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Ion pair formation is a fundamental molecular process that occurs in a wide variety of systems, including electrolytes, biological systems, and materials. In solution, the thiocyanate (SCN−) anion interacts with cations to form contact ion pairs (CIPs). Due to its ambidentate nature, thiocyanate can bind through either its sulfur or nitrogen atoms, depending on the solvent. This study focuses on the binding nature of thiocyanate with lithium ions as a function of the solvents using FTIR, 2D infrared spectroscopy (2DIR) spectroscopies, and theoretical calculations. The study reveals that the SCN− binding mode (S or N end) in CIPs can be identified through 2DIR spectroscopy but not by linear IR spectroscopy. Linear IR spectroscopy shows that the CN stretch frequencies are too close to one another to separate N- and S-bound CIPs. Moreover, the IR spectrum shows that the S–C stretch presents different frequencies for the salt in different solvents, but it is related to the anion speciation rather than to its binding mode. A similar trend is observed for the anion bend. 2DIR spectra show different dynamics for N-bound and S-bound thiocyanate. In particular, the frequency–frequency correlation function (FFCF) dynamics extracted from the 2DIR spectra have a single picosecond exponential decay for N-bound thiocyanate and a biexponential decay for S-bound thiocyanate, consistent with the binding mode of the anion. Finally, it is also observed that the binding mode also affects the line shape parameters, probably due to the different molecular mechanisms of the FFCF for N- and S-bound CIPs. [ABSTRACT FROM AUTHOR]

Here, lithium ions inserted crystalline carbon nitrides (LCCN) with different defect concentrations are prepared by elaborately regulating the mass transfer process in thermal polymerization. It is revealed that there is no conventional exciton–polarons‐induced exciton dissociation mechanism in LCCN due to the weak coupling between excitons and phonons. On the contrary, excitons continue to trap/detrap through defect‐induced traps, which weakens the Coulomb force between electron–hole pairs, thereby accelerating exciton dissociation. It is worth emphasizing that this is the first systematic research on the exciton dissociation characteristics and photocatalytic activity of LCCN of poly(heptazine imide) structure. A strategy of assisting exciton dissociation through defect‐induced traps to address the inherently high exciton binding energy and low exciton dissociation efficiency issues in polymer photocatalysts is proposed. [ABSTRACT FROM AUTHOR]

Abstract Non-covalent interactions play an important role for the framework formation of two-dimensional covalent organic frameworks. Until now, π–π interactions and hydrogen bonding are the main reported forces facilitating the stacking of framework layers. Here, we present a two-dimensional anionic covalent organic framework based on tetratopic borate linkages, where layers are connected by ionic interactions between the linkage site and counter cations. The crystalline covalent organic framework is accessed through the formation of an amorphous borate-based polymer and subsequent solvothermal treatment. The progress of crystallization is investigated, revealing the crystallite growth and morphological change from agglomerated dense particles to hollow crystallite spheres. Due to the pillared nature, the crystallites can be exfoliated into nanosheets by sonication of the material in the presence of methanol. The crystallization and ordered arrangement of the lithium ions in the interlayer space is shown to benefit the conductivity tenfold compared to the amorphous material.

Lithium is one of the lightest elements on Earth and it has been in the environment since the formation of the galaxy. While a common element, it has not been found to be an essential element in biological processes, ranging from single cell organisms to Homo sapiens. Instead, at an early stage of evolution, organisms committed to a range of elements such as sodium, potassium, calcium, magnesium, zinc, and iron to serve essential functions. Such ions serve critical functions in ion channels, as co-factors in enzymes, as a cofactor in oxygen transport, in DNA replication, as a storage molecule in bone and liver, and in a variety of other roles in biological processes. While seemingly excluded from a major essential role in such processes, lithium ions appear to be able to modulate a variety of biological processes and "correct" deviation from normal activity, as a deficiency of lithium can have biological consequences. Lithium salts are found in low levels in many foods and water supplies, but the effectiveness of Li salts to affect biological systems came to recent prominence with the work of Cade, who reported that administrating Li salts calmed guinea pigs and was subsequently effective at relatively high doses to "normalize" a subset of patients with bipolar disorders. Because of its ability to modulate many biological pathways and processes (e.g., cyclic AMP, GSK-3beta, inositol metabolism, NaK ATPases, neuro processes and centers, immune-related events, respectively) both in vitro and in vivo and during development and adult life, Li salts have become both a useful tool to better understand the molecular regulation of such processes and to also provide insights into altered biological processes in vivo during aging and in disease states. While the range of targets for lithium action supports its possible role as a modulator of biological dysregulation, it presents a conundrum for researchers attempting to elucidate its specific primary target in different tissues in vivo. This review will discuss aspects of the state of knowledge regarding some of the systems that can be influenced, focusing on those involving neural and autoimmunity as examples, some of the mechanisms involved, examples of how Li salts can be used to study model systems, as well as suggesting areas where the use of Li salts could lead to additional insights into both disease mechanisms and natural processes at the molecular and cell levels. In addition, caveats regarding lithium doses used, the strengths and weaknesses of rodent models, the background genetics of the strain of mice or rats employed, and the sex of the animals or the cells used, are discussed. Low-dose lithium may have excellent potential, alone or in combination with other interventions to prevent or alleviate aging-associated conditions and disease progression. [ABSTRACT FROM AUTHOR]

Magnetic aluminum-based adsorbents (MLDHs) were prepared with a coprecipitation method and used to separate lithium ions from the aqueous solutions. In static adsorption experiment, the adsorption capacity of MLDHs for lithium ions reached 8.22 mg/g. In a mixed solution of various metal ions, the adsorbents exhibited higher selectivity for lithium ions. Kinetic studies indicated that the adsorption process conformed to a pseudo-second-order model. The experimental data were fitted with nonlinear regression using commonly used adsorption isotherms. It was found that the adsorption isotherm process could be described by the Langmuir model. In addition, the thermodynamic parameters revealed that the adsorption of lithium was a spontaneous endothermic process. [ABSTRACT FROM AUTHOR]

With a motivation to unravel the effect of cation (Mn) doping-induced modifications in structure, charge transfer resistance, and Li-ion diffusion in V 2 O 5 a systematic study using X-ray diffraction (XRD), Raman Spectroscopy and electrochemical impedance spectroscopy (EIS) has been employed using three electrodes configuration. Structural investigations using XRD suggest the selective diffusion of Mn ion towards the c-axis at a low doping percentage. Raman spectroscopy suggests the shift in 994 cm-1 modes which substantiates the uniaxial diffusion of Mn ions. Nyquist plots show that interfacial charge transfer resistance is highest for the lowest doping i.e., 1% Mn-doped V 2 O 5 and exhibits the lowest diffusion coefficient as compared to other doped V 2 O 5 samples. Specific capacitance calculated from cyclic voltammetry is found to be highest for the 4% Mn-doped V 2 O 5 sample. Moreover, diffusion of Lithium ions improves with an increase in doping concentration due to higher concentration of defects as evident from Δd/d and Nelson–Riley factor (NRF) for pure V 2 O 5 and Mn-doped V 2 O 5. [ABSTRACT FROM AUTHOR]

Lithiophilic sites with high binding energy to lithium have a positive effect on the induction of Li deposition. However, saturation deposition of Li‐ions on lithiophilic sites causes a loss of lithiophilicity. Herein, a protection route of lithiophilic sites during the nucleation period is proposed for the first time. The designed heterointerface provides a directional built‐in electric field and a lithiophilic potential well. Li‐ions in the space field can nucleate on the semiconductor side by crossing metal‐based lithiophilic sites through the electric field‐driven mode and the chemical field‐driven mode. Based on a high‐efficiency dual‐mode transfer pathway for Li‐ions, which ensures continuous exposure of lithiophilic sites to the electric field and maximizes its positive effect during the nucleation period. A full cell utilizing the LiFePO4 cathode exhibits a stable voltage profile with low polarization for over 200 cycles at 1 C, demonstrating the importance of the continued role of the lithiophilic sites. This work provides a new direction to design lithiophilic sites in Li metal batteries, which can be extended to other alkali metal batteries. [ABSTRACT FROM AUTHOR]