Lithium Ion Binding Research Articles

Effect of Residual Solvents on Properties of Composite Solid Electrolytes

Solid-state electrolytes (SSEs) can stabilize lithium (Li) metal anodes and achieve high energy density. However, they often suffer from solvent residues during the preparation. The residual solvent will affect the performance of SSEs. In this paper, we take Li1.5Al0.5Ge1.5P3O12 (LAGP)/Poly(propylene carbonate) (PPC) composite solid electrolyte (CSE) as an example, the content of the solvent residue of CSE prepared by the solution casting method and its effect on performance are investigated. The result reveals that the solvent content decreases with the increase of drying time. It still contains more than 5 wt % solvent even after vacuum drying for 48 h. The presence of residual solvent promotes the binding of lithium ions (Li+) and carbonyls, which is conducive to the transfer of Li+. When the residual solvent content is high, SSE has high ionic conductivity, cycling capacity, and excellent cycling stability. When the solvent content decreases, the electrochemical window becomes wider. This result is of great significance for the future regulation of SSE solvent content.

Tri(ethylene glycol) modified HYC‐100 resin for lithium ion recovery from aqueous solution

AbstractPolymeric resin has shown great application in recovery the lithium ion from aqueous solution due to their structure's tunability and reusability. However, the conventional resins such as commercial HYC‐100 is suffering by its low lithium adsorption capacity and slow inclusion rate. Herein, a series of HYC‐100 modified resins (MRs) using oligo(ethylene glycol) as crosslinker were synthesized and their adsorption capacities for lithium ion in aqueous solution (pH 9.1, ionic concentration 500 mg/L, 25°C) were determined by adding 1 g resin to 500 mL lithium chloride aqueous solution. The new formed cyclic structure from oligo(ethylene glycol) provides lithium ion binding sites which play an important role for lithium ion adsorption. The tri(ethylene glycol) modified resin (3EGMR) showed the highest capacity to be 18 mg/g, which was three times more than that of HYC‐100 (5 mg/g). Therefore, Scale‐up experiment was conducted by using 20 L reactor and the adsorption capacity is satisfactory. This work might pave a new avenue to develop new polymeric resin to enhance the lithium ion adsorption performance.

Thermodynamic Insights into Polymorphism-Driven Lithium-Ion Storage in Monoelemental 2D Materials.

Monoelemental two-dimensional materials (borophene, silicene, etc.) are exciting candidates for electrodes in lithium-ion batteries because of their ultralight molar mass. However, these materials' lithium-ion binding mechanism can be complex as the inherited polymorphism may induce phase changes during the charge-discharge cycles. Here, we combine genetic-algorithm-based bottom-up and stochastic top-down structure searching techniques to conduct thermodynamic scrutiny of the lithiated compounds of 2D allotropes of four elements: B, Al, Si, and P. Our first-principles-based high-throughput computations unveil polymorphism-driven lithium-ion binding process and other nonidealities (e.g., bond cleavage, adsorbent phase change, and electroplating), which lacks mention in earlier works. While monolayer B (2479 mAh/g), Al (993 mAh/g), and Si (954 mAh/g) have been demonstrated here as excellent candidates for Li-ion storage, P falls short of the expectation. Our well-designed computational framework, which always searches for lithiated structures at global minima, provides convincing thermodynamical insights and realistic reversible specific-capacity values. This will expectedly open up future experimental efforts to design monoelemental two-dimensional material-based anodes with specific polymorphic structures.

Limiting sulfur and mastering the diffusion of lithium ions with cerium oxide-based porous carbon rods.

Cerium dioxide nanocrystals embedded in porous carbon rod materials were used for sulfur storage and embedding. Polar cerium dioxide effectively adsorbed polysulfide and inhibited the shuttle effect. By calculating the diffusion coefficient of the lithium-ions, it was concluded that the porous carbon rod material with cerium oxide was beneficial for the rapid binding of lithium ions and sulfur.

Lithium and sodium ion binding in nanostructured carbon composites

ABSTRACT High charge capacity in lithium and sodium-ion batteries can be achieved using anodes composed of nanostructured carbon composites. The tailoring of the nanostructure to achieve both high loading and low irreversible binding depends upon the binding mechanisms of the ion. In this work, reactive molecular dynamics simulations are performed on model carbon composite anodes to investigate and to compare the binding mechanisms of lithium and sodium ions. In composites composed of both crystalline and amorphous domains, lithium ions bind preferentially at the interface between the amorphous and crystalline domains, rather than via the standard intercalation mechanism observed in graphitic anodes. In these same composites, sodium ions bind preferentially in the crystalline domain, even though the intercalation of sodium in graphitic anodes is not a viable mechanism for charge storage. The difference in mechanisms is explained through a comparison of the binding energies in the carbon composite to the energies of the respective metals and metal hydrides.

How does the mood stabilizer lithium bind ATP, the energy currency of the cell: Insights from solid-state NMR

BackgroundLithium, in the form of a salt, is a mood stabilizer and a leading drug for the treatment of bipolar disorder. It has a very narrow therapeutic range and a variety of side effects. Lithium can replace magnesium and other cations in enzymes and small molecules, among them ATP, thereby affecting and inhibiting many biochemical pathways. The form of binding of lithium ions to ATP is not known. MethodsHere we extract the binding environment of lithium in solid ATP using a multi-nuclear multi-dimensional solid-state NMR approach. ResultsWe determine that the coordination sphere of lithium includes, at a distance of 3.0(±0.4) Å, three phosphates; the two phosphates closest to the ribose ring from one ATP molecule, and the middle phosphate from another ATP molecule. A water molecule most probably completes the fourth coordination. Despite the use of excess lithium in the preparations, sodium ions still remain bound to the sample, at distances of 4.3–5.5 Å from Li, and coordinate the first phosphate and two terminal phosphates. ConclusionsSolid-state NMR enables to unravel the exact coordination of lithium in ATP showing binding to three phosphates from two molecules, none of which are the terminal gamma phosphate. General significanceThe methods we use are applicable to study lithium bound to a variety of ATP-bound enzymes, or to other cellular targets of lithium, consequently suggesting a molecular basis for its mode of action.

Computational and NMR Studies on the Complexation of Lithium Ion to 8-Crown-4.

Lithium ion selective crown ethers have been the subject of much research for a multitude of applications. Current research is aimed at structurally rigidifying crown ethers, as restructuring of the crown ether ring upon ion binding is energetically unfavorable. In this work, the lithium ion binding ability of the relatively rigid 8‐crown‐4 was investigated both computationally by density functional theory calculations and experimentally by 1H and 7Li NMR spectroscopy. Although both computational and experimental results showed 8‐crown‐4 to bind lithium ion, this binding was found to be weak compared to larger crown ethers. The computational analysis revealed that the complexation is driven by enthalpy rather than entropy, illustrating that rigidity is only of nominal importance. To elucidate the origin of the favorable interaction of lithium ion with crown ethers, activation strain analyses and energy decomposition analyses were performed pointing to the favorable interaction being mainly electrostatic in nature. 8‐crown‐4 presents the smallest crown ether reported to date capable of binding lithium ion, possessing two distinct conformations from which it is able to do so.

An Ionophore for High Lithium Loading and Selective Capture from Brine.

The continuous demand and uneven dispersal of natural mineral resources of lithium with a low recycling rate of lithium commodities have forced researchers to look for alternative resources like geothermal brine, brackish brines, and sea brines. But selective lithium-ion extraction and even lithium-ion binding from these aqueous systems is a recognized challenge due to very high hydration energy and the coexistence of other like metal ions but appealing due to economic benefits. Therefore, the designed synthesis of synthetic ionophores with high lithium selectivity is crucial as they can work on dilute conditions without removal of interfering metal ions. However, most of the lithium selective ionophores known in the literature are mononucleated, and no emphasis is given on designing multinucleating ionophore systems to improve the lithium loading capacity which will open up unexplored paths toward the development of a more sustainable and economical extraction process. Herein, we describe a rare fluorogenic macrocyclic ionophore with two binding pockets for selective lithium recognition and extraction among various major alkali and alkaline earth metal ions of oceanic presence through both solid-state and solution studies. Under solid-liquid extraction conditions, this receptor shows a high lithium loading capacity of 135% with LiClO4 and 69.16% with LiCl salt with exclusive selectivity. Under liquid-liquid extraction conditions, this ionophore shows a loading capacity of 27% with 1 M LiCl and 48.57% with 1 M LiClO4 source phase concentration. This new ionophore, therefore, inspiring further to modify and develop a better multinucleating extractant with high lithium loading capacity which is rare in the literature.

Exploiting Weak Noncovalent Cation···π Interaction for Designing a Molecular Container for Storage of Methane Molecules with Lithiated Carbene Superbases

This study reports the multiprotonation sites exploiting noncovalent interactions to achieve hyperbasicity of an uncharged organic base. A new class of carbene based organic superbase has been designed to attain the proton affinity (PA) value of 301.9 kcal/mol at M06-2X/6-311+G**//B3LYP/6-31+G* level of theory. These designed scaffold molecules can possess three independent protonation sites, which is not available in the literature to date. The stabilization of the protonated forms of the superbases by noncovalent interactions such as C–H+···π interaction is responsible for augmenting the basicity of such carbene systems. The DFT calculated results show that such carbene systems can be suitable candidate for tris-protonation with pKa(MeCN) value of 43.3 and proton affinity value (MeCN) of 312.1 kcal/mol. Molecular electrostatic potential (MESP) analysis shows the existence of electron density at the reactive sites and the role of substituents to enhance the electron density in such designed systems. There is a good correlation with the absolute minima of the MESP (Vmin) located for such carbene systems with their calculated proton affinity values. The frontier molecular orbital energy of such carbenes also shows a good relationship with their proton affinity results. These carbene systems can be utilized further for selective binding of lithium ions over sodium ions. Such lithiated organic superbases can be used as a molecular container for the storage of hydrogen and methane molecules. The energy decomposition analysis (EDA) has been performed to explain the role of various factors which contribute to the total binding strength of the hydrogen or methane molecules with lithiated carbene superbases. The localized molecular orbital energy decomposition analysis reveals that the electrostatic and polarization effects are the major contributing factors in interactions with methane and hydrogen molecules. This is the first report where the organic superbase has been exploited as efficient methane storage materials.

Probing the influence of solvent effect on the lithium ion binding affinity of 12-crown-O3N derivatives with unsaturated side arms: A computational study

Molecular structures of crown ether derivatives play a crucial role in complexing and transporting alkali metal ions such as lithium ion. The complexation of such ions take place in solution, hence it is important to examine the complexation behavior of host systems in solution. We have investigated employing quantum chemical calculations the stable conformations of 12-crown-O3N derivatives with unsaturated side-arms and its corresponding Li+ ion complexation in low polar to high polar solvent medium. The General Gradient Approximation (GGA) using PW91 functional with DNP basis set calculated results show that the side-arms contribute via cation-π interaction in the complexation of lithium ion with the receptor molecules 2 and 3 quite effectively in the gas phase and in low polar solvent medium (CHCl3). The vinyl and acetylene groups attached to the receptor molecules are away from the cavity of the crown ether, however, orients toward the cavity while complexing with the lithium ion. The auxiliary effect of such side-arms to augment the binding affinity of Li+ ion is reduced in the high polar solvent medium. The side-arms also orient away from the complexed Li+ ion in relatively more polar solvents. These calculated results indicate that the complexing ability of aza-crowns toward the Li+ ion can be enhanced with the unsaturated side-arms in low polar solvent medium, which however, is less effective in more polar mediums.

Complexation Enhanced Excited‐State Deactivation by Lithium Ion Coordination to a Borondipyrromethene (Bodipy) Donor–Bridge–Acceptor Dyad

AbstractA donor–acceptor dyad was prepared comprised of a borondipyrromethene (Bodipy) chromophore as the acceptor and a dimethylamino moiety as the donor. The two groups are separated by a 2,2′‐biphenol moiety. The excited state of the Bodipy is efficiently quenched by electron transfer involving donation from the dimethyl amino group. The rate constant for forward electron transfer in DMF was measured to be ca. 2 × 1010 s–1. The charge recombination process is ultrafast. Titration of aliquots of LiClO4 to a DMF solution of the dyad resulted in alterations to the absorption spectrum associated with the 2,2′‐biphenol unit. Changes were modelled as Li+ ions bound to the oxygen atoms of the 2,2′‐biphenol to produce 1:1 (Li+/ligand) and 2:1 (Li+/ligand) complexes. The rate constant for excited state quenching is enhanced upon lithium ion binding.

Theoretical studies on hydrogen adsorption properties of lithium decorated diborene (B 2H 4Li 2) and diboryne (B 2H 2Li 2)

Using ab initio based quantum chemical calculations, we have studied the structure, stability and hydrogen adsorption properties of different boron hydrides decorated with lithium, examples of the corresponding anions being dihydrodiborate dianion, B 2H 2 2− and tetrahydrodiborate dianion, B 2H 4 2− which can be considered to be analogues and isoelectronic to acetylene (C 2H 2) and ethelene (C 2H 4) respectively. It is shown that there exists a B–B double bond in B 2H 4Li 2 and a B–B triple bond in B 2H 2Li 2. In both the complexes, the lithium sites are found to be cationic in nature and the calculated lithium ion binding energies are found to be very high. The cationic sites in these complexes are found to interact with molecular hydrogen through ion-quadrupole and ion-induced dipole interactions. In both the complexes, each lithium site is found to bind a maximum of three hydrogen molecules which corresponds to a gravimetric density of ∼23 wt% in B 2H 4Li 2 and ∼24 wt% in B 2H 2Li 2. We have also studied the hydrogen adsorption in a model one-dimensional nanowire with C 6H 4B 2Li 2 as the repeating unit and found that it can adsorb hydrogen to the extent 9.68 wt% and the adsorption energy is found to be −2.34 kcal/mol per molecular hydrogen.

Sodium or Lithium Ion-Binding-Induced Structural Changes in the K-Ring of V-ATPase from Enterococcus hirae Revealed by ATR-FTIR Spectroscopy

V-ATPase from Enterococcus hirae forms a large supramolecular protein complex (total molecular weight ∼700,000) and physiologically transports Na(+) and Li(+) across a hydrophobic lipid bilayer. Stabilization of these cations in the binding site has been discussed on the basis of X-ray crystal structures of a membrane-embedded domain, the K-ring (Na(+)- and Li(+)-bound forms). Here, sodium or lithium ion-binding-induced difference IR spectra of the intact V-ATPase have for the first time been measured at physiological temperature under a sufficient amount of hydration. The results suggest that sodium or lithium ion binding induces the deprotonation of Glu139, a hydrogen-bonding change in the tyrosine residue, and a small conformational change in the K-ring. These structural changes, especially the deprotonation of Glu139, are considered to be important for reducing energetic barriers to the transport of cations through the membrane.

Dynamics and Lithium Binding Energies of Polyelectrolytes Based on Functionalized Poly(para-phenylene terephthalamide)

Polyelectrolyte materials are an interesting class of electrolytes for use in fuel cell and battery applications. Poly(para-phenylene terephthalamide) (PPTA, Kevlar) is a liquid crystalline polymer that, when sulfonated, is a polyelectrolyte that exhibits moderate ion conductivity at elevated temperatures. In this work, quasi-elastic neutron scattering (QENS) experiments were performed to gain insight into the effect of the presence of lithium counterions on the chain dynamics in the material. It was found that the addition of lithium ions decreases the dynamics of the chains. Additionally, the binding of lithium ions to the sulfonic acids groups was investigated by density functional theory (DFT) calculations. It was found that the local surroundings of the sulfonic acid group have very little effect on the lithium-ion binding energy. Binding energies for a variety of different systems were all calculated to be around 150 kcal/mol. The DFT calculations also show the existence of a structure in which a single lithium ion interacts with two sulfonic acid moieties on different chains. The formation of such "electrostatic cross-links" is believed to be the source of the increased tendency to aggregate and the reduced dynamics in the presence of lithium ions.

Mixed Solvent and Polymer Coordination in PAN and PMMA Gel Polymer Electrolytes Studied by Ab Initio Calculations and Raman Spectroscopy

The local and mixed solvent and polymer coordination in PAN and PMMA/carbonate (EC/PC) based lithium ion conducting gel polymer electrolytes has been studied by using ab initio calculations and Raman spectroscopy. The energies of the coordination complexes were evaluated by density functional theory with a hybrid functional and by performing simple thermodynamic calculations. Observed frequency shifts for EC and PAN due to lithium ion coordination were confirmed by computing the Hessian matrixes for pure and mixed complexes. The lithium ion has been found to prefer to coordinate to EC solvent molecules. In the PAN based gels there was only a slight preference, while for PMMA gels the preference is much larger. The temperature-dependent coordination is found to be directly related to the differences in lithium ion binding energies in the mixed solvent and polymer ligand complexes. The implications for the formation and stability of gels and for the lithium ion transport in different gel systems are discussed.

Convergent synthesis of isomeric pairs of metallocene-containing polyether macrocycles.

A general method for rapid construction of metallocene-based hosts is described. Treatment of polyether bridged bis(diphenylacetylenes) with a source of cyclopentadienyl cobalt at high temperature leads, via macrocyclization and capture of the intermediate cyclobutadiene, to macrocyclic systems tethered to an integral metallocene platform. Equal yields of the two possible structural isomers, the products of parallel or antiparallel cycloaddition of the precursor, are obtained. A combination of X-ray crystallography and NMR is employed to assign structures to the individual isomers and to assess the strength of lithium ion binding by the individual macrocycles.

Binding Energies of the Silver Ion to Small Oxygen-Containing Ligands: Determination by Means of Density Functional Theory and Threshold Collision-Induced Dissociation

The binding enthalpies at 0 K of the silver ion to water, methanol, ethanol, diethyl ether, and acetone were calculated using density functional theory (DFT) using the hybrid B3LYP level of theory with the DZVP basis set; they were also measured using the threshold collision-induced dissociation (CID) method. There is good agreement between the two sets of data. For the five ligands, the DFT/threshold CID values are: water, 28.1/31.6 ± 2.5; methanol, 30.1/33.0 ± 3.7; ethanol, 32.0/33.9 ± 3.5; diethyl ether, 33.3/33.2 ± 1.5; and acetone, 36.2/38.0 ± 1.4 kcal/mol. The average of the absolute differences between the DFT and threshold CID results is 2.0 kcal/mol, a value smaller than the average experimental uncertainty of 2.5 kcal/mol. For identical ligands, the silver ion binding energies are lower than the lithium ion binding energies, but higher than the sodium ion binding energies.

Thermodynamic and structural properties of phosphatidylserine bilayer membranes in the presence of lithium ions and protons

The binding of lithium ions to phosphatidylserine has been studied by differential scanning calorimetry for dialkyl and diacyl lipid forms and by X-ray diffraction for dihexadecylphosphatidylserine (DHPS). On first mixing DHPS with LiCl solutions an ordered L β (L c) phase is formed with a bilayer repeat distance of 5.55 nm and one strong wide-angle, chain-chain reflection at 0.405 nm (26°C), corresponding to bilayers of little, (mono)hydrated lipid with chains approximately perpendicular to the membrane surface. On heating, this phase transforms to an inverted hexagonal phase (H 11, H α) with a repeat distance of 3.75 nm, at a chain-melting transition temperature of approximately 90°C (DHPS). Cooling, after equilibration of the DHPS −·Li + sample in the fluid phase, creates a new low-temperature phase (L c') which has a repeat distance of 4.0 nm, corresponding to strongly tilted chains ( ϕ=42°). The L c phase also transforms on heating to the H α phase, but at a considerably lower chain-melting temperature of approx. 70°C (DHPS). The calorimetric behavior as a function of Li + concentration is qualitatively very similar for the different dialkyl- and diacylphosphatidylserines studied, and is analogous to the results obtained on pH titration. After an initial small increase in transition temperature, that is caused by coulombic ion binding and concomitant surface charge neutralization, a much larger increase in the chain-melting transition temperature occurs, caused by dehydration of the lipid, as a consequence of a further stereospecific ion binding. This suggests that Li + and H + have similar binding sites on the PS headgroup.

Molecular mechanics study of ion binding by a cyclic pentapeptide.

We have used energy minimization and harmonic analysis to study the structural and thermodynamic changes which occur upon the binding of lithium ions to the cyclic pentapeptide, cyclo-(Gly-L-Pro-Gly-D-Ala-L-Pro) (GPGAP). A number of theoretically stable vacuum configurations of uncomplexed GPGAP were found, one of which is very close to the crystal conformation determined by X-ray diffraction. Stable complexes with lithium were found where the ion binds to the carbonyl oxygen atoms of three residues. Detailed conformational information is presented for both the uncomplexed and the complexed peptide, along with an analysis of the atomic interactions which stabilize the various peptide conformations.

Stereochemical studies of a multifunctional P-donor ligand capable of selective lithium ion binding for CO activation via ‘tripodal O 3N unit’

Stereochemical studies of a multifunctional P-donor ligand capable of selective lithium ion binding for CO activation via ‘tripodal O 3N unit’