Search Results (41)

O3-type layered transition-metal oxides are widely regarded as promising cathode materials for sodium-ion batteries due to their intrinsically high sodium content and favorable energy density. Nevertheless, their practical rate capability is hindered by sluggish Na⁺ transport and relatively high diffusion barriers. To address this issue, elemental substitution has emerged as an effective modification strategy. In this work, fluorine (F), characterized by strong electronegativity and a small ionic radius, is introduced to partially substitute oxygen in the bulk lattice of O3-type NaNi_1/3Fe_1/3Mn_1/3O₂ (NNFM). First-principles calculations demonstrate that F incorporation leads to an expansion of the interlayer spacing along the c-axis and a weakening of Na–O interactions, both of which facilitate Na⁺ migration. Among the considered configurations, Mn-adjacent substitution exhibits the lowest formation energy, indicating enhanced thermodynamic stability. Furthermore, electronic structure analysis reveals a reduced band gap (from 0.515 eV to 0.342–0.356 eV) and strengthened O-2p/Mn-3d orbital hybridization, contributing to improved electronic conductivity. These findings provide atomistic insights into F-induced modulation mechanisms and suggest an effective pathway for optimizing Na⁺ transport in O3-type cathodes. Full article

This study demonstrates an electrode–electrolyte co-design strategy to address the long-standing performance–safety trade-off in lithium-ion batteries by integrating electrospun TiNb₂O₇ (TNO) nanofiber anodes with fluorinated flame-retardant electrolytes. The electrochemical compatibility of TNO was systematically evaluated over a wide voltage window (0.01–3.0 V) using a conventional carbonate electrolyte and two fluorinated systems (TFMAF and NOMAF). At low current densities, the fluorinated electrolytes deliver capacities comparable to those of the carbonate electrolyte, whereas the carbonate system exhibits superior rate capability at high current densities. Among the flame-retardant electrolytes, TFMAF shows slightly improved electrochemical performance, particularly in terms of rate capability and cycling stability. Elevated temperatures enhance ionic conductivity and reduce polarization across all systems, while low-temperature EIS/DRT analysis reveals distinct, electrolyte-dependent differences in interfacial resistance and charge-transfer behavior. Accelerating rate calorimetry confirms that the fluorinated electrolytes significantly improve thermal safety. Notably, NOMAF exhibits superior thermal stability and emerges as a more practical electrolyte candidate due to its enhanced safety and lower cost. Full article

The trade-off between the ionic conductivity and the stability of the proton exchange membrane (PEM) is a major concern in the development of PEM water electrolysis (PEMWE). This review focuses on the design and fabrication of homogeneous and composite PEMs for water electrolysis and establishes the structure–performance relationships between the membrane chemical/physical structures and their efficiency metrics—specifically, proton conductivity, hydrogen permeability, and chemical and mechanical stability. A special focus is placed on the fundamental connection between the microstructure and performance of membrane materials. At the molecular level, we systematically illustrate the design principles for main chains, side chains, and sulfonate groups, covering both fluorinated PEMs (encompassing perfluorinated and partially fluorinated membranes) and non-fluorinated PEMs (including aromatic polymers with heteroatom backbones and all-carbon backbones). At the macroscopic level, the review provides an in-depth exploration of two primary modification strategies: creating composites with organic polymers and with inorganic nanofillers. In summary, this review elucidates how these composite approaches leverage material synergies to improve the membrane’s mechanical integrity, proton conduction efficiency, and chemical resistance and offers a theoretical framework for the rational design of next-generation, high-performance PEMs to advance the commercialization of PEMWE technology. Full article

Despite notable advancements in lithium-ion battery (LIB) technology, growing industrialization, rising energy demands, and evolving consumer electronics continue to raise performance requirements. As the primary determinant of battery performance, cathode materials have become a central research focus. Among emerging candidates, iron-based fluorides show great promise due to their high theoretical specific capacities, elevated operating voltages, low cost (owing to abundant iron and fluorine), and structurally diverse crystalline forms such as pyrochlore and tungsten bronze types. These features make them strong contenders for next-generation high-energy, low-cost LIBs. This review highlights recent progress in iron-based fluoride cathode materials, with an emphasis on structural regulation and performance enhancement strategies. Using pyrochlore-type hydrated iron trifluoride (Fe₂F₅·H₂O), synthesized via ionic liquids like BmimBF₄, as a representative example, we discuss key methods for tuning physicochemical properties—such as electronic conductivity, ion diffusion, and structural stability—via doping, compositing, nanostructuring, and surface engineering. Advanced characterization tools (XRD, SEM/TEM, XPS, Raman, synchrotron radiation) and electrochemical analyses are used to reveal structure–property–performance relationships. Finally, we explore current challenges and future directions to guide the practical deployment of iron-based fluorides in LIBs. This review provides theoretical insights for designing high-performance, cost-effective cathode materials. Full article

After reviewing the state of the art of the fluorination of inorganic solid electrolytes, an application of gas/solid fluorination is given and how it can be processed. Garnet-type oxide has been chosen. These oxides with an ideal structure of chemical formula A₃B₂(XO₄)₃ are mainly known for their magnetic and dielectric properties. Certain garnets may have a high enough Li⁺ ionic conductivity to be used as solid electrolyte of lithium ion battery. The surface of LLZO may be changed in contact with the moisture and CO₂ present in the atmosphere that results in a change of the conductivity at the interface of the solid. LiOH and/or lithium carbonate are formed at the surface of the garnet particles. In order to allow for handling and storage under normal conditions of this solid electrolyte, surface fluorination was performed using elemental fluorine. When controlled using mild conditions (temperature lower or equal to 200 °C, either in static or dynamic mode), the addition of fluorine atoms to LLZO with Li_6,4Al_0,2La₃Zr₂O₁₂ composition is limited to the surface, forming a covering layer of lithium fluoride LiF. The effect of the fluorination was evidenced by IR, Raman, and NMR spectroscopies. If present in the pristine LLZO powder, then the carbonate groups disappear. More interestingly, contrary to the pristine LLZO, the contents of these groups are drastically reduced even after storage in air up to 45 days when the powder is covered with the LiF layer. Surface fluorination could be applied to other solid electrolytes that are air sensitive. Full article

To enhance the specific energy and rate performance of lithium primary batteries, the development of advanced cathode materials with superior electrochemical properties is essential. Fluorides, composed of light fluorine elements and multivalent cations, exhibit multi-electron reaction characteristics, possess a high theoretical voltage, and demonstrate high discharge-specific energy. However, owing to fluorine’s high electronegativity, which leads to the formation of strong ionic bonds with other elements, most fluorides exhibit poor electronic conductivity, thereby constraining their electrochemical performance when used as cathode materials. Copper fluoride (CuF₂) exhibits a high theoretical specific capacity and discharge voltage but is constrained by its large bandgap, poor electronic conductivity, and difficulties in synthesizing anhydrous CuF₂ materials, which significantly limit its electrochemical activity. In this study, zinc (Zn) was chosen as a dopant for copper fluoride. By combining theoretical calculations with experimental validation, the impacts of Zn doping on the structural stability and electrochemical performance of copper fluoride were comprehensively analyzed. The resultant highly active Zn-doped copper fluoride achieved a discharge specific capacity of 528.6 mAh/g at 0.1 C and 489.1 mAh/g at 1 C, showcasing superior discharge-specific energy and good rate performance. This material holds great potential as a promising cathode candidate for lithium batteries, providing both high specific energy and power density. Full article

Carbon dioxide, the primary greenhouse gas responsible for global warming, represents today a critical environmental challenge for humans. Mitigating CO₂ emissions and other greenhouse gases is a pressing global concern. The primary goal of this study is to investigate the potential of particular ionic liquids (ILs) in capturing CO₂ for the sweetening of natural and other gases. The solubility of CO₂ was measured in three distinct ILs, which shared a common anion (triflate, TfO) but differed in their cations. The selected ionic liquids were {1-butyl-3-methylimidazolium triflate [BMIM][TfO], 1-butyl-1-methylpyrrolidinium triflate [BMP][TfO], and 1-butyl-4-methylpyridium triflate [MBPY][TfO]}. The solvents were screened based on results from a molecular computational study that predicted low CO₂ Henry’s Law constants. Solubility measurements were conducted at 303.15 K, 323.15 K, and 343.15 K and pressures up to 1.5 MPa using a gravimetric microbalance (IGA-003). The CO₂ experimental results were modeled using the Peng–Robinson Equation of state with three mixing rules: van der Waals one (vdWI), van der Waals two (vdWII), and the non-random two-liquid (NRTL) Wong–Sandler (WS) mixing rule. For the three ILs, the NRTL-WS mixing rule regressed the data with the lowest average deviation percentage of 1.24%. The three solvents had similar alkyl chains but slightly different polarities. [MBPY][TfO], with the largest size, exhibited the highest CO₂ solubility at all three temperatures. Calculation of its relative polarity descriptor (N) shows it was the least polar of the three ILs. Conversely, [BMP][TfO] showed the highest Henry’s Law constant (lowest solubility) across the studied temperature range. Comparing the results to published data, the study concludes that triflate-based ionic liquids with three fluorine atoms had lower capacity for CO₂ compared to bis(trifluoromethylsulfonyl) imide (Tf2N)-based ionic liquids with six fluorine atoms. Additionally, the study provided data on the enthalpy and entropy of absorption. A final comparison shows that the ILs had a lower CO₂ capacity than Selexol, a solvent widely used in commercial carbon capture operations. Compared to other ILs, the results confirm that the type of anion had a more significant impact on solubility than the cation. Full article

Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li_1.05Ni_0.33Mn_0.33Co_0.33O₂ as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF₄, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate. Full article

In lithium metal batteries, accurately estimating the Li⁺ solvation ability of solvents is essential for effectively modulating the Li⁺ solvation sheath to form a stable interphase and achieve high ionic conductivity. However, previous studies have shown that the theoretically calculated Li⁺ binding energy, commonly used to evaluate solvation ability, exhibits only a moderate correlation with experimentally measured ionic conductivity (R² = 0.68). In this study, to determine the effective theoretical descriptor for evaluating the solvation ability, Li⁺ solvation energy was adopted instead of Li⁺ binding energy, and its correlation with ionic conductivity was compared. Using a sophisticated calculation model that considers the Li⁺ counter anion and solvent, it was demonstrated that the tendency between the calculated Li⁺ solvation energies and experimentally measured ionic conductivities is highly consistent (R² = 0.97). Therefore, Li⁺ solvation energy is suggested as the theoretical descriptor for evaluating solvation ability. All these findings encourage the development of effective molecular design of solvents for lithium metal batteries. Full article

In this work, we designed a novel polyvinylidene fluoride (PVDF)@DNA solid polymer electrolyte, wherein DNA, as a plasticizer-like additive, reduced the crystallinity of the solid polymer electrolyte and improved its ionic conductivity. At the same time, due to its Lewis acid effect, DNA promotes the dissociation of lithium salts when interacting with lithium salt anions and can also fix the anions, creating more free lithium ions in the electrolyte and thus improving its ionic conductivity. However, owing to hydrogen bonding between DNA and PVDF, excess DNA occupies the lone pairs of electrons of the fluorine atoms on the PVDF molecular chains, affecting the conduction of lithium ions and the conductivity of the solid electrolyte. Hence, in this study, we investigated the effects of adding different DNA amounts to solid polymer electrolytes. The results show that 1% DNA addition resulted in the best improvement in the electrochemical performance of the electrolyte, demonstrating a high ionic conductivity of 3.74 × 10⁻⁵ S/cm (25 °C). The initial capacity reached 120 mAh/g; moreover, after 500 cycles, the all-solid-state batteries exhibited a capacity retention of approximately 71%, showing an outstanding cycling performance. Full article

Considerable research has been conducted on single-ion conductive polymeric electrolytes with high lithium ion transference numbers. However, low ionic conductivity is a long-standing challenge for lithium metal batteries, hindering the development of extending their cycle life. In this study, we synthesized a novel fluorine-containing single-ion polymeric electrolyte, LiP(VDF-co-MAF)BB (Polyvinylidene fluoride trifluoromethyl acrylate lithium borate polymer; subsequently referred to as PPMBB), exhibiting a room temperature conductivity of 1.03 × 10⁻³ S/cm. This electrolyte demonstrates a high lithium ion transference number of 0.7901 and an extended electrochemical stability window of 5.5 V. Under a 2 C discharge rate, it manifests a remarkable discharge specific capacity of 146.8 mAh/g. Moreover, even after 364 cycles, the capacity retention remains at 76%. The single-ion polymeric gel electrolyte designed in this work provides a promising strategy for the prolonged cycling performance of lithium metal batteries. Full article

Currently, lithium-ion batteries have an increasingly urgent need for high-performance electrolytes, and additives are highly valued for their convenience and cost-effectiveness features. In this work, the feasibilities of fullerenes and fluorinated fullerenes as typical bis(fluorosulfonyl)imide/1,2-dimethoxymethane (LiFSI/DME) electrolyte additives are rationally evaluated based on density functional theory calculations and molecular dynamic simulations. Interestingly, electronic structures of C₆₀, C₆₀F₂, C₆₀F₄, C₆₀F₆, 1-C₆₀F₈, and 2-C₆₀F₈ are found to be compatible with the properties required as additives. It is noted that that different numbers and positions of F atoms lead to changes in the deformation and electronic properties of fullerenes. The F atoms not only show strong covalent interactions with C cages, but also affect the C-C covalent interaction in C cages. In addition, molecular dynamic simulations unravel that the addition of trace amounts of C₆₀F₄, C₆₀F₆, and 2-C₆₀F₈ can effectively enhance the Li⁺ mobility in LiFSI/DME electrolytes. The results expand the range of applications for fullerenes and their derivatives and shed light on the research into novel additives for high-performance electrolytes. Full article

Fluorine-free single-component polyelectrolytes were developed via the hybridization of lithium methanesulfonylsulfonimide (LiMSSI) moieties to poly(ethylene glycol) (PEG) derivatives with different morphologies, and the relationship between the structure and its ionic conductivity was investigated. The PEG-LiMSSI derivatives with one, two, and three LiMSSI end groups were prepared via the concomitant Michael-type addition and lithiation of PEGs and N-methanesulfonylvinylsulfonimide. The ionic conductivity at 60 °C ranged from 1.8 × 10⁻⁷ to 2.0 × 10⁻⁴ S/cm. PEG-LiMSSI derivatives with one LiMSSI terminus and with two LiMSSI termini at both ends show higher ionic conductivity, that is as good as fluorine-free single-component polyelectrolytes, than that with two LiMSSI termini at one end and that with three LiMSSI termini. Full article

Due to the favorable features obtained through the incorporation of fluorine atom(s), fluorinated drugs are a group with emerging pharmaceutical importance. As their commercial availability is still very limited, to expand the range of possible candidates, new fluorinated tryptophan analogs were synthesized. Control of enantiopurity during the synthesis procedure requires that highly efficient enantioseparation methods be available. In this work, the enantioseparation of seven fluorinated tryptophans and tryptophan was studied and compared systematically to (i) develop analytical methods for enantioselective separations and (ii) explore the chromatographic features of the fluorotrytophans. For enantioresolution, macrocyclic glycopeptide-based selectors linked to core-shell particles were utilized, applying liquid chromatography-based methods. Application of the polar-ionic mode resulted in asymmetric and broadened peaks, while reversed-phase conditions, together with mobile-phase additives, resulted in baseline separation for all studied fluorinated tryptophans. The marked differences observed between the methanol and acetonitrile-containing eluent systems can be explained by the different solvation abilities of the bulk solvents of the applied mobile phases. Among the studied chiral selectors, teicoplanin and teicoplanin aglycone were found to work effectively. Under optimized conditions, baseline separations were achieved within 6 min. Ionic interactions were semi-quantitatively characterized and found to not influence enantiorecognition. Interestingly, fluorination of the analytes does not lead to marked changes in the chromatographic characteristics of the methanol-containing eluents, while larger differences were noticed when the polar but aprotic acetonitrile was applied. Experiments conducted on the influence of the separation temperature indicated that the separations are enthalpically driven, with only one exception. Enantiomeric elution order was found to be constant on both teicoplanin and teicoplanin aglycone-based chiral stationary phases (L < D) under all applied chromatographic conditions. Full article

Stretchable ionogels, as soft ion-conducting materials, have generated significant interest. However, the integration of multiple functions into a single ionogel, including temperature tolerance, self-adhesiveness, and stability in diverse environments, remains a challenge. In this study, a new class of fluorine-containing ionogels was synthesized through photo-initiated copolymerization of fluorinated hexafluorobutyl methacrylate and butyl acrylate in a fluorinated ionic liquid 1-butyl-3-methyl imidazolium bis (trifluoromethylsulfonyl) imide. The resulting ionogels demonstrate good stretchability with a fracture strain of ~1300%. Owing to the advantages of the fluorinated network and the ionic liquid, the ionogels show excellent stability in air and vacuum, as well as in various solvent media such as water, sodium chloride solution, and hexane. Additionally, the ionogels display impressive wide temperature tolerance, functioning effectively within a wide temperature range from −60 to 350 °C. Moreover, due to their adhesive properties, the ionogels can be easily attached to various substrates, including plastic, rubber, steel, and glass. Sensors made of these ionogels reliably respond to repetitive tensile-release motion and finger bending in both air and underwater. These findings suggest that the developed ionogels hold great promise for application in wearable devices. Full article