Lithium Cations Research Articles

Anionic Effects on Concentrated Aqueous Lithium Ion Dynamics.

The dynamics, orientational anisotropy, diffusivity, viscosity, and density were measured for concentrated lithium salt solutions, including lithium chloride (LiCl), lithium bromide (LiBr), lithium nitrite (LiNO2), and lithium nitrate (LiNO3), with methyl thiocyanate as an infrared vibrational probe molecule, using two-dimensional infrared spectroscopy (2D IR), nuclear magnetic resonance (NMR) spectroscopy, and viscometry. The 2D IR, NMR, and viscosity results show that LiNO2 exhibits longer correlation times, lower diffusivity, and nearly 4 times greater viscosity compared to those of the other lithium salt solutions of the same concentration, suggesting that nitrite anions may strongly facilitate structure formation via strengthening water-ion network interactions, directly impacting bulk solution properties at sufficiently high concentrations. Additionally, the LiNO2 and LiNO3 solutions show significantly weakened chemical interactions between the lithium cations and the methyl thiocyanate when compared with those of the lithium halide salts.

Ternary Solid Polymer Electrolytes at the Electrochemical Interface: A Computational Study.

Polymer-based solid-like gel electrolytes have emerged as a promising alternative to improve battery performance. However, there is a scarcity of studies on the behavior of these media at the electrochemical interface. In this work, we report classical MD simulations of ternary polymer electrolytes composed of poly(ethylene oxide), a lithium salt [lithium bis(trifluoromethanesulfonyl)imide], and different ionic liquids [1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide] confined between two charged and uncharged graphene-like surfaces. The molecular solvation of Li+ ions and their diffusion as well as the polymer conformational picture were characterized in terms of the radial distribution functions, coordination numbers, number density profiles, orientations, displacement variance, polymer radius of gyration, and polymer end-to-end distance. Our results show that the layering behavior of the ternary electrolyte in the interfacial region leads to a decrease of Li+ mobility in the direction perpendicular to the electrodes and high energy barriers that hinder lithium cations from coming into direct contact with the graphene-like surface. The nature of the ionic liquid and its concentration were found to influence the structural and dynamic properties at the electrode/electrolyte interface, the electrolyte with low amounts of the pyrrolidinium-based ionic liquid being that with the best performance since it favors the migration of Li+ cations toward the negative electrode when compared to the imidazolium-based one.

Acoustic Shock Wave-Induced Amorphous to Crystalline Phase Transitions of Li2SO4─Raman Spectroscopic and Thermal Calorimetric Approach.

In this context, we have reexamined the acoustical shock wave-induced amorphous-glassy-crystalline-amorphous phase transitions in the Li2SO4 sample under 0, 1, 2, and 3 shocked conditions by implementing the detailed Raman spectroscopic approach. The recorded Raman spectroscopic data clearly reveal that the transition from the amorphous-glassy-crystalline state occurs because of a significant reduction of the translational disorder of lithium cations, particularly [Li (2)] ions wherein a slight reduction of the librational disorder of SO4 anions takes place, whereas the crystalline to amorphous transition occurs only at the third shocked condition because of the librational disorder of SO4 anions. The double degenerate υ2 and υ4 Raman modes provide a clear indication of the occurrence of the librational disorder of SO4 anions at the third shocked condition. Followed by the internal Raman modes, a detailed discussion is provided on the external Raman modes of the Li ions and SO4 ions with respect to the observed phase transitions, wherein it is found that the regions of lattice modes are significantly altered at each and every point of phase transition. Furthermore, the thermal and magnetic measurements have been performed for the above-mentioned state of Li2SO4 samples, whereby the obtained results of the magnetic loops and the thermal property resemble the observed structural transitions with respect to the number of shock pulses such that the inter-relationship of the structure-electrical-magnetic-thermal properties of Li2SO4 could be explored.

Lithium and sodium 3-(3,4-di-hydroxy-phen-yl)propenoate hydrate.

Treatment of 3-(3,4-di-hydroxy-phen-yl)propenoic acid (caffeic acid or 3,4-di-hydroxy-cinnamic acid) with the alkali hydroxides MOH (M = Li, Na) in aqueous solution led to the formation of poly[aqua-[μ-3-(3,4-di-hydroxy-phen-yl)propenoato]lithium], [Li(C9H7O4)(H2O)]n, 1, and poly[aqua-[μ-3-(3,4-di-hydroxy-phen-yl)propenoato]sodium], [Na(C9H7O4)(H2O)]n, 2. The crystal structure of 1 consists of a lithium cation that is coordinated nearly tetra-hedrally by three carboxyl-ate oxygen atoms and a water mol-ecule. The carboxyl-ate groups adopt a μ3-κ3 O:O':O' coordination mode that leads to a chain-like catenation of Li cations and carboxyl-ate units parallel to the b axis. Moreover, the lithium carboxyl-ate chains are connected by hydrogen bonds between water mol-ecules attached to lithium and catechol OH groups. The crystal structure of 2 shows a sevenfold coordination of the sodium cation by one water mol-ecule, two monodentately binding carboxyl-ate groups and four oxygen atoms from two catechol groups. The coordination polyhedra are linked by face- and edge-sharing into chains extending parallel to the b axis. The chains are inter-linked by the bridging 3-(3,4-di-hydroxy-phen-yl)propenoate units and by inter-molecular hydrogen bonds to form the tri-periodic network.

Влияние концентрации перхлората лития на числа переноса катиона лития в сульфолановых растворах

To increase the accuracy of determining the lithium cation transference numbers we proposed to measure them at different values of the polarizing voltage and extrapolate the calculated values to the zero value of the polarizing voltage. It was established that the lithium cation transference numbers increased linearly with the increasing concentration of LiClO4 solutions in sulfolane. It is assumed that the increase in the lithium cation transference numbers takes place due to the change in lithium perchlorate state in sulfolane solution and the mechanism of ion transfer. It was shown that the maximum cation conductivity was achieved at the concentration of lithium perchlorate sulfolane solution of about 2M.

On the Fate of Lithium Ions in Sol-Gel Derived Zinc Oxide Nanocrystals.

Among diverse chemical synthetic approaches to zinc oxide nanocrystals (ZnO NCs), ubiquitous inorganic sol-gel methodology proved crucial for advancements in ZnO-based nanoscience. Strikingly, unlike the exquisite level of control over morphology and size dispersity achieved in ZnO NC syntheses, the purity of the crystalline phase, as well as the understanding of the surface structure and the character of the inorganic-organic interface, have been limited to vague descriptors until very recently. Herein, ZnO NCs applying the standard sol-gel synthetic protocol are synthesized with zinc acetate and lithium hydroxide and tracked the integration of lithium (Li) cations into the interior and exterior of nanoparticles by combining various techniques, including advanced solid-state NMR methods. In contrast to common views, it is demonstrated that Li+ ions remain kinetically trapped in the inorganic core, enter into a shallow subsurface layer, and generate "swelling" of the surface and interface regions. Thus, this work enabled both the determination of the NCs' structural imperfections and an in-depth understanding of the unappreciated role of the Li+ ions in impacting the doping and the passivation of sol-gel-derived ZnO nanomaterials.

The ferrocene-bonding NH2-UIO-66 as an ion sieve to intercept polysulfides and screen Li+ for upgrading performance of lithium-sulfur batteries

Intercepting polysulfides and screening Li+ is one of the most effective methods to achieve high-performance lithium-sulfur (Li-S) batteries. This study focuses on the covalent anchoring of ferrocene into NH2-UIO-66 for the modification of polypropylene (PP) separator. The introduction of ferrocene enables the reduction of the pore size of NH2-UIO-66 from 5.1 Å to 3.9 Å, thereby blocking polysulfides anions and penetrating lithium cations at the molecular level, resulting in significant inhibition in the shuttle effect of polysulfides. The cell with this functional separator exhibits a high initial specific capacity of 1490 mA h g−1 with a capacity decay of 0.018 % after 1000 cycles at 2C. This work provides an effective method of separator modification for high-performance energy storage systems.

A theoretical study on 1H-indole-2,3-dione complexes with lithium, sodium, and potassium cations.

A comparative study of the change in different properties of electronic and structural of the free 1H-indole-2,3-dione molecule and its complexes has been obtained. HOMA analysis was performed to investigate the effects of lithium sodium and potassium cations on the aromaticity of lithium sodium and potassium complexes of 1H-indole-2,3-dione. Several 1H-indole-2,3-dione complexes with lithium, sodium, and potassium cations were optimized at the B3LYP/6-311G(d,p) level. The cation and π interaction has been investigated from different aspects, including interaction energy calculations, charge transfer values, and changes in the aromaticity of the ring upon complexation. The charge transfer and natural population analysis for the complexes were performed with the natural bond orbital (NBO) analysis. The properties of bond critical points in complexes were studied by applying the quantum theory of atoms in molecules (QTAIM). Finally, the aromaticity change of phenyl induced upon complex formation was evaluated by applying the harmonic oscillator model of aromaticity (HOMA). [Li-INa]+ and [[Li-INb]+ were optimized with the wB97XD function using a version of Grimme's D2 dispersion model, and the absorption energy was compared with the calculation made with the B3LYP functional.

Effect of Lithium Triflate (LiTf) Salt on the Properties of the Pectin-based Polymer Electrolytes Films

Currently, liquid electrolytes (LEs) that have been used in many electrochemical devices, face safety concerns due to leakage problems. Consequently, solid polymer electrolytes (SPE) consisting of a natural polymer host that is leak-proof, biodegradable, and flexible are widely studied. In the current study, the effect of various weight percentages (%) (i.e.: 10, 20, 30, 40, and 50 wt.%) of lithium triflate (LiTf) salt on the structural and electrochemical properties of pectin-based SPE films was investigated. The SPE films were prepared using the solvent casting technique. Solid, flexible, and self-supporting films of pectin-based SPE were successfully acquired by the addition of up to 50 wt.% of LiTf. As proven by FTIR analyses, there occur interactions between the lithium cation and the pectin coordinating sites (OH and C=O). These interactions minimized the formation of hydrogen bonding between pectin chains, hence explaining the formation of flexible films. Also, the polymer-salt interactions contributed to the improvement in the amorphous phase of the system. The minimized formation of hydrogen bonding, improvement in the amorphous phase, and the increased amount of charge carriers in the LiTf-doped pectin-based SPE had contributed to the increase in the ionic conductivity of the system with salt content. The highest conducting sample, P5 (50 wt.% LiTf) exhibited the ionic conductivity of 3.87 × 10-5 S cm-1 which was four orders of magnitude higher than pure pectin film of 2.24 × 10-9 S cm-1.

Alkali Containing Layered Metal Oxides as Catalysts for the Oxygen Evolution Reaction

AbstractImproving the efficiency of the oxygen evolution reaction (OER) is essential to realise energy systems based on water electrolysis. Many catalysts have been developed for the OER to date, with iridium‐based oxides being the most promising due to their relative stability towards corrosion in acidic electrolytes under oxidising potentials. In recent years, examples of catalysts adopting layered structures have been shown to have promising characteristics such as higher conductivity and higher electrochemically active surface area compared to highly crystalline metal oxides. Furthermore, such materials possess additional tuneable properties such as interlayer spacing, identity and concentration of the interlayer species, edge and interlayer active sites, and higher active surface area. Recent attention has focused on mono‐ and polymetallic lithium‐containing layered materials, where the presence of interlayer lithium cations, in situ delithiation processes and combinations of transition metal oxides result in enhanced catalytic properties towards OER. This review aims to provide a summary of the recent developments of such layered materials, in which lithium or other alkali metal ions occupy interlayer sites in oxides.

Towards Responsive Spiroborate‐Based Assemblies of Podand‐Type Ligands Functionalized with Two Terminal/Peripheral Catecholate Moieties in the Presence of Alkali Cations

AbstractThe synthesis of two ligands bearing two terminal catecholate binding sites connected by an oligo(ethyleneglycol) bridge of two distinct lengths and their self‐assembly upon boron coordination and alkali cation binding (M=Li, Na, K, Cs) are reported. Attempts to synthesize positional isomers of the ligands are also described. Binding of the four alkali cations M+ through M−O interactions was studied depending on the length of the oligo(ethyleneglycol) chain in solution by 1H and DOSY NMR, mass spectrometry (MS) and in the solid‐state by X‐ray diffraction (XRD) on single crystals. MS spectrometry as well as 1H NMR revealed the presence of monomeric and oligomeric spiroborate compounds. Two monomeric macrocycles could be characterized by XRD, entrapping either lithium or cesium cations within the spiroborate macrocycle.

Fast-Charging Li4Ti5O12 Anode Driven by Light

Lithium-ion batteries with fast charging capabilities are crucial for widespread adoption of electric vehicles, as they will increase acceptance of the technology and reduce range anxiety for drivers. To achieve this, advanced fast charging technologies and alternative methods to enhance the slow electrochemical processes are desperately required. This study applied light-emitting diode (LED) photo-assisted fast charging to Li4Ti5O12 (LTO), a large bandgap cubic spinel material, to enhance charging speed through electronic-structure coupling. UV LED-generated light irradiation on to the electrode interface boosted the ion diffusion and lithium cation addition by a factor of 1.3 during electrochemical lithiation, resulting in a 30% decrease in charging time under ambient conditions. Red LED light was not effective in accelerating the reaction as it does not provide sufficient energy. The first-principles calculations support the concept that UV illumination generates charges by overcoming the material’s bandgap and effectively reducing it through the introduction of additional titanium defect states.

A dicarbonate solvent electrolyte for high performance 5 V-Class Lithium-based batteries

Rechargeable lithium batteries using 5 V positive electrode materials can deliver considerably higher energy density as compared to state-of-the-art lithium-ion batteries. However, their development remains plagued by the lack of electrolytes with concurrent anodic stability and Li metal compatibility. Here we report a new electrolyte based on dimethyl 2,5-dioxahexanedioate solvent for 5 V-class batteries. Benefiting from the particular chemical structure, weak interaction with lithium cation and resultant peculiar solvation structure, the resulting electrolyte not only enables stable, dendrite-free lithium plating-stripping, but also displays anodic stability up to 5.2 V (vs. Li/Li+), in additive or co-solvent-free formulation, and at low salt concentration of 1 M. Consequently, the Li | |LiNi0.5Mn1.5O4 cells using the 1 M LiPF6 in 2,5-dioxahexanedioate based electrolyte retain >97% of the initial capacity after 250 cycles, outperforming the conventional carbonate-based electrolyte formulations, making this, and potentially other dicarbonate solvents promising for future Lithium-based battery practical explorations.

Aqueous synthesis of lithium superionic-conducting complex hydride solid electrolytes

Lithium complex hydrides are synthesized via breakage and formation of the ionic bonds between lithium cations and complex anions. This unique bonding change enables the aqueous synthesis of superionic-conducting complex hydrides.

Speciation of the proton in water-in-salt electrolytes.

Water-in-salt (WiS) electrolytes are promising systems for a variety of energy storage devices. Indeed, they represent a great alternative to conventional organic electrolytes thanks to their environmental friendliness, non-flammability, and good electrochemical stability. Understanding the behaviour of such systems and their local organisation is a key direction for their rational design and successful implementation at the industrial scale. In the present paper, we focus our investigation on the 21 m bis(trifluoromethanesulfonyl)imide (LiTFSI) WiS electrolyte, recently reported to have acidic pH values. We explore the speciation of an excess proton in this system and its dependence on the initial local environment using ab initio molecular dynamics simulations. In particular, we observe the formation of HTFSI acid in the WiS system, known to act as a superacid in water. This acid is stabilised in the WiS solution for several picoseconds thanks to the formation of a complex with water molecules and a neighboring TFSI- anion. We further investigate how the excess proton affects the microstructure of WiS, in particular, the recently observed oligomerisation of lithium cations, and we report possible notable perturbations of the lithium nanochain organisation. These two phenomena are particularly important when considering WiS as electrolytes in batteries and supercapacitors, and our results contribute to the comprehension of these systems at the molecular level.

A pyridine-N-oxide catenane for cation recognition.

The rapid preparation of a pyridine-N-oxide containing [2]catenane is described. The [2]catenane was characterized by NMR spectroscopy, mass spectrometry and X-ray single crystal structure determination. 1H NMR titration experiments reveal the [2]catenane may be reversibly protonated, as well as an ability to bind lithium cations more strongly than sodium cations.

Switching of magnetic properties by topotactic reaction in a 1D CN-bridged Ni(II)-Nb(IV) system.

Two 1D CN-bridged assemblies: the nearly straight Li2[Ni(cyclam)][Nb(CN)8]·7.5H2O (1) chains and the zigzag-shaped Li2[Ni(cyclam)][Nb(CN)8]·2H2O (2) chains, are obtained in the reaction between [Ni(cyclam)]2+ and [Nb(CN)8]4- in warm concentrated LiCl water solution. Both compounds are composed of alternating bimetallic Ni(II)-Nb(IV) chains and contain incorporated lithium cations, which compensate the negative charge of the coordination skeleton. The straight chain 1 (Ni-Nb-Ni angle = 153.2°) can be reversibly dehydrated under dry nitrogen flow at room temperature to an intermediate dihydrate phase 1d and further transformed to the zigzag-shaped chain 2 (Ni-Nb-Ni angle = 86.6°) by annealing at 150 °C. The process can be reversed by exposure to high humidity at room temperature, upon which 2 is converted back to 1. This water sorption-induced breathing effect is accompanied by changes in magnetic properties, most notably reflected in different values of saturation magnetization and critical field of metamagnetic transition, which indicate that both intra- and inter-chain interactions are affected by the structure reorganization.

The Effect of pH and Sodium Silicate Dosage on the Separation of Magnesium and Lithium from Artificial Brine Water Using Chemical Precipitation Techniques

This study aims to report the findings of an investigation into the separation of lithium and magnesium ions in the artificial brine water. The artificial brine water contains concentrations of magnesium, calcium, and lithium cations that closely resemble the concentrations seen in natural brine water sourced from Gunung Panjang using magnesium chloride, calcium chloride, and lithium chloride p.a. The objective of this experiment was to investigate the impact of pH and the addition of sodium silicate on the separation of magnesium and calcium ions from lithium ions in artificial brine water. The best outcomes were achieved when the pH of the brine water was set at 10, and sodium silicate was added in a stoichiometric ratio of 219%. These parameters led to a lithium content of 90.06%, magnesium removal of 70.32%, and a Mg/Li ratio of 6.29, indicating a substantial presence of magnesium ions precipitated as solids with pyroxene (MgSiO3) phase. This research also succeeded in increasing the lithium content by 94.28% and reducing the Mg/Li ratio to 4.96 after the precipitated solids were subjected to a water-leaching process.

Improved Cycle Life and Determination of Li Ion Transport Parameters in Mixed Cation Doped Ni-Rich NMC

Ni-rich Li-ion cathode materials like NMC-9.5.5 (LiNi0.9Mn0.05Co0.05O2) are of interest due to their higher energy density and limited cobalt content, aiding the transition away from critical raw materials, when compared to materials like NMC111 - 622. This has the advantage of reducing production costs while maintaining a high working voltage and capacity. However, the high nickel content of these materials can be detrimental due to disorder brought by Li+/Ni2+ cation mixing, lithium residuals, and irreversible phase changes during operation resulting in significant capacity fade during cycling. Similarly, the different synthesis methods and treatments drastically affect the morphological, structural, and electrochemical propertiesWe present a structural and electrochemical study of NMC-9.5.5 prepared at scale via a hydroxide coprecipitation synthesis in a 5 L continuous stirred reactor tank (CSTR). In this work, bulk doping and co-doping with two metal cations are investigated with a simple and scalable method to achieve mixed metal and mixed valence doped NMC-9.5.5 with the aim to further improve cycle life and stability. Additionally, the effect of bulk doping on the thermodynamic and kinetic properties of the cathode material are investigated in both half-cells and full-cells using galvanostatic intermittent titration technique (GITT) and electrical impedance spectroscopy (EIS), where a 3-electrode configuration is used to elucidate the individual electrode potentials and stoichiometries.The bulk doping of the transition metal layer was found to significantly reduce the capacity fade in the NMC-9.5.5, increasing the capacity retention after 100 cycles from 78% in the undoped material to 92% and 89% in the doped and co-doped NMC-9.5.5 half-cells. The mixed metal co-doped material was also effective in delivering a higher specific capacity than the baseline throughout the full cycling range. The improved cycling performance can be understood by the inspection of the differential capacity plots, which show a suppression of the H2-H3 irreversible phase transition in the doped material and stabilisation of the peak to a higher voltage compared to the baseline. The effect of doping on the structural stabilisation is similarly reflected in the XRD characterisation, in which the introduction of the metal cation acts to constrain the detrimental Li+/Ni2+ cation mixing due to a widening of the transition metal channel. This is also supported by the EXAFS characterisation that indicate the dopants may act to stabilise the local Ni environment. These structural changes appear to be further beneficial in facilitating improved Li ion transport properties in the doped material as evidenced by the lower charge transfer resistances during cycling and increased diffusion coefficient.This research illustrates the high capacity performance of low cobalt cathode materials thus reducing the reliance on critical materials, as well as the ability to produce Ni-rich cathode material at large scale and further stabilise its cycle life by simple structural engineering. Improved materials manufacturing processes will enable a greater understanding of the synthesis process and enable more sustainable methods of synthesis. There are also benefits for cell makers with improvement in processability and additional stabilisation knowledge for battery manufacturers, as well as the consumers that benefit from longer driving ranges and battery life in their EV’s. Figure 1

All Dry in One Step (ADIOS to Water) Synthesis of W-Coated Li1+X(Ni0.7Mn0.3)1-XO2

Cathode powders for lithium-ion batteries are typically made from hydroxide precursors with the intended transition metal composition and calcined with a lithium source at high temperatures to make LiMO2, where M = Ni, Mn, Co. However, large amounts of process water and salts like NaOH are used in the co-precipitation process employed to make these hydroxide precursors1. Purifying and drying the precursors after co-precipitation requires additional energy input and produces waste streams that are difficult to treat, as illustrated in Fig. 1a. In this work, we introduce a simple, solvent-free method to produce tungsten (W) coated Li1+x(Ni0.7Mn0.3)1-xO2 (NM73) materials from a mixture of Ni, MnO2, LiOH·H2O and W precursors. NM73 was chosen as the primary focus of investigation so that cobalt is avoided due to its scarcity and high cost.The starting reagents are dry mixed and calcined, followed by jet-milling. An extra reheating step after jet-milling is advantageous for minimizing cation disorder and lithium surface impurities. Pure phase, R -3m single crystal NM73 materials can be made with this method and Rietveld refinement analysis showed that low Ni/Li mixing was achieved. W is believed to remain at the surface, forming a separate LixWyOz phase2. The addition of W was found to reduce the mean particle size and improve both the initial discharge capacity and first cycle efficiency. Small amounts of W increase the initial discharge capacity up to 197 mAh/g. Full coin cells were made from both coated and uncoated materials. Their cycling performance is shown in Fig. 1b, revealing improved capacity retention as another improvement afforded by the W coating.The proposed method simplifies the current production process of LiMO2 by eliminating the need for hydroxide precursors entirely. Cobalt-free single crystal materials with excellent electrochemical performance can be made all-dry in one step, potentially reducing the cost of cathode materials significantly and eliminating waste streams.