Type Of Electrolyte Research Articles

Revealing the Dynamic Evolution of Electrolyte Configuration on the Cathode-Electrolyte Interface by Visualizing (De) Solvation Processes.

Electrolyte engineering is crucial for improving cathode electrolyte interphase (CEI) to enhance the performance of lithium-ion batteries, especially at high charging cut-off voltages. However, typical electrolyte modification strategies always focus on the solvation structure in the bulk region, but consistently neglect the dynamic evolution of electrolyte solvation configuration at the cathode-electrolyte interface, which directly influences the CEI construction. Herein, we reveal an anti-synergy effect between Li+-solvation and interfacial electric field by visualizing the dynamic evolution of electrolyte solvation configuration at the cathode-electrolyte interface, which determines the concentration of interfacial solvated-Li+. The Li+ solvation in the charging process facilitates the construction of a concentrated (Li+-solvent/anion-rich) interface and anion-derived CEI, while the repulsive force derived from interfacial electric field induces the formation of a diluted (solvent-rich) interface and solvent-derived CEI. Modifying the electrochemical protocols and electrolyte formulation, we regulate the "inflection voltage" arising from the anti-synergy effect and prolong the lifetime of the concentrated interface, which further improves the functionality of CEI architecture.

Colloidal route towards sodium ionic conductor (NASICON) 3D complex solid electrolyte structures fabricated by Direct Ink Writing (DIW)

Progressing towards a sustainable energy model, safer new generation high-performance energy storage devices with large energy density and power are needed. In this sense, the improvement in terms of efficiency and sustainability has led to the interest in solid-state batteries (SSBs). Lately, sodium-ion batteries (SIBs) have become an emerging alternative due to the abundance of raw materials, low cost, and improvements in terms of fast sodium-ion conductor solid electrolytes (SCSEs). Among all the SCSEs, the sodium superionic conductor (NASICON) type electrolyte is one of the most well-known electrolytes, being widely developed in terms of synthesis and materials. However, the processing and manufacturing of these electrolytes have gone almost unnoticed, without considering that well-designed structures of electrodes/electrolytes are the bridge toward turning advanced energy materials into high-performance devices. This work presents the fabrication of 3D complex structures based on NASICON sodium solid electrolytes, obtained for the first time by direct ink writing (DIW). Through a colloidal route, fine NASICON phase powder with high pureness was prepared, enabling the manufacturing of intricate NASICON-printed electrolytes in a one-step fabrication process. By optimizing the ink, a dense electrolyte layer, acting as an ionic conductor and separator, was inserted between two complex porous pattern layers obtaining a device with a total height below 1.15 mm. Further, the densification of the 3D electrolyte was enhanced, reaching high ionic conductivities at room temperature (3.10-4 S·cm-1). Thus, a high-performance sodium ion conductor NASICON solid electrolyte with shorter diffusion pathways and larger interfacial surface areas between electrode/electrolyte was obtained, improving the overall electrochemical performance of the device by a 3D layer-by-layer design.

Preparation of Hydrogels of Methacrylamide with Mono and Dicarboxylic Acids: Investigation of Their Swelling Behavior

Methacrylamide (MAAm) hydrogels were synthesized with mono- (crotonic acid, CrA) and dicarboxylic (maleic acid, MAA) acids via radical copolymerization, utilizing potassium persulfate (KPS) as the initiator and methylenebisacrylamide (MBAAm) as the crosslinker. The swelling behavior of the resulting hydrogels was systematically investigated, with particular focus on the effects of monomer ratio, initiator and crosslinker concentrations, as well as polymerization temperature. These parameters were optimized to maximize the swelling ratio. For poly(MAAm/CrA) hydrogels, the formulation containing 85/15 MAAm/CrA (mol/mol), 2 mol% KPS, 1 mol% MBAAm, and synthesized at 55 °C exhibited the highest swelling capacity (480%) in distilled water. In contrast, for poly(MAAm/MAA) hydrogels, the composition of 75/25 MAAm/MAA (mol/mol) with 1 mol% KPS, 1 mol% MBAAm, and polymerized at 55 °C showed a maximum swelling of 1100%. Further investigations explored the influence of pH, temperature, and electrolyte concentration and type on the swelling properties of the hydrogels prepared under optimized conditions. Both hydrogels demonstrated peak swelling behavior at pH 7, with their swelling profiles varying in response to changes in temperature, electrolyte concentration, and electrolyte type. Swelling kinetics studies revealed that the MAAm/CrA hydrogel exhibited Fickian diffusion in distilled water at room temperature, while the MAAm/MAA hydrogel followed a non-Fickian diffusion mechanism. Scanning electron microscopy (SEM) analysis indicated that the hydrogels synthesized under optimal conditions possessed a porous and well-organized network structure.

Electro-activated peroxymonosulfate based on hollow cubic skeleton nanoflower cathode catalyst MoSe2/cubic nanocage (CNC) for enhanced degradation of norfloxacin: Performance, mechanism, degradation pathways and toxicity

Recently, antibiotic wastewater pollution has become increasingly serious. In this study, a novel hollow cubic framework self-supported nanoflower-like cathode catalyst (MoSe2/CNC) based on Co Fe prussian blue analogues (CoFePBA)-derived cubic nanocage (CNC) loaded with MoSe2 was successfully prepared and utilized in an electro-activated peroxymonosulfate (PMS) system for norfloxacin (NOR) degradation. Benefit from the combined structures of MoSe2, MoC, and Co/FeNC, the electrocatalytic activity and specific surface area were greatly improved. The effects of catalyst dosage and ratio, current, PMS concentration, electrolyte type, pH, as well as initial concentration were comprehensively investigated. Under the optimal conditions, NOR and TOC removal reached 92.70% and 82.17%, respectively, which was superior to the previous studies. Additionally, ·O2− was proved to be the primary reactive species for NOR degradation.·Based on density functional theory (DFT) and intermediates analysis, NOR underwent substitution and ring-opening reactions in the piperazine ring, substitution of fluoride ions, and cleavage of the carboxyl group and tetrahydropyridine ring, ultimately converting into water, carbon dioxide, and inorganic ions. Moreover, toxicity assessment and seed germination experiments demonstrated that the toxicity of NOR and intermediates were strongly decreased by electro-activated PMS system based on MoSe2/CNC cathode. Overall, this study not only contributes to the evolution of efficient and sustainable wastewater purification technology, but also provides valuable insights into the degradation of antibiotic wastewater.

From Fundamentals to Practice: Electrolyte Strategies for Zinc‐Ion Batteries in Extreme Temperature

ABSTRACTIn the pursuit of advanced energy storage technologies that promote sustainable energy solutions, zinc‐ion batteries (ZIBs) have emerged as a promising alternative to lithium‐ion batteries due to their abundance, safety, and environmental advantages. However, the failure mechanisms of ZIBs under extreme temperatures are still not fully understood, presenting significant challenges to their development and commercialization. Therefore, innovative strategies are essential to enhance their adaptability to temperature extremes. In this review, we first explore the thermodynamic and kinetic aspects of performance degradation under extreme temperatures, focusing on key factors such as ion diffusion and redox processes at electrode interfaces. We then comprehensively summarize and discuss the existing approaches for various electrolyte types, including aqueous, nonaqueous, and solid state. Finally, we highlight the key challenges and future prospects for ZIBs operating under extreme temperature conditions. The insights presented in this review are expected to accelerate the advancement of ZIBs and facilitate their practical implementation in large‐scale energy storage systems.

Unlocking the Full Redox Capability of Organic Charge‐Transfer Complex in High‐Loading Electrodes for Organic Rechargeable Batteries

AbstractOrganic charge‐transfer complex (OCTC) comprising redox‐active donor and acceptor molecules is a promising electrode material group, potentially resolving issues of low power and inferior cycle stability of organic electrodes in rechargeable batteries. Strong intermolecular interactions in OCTC such as π–π interaction and hydrogen bonding enable high electronic conductivity and suppress solubility to solvents. However, full redox activities of OCTC have not been achieved yet despite the inherent redox capabilities of respective donor and acceptor molecules. Here, it is revealed that the limited redox activities of OCTC stem from electrolyte‐incorporated complex formation, which weakens the characteristic intermolecular interactions, thereby hindering the redox reaction, particularly in Li‐based electrolytes. It is further shown that tailoring electrolyte types, specifically using Zn‐aqueous electrolytes, can substantially mitigate the complex formation and unlock the four‐electron redox activity of OCTC (phenazine (PNZ)‐7,7,8,8‐tetracyanoquinodimethane (TCNQ), that is, PNZ–TCNQ), with superior cycle stability retaining 88% of maximum capacity over 100 cycles. Surprisingly, the full redox reaction achieves an unprecedentedly high electrode‐level energy density, delivering ≈10 mAh cm−2 of areal capacity (580 µm‐thick electrodes) in Zn‐aqueous batteries. The findings elucidate the complex interplay between organic electrodes and electrolytes in the charge storage mechanism, highlighting the importance of electrolyte design in developing organic electrode materials.

Pyrite‐Based Solid‐State Batteries: Progresses, Challenges, and Perspectives

AbstractPyrite (FeS2), as a transition metal sulfide, has a promise application in the field of secondary batteries due to its abundant reserves, high theoretical capacity, safety, and non‐toxicity. However, serious volume expansion and shuttle effect of FeS2 in liquid secondary batteries limit its further development. Solid‐state batteries offer effective solutions to these challenges. In this review, the synthesis methods of FeS2 and recent progress in FeS2‐based solid‐state lithium/sodium batteries are presented, and the effects of FeS2 size and morphology, solid electrolyte type, and battery structure design on the electrochemical performance of solid‐state batteries are discussed. By analyzing and summarizing the problems in applying FeS2 in solid‐state batteries, the remaining challenges in this field are discussed and future directions are proposed. This review aims to guide research on high‐performance solid‐state batteries based on FeS2 and promote further development of FeS2 in electrochemical energy storage.

Electrochemically enhanced hydrophobic modification of La-doped PbO2 anode by peroxymonosulfate for ceftazidime removal

In this study, a novel electrochemical anode-activated PMS system was constructed to degrade ceftazidime (CAZ) by peroxymonosulfate (PMS)-enhanced modified anode material, BTNA/Sb-SnO2/β-PbO2-La-PVDF. Numerous catalytically active sites are provided by doping La elemental and the hydrophobic alteration of PVDF, which can also facilitate the reaction process. In the PMS system, the anode of BTNA/Sb-SnO2/β-PbO2-La-PVDF has an oxidation rate of 1.3 (3.278×10–2 min-1). The oxidation rate was 1.4 times higher than in the non-PMS system and 1.3 times higher than before the modification. Moreover, the synergistic effect of BTNA/Sb-SnO2/β-PbO2-La-PVDF anode and PMS activation produced a synergistic effect on CAZ degradation, which was mainly reflected in the direct electron transfer of CAZ to PMS occurring on the surface of the BTNA/Sb-SnO2/β-PbO2-La-PVDF anode, and the contribution of free radicals to the degradation, respectively, was •OH (50.98 %), SO4•- (19.92 %), 1O2 (16.36 %) and other radicals (12.74 %). In addition, the effects of operating parameters (PMS concentration, current density, and initial pH) and electrolyte types on the removal of CAZ by the BTNA/Sb-SnO2/β-PbO2-La-PVDF-PMS system were investigated. Meanwhile, we predicted the possible degradation pathways for degrading CAZ. Based on the BTNA/Sb-SnO2/β-PbO2-La-PVDF, an electrochemical anode-activated PMS system is expected to provide an idea for efficient degradation of natural pharmaceutical wastewater.

Impact of conducting agents on sulfide and halide electrolytes in disordered rocksalt cathode‐based all‐solid‐state batteries

AbstractAll‐solid‐state battery (ASSB) systems have attracted significant attention due to their high energy density and safety compared with conventional batteries. Moreover, the application of Mn‐based cation‐disordered rock‐salt (DRX) that possesses cost‐effectiveness and high energy density on the ASSB system as a cathode is expected to be the superior next‐generation battery system. However, DRX cathodes require high carbon contents due to their low electronic conductivity, leading to challenges in introducing them in ASSB systems, as the high carbon levels can cause electrolyte decomposition which potentially affects overall electrochemical performance. In this work, we applied Mn‐based DRX cathodes to ASSB systems within a voltage range of 1.5–4.8 V and evaluated the suitability of cathode composites using halide and sulfide electrolytes as catholytes, respectively. The experimental results showed that the high carbon contents induced side reactions with the argyrodite, resulting in electrochemical degradation such as the drop of initial discharge voltage and the capacity fading. Meanwhile, cathode composites using a halide electrolyte exhibited relatively enhanced electrochemical performance due to its high oxidation stability regardless of the high amount of carbon contents. Consequently, the electrochemical reactions of the electrolyte, influenced by the content of conductive additives and the type of electrolyte, had a great impact on the performance of ASSB systems. This study provides a deep understanding of the interplaying among solid electrolytes, cathodes, and conductive additives and offers an important foundation for future research and development in ASSB systems.image

Investigation of Electrochemical Discharge Machining for Tungsten Carbide: Effects of Electrolyte Composition on Material Removal Rate and Surface Quality

Abstract Tungsten carbide (WC-Co) with a cobalt binder has been widely used in industrial application. Through their high wear resistance and hardness, which make it a challenge to machine. Electrochemical discharge machining (ECDM) is a newly developed hybrid technique used to machine conductive and nonconductive materials. Tungsten carbide machining is an area that needs more investigation. In this study, different types of electrolytes have been tested in the electrochemical machining of tungsten carbide. It has been concluded that tungsten carbide was successfully machined with electrolytes that were either neutral salts or a combination of neutral salts and hydroxides, the highest material removal rate achieved was (0.09250 g/min), and the average surface roughness achieved in this work was measured at (Ra 0.9275 µm). However, deposition took place on the surface of machined tungsten carbide when the samples were treated with sodium hydroxide and potassium hydroxide. EDX analysis of successfully machined tungsten carbide samples reveal the presence of carbon (C) due to diffusion from the base material and oxygen (O), most likely due to oxidation brought on by the high temperatures utilized. Scanning electron microscopy confirmed that the machined surfaces had craters, pores, restricted microcracks, and re-deposited melt particles, among other things.

Green Electrolytes for Aqueous Ion Batteries: Towards High‐Energy and Low‐Temperature Applications

AbstractAqueous battery systems are increasingly recognized for their potential as environmentally friendly next‐generation energy storage solutions. However, their commercialization faces challenges due to the need for electrolytes that can operate stably at high voltages and in low‐temperatures. Traditional approaches to address these issues often involve materials that compromise the green nature. This review highlights the importance of developing environmentally friendly materials to improve the performance of aqueous electrolytes under high voltage in different types of aqueous electrolytes such as water‐in‐salt, molecular crowding electrolytes, eutectic electrolytes and cosolvents. In addition, we review advances in different types of aqueous electrolytes focused on using sustainable materials to achieve stable electrolytes at low‐temperature by suppressing water crystallization and lowering the freezing point. By integrating these innovations, we envision a future where aqueous batteries offer both high performance and eco‐friendliness, contributing significantly to the development of sustainable energy systems.

Elucidating Wettability Alteration on Clay Surface Contacting Mixed Electrolyte Solution: Implications to Low-Salinity Waterflooding

Summary Many mechanisms have been proposed in the literature to explain wettability alteration at low-salinity waterflooding (LSWF). Some of these mechanisms include electrical double layer (EDL) expansion, multi-ion exchange, and cation hydration. However, no consensus has been reached on which one is the key mechanism in low-salinity enhanced oil recovery (EOR). Moreover, the mechanisms by which low-salinity flooding can enhance oil recovery are poorly understood. Parameters such as salinity, electrolyte type, oil components, and presence of clay minerals are often associated with the degree to which the injection of low-salinity water increases oil production. Therefore, an investigation of the geochemistry of the clay/fluid interface is crucial to understand the role of petrophysical properties such as wettability on oil production. We use molecular dynamics (MD) to (i) quantify the impacts of different types of oil components, electrolytes, and its mixture at varying ionic strengths on interfacial properties and (ii) investigate wettability alteration by means of water adsorption quantification. We investigate the brine/clay and oil/brine/clay interfacial interactions involved in the adsorption of ions and water molecules onto the clay surface. Clay is represented by illite, and brine is composed of water molecules and different electrolyte types such as NaCl, CaCl2, and their mixtures at varied concentrations. The oil components investigated in this work include decane (C10H22), decanoic acid (CH₃(CH₂)₈COOH), and sodium decanoate (C10H19NaO2). These components were selected to represent the range of oil molecules typically found in reservoirs, which include nonpolar, polar, and charged polar molecules. Initially, we set up systems composed of different ion composition and salinity to investigate the effect of these parameters on EDL structure and water adsorption. Then, we created systems composed of mixed electrolyte and different oil components to verify the impacts of these molecules on the oil/brine/clay interface. Finally, we increased the NaCl concentration in the system containing sodium decanoate to investigate the role of Na in wettability alteration. MD simulations were performed at 330 K, and particle density profiles of water, hydrocarbon, and ions inside the illite nanopores were computed. We observed that the ion composition and salt concentration of the systems composed of clay minerals and brine do not result in significant changes in the adsorption planes of cations. For the same systems, we also computed the number of water molecules per unit cell in each hydration layer. We observed that the change in the thickness of these hydration layers is also very small. The results showed that nonpolar-charged hydrocarbon molecules have the lowest mobility, suggesting that this component has a more intense interaction with the illite surface compared with other hydrocarbons. Additionally, snapshots of the simulation indicate that calcium preferentially forms bridges with sodium decanoate molecules compared with other organic components. Despite being widely known as an efficient method for achieving EOR, the underpinning mechanism for wettability alteration at LSWF is still not fully understood. The outcomes of this work improve our understanding of the key parameters affecting interactions at the oil/rock/brine interface during LSWF.

A novel strategy inspired by Luban lock towards endowing polyzwitterionic electrolyte hydrogel with UCST behaviors

The electrostatic interaction in polyzwitterionic electrolyte hydrogels is the prerequisite for materials to exhibit temperature-sensitive behaviors. Few reports mention the potential temperature-sensitive properties of these hydrogels, although amounts of polyzwitterionic electrolyte hydrogels with bright prospects in advanced fields have been reported. PMAD (copolymer of AM, AA and DMC) is a typical polyzwitterionic electrolyte, which is taken as an example to elucidate the essential conditions for the UCST behaviors of polyzwitterionic electrolyte hydrogels. The temperature-sensitive properties of PMAD hydrogels depends on the tight stacking of zwitterionic polymer chains, while the introduction of chemical crosslinker could limit the movement of PMAD chains and increase the difficulty of forming effective electrostatic interactions between zwitterionic segments resulting in the disappearance of UCST behaviors. Accordingly, the strategy inspired by the Chinese Luban lock for compressing the distance of PMAD chains by utilizing the “mortise-tenon” structure could recovery the UCST behaviors of PMAD and are expected to endow more polyzwitterionic electrolyte hydrogels with temperature-responsive properties.

Advanced materials and fabricating approaches for proton exchange membrane fuel cells

AbstractProduction of electrical energy in an environmental‐friendly manner is important for meeting the increasing demand of electricity in smart vehicles and energy devices. Benefitted from its moderate working temperatures and high conversion efficiency, proton exchange membrane fuel cell (PEMFC) has received broad attention and commercialized rapidly in the past decades. Herein, we comprehensively review the advanced types of electrolytes and their underlying working mechanisms to offer a considerate guidance to develop novel electrolytes with high proton conductivity and wide working temperature window. Moreover, to rationally design cost‐effective and robust electrodes, the well‐developed anode and cathode and their fundamental working principles are elaborately reviewed and discussed. Furthermore, from the viewpoint of overall structure, fabricating approaches of functional components of PEMFC and their corresponding influencing factors are minutely reviewed and analyzed with the aim of tuning cell performance and preparing PEMFC in a high‐throughput way. Lastly, we highlight the conclusions of this review and present the penitential developing directions.

Li10GeP2S12-xSex solid solution as a new Li+ solid-state electrolyte

A new type electrolyte Li10GeP2S12-xSex (LGPSS, 0 < x ≤ 7) was designed and synthesized by solid-state reaction method. The cell parameters a and c of Li10GeP2S12-xSex (0 ≤ x ≤ 7) increase from 8.7295(8) to 8.995(2) Å and 12.675(1) to 13.102(3)Å with x increasing from 0 to 7, respectively. S2 site is mainly occupied by Se, while the secondly occupied is S3 site. Li1 is occupied by Li completely and embedded in framework, while other Li sites are all partially occupied and involved in conducting. The occupancy of Li2, Li3, Li4 site are 0.71, 0.70 and 0.47, respectively, when x = 4. Li2 has lowest energy, and Li2 site are preferred to be the destination of Li+ migration pathway. Substitution of S is proved to be selective and there is a priority for Se to bind with Ge. The maximum conductivity 4.98 mS/cm is obtained by Li10GeP2S8Se4 at 25 °C, which is about three times higher than that of Li10GeP2S12 (LGPS). The activation energy (Ea) and electrochemical window of Li10GeP2S8Se4 are 0.23 eV and 0–3 V. Li+ migration mechanism is calculated using bond valency theory, the migration of Li + presents 1D pathway has maximum barrier of 0.233 eV and 3D pathway barrier is 0.392 eV Li10GeP2S8Se4 has favorable stability that there is no breakdown occurring under 0.72 mA/cm2 current density.

Performance and potential mechanisms for reactive electrochemical ceramic membrane system to inhibit resistance transmission in antibiotic-resistant contaminated wastewater: From a microbial perspective

Due to the widespread presence of antibiotic resistance genes (ARGs) in traditional biological wastewater treatment systems, electrochemical disinfection techniques have received extensive attention. The rTNA/Sb-SnO2/PbO2 Reactive Electrochemical Ceramic Membrane (RECM) system has demonstrated outstanding performance in effectively removing refractory antibiotics. However, its capacity to remove antibiotic resistant bacteria (ARB) remains unclear. In this study, an antibiotic resistant strain of Escherichia coli (AR E. coli) was employed to investigate the disinfection efficiency of the RECM system at a macroscopic level, along with its disinfection mechanism at a microscopic level. Furthermore, the secondary effluent from an antibiotic production wastewater treatment plant was collected to validate the disinfection performance of this system against ARB in actual wastewater. In the RECM system, the inactivation of AR E. coli and the removal of ARGs were primarily governed by the electrocatalytic process, with notable influences from critical factors such as current density, electrolyte type, and hydraulic retention time. Morphological observation and flow cytometry experiments confirmed that the AR E. coli in the RECM system was inactivated by alterations in cell morphology, leading to fragmentation, and by improvement in cell membrane permeability. More significantly, this system exhibited noteworthy efficiency in treating wastewater contaminated with antibiotic resistant pollutants, effectively eliminating both antibiotics and ARGs from the secondary effluent. Overall, our study comprehensively investigated the performance and underlying mechanisms of the RECM system in mitigating the dissemination of ARGs, as well as its potential feasibility of practical application.

Enhancing photovoltaic cell design with multilayer sequential neural networks: A study on neodymium-doped ZnO nanoparticles

Multilayer sequential neural networks, a powerful machine learning model, demonstrate the ability to learn intricate relationships between input features and desired outputs. This study focuses on employing such models to design photovoltaic cells. Specifically, neodymium (Nd)-doped ZnO nanoparticles (NPs) were utilized as a photoanode for fabricating dye-sensitized solar cells (DSSCs). A natural dye extracted from Spinacia oleracea was employed, while two types of electrolytes, liquid and gel (polyethylene glycol-based), were used for comparative analysis. Extensive material characterization of the photoanode highlights the impact of Nd content on the physicochemical properties of ZnO. Notably, when the doped photoanode and gel electrolyte were combined, a substantial 110% improvement in power conversion efficiency (PCE) was achieved. Building on these findings, the machine learning model in this research accurately predicts the current-voltage (I-V) curve values for such photoanodes, with an impressive accuracy of 98%. Additionally, the model illuminates the significance of variables like crystal distortion, texture coefficient, and doping concentration, underscoring their importance in the context of photovoltaic cell design.

Electrical conductance study of Schiff base in different solvents and temperatures: DFT calculation

The electrical conductivities of the N-(2-chlorobenzylidene)benzylamine (NCB) as Schiff bases (SB) compound in water and methanol were studied in different temperatures, the mixtures of methanol and water studied in various percentages of methanol at 298 K. Initially, the relationship between equivalent conductivity and the square root of molar concentration was plotted to find electrolyte types using Kohlrausch equations. The plot indicates that NCB was weakly associated with water, methanol, and mixtures. Lee-Wheaton equation treated the experimental results of symmetrical electrolytes (1:1) to calculate the conductivity confines: equivalent conductance at infinite dilution Λₒ, association constant KA, and the main distance between ions in solution (R) at best-fit values of (ϬΛ). Thermodynamic quantities for the ion association reaction (∆Go, ∆Ho and ∆So) have been measured. Also, the theoretical calculation was used to optimize the energy of the molecule in the gas phase then measured many descriptors by using (AM1, PM3) then DFT. In addition, recalculated the optimization energy in water, and methanol. After theoretical calculation and analysis, it was found that the Λₒ value is related to the molecular volume of the system (molecules assembled in the solvent). As the molecular volume increases, the Λₒ value decreases due to association. KEY WORDS: Schiff bases, Electrical conductivities, Lee-Wheaton equation, Thermodynamic parameter, DFT Bull. Chem. Soc. Ethiop. 2025, 39(1), 177-187. DOI: https://dx.doi.org/10.4314/bcse.v39i1.15

Effects of fluorine and phosphorus-based flame retardants addition on the lower flammability limit of dimethyl carbonate

This study initially examines the alteration pattern of the lower flammable limit (LFL) of dimethyl carbonate (DMC), a typical electrolyte component in lithium batteries, under the influence of inhibitors, namely di(2,2,2trifluoroethyl) carbonate (DtFEC), perfluorohexanone (C6F12O), and trimethylphosphate (TMP), through experimental investigation. Additionally, the critical inhibitory concentration required for complete inhibition is investigated. Subsequently, numerical simulations and chemical kinetic path analyses reveal how these inhibitors control combustion. Results show that C6F12O and DtFEC initially decrease and then increase the LFL of DMC, while TMP causes a monotonic increase. This is due to the competition between reaction-thermal and reaction-radical effects. Reaction kinetic analysis reveal that when small amounts of C6F12O and DtFEC are added, the fluorine-containing components decomposed by the reaction undergo oxidation, thereby promoting combustion. However, with increased amounts, these components combine with H and OH radicals to form stable substances like HF, inhibiting the combustion process. In the case of TMP, the phosphorus-containing intermediate components produced by cleavage catalyze the recombination of H and OH radicals, thereby inhibiting DMC combustion. The research findings offer a theoretical foundation for the development of safer lithium batteries and provide crucial data references for enhancing battery safety and prevention measures.

Simultaneous determination of chlorides, bromides, and fluorides in ion-conducting electrolyte

There are developed the techniques of determining the content of chlorides, bromides and fluorides at their joint presence in two types of solid electrolytes differing in matrix content: the first type contains lithium, the second one — both lithium and aluminium, simultaneously. Determination of bromides mass fraction is fulfilled using a method of iodometric titration of iodic potassium excess after bromides are oxidized until free bromine. The fluorides mass fraction is measured by the gravimetric method in the form of fluoro-chloride of lead, in this case the aluminium interfering influence is eliminated by its precipitation in the form of hydroxide after it is fused with carbonates of potassium and natrium, as well as by the method of potentiometric titration with a fluoride ion-selective electrode using the nitrate lanthanum solution. The absence of aluminium interfering influence on the result of fluorine determination is estimated by the «input – found» method. The mass fraction of chlorides is determined by calculation by difference between results of determining the sum of chlorides and bromides using the method of mercurometric titration and — separately — the bromides mass fraction. Optimal conditions of samples preparation and analysis for each of mentioned methods of analysis were selected. The limits of the relative total error of determining bromides in the range of mass fractions from 28.0 to 41.0% is ±2.1%, chlorides within the mass fraction range from 8.0 to 15.0% — ±3.6%, fluorides within the mass fraction range from 3.0 to 7.0% — ±3.4% using gravimetric method and within the mass fraction range from 5.0 to 8.0% — ±1.5% using a method of potentiometric titration. The developed techniques were certified by a metrological service of the enterprise and are used to control the chemical composition of the ion-conducting electrolyte. The techniques do not require expensive equipment, and can be used in factory laboratories.