Search Results (69)

Hazardous compounds from used batteries pose a great threat to the environment. To prevent pollution and to recover critical materials from battery waste, efficient recycling is required. Until now, battery recycling has focused on the recovery of valuable metals from cathode materials, while organic fractions have often been neglected due to their low material value. New approaches to battery recycling are therefore necessary, where recycling methods based on supercritical carbon dioxide (SC-CO₂) extraction show great potential. In this work, a SC-CO₂ method was implemented to extract electrolyte solvents for the purification and recovery of a separator waste material (SWM) sorted out from lithium-ion battery (LIB)-based black mass. In addition, two other separation routes (ultrasonic washing and thermal treatment) were used for comparison. Based on the results from the three routes, mass balances revealed the gravimetric composition of the SWM, which includes separator, electrolyte, and electrode powder. The composition of electrolyte solvents was determined via Gas Chromatography-Mass Spectroscopy analysis. Furthermore, the polymeric separator was analyzed using Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Calorimetry analysis to evaluate the effects of SC-CO₂ extraction on the physicochemical properties. The recovery of electrolyte by the SC-CO₂ route is more efficient than the others, with extraction yields of 162 mg of electrolyte per gram of SWM. Moreover, no changes are observed in the analyzed properties of the polymeric separator material due to the SC-CO₂ extraction. Thus, the SC-CO₂ process proves to be a promising method for an efficient and sustainable recycling of electrolyte solvent and purifying of separator material from LIB waste. Full article

Sodium-ion batteries (SIBs) represent a topic of extreme interest in the research field, especially because the materials used are cheaper than those in lithium-ion batteries (LIBs). In SIBs, the choice of cathodes and electrolytes is very important because they will affect the energy density, cycling stability, and safety of the battery. This work focuses on the prospect of hybrid electrolyte cells that incorporate ionic liquids (ILs) into organic liquids in order to improve the safety and performance of SIBs. Organic solutes make ionic conductivity higher due to larger IL electrochemical windows, good thermal stability and low volatility. They have some issues like flammability, dissolution, and transport limitations, but these aspects could be solved by using hybrid electrolyte systems. In this study, we investigate the effect of using different salts and solvents on the characteristics of the SIBs. We analyze ionic conductivity, electrochemical stability, and the development of stable solid electrolyte interphase (SEI) in the SIBs by using hybrid electrolytes. Additionally, we demonstrate that the addition of ILs to organic electrolytes can improve their thermal stability, so as a result, the safety and lifecycle of the battery will be increased. In conclusion, this research shows how hybrid electrolytes could have great potential for SIB battery technology in high-performance and large-scale energy storage applications. Full article

Deep eutectic solvents (DES) have emerged as a versatile and sustainable medium for the green synthesis of nanomaterials, offering a viable alternative to conventional organic solvents and ionic liquids. Nanomaterials can be synthesised in DESs via multiple routes, including chemical reduction, solvothermal, and electrochemical methods. Among the different pathways, this review focuses on the electrochemical synthesis of nanomaterials in DESs, as it offers several advantages: low cost, scalability for large-scale production, and low-temperature processing. The size, shape, and morphology (e.g., nanoparticles, nanoflowers, nanowires) of the resulting nanostructures can be tuned by adjusting the concentration of the electroactive species, the applied potential, the current density, mechanical agitation, and the electrolyte temperature. The use of DES as an electrolytic medium represents an environmentally friendly alternative. From an electrochemical perspective, it exhibits high electrochemical stability, good solubility for a wide range of precursors, and a broad electrochemical window. Furthermore, their low surface tensions promote high nucleation rates, and their high ionic strengths induce structural effects such as templating, capping and stabilisation, that play a crucial role in controlling particle morphology, size distribution and aggregation. Despite significant progress, key challenges persist, including incomplete mechanistic understanding, limited recyclability, and difficulties in scaling up synthesis while maintaining structural precision. This review highlights recent advances in the development of metal, alloy, oxide, and carbon-based composite nanomaterials obtained by electrochemical routes from DESs, along with their applications. Full article

Deep Eutectic Solvents (DESs) have emerged as promising candidates to replace conventional organic solvents in various technological applications due to their low vapor pressure, non-flammability, and ease of preparation at low costs. In particular, Type IV DESs, which are composed of metal salts and hydrogen bond donors, are possible replacements for lithium-ion battery electrolytes. In this study, we investigate the molecular dynamics of solvents of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and pyrazole (PYR) at varying LiTFSI:PYR molar ratios (1:2, 1:3, 1:4, 1:5) using Nuclear Magnetic Resonance Dispersion (NMRD) and Pulsed Field Gradient (PFG) Nuclear Magnetic Resonance (NMR). PFG NMR reveals composition-dependent diffusion trends, while NMRD provides molecular-level insights into the longitudinal relaxation rate (R₁ = 1/T₁). Notably, the LiTFSI:PYR (1:2) sample shows distinct behavior across both techniques, exhibiting enhanced relaxation rates and lower self-diffusion for ¹H compared to the other nuclei (¹⁹F and ⁷Li), suggestive of stronger and more efficient Li⁺–pyrazole interactions, as confirmed by the modeling of the relaxation profiles. Our study advances understanding of ion dynamics in azole-based eutectic solvents, supporting their potential use in safer battery electrolytes. Full article

Due to its conjugated structure, 1,4,6,8-tetrakis((E)-2-(thiophen-2-yl)vinyl)azulene (L) has a high potential for nonlinear optics and coloring. This compound was studied electrochemically using cyclic voltammetry, pulse differential voltammetry and rotating disk voltammetry in organic electrolytes. The main processes occurring during oxidation and reduction scans were highlighted and characterized. Density functional theory (DFT) calculations were conducted to assess the chemical reactivity of this compound. UV-Vis studies of L were performed in acetonitrile to establish the optical parameters in this solvent and its complexing power towards heavy metal (HM) ions. Chemically modified electrodes (CMEs) based on L were prepared by electrooxidation of L in organic electrolytes. To evaluate the electrochemical behavior of the CMEs, they were characterized with a ferrocene redox probe. They were also tested for the analysis of synthetic samples of heavy metal ions (HM): Cd(II), Pb(II), Cu(II) and Hg(II) by anodic stripping. Specific responses were obtained for Pb(II) and Cd(II) ions. The preparation conditions have an influence on the electrochemical responses. This study is relevant for the design and further development of advanced materials based on this azulene for the analysis of HMs in water samples. Electrochemical experiments and DFT calculations recommended L as a new ligand for modifying the electrode surface for the analysis of HMs. Full article

The flammability and volatility of conventional lithium hexafluorophosphate (LiPF₆)-based electrolytes with organic carbonate solvents remain critical issues to the safety and thermal stability of lithium-ion batteries (LIBs). This study investigates the incorporation of phosphate-based additives including ammonium dihydrogen phosphate (ADP), trimethyl phosphate (TMP), and trimethyl phosphite (TMPi) into LiPF₆ electrolytes for improving the ionic conductivity, safety, and electrochemical performance of LIBs. Self-extinguishing time (SET) measurements demonstrated that the ADP-based LiPF₆ electrolyte significantly reduced flammability, achieving a shorter SET of 04 min 53 s, compared to 12 min for the pristine LiPF₆ electrolyte. The ADP-based LiPF₆ electrolyte possessed the highest ionic conductivity (14.08 mS·cm⁻¹) with an excellent lithium-ion transference number of 0.0076. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (C-V) analyses demonstrated that ADP lowered interfacial resistance and stabilized long-term cycling behavior. In particular, the 1% ADP-based LiPF₆ electrolyte maintained improved charge-discharge profiles and Coulombic efficiency over 200 cycles. These results highlight ADP’s dual functionality in suppressing gas-phase flammability and enhancing condensed-phase electrochemical stability, making it a promising candidate for next-generation, high-safety, high-performance LIB electrolytes. Full article

AQ suspensions show strong potential as organic anodes for Li-ion slurry batteries. However, the influence of slurry electrolyte composition on the electrochemical behavior of AQ lacks systematic investigation. We explored the effects of different lithium salts and solvents in the electrolyte on the redox behavior of the AQ material electrode. An electrolyte (1 M LiTFSI dissolved in DME: DOL with a volume ratio of 1:1) optimized for AQ lithium slurry batteries exhibits a stable 2.3 V charge/discharge platform delivering a discharge specific capacity of 246.2 mAh g⁻¹ at 1.25 A g⁻¹ (approaching the theoretical value) with stable slurry reactor operation for over 47 h. This work establishes a structure-property relationship between electrolyte formulation and AQ electrode performance, offering a design principle for electrolyte selection in organic slurry-based battery systems. Full article

Electrochemical reduction is a promising strategy for the dechlorination of halogenated organic compounds, offering advantages such as enhanced electron transfer efficiency and increased hydrogen atom concentration. It has garnered significant attention for application in mitigating halogenated disinfection by-products (DBPs) in drinking water, owing to its high efficiency and simple operation. In this study, trichloroacetic acid (TCAA), a representative DBP, was selected as the target contaminant. A novel composite cathode comprising a metal–organic framework MIL-53(Fe)@C supported on an Nd magnet (MIL-53(Fe)@C-MAG) and its dechlorination performance for TCAA were systematically investigated. The innovative aspect of this study is the magnetic attachment of the MOF catalyst to the carbonized cathode surface treated through carbonization, which fundamentally differs from conventional solvent-based adhesion methods. Compared to the bare electrode, the MIL-53(Fe)@C-MAG achieved a TCAA removal efficiency exceeding 96.03% within 8 h of contact time. The structural characterization revealed that the α-Fe⁰ crystalline phase serves as the primary active center within the MIL-53(Fe)@C catalyst, facilitating efficient electron transfer and TCAA degradation. The scavenger experiments revealed that TCAA reduction involves a dual pathway: direct electron transfer and atomic hydrogen generation. The modified MIL-53(Fe)@C-MAG electrode exhibited robust electrolytic performance over a broad pH range of 3–7, with TCAA removal efficiency showing a positive correlation with current density within the range of 10–50 mA/cm². Furthermore, the electrode maintained exceptional stability, retaining more than 90% removal efficiency after five consecutive operational cycles. The versatility of the system was further validated by the rapid and efficient dechlorination of various chlorinated DBPs, demonstrating the broad applicability of the electrode. The innovative magnetic composite electrode demonstrates a significant advancement in electrochemical dechlorination technology, offering a reliable and efficient solution for the purification of drinking water contaminated with diverse halogenated DBPs. These results provide valuable insights into the development of electrolysis for dechlorination in water treatment applications. Full article

Each battery cell consists of three main components: the anode, the cathode, and the separator soaked with liquid electrolyte, the medium in the battery that allows charged ions to move between the two electrodes. Besides a wide electrochemical stability window and good compatibility with both electrodes, the electrolyte should also be safe, thermally stable and environmentally benign, showing a high ionic conductivity of the charge-carrying Li ions and finally a low price. This unique combination of properties is impossible to achieve with a simple salt–solvent mixture and usually requires a combination of different electrolyte components, i.e., several liquid solvents and additives and one or more conducting salt(s). For lithium-based batteries, which are the most common electrochemical energy storage devices today, a solution based on lithium hexafluorophosphate (LiPF₆) in a mixture of organic carbonates as the solvent is used. Usually, the conducting salt concentrations used for lithium-based electrolytes are in the range of ≈1 to 1.2 M, but recently, electrolytes with much higher conducting salt concentrations of 5 M and even over 10 M have been investigated as they offer several benefits ranging from increased safety to a broadened electrochemical stability window, thus enabling cheap and safe solvents, even water. Full article

The application of deep eutectic solvents (DESs) as an innovative class of environmentally friendly liquid media represents a significant advancement in materials science, especially for the development and enhancement of structural materials. Among the promising applications, DESs are particularly attractive for the electrodeposition of corrosion-resistant coatings. It is established that corrosion-resistant and protective coatings, including those based on metals, alloys, and composite materials, can be synthesized using both traditional aqueous electrolytes and non-aqueous systems, such as organic solvents and ionic liquids. The integration of DESs in electroplating introduces a unique capacity for precise control over microstructure, chemical composition, and morphology, thereby improving the electrochemical corrosion resistance and protective performance of coatings. This review focuses on the electrodeposition of corrosion-resistant and protective coatings from DES-based electrolytes, emphasizing their environmental, technological, and economic benefits relative to traditional aqueous and organic solvent systems. Detailed descriptions are provided for the electrodeposition processes of coatings based on zinc, nickel, and chromium from DES-based baths. The corrosion–electrochemical behavior and protective characteristics of the resulting coatings are thoroughly analyzed, highlighting the potential and future directions for developing anti-corrosion and protective coatings using DES-assisted electroplating techniques. Full article

Lithium-ion battery (LIB) electrolytes are generally composed of a mixture of organic hydrocarbons and lithium salt (e.g., LiPF₆). Experimental density data for basic and realistic multicomponent mixtures are scarce in the literature, and a predictive model for electrolyte solution density is not yet widely available. This work resolves to create a simple predictive method that can be used to estimate the density of these mixtures. A model that accounts for intermolecular forces in the electrolyte mixture was developed and fitted to density data available in the literature that was internally vetted for consistency. The model exhibited high accuracy for single-component electrolyte mixtures, with most predictions falling within 1% of measured values and all predictions falling within 5%. The model was further extended to more realistic, multi-solvent electrolyte mixtures that exhibited similar accuracy. In addition, a novel, accurate method for computing absolute molar and mass fractions of multi-solvent mixtures with specified volumetric concentrations (e.g., 1.2 M LiPF₆ in 1:1:1% vol. ethylene carbonate-EC/diethyl carbonate-DEC/dimethyl carbonate-DMC) is also described. The two separate approaches were combined to yield a modeling framework capable of computing molar concentrations and densities of all LIB electrolyte solutions based on LiPF₆ loaded in any combination of EC, EMC, DEC, DMC, and PC. Additional ionic salt data for NaPF₆ and LiFSI were also evaluated to illustrate the adaptability of the model to different salts and electrolytes. Once again, the model was successful, with most density predictions falling within 1% error and all falling within 5%. This work ultimately provides a simple, adaptable modeling framework for accurate prediction of electrolyte mixture densities. Full article

Lithium metal batteries (LiMBs) have emerged as extremely viable options for next-generation energy storage owing to their elevated energy density and improved theoretical specific capacity relative to traditional lithium batteries. However, safety concerns, such as the flammability of organic liquid electrolytes, have limited their extensive application. In the present study, we utilize molecular dynamics and Density Functional Theory based simulations to investigate the Li interactions in gel polymer electrolytes (GPEs), composed of a 3D cross-linked polymer matrix combined with two different non-flammable electrolytes: 1 M lithium hexafluorophosphate (LiPF₆) in ethylene carbonate (EC)/dimethyl carbonate (DMC) and 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in trimethyl phosphate (TMP) solvents. The findings derived from radial distribution functions, coordination numbers, and interaction energy calculations indicate that Li⁺ exhibits an affinity with solvent molecules and counter-anions over the functional groups on the polymer matrix, highlighting the preeminent influence of electrolyte components in Li⁺ solvation and transport. Furthermore, the second electrolyte demonstrated enhanced binding energies, implying greater ionic stability and conductivity relative to the first system. These findings offer insights into the Li⁺ transport mechanism at the molecular scale in the GPE by suggesting that lithium-ion transport does not occur by hopping between polymer functional groups but by diffusion into the solvent/counter anion system. The information provided in the work allows for the improvement of the design of electrolytes in LiMBs to augment both safety and efficiency. Full article

Environmental impacts and resource availability are significant concerns for the future of lithium-ion batteries. This study focuses on developing novel fluorine-free electrolytes compatible with aqueous-processed cobalt-free cathode materials. The new electrolyte contains lithium 1,1,2,3,3-pentacyanopropenide (LiPCP) salt. After screening various organic carbonates, a mixture of 30:70 wt.% ethylene carbonate and dimethyl carbonate was chosen as the solvent. The optimal salt concentration, yielding the highest conductivity of 9.6 mS·cm⁻¹ at 20 °C, was 0.8 mol·kg⁻¹. Vinylene carbonate was selected as a SEI-stabilizing additive, and the electrolyte demonstrated stability up to 4.4 V vs. Li+/Li. LiFePO₄ and LiMn_0.6Fe_0.4PO₄ were identified as suitable cobalt-free cathode materials. They were processed using sodium carboxymethyl cellulose as a binder and water as the solvent. Performance testing of various cathode compositions was conducted using cyclic voltammetry and galvanostatic cycling with the LiPCP-based electrolyte and a standard LiPF6-based one. The optimized cathode compositions, with an 87:10:3 ratio of active material to conductive additive to binder, showed good compatibility and performance with the new electrolyte. Aqueous-processed LiFePO₄ and LiMn_0.6Fe_0.4PO₄ achieved capacities of 160 mAh·g⁻¹ and 70 mAh·g⁻¹ at C/10 after 40 cycles, respectively. These findings represent the first stage of investigating LiPCP for the development of greener and more sustainable lithium-ion batteries. Full article

Potential photovoltaic technology includes the newly developed dye-sensitized solar cells (DSSCs) and bulk heterojunction (BHJ) solar cells. Owing to their diverse qualities, polymers can be employed in third-generation photovoltaic cells to specifically alter their device elements and frameworks. Polymers containing phenothiazine, either as a part of their structure or as a dopant, are easy and economical to synthesize, are soluble in common organic solvents, and have the potential to acquire desired electrochemical and photophysical properties by mere tuning of their chemical structures. Such polymers have therefore been used either as photosensitizers in dye-sensitized solar cells, where they have produced power conversion efficiency (PCE) values as high as 5.30%, or as donor or acceptor materials in bulk heterojunction solar cells. Furthermore, they have been employed to prepare liquid-free polymer electrolytes for dye-sensitized and bulk heterojunction solar cells, producing a PCE of 8.5% in the case of DSSCs. This paper reviews and analyzes almost all research works published to date on phenothiazine-based polymers and their uses in dye-sensitized and bulk heterojunction solar cells. The impacts of their structure and molecular weight and the amount when used as a dopant in other polymers on the absorption, photoluminescence, energy levels of frontier orbitals, and, finally, photovoltaic parameters are reviewed. The advantages of phenothiazine polymers for solar cells, the difficulties in their actual implementation and potential remedies are also evaluated. Full article

The current study focuses on reviewing the actual progress of the use of ionic liquids and derivatives in several electrochemical application. Ionic liquids can be prepared at room temperature conditions and by including a solution that can be a salt in water, or a base or acid, and are composed of organic cations and many charge-delocalized organic or inorganic anions. The electrochemical properties, including the ionic and electronic conductivities of these innovative fluids and hybrids, are addressed in depth, together with their key influencing parameters including type, fraction, functionalization of the nanoparticles, and operating temperature, as well as the incorporation of surfactants or additives. Also, the present review assesses the recent applications of ionic liquids and corresponding hybrids with the addition of nanoparticles in diverse electrochemical equipment and processes, together with a critical evaluation of the related feasibility concerns in different applications. Those ranging from the metal-ion batteries, in which ionic liquids possess a prominent role as electrolytes and reference electrodes passing through the dye of sensitized solar cells and fuel cells, to finishing processes like the ones related with low-grade heat harvesting and supercapacitors. Moreover, the overview of the scientific articles on the theme resulted in the comparatively brief examination of the benefits closely linked with the use of ionic fluids and corresponding hybrids, such as improved ionic conductivity, thermal and electrochemical stabilities, and tunability, in comparison with the traditional solvents, electrolytes, and electrodes. Finally, this work analyzes the fundamental limitations of such novel fluids such as their corrosivity potential, elevated dynamic viscosity, and leakage risk, and highlights the essential prospects for the research and exploration of ionic liquids and derivatives in various electrochemical devices and procedures. Full article