Lithium versus Mono/Polyvalent Ion Intercalation: Hybrid Metal Ion Systems for Energy Storage

The energy storage by redox intercalation reactions is, nowadays, the most effective rechargeable ion battery. When lithium is used as intercalating agents, the high energy density is achieved at an expense of non‐sustainability. The replacement of Li⁺ with cheaper monovalent ions enables to make greener battery alternatives. The utilization of polyvalent ions instead of Li⁺ permits to multiplying the battery capacity. Contrary to Li⁺, the realization of quick and reversible intercalation of bigger monovalent and of polyvalent ions is a scientific challenge due to kinetic constraints, polarizing ion effects and Coulomb interactions. Herein we provide a vision how to make the intercalation of these ions feasible. The idea is to perform dual intercalation of ions having different charges, radii, preferred coordination and diffusion pathway topology. All these features are demonstrated by the recent knowledge on selective and non‐selective intercalation properties of oxides and polyanion compounds with layered and tunnel structures. Based on dual intercalation properties, the fabrication of hybrid metal ion batteries is presented and discussed.     

Gas-phase ion-molecule bimolecular and clustering reactions in dilute solutions of acetonitrile in xenon,krypton, argon,neon and helium

Gas-phase bimolecular and clustering reactions of acetonitrile in Xe, Kr, Ar, Ne and He were studied at high chemical ionization pressures in the new coaxial ion source at Auburn. With electron energies near the ionization threshold, the mass spectra are exceedingly simple and are comprised of [CH₄CH]⁺ and clusters of [CH₄CN]⁺ with various ligands such as H₂O and CH₃CN. At higher electron energies many other peaks appear. The intensities of the new peaks depend upon the ionization potential of the charge transfer gas, the ionizing electron energy and the ion source conditions, and are due to reactions of fragment ions. Residence time distributions at electron energies above the ionization threshold (∼ 30 eV) demonstrate that two molecular structures are present in the ion beam at m/z 42, one presumably is protonated acetonitrile ([CH₃CNH]⁺) while the evidence indicates that the second species does not contain acidic hydrogens. With ionizing electron energies near threshold (∼ 10. 5 eV) only one structure is observed. Studies with electron energies near the ionization threshold under high-pressure chemical ionization conditions result in greatly simplified mass spectra and are possible only because of the coaxial geometry of the ion source.     

A Black Phosphorus–Graphite Composite Anode for Li‐/Na‐/K‐Ion Batteries

Black phosphorus (BP) is a desirable anode material for alkali metal ion storage owing to its high electronic/ionic conductivity and theoretical capacity. In‐depth understanding of the redox reactions between BP and the alkali metal ions is key to reveal the potential and limitations of BP, and thus to guide the design of BP‐based composites for high‐performance alkali metal ion batteries. Comparative studies of the electrochemical reactions of Li⁺, Na⁺, and K⁺ with BP were performed. Ex situ X‐ray absorption near‐edge spectroscopy combined with theoretical calculation reveal the lowest utilization of BP for K⁺ storage than for Na⁺ and Li⁺, which is ascribed to the highest formation energy and the lowest ion diffusion coefficient of the final potassiation product K₃P, compared with Li₃P and Na₃P. As a result, restricting the formation of K₃P by limiting the discharge voltage achieves a gravimetric capacity of 1300 mAh g^?1 which retains at 600 mAh g^?1 after 50 cycles at 0.25 A g^?1.     

The Remarkable Effect of the Manganese Ion with Dioxygen on the Stability of π‐Conjugated Radical Cations

In this paper, nanosecond laser flash photolysis has been used to investigate the influence of metal ions on the kinetics of radical cations of a range of carotenoids (astaxanthin (ASTA), canthaxanthin (CAN), and β‐carotene (β‐CAR)) and various electron donors (1,4‐diphenyl‐1,3‐butadiene (14DPB), 1,6‐diphenyl‐1,3,5‐hexatriene (16DPH), 4‐methoxy‐trans‐stilbene (4 MeOSt), and trans‐stilbene (trans‐St)) in benzonitrile. Radical cations have been generated by means of photosensitized electron‐transfer (ET) using 1,4‐dicyanonaphthalene (14DCN) and biphenyl (BP). The kinetic decay of CAR ^{. +} shows a strong dependence on the identity of the examined metal ion. For example, whereas NaClO₄ has a weak effect on the kinetics of CAR ^{. +}, Ni(ClO₄)₂ causes a strong retardation of the decay of CAR ^{. +}. It is also interesting to note that Mn²⁺, which is a biologically relevant metal ion, shows the strongest effect of all the investigated metal ions (e.g., in the presence of Mn²⁺ ions, the half‐life (t_1/2) of CAN ^{. +} (t_1/2>90 ms) is more than three orders of magnitude higher than in the absence of the metal ions (t_1/2≈16 μs)). Furthermore, the influence of metal‐ion and oxygen concentrations on the kinetics of CAR ^{. +} reveals their pronounced effect on the kinetic decay of CAR ^{. +}. However, these remarkable effects are greatly diminished if either oxygen or metal ions are removed from the investigated solutions. Therefore, it can be concluded that oxygen and metal ions interact cooperatively to induce the observed substantial effects on the stabilities of CAR ^{. +}. These results are the first direct observation of the major role of oxygen in the stabilization of radical cations, and they support the earlier mechanism proposed by Astruc et al. for the role of oxygen in the inhibition of cage reactions. On the basis of these results, the factors that affect the stability of radical cations are discussed and the mechanism that shows the role of oxygen and metal ions in the enhancement of radical‐cation stability is described.     

IR Spectrum and Structure of Protonated Monosilanol: Dative Bonding between Water and the Silylium Ion

We report the spectroscopic characterization of protonated monosilanol (SiH₃OH₂⁺) isolated in the gas phase, thus providing the first experimental determination of the structure and bonding of a member of the elusive silanol family. The SiH₃OH₂⁺ ion is generated in a silane/water plasma expansion, and its structure is derived from the IR photodissociation (IRPD) spectrum of its Ar cluster measured in a tandem mass spectrometer. The chemical bonding in SiH₃OH₂⁺ is analyzed by density functional theory (DFT) calculations, providing detailed insight into the nature of the dative H₃Si⁺‐OH₂ bond. Comparison with protonated methanol illustrates the differences in bonding between carbon and silicon, which are mainly related to their different electronegativity and the different energy of the vacant valence p_z orbital of SiH₃⁺ and CH₃⁺.     

Host‐Guest Complexes of Dodeka(ethylene)octamine: Prediction of Ion Selectivity by Quantum Chemical Calculations IX

In this contribution we investigated the ion complexation of Bühl's cryptand, dodeka(ethylene)octamine by quantum chemical methods (B3LYP/LANL2DZp). This cryptand is an isomer of a well‐known Lehn‐type cryptand [TriPip222]. The ion selectivity was determined based on the energetic criteria derived by model reactions starting from solvated metal ions and empty dodeka(ethylene)octamine, and by comparing the M–N bond length in [M ? dodeka(ethylene)octamine]^m+ and [M(NH₃)₆]^m+. We calculated that Bühl's cryptand will complex best Na⁺ followed by Li⁺ as alkaline cations and Ca²⁺ followed by Mg²⁺ as alkaline earth metal ions. Based on this data we conclude that Bühl's cryptand offers a smaller cavity to nest ions than the Lehn‐type [TriPip222].     

Chemical discrimination of multilayered paint cross sections for potential forensic applications using time‐of‐flight secondary ion mass spectrometry

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) equipped with a bismuth imaging source and an argon gas cluster ion beam (GCIB) was used to image polished cross‐sections of four automotive multilayer paint samples. Secondary ion mass spectrometry chemical imaging of the individual layers was possible after a GCIB sputter ion dose of (7 × 10¹⁵) ions/cm² was applied for the removal of polishing residue, at which point the chemical composition of the individual clear coats could be distinguished using principal components analysis. For the differentiation of the four clear coat chemistries, only four secondary ion peaks were necessary; C₂H₅O⁺ (m/z 45.04), C₉H₉NO₂⁺ (m/z 163.09), and C₁₀H₁₁NO₂⁺ (m/z 177.10) that appeared to be fragments of the carbamate‐based clear coat, and C₇H₁₁⁺ (m/z 95.09) that was strongly associated with the polyurethane‐based clear coat. Clear identification of the four paint samples based on this short peak list highlights the strength of the SIMS technique as a potential forensic approach to discriminate automotive paints and suggests that many more variables could be included in the multivariate and statistical analysis to differentiate a wider range of clear coat chemistries.     

Reaction of cyclohexanone with [NH4]+ under chemical ionization conditions. 1—formation of protonated unsubstituted imines

High resolution and metastable decomposition spectra of the ions [M + NH₄]⁺ (and [M + ND₄]⁺) formed by reaction of [NH₄]⁺ (and [ND₄]⁺) with cyclohexanone have been measured. The results provide evidence that the m/z 98 ion, which is abundant in the chemical ionization (NH₃) spectrum of cyclohexanone, is in fact composed of two isobaric ions: a protonated imine ion and the molecular ion of cyclohexanone. The former is formed by a mechanism analogous to that occurring in solution.     

Proton transfer and isotope‐induced reaction in aniline cluster ions

The proton transfer (PT) and other intraclusters reactions occurring after electron ionization of aniline clusters (PhNH₂)_N are investigated by the time‐of‐flight mass spectrometry. The mass spectra are recorded for different expansion conditions leading to the generation of different cluster sizes. Several fragment ions are shown to originate from intracluster reactions, namely, [Ph]⁺, [PhNH₃]⁺ and [Ph–N–Ph]⁺. Reaction schemes are proposed for these ions starting with the PT process. The mass region beyond the monomer mass is dominated by cluster ions (PhNH₂)_n⁺ accompanied by satellites with ±H and +2H. In experiments with deuterated species, new fragment ions are identified. The aniline isotopomer d₅‐PhNH₂ yields the fragment ions (PhNH₂)_n?(N–Ph–NH₂)⁺. Analogical series is observed in experiments with d₇‐PhND₂, and additional fragments occur corresponding to (PhND₂)_n?(D₂N–ND–Ph–ND–ND₂)⁺ ions. The possible reaction pathways to these ions and the unusual isotope effects are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Characterization of [peptide+(Ag)n]+ complexes using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Silver ion complexes of peptides [M + (Ag)_n]⁺, M = angiotensin I or substance P where n = 1–8 and 17–23 for angiotensin I and n = 1–5 for substance P, are identified and characterized using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The Ag⁺ coordination number exceeds the number of available amino acid residues in angiotensin I whereas the number of observed complexes in substance P is less than the number of amino acid residues in it. The larger coordination number of angiotensin I with Ag⁺ indicates the simultaneous binding of several Ag⁺ ions to the amino acid residue present in it. The lower number of observed complexes in substance P suggests the binding of two or more residues to one Ag⁺ ion. The presence of trifluoroacetic acid in the peptide samples reduces the Ag⁺ coordination ability in both the peptides which indicates that the basic residues in it are already protonated and do not participate in the Ag⁺‐binding process. The Ag⁺ ion also forms a complex with the α‐cyano‐4‐hydroxycinnamic acid (CHCA) matrix and is observed in the MALDI mass spectra and the formation of [CHCA + Ag]⁺, [CHCA + AgNO₃]⁺ and [(CHCA)₂ + Ag]⁺ ions is due to the high binding affinity of Ag⁺ to the CN group of CHCA. Copyright © 2010 John Wiley & Sons, Ltd.     

Coordinative saturation of cationic niobium– and rhodium–argon complexes

Mass spectra of Nb⁺ and Rh⁺ complexes with argon ligands exhibit `magic' peaks Nb⁺Ar₄ and Rh⁺Ar₆, similar to observations for V⁺Ar₄ and Co⁺Ar₆, indicating coordinative saturation. A consistent explanation is obtained by assuming that the rare gas ligands seek out electron density minima in the valence shell of the ion, which permit a closer approach to the metal core and a stronger charge-induced dipole bond. Ab initio density functional calculations, which predict stable square planar complexes for the d⁴ ions and octahedral for the d⁸ species, support this interpretation and show that rare gas complexes of d⁴ metal ions fit perfectly well into the coordination chemical framework based on the Jahn–Teller effect.     

Complexation of poly(ethyleneimine) with copper(II) and nickel(II) ions in 0.5 M KNO3 solution

Complexation of poly(ethyleneimine) (PEI) with copper(II) and nickel(II) ions was studied in a 0.5M aqueous KNO₃ solution. The potentiometrically determined logarithm of the three successive formation constants (log k_J) were 8.14, 7.96, and 7.37 for Cu⁺²-PEI complexation and 6.74, 6.52, and 6.23 for Ni⁺²–PEI complexation at 25°C, according to Bjerrum's modified method. The maximum average coordination number was 3.2 for the Cu⁺²–PEI system and 3.7 for the Ni⁺²–PEI system. An entropy effect was observed in the third coordination. The wavelengths of maximum absorption of the complexes and the continuous variation method showed that at least two coordination sites of Cu⁺² ion and three coordination sites of Ni⁺² ion were occupied immediately by PEI as the solutions of PEI and the metal ions were mixed.     

Charge Reversal Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

We report the first charge reversal experiments performed by tandem-in-time rather than tandem-in-space MS/MS. Precursor odd-electron anions from fullerene C₆₀, and even-electron ions from 2,7-di-tert-butylfluorene-9-carboxylic acid and 3,3′-bicarbazole were converted into positive product ions (^–CR⁺) inside the magnet of a Fourier transform ion cyclotron resonance mass spectrometer. Charge reversal was activated by irradiating precursor ions with high energy electrons or UV photons: the first reported use of those activation methods for charge reversal. We suggest that high energy electrons achieve charge reversal in one step as double electron transfer, whereas UV-activated ^–CR⁺ takes place stepwise through two single electron transfers and formally corresponds to a neutralization-reionization (^–NR⁺) experiment.      

Engineering Active Sites of Polyaniline for AlCl2+ Storage in an Aluminum‐Ion Battery

The reversible capacity of AlCl₄^? intercalation/de‐intercalation in conventional cathodes of aluminum‐ion batteries (AIBs) is difficult to improve due to the large size of AlCl₄^? anions. Therefore, it is highly desirable to realize the intercalation/de‐intercalation of smaller Al‐based ions. Here, we fabricated polyaniline/single‐walled carbon nanotubes (PANI/SWCNTs) composite films and protonated the PANI nanorods. The protonation endows PANI with more active sites and enhanced conductivity. Hyper self‐protonated PANI (PANI(H⁺)) exhibits reversible AlCl₂⁺ intercalation/de‐intercalation during the discharge/charge process. As a result, the discharge capacity of the Al/PANI(H⁺) battery is twice as high as that of the initial composite films. PANI(H⁺)@SWCNT electrodes also have a stable cycling life with only 0.003 % capacity decay per cycle over 8000 cycles. Owing to the excellent mechanical properties, PANI(H⁺)@SWCNT composite films can act as the electrodes of flexible AIBs.     

Alkaline‐Earth Metal Cations as Structure Building Blocks for Molecular Cages with Entrapment and Controlled Release of Quintuple Ionic Aggregates

Currently, main‐group metal cations are totally neglected as the structure‐building blocks for the self‐assembly of supramolecular coordination metallocages due to the lack of directional bonding. However, here we show that a common Arrhenius acid–base neutralization allows the alkaline‐earth metal cations to act as charged binders, easily connecting two or more highly directional anionic transition‐metal‐based metalloligands to coordination polymers. With a metal salt such as K⁺PF₆^? added during the neutralization, the main‐group metal‐connected skeleton can be templated by the largest yet reported ionic‐aggregate anion, K₂(PF₆)₃^?, formed from KPF₆ in solution, into molecular metallocages, encapsulating the ion. Crystal‐structure details, DFT‐calculation results, and controlled‐release behavior support the presence of K₂(PF₆)₃^? as a guest in the cage. Upon removal of PF₆^? ions, the cage stays intact. Other ions like BF₄^? can be put back in.     

Ion manipulation and enrichment mass spectrometer for cleavage of disulfide bond via ion/ion reaction

A novel mass spectrometer with the capability of ion manipulation and enrichment was developed to perform gas‐phase ion/ion reactions followed by product ions accumulation. The development of this apparatus opens opportunities for more complex sequences of ion manipulations, thus offers the potential on extensive application involving ion/ion reaction. Here, cleavage of disulfide bond in peptide was demonstrated based upon this ion manipulation and enrichment mass spectrometer. Two typical peptides including S‐glutathionylated ARACAKA with an intermolecular disulfide bond, and oxytocin with an intramolecular disulfide bond were chosen as typical samples to demonstrate the ability of the apparatus. After ion/ion reaction between selected peptide cations and periodate ions (IO₄^?), two kinds of product ions (eg, [M + O + H]⁺ and [M + H + Na + IO₄]⁺) were enriched with a number of accumulation events. Afterwards, the enriched ions were subjected to activation, and the disulfide bond cleavage was clearly observed from the tandem mass spectra. These results illustrate the potential of this apparatus for ion manipulation performing ion/ion reaction, and low abundance product ion enrichment.     

Gas-phase C-F bond cleavage in perfluorohexane using W-, Si-, P-, Br-, and I-containing ions: Comparisons with reactions at fluorocarbon surfaces

Gas-phase reactions of W-, Si-, P-, Br-, and I-containing ions with the target molecule perfluorohexane at low collision energies (<15 eV) parallel known ion/surface reactions of the same projectile ions at fluorinated self-assembled monolayer surfaces. Charge exchange, dissociative charge exchange, and fluorine atom abstraction are observed and the majority of the projectile ions also undergo reactive charge exchange to produce specific fluorocarbon fragment ions of the target molecule in distinctive relative abundances. Abstraction of up to five fluorine atoms is observed upon collision of W⁺ with gaseous perfluorohexane, while similar experiments with CI⁺, SiCl⁺, and PCl^+· show abstraction of one or two fluorine atoms. Other projectiles, including Si^+·, PCl ₂ ⁺ , Br⁺, CBr⁺, and I⁺, abstract only a single fluorine atom. These patterns of fluorine atom abstraction are similar to those observed in ion/surface collisions. Also paralleling the ion/surface reactions, halogen exchange (Cl-for-F) reactions occur between the Cl-containing projectile ions and perfluorohexane to produce C₆F₁₂Cl⁺, a product of chemical modification of the target. Collisions of PCl^+· and PCl ₂ ⁺ also result in production of C₆F ₁₂ ^+· , indicating that the corresponding surface modification reaction involving molecular defluorination should be sought. Implications for previously proposed mechanisms, new ion/surface reactions, and for the use of gas-phase studies to guide investigations of the ion/surface reactions are discussed.     

A Metal–Organic Compound as Cathode Material with Superhigh Capacity Achieved by Reversible Cationic and Anionic Redox Chemistry for High‐Energy Sodium‐Ion Batteries

Although sodium‐ion batteries (SIBs) are considered as alternatives to lithium‐ion batteries (LIBs), the electrochemical performances, in particular the energy density, are much lower than LIBs. A metal–organic compound, cuprous 7,7,8,8‐tetracyanoquinodimethane (CuTCNQ), is presented as a new kind of cathode material for SIBs. It consists of both cationic (Cu^II↔Cu^I) and anionic (TCNQ⁰↔TCNQ⁻↔ TCNQ²⁻) reversible redox reactions, delivering a discharge capacity as high as 255 mAh g⁻¹ at a current density of 20 mA g⁻¹. The synergistic effect of both redox‐active metal cations and organic anions brings an electrochemical transfer of multiple electrons. The transformation of cupric ions to cuprous ions occurs at near 3.80 V vs. Na⁺/Na, while the full reduction of TCNQ⁰ to TCNQ⁻ happens at 3.00–3.30 V. The remarkably high voltage is attributed to the strong inductive effect of the four cyano groups.     

Fast Sodium‐Ion Conductivity in Supertetrahedral Phosphidosilicates

Fast sodium‐ion conductors are key components of Na‐based all‐solid‐state batteries which hold promise for large‐scale storage of electrical power. We report the synthesis, crystal‐structure determination, and Na⁺‐ion conductivities of six new Na‐ion conductors, the phosphidosilicates Na₁₉Si₁₃P₂₅, Na₂₃Si₁₉P₃₃, Na₂₃Si₂₈P₄₅, Na₂₃Si₃₇P₅₇, LT‐NaSi₂P₃ and HT‐NaSi₂P₃, based entirely on earth‐abundant elements. They have SiP₄ tetrahedra assembled interpenetrating networks of T3 to T5 supertetrahedral clusters and can be hierarchically assigned to sphalerite‐ or diamond‐type structures. ²³Na solid‐state NMR spectra and geometrical pathway analysis show Na⁺‐ion mobility between the supertetrahedral cluster networks. Electrochemical impedance spectroscopy shows Na⁺‐ion conductivities up to σ (Na⁺)=4×10^?4 S cm^?1. The conductivities increase with the size of the supertetrahedral clusters through dilution of Na⁺‐ions as the charge density of the anionic networks decreases.     

Mass spectrometry of coordination compounds of transition metals with tetradentate ligands. 11. isomeric quasi-macrocyclic Ni(II) complexes based on S-substituted isothiocarbohydrazides and the structure of “small” ions derived from them

Two series of bonding isomers of Ni(II) coordination compounds with tetradentate quasimacrocyclic ligands based on S-substituted isothiocarbohydrazides were characterized by electron impact (EI) mass spectrometry and by tandem mass spectrometry methods. Conventional EI mass spectra were more isomer specific than metastable ion (MI) and collision induced dissociation (CID) mass spectra of the molecular ions. The MI (and CID) mass spectra of the isomers were very similar. This effect resulted from a facile randomization of Ni–N bonds in the ions possessing low internal energies, prior to their dissociation. The compounds were found to be convenient precursors for coordinatively unsaturated metal-containing ions, [NiL_n]⁺ and [RNiL_n]⁺ (n = 1, 2; L = NCCH₃, NCSCH₃; R = OH, NO). Most of these species had a structure of mono- or disolvated nickel ion. The dissociation of [HONiNCCH₃]⁺ ions was consistent with the formation of two isomers: one corresponding to the [HONi]⁺ ion solvated by acetonitrile and the other is a complex of H₂O with [NiNCCH₂]⁺. A structure of [HO,Ni,(NCCH₃)₂]⁺ ions was best represented by a five-membered cycle formed by two acetonitrile units and the metal atom with the OH group attached to one of the nitrogen atoms.