Double Ion Research Articles

Al/Ga co-doped V6O13 nanorods with high discharge specific capacity as cathode materials for lithium-ion batteries

Abstract Element doping has been proven to be one of the effective means to improve the electrical transport performance of materials due to the introduction of impurity levels. In this work, Al/Ga co-doped V6O13 nanorods were prepared via a particularly simple solvothermal method. Al/Ga co-doping delivers an extraordinary compelling advantage that can expand the cell volume as well as introduce oxygen vacancies, which can effectively improve the electrochemical performance of the battery. On the hand, Al/Ga co-doped V6O13 presents a uniform rod-like structure with a diameter of about 100–300 nm and a length of micrometers. On the other hand, when it was used as a cathode electrode material for lithium ion batteries, the Al/Ga co-doped V6O13 nanorod exhibited an initial capacity of 411.5 mAh/g at 0.1C, higher than pure phase V6O13 with capacity of 286.4 mAh/g. Noted that the capacity retention rate of Al/Ga co-doped V6O13 nanorods reached 64.4% after 100 cycles at 1C, which is more than twice that of pure phase V6O13. Al/Ga double ion doping provides an insight that better enhance the electrical transport properties of materials.

Honeycomb-like gallium nitride prepared via dual-ion synergistic etching mechanism using amino acid as etchant

Amino acid, taking the glycine (Gly) for example, was used for the first time as etchant to assemble honeycomb-like structure on gallium nitride (GaN) by photo-electrochemical etching (PECE) technique. Conspicuously, a novel dual-ion dissolution etching mechanism model was proposed, of which could extensively promote to almost all amino acids and their derivatives as well. Importantly, double ions of amino acids are of a synergistic effect with amino and carboxyl groups, which facilitate the generation and stabilization of the honeycomb-like structure with uniform pore size (~26.5 nm), high pore density and superior reusability, and the intermolecular hydrogen bonding can maintain the honeycomb-like structure without being destroyed. From the point of view of costs, scale-up production, biocompatibility and environmental friendliness, Gly has obvious advantages over the traditional strong acid and alkali etchant.

Be2+ and Mg2+-decorated sulflower: Potential systems for molecular hydrogen storage

The hydrogen binding efficiency of multiple metal-ion (Be2+, Mg2+)-decorated “First Generation” Sulflower (C16S8) systems has been investigated for the first time using density functional ω-B97XD method and 6311++G(d,p) basis set. Our calculations show that the central ring of the aforesaid system can be decorated by a single di-positive metal ion, followed by favorable decoration of at most one pair of metal ions (di-positive each) on the peripheral five-membered rings, both on same and opposite faces with certain preferences. All of the metal ion-decorated complexes are capable of efficient hydrogen binding. Be2+ and Mg2+-decked single ion complexes effectively bind six and four H2 molecules respectively. Moreover, each of the double ion-decorated systems can adsorb ten H2 molecules irrespective of the facial orientation of the metal ions. The average interaction energy (ΔE) between sulflower and metal ions (single and double ions) as well as the average binding energy (ΔBE) per molecular hydrogen of the concerned metal-ion-decorated complexes is found to be much higher for Be2+-decked systems. The nature of interaction between hydrogen molecules and metal ions is explicated by the topological analysis (AIM Analysis) and NBO formalisms. In case of Be2+-decked systems, the amount of charge transfer from H2 bonding orbital to metal anti-bonding orbital is much higher than analogous Mg2+-decorated systems. The Natural Population Analysis (NPA) evaluates the charge variation on the acceptor metal ions due to hydrogen adsorption. In short, our theoretical study gives a comprehensive account of the relationship between the metal ion-decorated sulflower systems and hydrogen molecules, which will further motivate researchers in the field of efficient hydrogen storage materials.

Evidence of improved tolerance to electronic excitation in nanostructured Nd2Zr2O7

Grain size driven effects on electronic excitation-induced structural modifications have been investigated in nanocrystalline (NC) Nd2Zr2O7 on irradiation with 100 MeV iodine ions. Characterizations have been performed with in situ x-ray diffraction, Raman spectroscopy, and plane-view high-resolution transmission electron microscopy techniques. NC-powders of Nd2Zr2O7 were synthesized by auto gel-combustion and sintered at different temperatures to obtain different grain-sized samples. XRD analysis of the smallest grain-sized sample reveals the highest order–disorder transition (from pyrochlore to a more radiation-resistant phase; anion-deficient fluorite) rate at initial ion fluences followed by least amorphization at higher ion fluences. A strong correlation of the transformation build-up with the double ion impact model confirms the two step amorphization process in NC-Nd2Zr2O7 with the disordered anion-deficient fluorite structure as an intermediate phase. TEM result supports the formation of circular ion track consisting of randomly distributed regions (anion-deficient fluorite structure and amorphous regions), surrounded by a microstrain induced defect-rich pyrochlore superstructure. Lesser ordering at cationic sites and a relatively larger number of grain boundaries are responsible for the highest radiation tolerance exhibited by the smallest grain-sized sample. The present study reports a relatively higher radiation stability of NC-ternary pyrochlore oxide, Nd2Zr2O7, with a grain size of a few tens of nm, which establishes its application as a potential inert matrix for nuclear applications.

One-dimensional PPy@CNT based on reversible anions doping/dedoping as a novel high-performance cathode for potassium based double ion batteries

Recently, potassium ion batteries (PIBs) have emerged as promising substitutes to lithium-ion batteries (LIBs) for large-scale energy storages owing to the abundance of potassium. However, the large K+ causes phase transition and structural deterioration for traditional inorganic cathodes during K+ insertion/extraction. Compared with traditional inorganic cathodes, conductive polymers are particularly promising because their structural diversity and great tensile strength. Herein, the one-dimensional polypyrrole@carbon nanotube (1D PPy@CNT) was prepared via one-step in situ oxidative polymerization and investigated as a cathode for potassium based double ion batteries. The nano PPy layer is uniformly coated on the surface of CNT framework, in which CNT can facilitate the ion transport and electron transfer, and nano PPy layer can enrich active sites and ion storage. As expected, the 1D PPy@CNT delivers a high reversible capacity of 148 mAh g−1 with a capacity retention rate of 75.5% up to 200 cycles. The storage mechanism and reaction kinetics of 1D PPy@CNT are well explored by a combination of ex situ Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electrochemical characterizations. The results of measurements suggest that the storage mechanism of PPy@CNT is based on reversible doping/dedoping of anions (PF6−). The present work indicates the potential of PPy as a promising high-performance cathode for potassium based double ion batteries.

Efficient separation of phosphopeptides employing a Ti/Nb-functionalized core-shell structure solid-phase extraction nanosphere.

Astrategy for effectively enriching global phosphopeptides was successfully developed by using ammonia methyl phosphate (APA) as a novel chelating ligand and Ti4+ and Nb5+ as double functional ions (referred to as Fe3O4@mSiO2@APA@Ti4+/Nb5+). With the advantage of large specific surface area (151.1m2/g), preeminent immobilized ability for metal ions (about 8% of total atoms), and unbiased enrichment towards phosphopeptides, Fe3O4@mSiO2@APA@Ti4+/Nb5+ displays high selectivity (maximum mass ratio β-casein to BSA is 1:1500), low limit of detection (LOD, as low as 0.05fmol), good relative standard deviation (RSD, lower than 7%), recovery rate of 87% (18O isotope labeling method), outstanding phosphopeptide loading capacity (330μg/mg), and at least five times re-use abilities. In the examination of the actual sample, 24 phosphopeptides were successfully detected insaliva and 4 phosphopeptides were also selectively extracted from human serum. All experiments have shown that Fe3O4@mSiO2@APA@Ti4+/Nb5+ exhibits exciting potential in view of the challenge of low abundance of phosphopeptides. Graphical abstract.

Ferromagnetic alloy for high-efficiency photovoltaic conversion in solar cells: first-principles insights when doping SnO2 rutile with coupled Eu-Gd.

From results of first-principles all-electron full-potential augmented spherical-wave calculations within a generalized gradient approximation, a materials design for half-metallic ferromagnetic semiconductors based on (Eu,Gd)-doped SnO2 rutile is proposed. Moreover, their half-metallic ferromagnetic properties are homogenous and energetically stable for different crystallographic directions. Therefore, the interatomic exchange interaction between the spins of double impurity ions is a long-range ferromagnetic interaction that is sharply weakened when the distance between Eu–Gd increases. The double impurities most likely substitute adjacent Sn sites and result in strong ferromagnetic interactions by p–f hybridization between rare earth 4f and Op states. There is great interest in the configuration that has the lowest energy difference, where the double impurity substitutes the nearest neighbor Sn sites along the z-axis of SnO2 rutile. Generalized gradient approximation GGA and GGA+U calculations were performed. According to our revPBE-GGA calculations, the ferromagnetic compound is capable of absorbing 96% from the visible light. Furthermore, the transport properties at room temperature ensure excellent electrical conductivity, low thermal conductivity, and the most optimal figure of merit (ZT), which leads to high thermoelectric performance. As the latter are closely related to free flow charge carriers, we can subsequently predict that the ferromagnetic alloy will be able to be a great power source for highly effective photovoltaic conversion in solar cells. Further experimentation will be necessary to obtain confirmation of our ab initio predictions.

TiC nano-coating and their tribological properties were deposited by doal-ion beam sputtering on the tool surface

By using the method of doal-ion beam sputtering deposition, N element is injected with ions to assist sputtering deposition of TiC to prepare the TiC nano-coating with high binding strength. SEM, XRD, dynamic ultra-micro hardness tester, friction and wear testing machine were used to characterize and analyze TiC properties. The results show that the TiC coating prepared by double ion beam sputtering deposition has high hardness, high bonding strength, good friction and wear performance, and improves tool service life.

Energy Transfer Between Yb3+- Mn2+ in Zn(Po3 ) 2 Glasses Giving Green, Red and Infrared Light

The Yb3+-Mn2+codoped zinc metaphosphate glass gives rise to several processes such as upconversion, downshifting and double ion absorptions producing light from the visible to the IR wavelengths. These processes are possible since the Mn2+ and the Yb3+ ions replaces the Zn2+ ion in nanoparticles of the α phase of the compound Zn(PO3)2. An important result is that the α structure presence allows the formation of Yb3+-Mn2+ dimers, that gives rise to a superexchange coupling that allows an upconversion process from the IR to the red region of the electromagnetic spectrum. The experimental results also show that these dimers can couple to produce Yb3+ ion pairs that led to a cooperative emission in the green, around 500nm, coupling also the Mn2+ ions that in turn allows to produce a double absorption of this ions in the red region of the electromagnetic spectrum and as well a downshifting process conducting to the Yb3+ emission in the infrared. If the manganese ion concentration is higher than 10% most of these effects are masked. All these results make the material an effective option for different applications, due to the large wavelength variety that can be selected for excitation or emission.

Energy Transfer Between Yb3+- Mn2+ in Zn(Po3 ) 2 Glasses Giving Green, Red and Infrared Light

The Yb3+-Mn2+codoped zinc metaphosphate glass gives rise to several processes such as upconversion, downshifting and double ion absorptions producing light from the visible to the IR wavelengths. These processes are possible since the Mn2+ and the Yb3+ ions replaces the Zn2+ ion in nanoparticles of the α phase of the compound Zn(PO3)2. An important result is that the α structure presence allows the formation of Yb3+-Mn2+ dimers, that gives rise to a superexchange coupling that allows an upconversion process from the IR to the red region of the electromagnetic spectrum. The experimental results also show that these dimers can couple to produce Yb3+ ion pairs that led to a cooperative emission in the green, around 500nm, coupling also the Mn2+ ions that in turn allows to produce a double absorption of this ions in the red region of the electromagnetic spectrum and as well a downshifting process conducting to the Yb3+ emission in the infrared. If the manganese ion concentration is higher than 10% most of these effects are masked. All these results make the material an effective option for different applications, due to the large wavelength variety that can be selected for excitation or emission

Double-step gas cluster ion beam smoothing

In this study we use the double step gas cluster ion beam treatment to improve smoothing process of mechanically polished 4H-SiC (1000) wafers and compare it with conventional single-step smoothing. The first step is a higher energy treatment with 15 keV Ar cluster ions, and the second step is a lower 5 keV treatment. Single-step treatments are performed at 15 and 5 keV. It is shown that single-step 15 keV smoothing as compared with lower 5 keV one is very effective for removing the initial surface morphological feature (scratches), however, cluster ions impacting on the surface can create larger craters, resulting in roughness <i>R</i><i><sub>q</sub></i> of 1.05 nm. Whereas, 5 keV treatment at a selected fluence cannot remove initial scratches, which requires using higher fluences, i.e. such smoothing becomes time consuming. On the other hand, crater morphology with such a treatment is less developed, hence, the roughness slightly decreases to 0.9 nm. Using the double-step treatment, one can obtain the surface with lower <i>R</i><sub><i>q</i></sub> roughness of 0.78 nm as compared with single-step treatment, at the same total cluster ion fluence. Therefore, the double-step treatment combines the advantages of the effective smoothing of scratches at high energy and smaller crater morphology at low energy. To evaluate the contribution of the cluster morphology introduced by the accelerated clusters into the total roughness, the cluster ion beam treatment of an atomically smooth 4H-SiC (1000) surface is also carried out. It is shown that the crater diameter increases in a range of 15–30 nm with the cluster energy increasing. More detailed analysis of the smoothing process is carried out by using two-dimensional isotropic PSD function. It is shown that the cluster treatment of mechanically polished 4H-SiC wafers effectively reduces the roughness in a wavelength range of 0.05–0.20 μm and the efficiency of smoothing is higher at higher cluster energy. In a range of 0.02–0.05 μm, a roughening effect is observed, which is due to the formation of craters. This roughening effect can be effectively reduced by the subsequent lower energy step treatment, which can be shown by the PSD function analysis of the smooth SiC surface treated initially by cluster ion beam.

Mathematical modelling of transport of single and double charged ions through layered ion exchange membranes

Monovalent selectivity of ion exchange membranes is important for such areas as hardness removal, stabilization of mining waters and fining of foods. The modern approach to the creation of monovalent selective ion exchange membranes is layer-by-layer adsorption of polyelectrolytes onto a membrane surface, which showed significant improvement in comparison with previously used approaches, most notably in comparison with the creation of a single thick layer of polyelectrolyte. Despite the practical importance, the mechanism of improvement in selectivity is unknown. Knowledge of the distribution of ions within the membrane and adjacent layers of solution would answer the question of the mechanism, but such information is unobtainable through the experiment. Hence we develop the 1D mathematical model based on Nernst-Planck-Poisson equations to describe the fluxes and the concentrations of single and double charged ions, as well as potential drop / current density through the ion exchange membrane. In this paper we formulate the problem and list experimentally determined parameters. Results of calculations will be compared with experimentally recorded I-V and V-t curves.

Effects of Weak Electrolytes on Electric Double Layer Ion Distributions.

Many common experimental systems have electric double layers containing weak electrolytes, including systems with buffers. The pH at the boundary of the diffuse layer is an important parameter for determining the physicochemical state of the system, including surface charge density. We show that the Boltzmann equilibrium relation can be used as an exact solution for weak electrolyte electric double layers. Using these results, we provide a closed-form relation for the maximum pH change in a buffered electric double layer, in terms of the boundary potential. Importantly, our results suggest that equilibrium electric double layer concepts developed for strong electrolytes can be expanded to include weak electrolytes.

A high-performance graphite-graphite dual ion battery based on AlCl3/NaCl molten salts

A novel double graphite dual ion battery (DIB) based on low-temperature inorganic molten salt (AlCl3/NaCl) electrolytes is first investigated. As a result, it is found that chloroaluminate ions are intercalated/de-intercalated at the cathode and metallic aluminum are dissolved and deposited at the anode. In addition, the self-discharge phenomenon of the DIB is systematically studied and found that it has obvious self-charging phenomenon due to the adsorption of the charged ions when standing at low voltage. Due to low cohesion and the relatively high working temperature for the inorganic molten salt, the DIB exhibits unexpected electrochemical performance. The initial capacity is 183.8 mAh g−1 at 1 A g−1, and the capacity is 132 mAh g−1 even at 4 A g−1. After 700 cycles, the capacity retention rate is 79.5% and the coulombic efficiency increase from 85.1% to 93.9%. Given the advantages of cost-effectiveness and environmental friendliness, the DIB will play a decisive role in the future of aluminum-based batteries.

Ion Implanted Phosphorous for 4H-SiC VDMOSFETs Source Regions: Effect of the Post Implantation Annealing Time

Van der Pauw devices have been fabricated by double ion implantation processes, namely P+ and Al+ co-implantation. Similarly to the source area in a SiC VD-MOSFET, a 5 × 1018 cm-3 P plateau is formed on the top of a buried 3 × 1018 cm-3 Al distribution for electrical isolation from the n- epilayer. The post implantation annealing temperature was 1600 °C. Annealing times equal to 30 min and 300 min have been compared. The increase of the annealing time produces both an increase of electron density as well as electron mobility. For comparison a HPSI 4H-SiC wafer, 1×1020 cm-3 P+ ion implanted and 1700 °C annealed for 30 min was also characterized.

A High‐Potential Anion‐Insertion Carbon Cathode for Aqueous Zinc Dual‐Ion Battery

AbstractAqueous dual‐ion batteries (DIBs) are promising for large‐scale energy storage due to low cost and inherent safety. However, DIBs are limited by low capacity and poor cycling of cathode materials and the challenge of electrolyte decomposition. In this study, a new cathode material of nitrogen‐doped microcrystalline graphene‐like carbon is investigated in a water‐in‐salt electrolyte of 30 m ZnCl2, where this carbon cathode stores anions reversibly via both electrical double layer adsorption and ion insertion. The (de)insertion of anions in carbon lattice delivers a high‐potential plateau at 1.85 V versus Zn2+/Zn, contributing nearly 1/3 of the capacity of 134 mAh g−1 and half of the stored energy. This study shows that both the unique carbon structure and concentrated ZnCl2 electrolyte play critical roles in allowing anion storage in carbon cathode for this aqueous DIB.

Utilization of extracellular polymeric substances (EPS) immobilized in epoxy polymer as double ion exchanger biosorbent for removal of chromium from aqueous solution

Cation and industrial pollutant anions are removed from wastewater using organic cation and anion exchange resin. "Extracellular Polymeric Substance" (EPS) from bacterial extraction can accumulate cation and anion elements through biosorption by adsorption mechanism, ion exchange, formation of complex compounds and hydrogen bonds. EPS can be used as an biosorbent and ion exchange bioresin replacing organic resins, because EPS contains organic functional groups that are negatively charged (RCOOH, ROPO3H, ROPO3Na, ROSO3H, ROSO3Na, etc.) cation absorbers and positively charged (ROH, RCNH2HCOOH, etc.) anion absorber. EPS consists of 40-95% polysaccharide compounds, protein 1-60%, nucleic acids 1-10%, lipids 1-10% and the remaining amino acid polymers and other compounds. The tannery industry produces trivalent (Cr+3) chromium pollutants at levels of 15.2 ppm and hexavalent (CrO4-2 or Cr2O7-2) levels of 0.77 ppm which exceeds the standard quality for a total Cr of 0.6 ppm. Cr pollutants are very dangerous for human health. Research had been done on the use of immobilized EPS bioresin in epoxy polymers for chromium binding. EPS was extracted from bacterial activated sludge by centrifugation at 9000 rpm for 20 minutes at 4°C, the filtrate was EPS. The analysis showed EPS content were 16% fat, 12% carbohydrate, and 16% protein. The functional group analysis results with infrared ray spectroscopy (FTIR) showed EPS containing chemical bonds such as -CH, -OH, -NH, and -C=O which proved that EPS extraction contained RCOOH, ROH, and RCNH2HCOOH functional components which were exchanging components cations and anions. Epoxy polymers were prepared by mixing bisphenol A monomers and 1: 1 ratio epichlorohydrin. Immobilized EPS double ion exchange biorecin in epoxy polymers was prepared by mixing 200 mg EPS and 1800 mg epoxy. The binding of chromium ions in the resin was carried out by recirculating the chromium solution through a burette column filled with 2 rams of bioresin at pH 5, 6 and 7. The optimum results gave chromium ion absorption efficiency of 89.20% at pH 5. Column operations could be optimized by varied the amount of bioresin used.

A study of the valence shell absolute photoabsorption, photoionization and photodissociation cross sections, and the photoionization quantum efficiency of carbon monoxide

The spectroscopic characteristics and the decay mechanisms of the Rydberg states arising from valence shell excitations in carbon monoxide have been investigated by using a double ion chamber and synchrotron radiation to measure the absolute photoabsorption, photoionization and photodissociation cross sections, and the photoionization quantum efficiency, in the energy range between the ionization threshold and 36 eV. Guided by earlier theoretical predictions, the prominent absorption bands due to Rydberg states belonging to series converging onto the A 2Π state ionization threshold have been assigned, in accord with previous studies, to the ndδ and the [(n + 1)s + nd]σ transitions. Apart from the (4s + 3d)σ state which decays predominantly by predissociation into neutral fragments, most of the Rydberg states belonging to these series decay preferentially by autoionization. Another Rydberg series converging onto the A 2Π state limit has been tentatively assigned to the npσ transitions, even though these transitions are predicted to be weak. The v′ = 0 and v′ = 1 vibrational levels of the 4pσ state decay preferentially by predissociation into neutral fragments. The [(n + 1)s − nd]σ transitions are also calculated to be weak but may be associated with some previously unassigned absorption bands. Structure observed in the absorption spectrum between ∼19.5 and 23.5 eV may be due to Rydberg states associated with series converging onto the D 2Π or the 3 2Σ+ state limits. This structure is discussed in relation to dispersed fluorescence spectra and negative ion yields recorded over the same energy range.

Ultrafast Photochemistry of the [Cr(NCS)6]3- Complex in Dimethyl Sulfoxide and Dimethylformamide upon Excitation into Ligand-Field Electronic State.

The ultrafast photochemistry of the [Cr(NCS)6]3- complex upon excitation to the 4T2 ligand-field (LF) state was studied in dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) in a wide temporal range (100 fs to 9 ms) by a combination of femtosecond and nanosecond transient absorption spectroscopy techniques and supported by quantum-chemical DFT/TD-DFT calculations. The initially excited 4T2 state undergoes intersystem crossing to the vibrationally hot 2E state with time constants of 1.1 ± 0.2 and 1.8 ± 0.1 ps in DMSO and DMF, respectively. Vibrational relaxation occurs in the same time scale and takes 1-5 ps. A major part of the [Cr(NCS)6]3- complex in the 2E state undergoes intersystem crossing to the ground state with time constants of 65 ± 5 and 85 ± 5 ns in DMSO and DMF, respectively. A minor part of electronically excited [Cr(NCS)6]3- undergoes irreversible photochemical decomposition. In DMSO, the photolysis of the [Cr(NCS)6]3- complex results in single or double isothiocyanate ion release followed by the coordination of the solvent molecules with a time constant of 1 ± 0.2 ms.

120 MeV Ni10+ swift heavy ions irradiation on CdSe nanocrystals induces cubic to hexagonal phase transformation - A study of microstructural modification

In the present work, chemically synthesized cadmium selenide (CdSe) nanocrystals, which have a cubic lattice structure as per X-ray diffraction (XRD) analysis, has been irradiated with 120 MeV Ni10+ swift heavy ions (SHI) for the study of their structural modification. A significant change in the lattice structure has been found with different ion fluence of 120 MeV Ni10+ irradiation, which may be due to the high electronic energy loss of SHI. AFM analysis also shows changes in morphological properties with ion irradiation. The evolution of lattice structure with different fluence has been studied using double ion impact model. Further, SHI induced cubic to hexagonal transformation effect the microstructural parameters such as intrinsic strain, dislocation density of CdSe nanocrystals. SHI induced microstructural modifications have also been studied with the help of Variance model.