and crystal structure of the nanoarray film were investigated. Controlling the ammonia and persulfate concentrations was the key to controlling the morphology of the nanoarray film. The experimental results showed that the single-crystalline NiO nanoplatelet array was a promising candidate for the supercapacitor electrode. It exhibited a high specific capacitance, prompt charge/discharge rate, and good stability of cycling performance. It is believed that the vertically oriented aligned single-crystalline NiO nanoplatelet array is beneficial to the charge transfer in the electrode and to the ion transport in the solution during redox reaction.

Single-crystalline Ni(OH)2 and NiO nanoplatelet arrays as supercapacitor electrodes

The stiffness constants, c
 ij
 , of monocrystalline Ni3Al of three different compositions, 23.2, 24.0, and 25.0 at. pct Al, were measured over the temperature range from 300 to 1100 K using the rectangular parallelepiped resonance (RPR) method. The bulk modulus, as well as the shear modulus, Young’s modulus, and Poisson’s ratio for randomly oriented polycrystalline stoichiometric Ni3Al, were derived from the stiffness constants. The data indicate that c
 44 is essentially independent of composition, decreasing slightly with increasing temperature for all three alloys. The values of c
 11 and c
 12, however, decrease with increasing aluminum content, the difference being small at room temperature but becoming larger at higher temperatures. We find that c
 11 and c
 12 are not as sensitive to aluminum concentration as is implied by previous results. A comparison of different shear moduli of Ni3Al and the saturated Ni-Al solid solution in equilibrium with it indicates that the ordered phase is generally elastically stiffer than the solid solution over the range of temperatures at which coarsening of the Ni3Al precipitate has been heavily investigated.

Temperature and composition dependence of the elastic constants of Ni3Al

Electron microscopic demonstration and evaluation of irreversible electroporation-induced nanopores on hepatocyte membranes.

Chip-scale integrated light sources are a crucial component in a broad range of photonics applications. III–V semiconductor nanowire emitters have gained attention as a fascinating approach due to their superior material properties, extremely compact size, and capability to grow directly on lattice-mismatched silicon substrates. Although there have been remarkable advances in nanowire-based emitters, their practical applications are still in the early stages due to the difficulties in integrating nanowire emitters with photonic integrated circuits. Here, we demonstrate for the first time optically pumped III–V nanowire array lasers monolithically integrated on silicon-on-insulator (SOI) platform. Selective-area growth of InGaAs/InGaP core/shell nanowires on an SOI substrate enables the nanowire array to form a photonic crystal nanobeam cavity with superior optical and structural properties, resulting in the laser to operate at room temperature. We also show that the nanowire array lasers are effectively c...

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Monolithic InGaAs nanowire array lasers on silicon-on-insulator operating at room temperature

Vertical indium phosphide nanowires have been grown epitaxially on silicon (111) by metalorganic vapor-phase epitaxy. Liquid indium droplets were formed in situ and used to catalyze deposition. For growth at 350 °C, about 70% of the wires were vertical, while the remaining ones were distributed in the 3 other directions. The vertical fraction, growth rate, and tapering of the wires increased with temperature and V/III ratio. At 370 °C and V/III equal to 200, 100% of the wires were vertical with a density of ∼1.0 × 109 cm−2 and average dimensions of 3.9 μm in length, 45 nm in base width, and 15 nm in tip width. X-ray diffraction and transmission electron microscopy revealed that the wires were single-crystal zinc blende, although they contained a high density of rotational twins perpendicular to the growth direction. The room temperature photoluminescence spectrum exhibited one peak centered at 912 ± 10 nm with a FWHM of ∼60 nm.

/pdf/self-catalyzed-epitaxial-growth-of-vertical-indium-phosphide-1uldp93x6t.pdf

Sergey V. Prikhodko

Papers

Temperature and composition dependence of the elastic constants of Ni3Al

Electron microscopic demonstration and evaluation of irreversible electroporation-induced nanopores on hepatocyte membranes.

Monolithic InGaAs nanowire array lasers on silicon-on-insulator operating at room temperature

Self-Catalyzed Epitaxial Growth of Vertical Indium Phosphide Nanowires on Silicon

Elastic Constants of a Ni-12.69 AT. % Al Alloy From 295 to 1300 K