Showing papers on "Ion published in 2012"
TL;DR: The historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion is reviewed and several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers are described.
Abstract: For many years, laser-driven ion acceleration, mainly proton acceleration, has been proposed and a number of proof-of-principle experiments have been carried out with lasers whose pulse duration was in the nanosecond range. In the 1990s, ion acceleration in a relativistic plasma was demonstrated with ultra-short pulse lasers based on the chirped pulse amplification technique which can provide not only picosecond or femtosecond laser pulse duration, but simultaneously ultra-high peak power of terawatt to petawatt levels. Starting from the year 2000, several groups demonstrated low transverse emittance, tens of MeV proton beams with a conversion efficiency of up to several percent. The laser-accelerated particle beams have a duration of the order of a few picoseconds at the source, an ultra-high peak current and a broad energy spectrum, which make them suitable for many, including several unique, applications. This paper reviews, firstly, the historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion. Secondly, we describe several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers. We pay special attention to relatively simple models of several acceleration regimes. The models connect the laser, plasma and proton/ion beam parameters, predicting important features, such as energy spectral shape, optimum conditions and scalings under these conditions for maximum ion energy, conversion efficiency, etc. The models also suggest possible ways to manipulate the proton/ion beams by tailoring the target and irradiation conditions. Thirdly, we review experimental results on proton/ion acceleration, starting with the description of driving lasers. We list experimental results and show general trends of parameter dependences and compare them with the theoretical predictions and simulations. The fourth topic includes a review of scientific, industrial and medical applications of laser-driven proton or ion sources, some of which have already been established, while the others are yet to be demonstrated. In most applications, the laser-driven ion sources are complementary to the conventional accelerators, exhibiting significantly different properties. Finally, we summarize the paper.
886 citations
803 citations
TL;DR: In this paper, the authors reviewed the latest advances in the exploration and development of Ti-based compounds, such as Li4Ti5O12, Li2Ti3O7, TiO2-B and H2Ti 3O7 as high performance anode materials for Li-ion batteries.
Abstract: Li-ion batteries are one of the most promising electrochemical power sources to be widely used in portable electronics, electric vehicles, and stationary energy storage systems. Ti-based materials have been intensively investigated as important anodes for Li-ion batteries due to their high safety and excellent cycling stability. The present work reviews the latest advances in the exploration and development of Ti-based compounds, such as Li4Ti5O12, Li2Ti3O7, TiO2-B and H2Ti3O7, as high performance anode materials for Li-ion batteries. The relationship between the preparation, composition, structure, morphology and electrochemical performance are summarized and analyzed. Further, the related advancements and challenges in practical energy applications are discussed.
765 citations
TL;DR: The number of reports on multishelled nonspherical hollow structures is significantly limited due to the paucity of nonsphericals templates and difficulty in forming uniform coatings, especially multilayered Coatings, around high-curvature surfaces.
Abstract: New double-shelled CoMn2O4 hollow microcubes with nanometer-sized building blocks are prepared by annealing Co0.33Mn0.67CO3 (600 °C, 5 h in air) obtained by coprecipitation from aqueous solutions of Co(NO3)2, MnSO4, EtOH, (NH4)2SO4, and NH4HCO3 (50 °C, 9 h).
649 citations
TL;DR: In this paper, the diffusivity, stability, and electrochemical window of the recently discovered superionic conductor Li10GeP2S12 were investigated using ab initio MD simulations and energy calculations.
Abstract: Using ab initio MD simulations and energy calculations, we investigate the diffusivity, stability, and electrochemical window of the recently discovered superionic conductor Li10GeP2S12. We provide an explanation for the observed wide electrochemical stability of Li10GeP2S12 and demonstrate that Li10GeP2S12 is a 3D, rather than 1D. ion conductor.
579 citations
TL;DR: In this paper, a recycling process for portable Li-ion batteries was developed combining a mechanical pretreatment with hydro-and pyrometallurgical process steps for the recovery of cobalt and lithium.
548 citations
TL;DR: In this article, it was shown that BSCF82 can quickly undergo amorphization of its surface at OER potentials, which is accompanied by reduced surface concentrations of Ba2+ and Sr2+ ions as well as increased pseudocapacitive and OER currents.
Abstract: Perovskites such as Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF82) can be highly active for the oxygen evolution reaction (OER) upon water oxidation in alkaline solution. Here we report that BSCF82 can quickly undergo amorphization of its surface at OER potentials, which is accompanied by reduced surface concentrations of Ba2+ and Sr2+ ions as well as increased pseudocapacitive and OER currents. Such quick amorphization during OER was also observed for perovskite catalysts with similar OER activities such as Ba0.5Sr0.5Co0.4Fe0.6O3−δ and SrCo0.8Fe0.2O3−δ. In contrast, perovskite oxides with lower OER activities than BSCF82 did not undergo this transformation when subjected to identical electrochemical conditions. These findings demonstrate that the active chemistry and structure of oxide catalysts during OER can significantly differ from those of the as-synthesized material and that understanding how the oxide surface may change and impact the OER activity is critical to the design of highly active and stable OER catal...
525 citations
TL;DR: In this paper, the authors analyzed the properties of ionic parameters to explain the ability of some ions to permeate by rearranging the water molecules within their hydration shells during transport as well as near membrane inter-ionic interactions.
425 citations
TL;DR: This protocol describes the procedures for identifying new-particle-formation (NPF) events, and for determining the nucleation, formation and growth rates during such events under atmospheric conditions, and discusses the reliability of the methods used and requirements for proper measurements and data analysis.
Abstract: The formation of new atmospheric aerosol particles and their subsequent growth have been observed frequently at various locations all over the world. The atmospheric nucleation rate (or formation rate) and growth rate (GR) are key parameters to characterize the phenomenon. Recent progress in measurement techniques enables us to measure atmospheric nucleation at the size (mobility diameter) of 1.5 (±0.4) nm. The detection limit has decreased from 3 to 1 nm within the past 10 years. In this protocol, we describe the procedures for identifying new-particle-formation (NPF) events, and for determining the nucleation, formation and growth rates during such events under atmospheric conditions. We describe the present instrumentation, best practices and other tools used to investigate atmospheric nucleation and NPF at a certain mobility diameter (1.5, 2.0 or 3.0 nm). The key instruments comprise devices capable of measuring the number concentration of the formed nanoparticles and their size, such as a suite of modern condensation particle counters (CPCs) and air ion spectrometers, and devices for characterizing the pre-existing particle number concentration distribution, such as a differential mobility particle sizer (DMPS). We also discuss the reliability of the methods used and requirements for proper measurements and data analysis. The time scale for realizing this procedure is 1 year.
416 citations
TL;DR: In this paper, the authors provide an overview of the major developments in the field of LiMO2 cathode materials and highlight the changes in structure during Li extraction and the phase compatibility of Li mixed metal oxides.
Abstract: Development and discovery of cathode materials with superior performance seem to be tremendous challenges for Li-ion battery scientists. Since the topotactic reaction was first demonstrated in the 1970s, layered Li transition metal oxides (LiMO2, M = Co, Ni, Mn) have been a shining star throughout the research and innovation in intercalation materials due to their appealing merits. Generally the basic LiMO2 with a single kind of transition metal ion suffers from safety concerns and structural instability and can not support high energy Li-ion batteries. Nowadays, Li-stoichiometric mixed metal oxides and Li-excess Mn-based oxides have been considered as the most promising families of cathode materials for large-scale Li-ion batteries with high energy density used for transportation. In the present paper, with the help of a phase diagram tetrahedron, we provide an overview of the major developments in the field of LiMO2 cathode materials. The changes in structure during Li extraction and the phase compatibility of Li mixed metal oxides are highlighted. The latest progress in the research of Li-excess Mn-based oxides is also included.
409 citations
Book•
29 Nov 2012
TL;DR: The concept of treating the penetration of energetic ions through solids in the context of the physics of binary atomic collisions requires some initial consideration as mentioned in this paper, and the approach then is to apply our knowledge of single collision atomic processes to the anticipated results of a sequence of binary processes.
Abstract: The concept of treating the penetration of energetic ions through solids in the context of the physics of binary atomic collisions requires some initial consideration. Clearly atomic collision processes which occur at distances larger than interatomic spaces in solids are difficult if not impossible to treat on a purely binary basis; on the other hand as the velocity of the penetrating ion increases, many processes involving these large impact parameters become less dominant and an atomistic treatment becomes more relevant. In the case of elastic scattering, for example, the large impact parameter effects upon deflection by atomic cores and the energy transfer to target atoms decrease with increasing projectile velocity. For collisions which lead to inner-shell ionization, the impact parameters are so small that the presence of the target atom in a solid medium will have hardly any effect except insofar as the state of the projectile ion is altered by its previous collision history in the solid. The approach then is to apply our knowledge of single collision atomic processes to the anticipated results of a sequence of binary processes.
TL;DR: The CHIANTI spectral code consists of an atomic database and a suite of computer programs to calculate the optically thin spectrum of astrophysical objects and carry out spectroscopic plasma diagnostics as discussed by the authors.
Abstract: The CHIANTI spectral code consists of an atomic database and a suite of computer programs to calculate the optically thin spectrum of astrophysical objects and carry out spectroscopic plasma diagnostics. The database includes atomic energy levels, wavelengths, radiative transition probabilities, collision excitation rate coefficients, and ionization and recombination rate coefficients, as well as data to calculate free-free, free-bound, and two-photon continuum emission. Version 7 has been released, which includes several new ions, significant updates to existing ions, as well as Chianti-Py, the implementation of CHIANTI software in the Python programming language. All data and programs are freely available at http://www.chiantidatabase.org, while the Python interface to CHIANTI can be found at http://chiantipy.sourceforge.net.
TL;DR: Hierarchical porous TiO(2)-B with thin nanosheets with joint advantages endow this material with high reversible capacity, excellent cycling performance, and superior rate capability.
Abstract: Hierarchical porous TiO(2)-B with thin nanosheets is successfully synthesized. TiO(2)-B polymorph ensures fast insertion of Li-ion due to its pseudocapacitive mechanism. The thin nanosheet walls with porous structure allow exposure to electrolytes for facile ionic transport and interfacial reaction. The joint advantages endow this material with high reversible capacity, excellent cycling performance, and superior rate capability.
TL;DR: A novel version of this instrument family, the Orbitrap Elite, which is improved in three main areas: the ion transfer optics has an ion path that blocks the line of sight to achieve more robust operation, the tandem MS acquisition speed of the dual cell linear ion trap now exceeds 12 Hz, and the resolving power of the orbitrap analyzer has been increased twofold.
TL;DR: With first-principles DFT calculations, the interaction between Li and carbon in graphene-based nanostructures is investigated as Li is adsorbed on graphene and it is found that the Li/C ratio of less than 1/6 for the single-layer graphene is favorable energetically.
Abstract: With first-principles DFT calculations, the interaction between Li and carbon in graphene-based nanostructures is investigated as Li is adsorbed on graphene. It is found that the Li/C ratio of less than 1/6 for the single-layer graphene is favorable energetically, which can explain what has been observed in Raman spectrum reported recently. In addition, it is also found that the pristine graphene cannot enhance the diffusion energetics of Li ion. However, the presence of vacancy defects can increase the ratio of Li/C largely. With double-vacancy and higher-order defects, Li ion can diffuse freely in the direction perpendicular to the graphene sheets and hence boost the diffusion energetics to some extent.
TL;DR: AtomDB 2.0.2 as mentioned in this paper is a database of atomic data and a plasma modeling code with a focus on X-ray astronomy, which includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions.
Abstract: We describe the latest release of AtomDB, version 2.0.2, a database of atomic data and a plasma modeling code with a focus on X-ray astronomy. This release includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions, including the iron L-shell ions from Fe$^{+16}$ to Fe$^{+23}$ and all of the hydrogen- and helium-like sequences. We also describe some of the effects that these changes have on calculated emission and diagnostic line ratios, such as changes in the temperature implied by the He-like G-ratios of up to a factor of 2.
TL;DR: The ability of T-wave IM spectrometry to differentiate diastereomers differing in Ω(N(2)) value by only 1 Å(2) is demonstrated, even though the resolution of these IM experiments were ∼40 (Ω/ΔΩ).
Abstract: We present the use of drug-like molecules as a traveling wave (T-wave) ion mobility (IM) calibration sample set, covering the m/z range of 122.1–609.3, the nitrogen collision cross-section (ΩN2) range of 124.5–254.3 A2 and the helium collision cross-section (ΩHe) range of 63.0–178.8 A2. Absolute ΩN2 and ΩHe values for the drug-like calibrants and two diastereomers were measured using a drift-tube instrument with radio frequency (RF) ion confinement. T-wave drift-times for the protonated diastereomers betamethasone and dexamethasone are reproducibly different. Calibration of these drift-times yields T-wave ΩN2 values of 189.4 and 190.4 A2, respectively. These results demonstrate the ability of T-wave IM spectrometry to differentiate diastereomers differing in ΩN2 value by only 1 A2, even though the resolution of these IM experiments were ∼40 (Ω/ΔΩ). Demonstrated through density functional theory optimized geometries and ionic electrostatic surface potential analysis, the small but measurable mobility diffe...
TL;DR: Li4Ti5O12/C composite with lump morphology and excellent rate performance are synthesized using a facile hydrothermal method followed by a low temperature heat treatment as discussed by the authors.
Abstract: The Li4Ti5O12/C composite with lump morphology and excellent rate performance are synthesized using a facile hydrothermal method followed by a low temperature heat treatment. In the hydrothermal process, the introduction of cetyltrimethylammonium bromide (CTAB) as a surfactant significantly improves the rate performance of Li4Ti5O12/C composite as anode material for lithium ion battery (LIB). The specific capacities of the obtained composite at charge and discharge rates of 0.1, 1, 5, 10 and 20 C are 176, 163, 156, 151 and 136 mA h g−1, respectively, which is apparently larger than those of the Li4Ti5O12/C free from CTAB in the preparation. The Li4Ti5O12/C prepared in presence of CTAB also shows excellent cycling performance at high rate, which is attributed to its larger diffusion coefficient of lithium ion (6.82 × 10−12 cm2 s−1) and smaller charge-transfer resistance (Rct) (19.2 Ω) than those of the composite (1.22 × 10−13 cm2 s−1 and 50.2 Ω) free from CTAB in the preparation. The Li4Ti5O12 particles obtained in presence of CTAB are coated uniformly by a thin carbon layer with a thickness of ∼1 nm, whereas the Li4Ti5O12 particles obtained in absence of CTAB are covered by relatively thick surface layers with a thickness of ∼2.5 nm, which is too thick, blocks the lithium ion diffusion and leads to low ionic conductivity.
TL;DR: X-ray absorption near-edge structure analyses demonstrate the formation of a super-reduced state of the POM, namely, [PMo(12)O(40)](27-), which stores 24 electrons, and this electron number can explain the large capacity of thePOM-MCBs.
Abstract: We carried out in operando Mo K-edge X-ray absorption fine structure measurements on the rechargeable molecular cluster batteries (MCBs) of polyoxometalates (POMs), in which a Keggin-type POM, [PMo12O40]3–, is utilized as a cathode active material with a lithium metal anode. The POM-MCBs exhibit a large capacity of ca. 270 (A h)/kg in a voltage range between V = 4.0 V and V = 1.5 V. X-ray absorption near-edge structure analyses demonstrate that all 12 Mo6+ ions in [PMo12O40]3– are reduced to Mo4+ in the discharging process. This means the formation of a super-reduced state of the POM, namely, [PMo12O40]27–, which stores 24 electrons, and this electron number can explain the large capacity of the POM-MCBs. Furthermore, extended X-ray absorption fine structure analyses reveal the molecular structure of [PMo12O40]27–, which is slightly reduced in size compared to the original [PMo12O40]3– and involves Mo4+ metal–metal-bonded triangles. Density functional theory calculations suggest that these triangles are f...
TL;DR: The results support the ability of the newly developed parameters to improve the kinetic description of the Mg(2+) and phosphate ions and their applicability in nucleic acid simulation.
Abstract: Magnesium ions have an important role in the structure and folding mechanism of ribonucleic acid systems. To properly simulate these biophysical processes, the applied molecular models should reproduce, among other things, the kinetic properties of the ions in water solution. Here, we have studied the kinetics of the binding of magnesium ions with water molecules and nucleic acid systems using molecular dynamics simulation in detail. We have validated the parameters used in biomolecular force fields, such as AMBER and CHARMM, for Mg2+ ions and also for the biologically relevant ions Na+, K+, and Ca2+ together with three different water models (TIP3P, SPC/E, and TIP5P). The results show that Mg2+ ions have a slower exchange rate than Na+, K+, and Ca2+ in agreement with the experimental trend, but the simulated value underestimates the experimentally observed Mg2+–water exchange rate by several orders of magnitude, irrespective of the force field and water model. A new set of parameters for Mg2+ was develop...
TL;DR: In this article, the authors focus on some of the recent achievements of the academic and industrial community in boosting the power densities of Lithium ion batteries through the development of novel nanostructured anode and cathode architectures.
TL;DR: Control is shown over both the location and average complexity of defect formation in graphene by tailoring its exposure to a focussed electron beam and some of the created defects were stable, whereas others relaxed to simpler structures through bond rotations and surface adatom incorporation.
Abstract: Defects in graphene alter its electrical, chemical, magnetic and mechanical properties. The intentional creation of defects in graphene offers a means for engineering its properties. Techniques such as ion irradiation intentionally induce atomic defects in graphene, for example, divacancies, but these defects are randomly scattered over large distances. Control of defect formation with nanoscale precision remains a significant challenge. Here we show control over both the location and average complexity of defect formation in graphene by tailoring its exposure to a focussed electron beam. Divacancies and larger disordered structures are produced within a 10 × 10 nm(2) region of graphene and imaged after creation using an aberration-corrected transmission electron microscope. Some of the created defects were stable, whereas others relaxed to simpler structures through bond rotations and surface adatom incorporation. These results are important for the utilization of atomic defects in graphene-based research.
TL;DR: In this article, the authors developed a new stress-dependent chemical potential for solid state diffusion under multiple driving forces including mechanical stresses, which accounts for nonlinear, inelastic, and finite deformation.
Abstract: This paper reports the development of a new stress-dependent chemical potential for solid state diffusion under multiple driving forces including mechanical stresses. The new stress-dependent chemical potential accounts for nonlinear, inelastic, and finite deformation. By using this stress-dependent chemical potential, insertion and extraction of lithium ions into a silicon particle is investigated. The distribution and evolution of diffusion-induced stress during the insertion/extraction processes are numerically calculated. Critical particle size is obtained as a function of the charging/discharging rates. It is also found that when plastic deformation occurs, the hoop stresses on the particle surface, contrary to intuition, can become positive even during the charging process, which may explain some of the recent experimental observations.
TL;DR: The results provide compelling evidence in support of weak intermolecular interactions, in contrast to the notion that the electroviscous effect is important in governing the viscoelastic behavior of concentrated mAb solutions.
TL;DR: It is demonstrated that, depending on the electron-donating abilities (Lewis basicity) of anions and electron-accepting abilities (π-acidity) of NDIs, modes of anion-NDI interactions vary from extremely weak non-chromogenic anions-π interactions to chromogenicAnion-induced charge-transfer (CT) and electron -transfer (ET) phenomena.
Abstract: The recent emergence of anion−π interactions has added a new dimension to supramolecular chemistry of anions. Yet, after a decade since its inception, actual mechanisms of anion−π interactions remain highly debated. To elicit a complete and accurate understanding of how different anions interact with π-electron-deficient 1,4,5,8-naphthalenediimides (NDIs) under different conditions, we have extensively studied these interactions using powerful experimental techniques. Herein, we demonstrate that, depending on the electron-donating abilities (Lewis basicity) of anions and electron-accepting abilities (π-acidity) of NDIs, modes of anion–NDI interactions vary from extremely weak non-chromogenic anion−π interactions to chromogenic anion-induced charge-transfer (CT) and electron-transfer (ET) phenomena. In aprotic solvents, electron-donating abilities of anions generally follow their Lewis basicity order, whereas π-acidity of NDIs can be fine-tuned by installing different electron-rich and electron-deficient s...
TL;DR: This work fine-tuned van der Waals interaction parameters for specific ion pairs to reproduce experimental osmotic pressure of binary electrolyte solutions of biologically relevant ions in molecular dynamics simulations of an array of 64 parallel duplex DNA.
Abstract: Atomic-scale modeling of compacted nucleic acids has the ability to reveal the inner workings of spectacular biomolecular machines, yet the outcome of such modeling efforts sensitively depends on the accuracy of the underlying computational models. Our molecular dynamics simulations of an array of 64 parallel duplex DNA revealed considerable artifacts of cation–DNA phosphate interactions in CHARMM and AMBER parameter sets: both the DNA arrangement and the pressure inside the DNA arrays were found to be in considerable disagreement with experiment. To improve the models, we fine-tuned van der Waals interaction parameters for specific ion pairs to reproduce experimental osmotic pressure of binary electrolyte solutions of biologically relevant ions. Repeating the DNA array simulations using our parameters produced results consistent with experiment. Our improved parametrization can be directly applied to molecular dynamics simulations of various charged biomolecular systems, including nucleic acids, proteins...
TL;DR: In this paper, the authors investigated the dependence of the width of void-denuded zones (VDZs) on grain boundary (GB) characters in Cu irradiated with He ions at elevated temperature.
TL;DR: These binder-free Cathodes with excellent flexibility and conductivity are obtained by constructing a continuous three-dimensional super-aligned carbon nanotube (SACNT) framework with embedded LiCoO(2) particles.
Abstract: Binder-free LiCoO(2) -SACNT cathodes with excellent flexibility and conductivity are obtained by constructing a continuous three-dimensional super-aligned carbon nanotube (SACNT) framework with embedded LiCoO(2) particles. These binder-free cathodes display much better cycling stability, greater rate performance, and higher energy density than classical cathodes with binder. Various functional binder-free SACNT composites can be mass produced by the ultrasonication and co-deposition method described in this paper.
TL;DR: The spectral features provide evidence of a multispecies scenario of radiation pressure acceleration in the light sail mode and indicates that monoenergetic peaks with more than 100 MeV/nucleon are obtainable with moderate improvements of the target and laser characteristics, which are within reach of ongoing technical developments.
Abstract: The acceleration of ions from ultrathin foils has been investigated by using 250 TW, subpicosecond laser pulses, focused to intensities of up to 3 × 10(20) W cm(-2). The ion spectra show the appearance of narrow-band features for protons and carbon ions peaked at higher energies (in the 5-10 MeV/nucleon range) and with significantly higher flux than previously reported. The spectral features and their scaling with laser and target parameters provide evidence of a multispecies scenario of radiation pressure acceleration in the light sail mode, as confirmed by analytical estimates and 2D particle-in-cell simulations. The scaling indicates that monoenergetic peaks with more than 100 MeV/nucleon are obtainable with moderate improvements of the target and laser characteristics, which are within reach of ongoing technical developments.