Metal Sulfates Research Articles

Upcycling of lithium cobalt oxide to LiNi1/3Mn1/3Co1/3O2

Upcycling of lithium cobalt oxide (LCO) into lithium nickel manganese cobalt oxide (NMC111) cathode material using acetone antisolvent crystallization of citrate leachate followed by sol–gel synthesis with complementary metal acetate or sulfate salts.

A sustainable synthesis, characterization of modified waste onion peels and its exploration in various applications

The modification of waste to a bio-based material that is economical, environmentally sustainable, and extremely effective is crucial for organic conversions. For bio waste, that doesn’t decompose easily and have bad impact on environment such as onion peels, a suitable method is introduced which focuses on utilizing onion peels, a commonly discarded agricultural waste, as a valuable resource for antibacterial studies and bio sensing of heavy metals. A comparative study to analyse these properties were done using onion peel extract and saponified onion peels. The saponified material was obtained by treating onion peels (Allium cepa) with sodium hydroxide in the presence of calcium carbonate. The popularity of saponification reaction and saponified material is rising because of their special qualities and uses as disinfectants, surfactants, antifungal agents, in drugs for target based delivery etc. The saponified onion peels was analyzed by FTIR (Fourier transform infrared spectroscopy), and XRD (X-ray diffraction), EDX (energy-dispersive X-ray), SEM (scanning electron microscopy). Furthermore, against Bacillus subtilis (Gram positive), antibacterial activity of onion extract and saponified onion peels were studied. In comparative study onion peel extract shows better inhibition zone then saponified onion peels. Bio sensing of heavy metals were done by using these materials, onion peel extract shows visual colour change with Nickel chloride (NiCl2), Cobalt chloride (CoCl2), Potassium bromide (KBr), Manganese sulphate (MnSO4), Mercury chloride (HgCl2) and Copper sulphate (CuSO4) metal salts.

Effectivity of anaerobic deposition reactor (ADR) based on sulphate reducing bacteria for laboratorium wastewater treatment

Laboratory wastewater is classified as hazardous waste that is disposed of into the environment and will be very risky to environmental health. In this study, the use of a consortium of Sulphate Reducing Bacteria (SRB) was studied which was grown simply in an anaerobic column. SRB suspension was applied to the prototype anaerobic bioreactor to treat of laboratory wastewater with containing heavy metals and acidic. SRB was grown in medium of fermented compost and Postgate’s B. This research formulated that the SRB solution nursery as the optimal bioreactor activator after 15 days with the composition of the growth medium consisting of Postgate B solution (65%), Fermented compost liquid (30%) and active suspension liquid (5%), with a total population of cell colonies reaching 1.2 x 105 CFU/mL. The bioreactor requires an adjustment process for 15 days, after which the sulphate and heavy metal ion reduction process occurs significantly, and is effective with the combination of fermented compost content with the right Postgate solution, and a bioreactor with 30% compost fermented effective in reducing Pb metal ions, but for Cu and Fe metal ions were only effective after 7 days of adjustment.

A homoleptic AgIII complex stabilized by succinimidate ligands.

Herein, the first example of a homoleptic AgIII complex stabilized by a monodentate N-donor ligand is presented. Na2[S2O8] oxidizes the linear AgI complex, Na[Ag(succ)2] (1Na), to form a square planar argentate(iii) ion, [Ag(succ)4]-, which crystallizes with a polymeric chain-structure, M[Ag(succ)4] (2M), when treated with alkali metal sulfate M2SO4 (M = K, Rb, Cs). A mixed-valent Robin-Day class I system, [(H2O)Ag][Ag(succ)4] (2Ag), forms in the absence of K+/Rb+/Cs+ ion. Diamagnetic 2Cs displays a succinimide C[double bond, length as m-dash]O stretching frequency at higher energy than does the isoelectronic PdII complex, [(H2O)Na]2[Pd(succ)4] (3Na). Moreover, 2Cs displays UV-vis absorptions that are more intense and occur at lower energy than those in 3Na. The electron-deficient nature of 2Cs is further evident from its ability to oxidize water to O2. From 109Ag magic-angle spinning NMR studies, a highly deshielded AgIII environment in 2Cs (2080 ppm) relative to the AgI starting material 1Na (492 ppm) is observed.

Biological upcycling of nickel and sulfate as electrocatalyst from electroplating wastewater

Upcycling nickel (Ni) to useful catalyst is an appealing route to realize low-carbon treatment of electroplating wastewater and simultaneously recovering Ni resource, but has been restricted by the needs for costly membranes or consumption of large amount of chemicals in the existing upcycling processes. Herein, a biological upcycling route for synchronous recovery of Ni and sulfate as electrocatalysts, with certain amount of ferric salt (Fe3+) added to tune the product composition, is proposed. Efficient biosynthesis of bio-NiFeS nanoparticles from electroplating wastewater was achieved by harnessing the sulfate reduction and metal detoxification ability of Desulfovibrio vulgaris. The optimal bio-NiFeS, after further annealing at 300 °C, served as an efficient oxygen evolution electrocatalyst, achieving a current density of 10 mA·cm−1 at an overpotential of 247 mV and a Tafel slope of 60.2 mV·dec−1. It exhibited comparable electrocatalytic activity with the chemically-synthesized counterparts and outperformed the commercial RuO2. The feasibility of the biological upcycling approach for treating real Ni-containing electroplating wastewater was also demonstrated, achieving 99.5 % Ni2+removal and 41.0 % SO42− removal and enabling low-cost fabrication of electrocatalyst. Our work paves a new path for sustainable treatment of Ni-containing wastewater and may inspire technology innovations in recycling/ removal of various metal ions.

AMMONIUM-SALT METHODS ARE THE BASIS FOR BUILDING EFFECTIVE NEW TECHNOLOGIES IN CHEMICAL AND METALLURGY INDUSTRIES

The article contains new data, which is a continuation of the research for the development of scientific theoretical applied directions, which appeared in previous publications related to the field of chemical technologies and metallurgy. Previous studies have used ammonium salts as reagents for the production of synthetic sodium carbonate and fluorides, but this publication shows the possibilities of using them for the development of non-ferrous metallurgy. The purpose of the work is to show the importance of the anionic hydrogen atom contained in ammonium bisulfate (ABS) in entering the compound. Thermodynamic, thermal, renggenphase analysis and mathematical programs were used in the research methods. Physical and chemical changes in reaction mixtures, some synthesized salts when heated using the system derrivatograph Q-1000/D of the company" mom " F.Paylik, J. Paylik, L. Erdey and LabSys Evo were studied using special standardized factory structures such as TG-DTA/DSC (Setaram, France). The probability of some reactions occurring or not occurring was thermodynamically evaluated using the HCs-5.1 Chemistry (Outokumpu) "Astra-4" software package (complex). In the results of the study, the method of processing raw materials of non-ferrousmetals is presented in the form of a basic technological scheme.The possibility of formation of intermediate complex Tutton salts during production of the final product and reactions leading to their decomposition has been shown by thermodynamic studies. It is shown that the decomposition of such ammonium nickel sulfate salt releases ammonia into the melt of crystalline metal sulfate and ammonium bisulfate at about 235-260°С, where the pyrolysis of ammonium sulfate begins. It was observed that the by-products of (NH4)2Ni(SO4)2nickel ammonium Tutton's salt heated in the ABS melt up to 300-350°C are nickel sulfate and ABS melt, and ammonia also reacts upon re-cooling. It was experimentally determined that this "heating-cooling" process changes the color of ABS melt from lemon yellow to white. During the repetition of the process, it was found that this phenomenon is repeated until the excess melt is exhausted. This phenomenon is explained by the formation of nickel acid salt between nickel sulfate and ABS melt, which no one has studied before. It was concluded that this phenomenon should be common to ABS melt with sulfate of other metals.

Unraveling the impact of SO2 on electron transfer and oxygen vacancy over MnOx-CeO2 for ozone decomposition

Mn-based catalysts for O3 decomposition (deO3) in industrial flue gas suffer from serious deactivation due to SO2, especially its impact on surface electron transfer and oxygen vacancy remains unclear. Herein, irreversible deactivation over MnOx-CeO2 in presence of SO2 and H2O was mainly attributed to the decrease of surface area, low-temperature reducibility and oxygen vacancies (Vo). SO2 was easily adsorbed on MnOx-CeO2 and further oxidized into SO42− under the aid of O3. Electron transfer from SO2 to Mn4+ and Ce4+ produced stable and inactive metal sulfates, which inhibited electron transfer in the redox cycles between Mn and O in O3 and between Mn and Ce. Moreover, metal sulfates occupied Vo, while Vo generation became difficult and its recovery from desorption of adsorbed oxygen intermediates was restricted, hence less O3 could be adsorbed and decomposed. Metal Ce protected active Mn species by reacting with SO2 preferentially. H2O generated active hydroxyl groups on Vo to react with O3 and hindered the contact of SO2 with Mn species, increasing deO3 activity under SO2 atmosphere. This study offers new insights into the poisoning mechanism of SO2 on electron transfer and oxygen vacancy in deO3 process, and sheds light on rational design of anti-SO2 deO3 catalysts.

Simultaneous Extraction of Valuable Metals from Iron-Containing Residues by Selective Chlorination and Evaporation

In different nonferrous metal-producing industry sectors, the impurity element iron has to be removed from the process solution. Examples for the arising residues are jarosite or goethite precipitates from nickel or zinc production but also red mud from aluminum production. Regardless of environmental concerns, the material is landfilled in almost any case, although valuables such as indium, silver, nickel, or zinc are present in considerable amounts. Within the presented research, a low carbon dioxide emitting multi-metal recovery from such iron-containing residues by means of a selective chlorination extraction has been fundamentally evaluated by experiments but also by comprehensive thermodynamic calculations. The paper summarizes the thermodynamic fundamental concept exploited to separate the dominating iron matrix from the valuable elements and shows verification experiments in a lab size of several grams. Through thermodynamic calculations and small-scale experiments with pure metal oxides and sulfates, it has been proven that the metal chlorides AlCl3∙6H2O, FeCl3∙6H2O, and MgCl2∙6H2O are viable and effective reactants for chlorination. In trials with actual industrial iron precipitation residues from the zinc industry, especially, the use of MgCl2∙6H2O and FeCl3∙6H2O leads to high extraction rates for the investigated valuable metals Ag, Au, Bi, Cu, In, Pb, Sn, and Zn.

Sequential Recovery of Critical Metals from Leached Liquor of Processed Spent Lithium-Ion Batteries

The processing and extraction of critical metals from black mass is important to battery recycling. Separation and recovery of critical metals (Co, Ni, Li, and Mn) from other metal impurities must yield purified metal salts, while avoiding substantial losses of critical metals. Solvent extraction in batch experiments were conducted using mixed metal sulphates obtained from the leach liquor obtained from spent and shredded lithium-ion batteries. Selective extraction of Mn2+, Fe3+, Al3+ and Cu2+ from simulated and real leached mixed metals solution was carried out using di-2-ethylhexylphophoric acid (D2EPHA) and Cyanex-272 at varying pH. Further experiments with the preferred extractant (D2EPHA) were performed under different conditions: changing the concentration of extractant, organic to aqueous ratio, and varying the diluents. At optimum conditions (40% v/v D2EPHA in kerosene, pH 2.5, O:A = 1:1, 25 °C, and 20 min), 85% Mn2+, 98% Al3+, 100% Fe3+, and 43% Cu2+ were extracted with losses of only trace amounts (<5.0%) of Co2+, Ni2+, and Li+. The order of extraction efficiency for the diluents was found to be kerosene > Exxal-10 >>> dichloromethane (CH2Cl2) > toluene. Four stages of stripping of metals loaded on D2EPHA were performed as co-extracted metal impurities were selectively stripped, and a purified MnSO4 solution was produced. Spent extractant was regenerated after Fe3+ and Al3+ were completely stripped using 1.0 M oxalic acid (C2H2O4).

Numerical Modelling and Kinetic Effects of Synthesized Allium Cepa- Zinc Oxide Nanoparticles for the Degradation of Sodium Lauryl Sulphate-Box Behnken Design

SEM, XRD, and FTIR methods were used to create and characterise Allium cepa Zinc Oxide Nanoparticles. The goal of the current study was to determine the ideal circumstances for Sodium Lauryl Sulphate (SLS) removal by ZnO-NP utilising onion peels. Utilising the precipitation process and metallic precursor sulphates, ZnO nanoparticles were created. SEM analysis was used to measure the particle size, which ranged from 180.4 to 284.1 nm. The crystalline structure of the Synthesised ZnO-NPs' hexagonal wurtzite structure is amply verified by XRD, and FTIR discloses the numerous functional groups that are present. The research's findings demonstrate how the Bio-nanocomposites can effectively remove SLS by varying various factors (such as time, dosage, pH, temperature, and initial concentration) and achieving the best results possible through experimentation, such as 35 min, 0.35 g/lit, pH 9, 313 K, and an initial concentration of 100 ppm of SLS in an aqueous solution. These Optimum settings increase the effectiveness of removing.

Acid mine drainage (AMD) treatment using a novel tannic acid functionalized Boehmite/polyether sulfone nanofiltration membrane

This study focuses on the fabrication of TA-BM/PES membranes by the incorporation of tannic acid functionalized Boehmite nanoparticles into the PES membrane matrix through the phase inversion technique. The presence of TA-BM nanoparticles in the TA-BM/PES membranes was confirmed by analysis of the FT-IR spectra of the embedded membranes. The hydrophilicity, permeability, surface morphology, and fouling resistance properties of membranes modified with TA-BM nanoparticles were compared to those of the naked membrane. The fouling behavior of the modified membranes was assessed in the presence of a foulant solution containing 200 ppm BSA (bovine serum albumin) and 200 ppm Na2SO4. The flux recovery ratio results showed an improvement in all modified membranes, especially M2 membrane. The modified membranes shown remarkable efficiency in the rejection of heavy metal ions (over 72 %), sulfate (over 80 %), and salt (Na2SO4 > 84 % and NaCl>48 %). The M2 membrane was chosen as the most suitable membrane and shown effective performance in eliminating heavy metals (Fe2+ = 65.5, Mn2+ = 88.8, Mg2+ = 83.5 and Ca2+ = 78.6 %) as well as sulfate (SO42− = 83.5 %) from a synthetic acid mine drainage (AMD) wastewater. Based on the findings presented in this research, it can be concluded that the TA-BM/PES nanofiltration membrane has potential for effective use in the treatment of AMD wastewater.

Shielding ceria based catalysts from SO2 poisoning in NH3-SCR reaction: Modification effect of acid metal oxides

Modifying CeO2 with acid sites is a common strategy for designing efficient catalysts for the selective catalytic reduction of NOx by NH3 (NH3-SCR of NOx). However, the effect of acid metal oxide modification on the SO2 resistance of CeO2 has not been well revealed. In this work, it was found that the SO2 resistance of CeO2 modified with several acid metal oxides (i.e., MoO3, WO3 and Nb2O5), followed an order of Mo/CeO2 ≥ W/CeO2 > Nb/CeO2. Further systematic characterizations revealed that Mo-OH and W-OH on CeO2 as Brønsted acid sites could better inhibit the SO2 adsorption and the sulfation of active sites than highly dispersed NbOx mainly as Lewis acid sites because NH4+ coordinated to Brønsted acid sites could help trap SO2 to form ammonium sulfates rather than metal sulfates. The findings in this work provided important guidance for the design of efficient catalysts with superior SO2 resistance performance.

The effect of dopants (Fe, Al) on the low-temperature activity and SO2 tolerance in solvothermally synthesized MnOx NH3-SCR catalysts

Fe-doped MnOx catalyst prepared by a preferred solvothermal method displayed noticeably better low-temperature (LT) NH3-SCR performance and water stability than an analogously prepared Al-doped MnOx catalyst. The SCR activity of both catalysts decreased markedly when exposed to SO2, but the resultant MnFeOx-S catalyst retained higher LT activity than MnAlOx-S and recovered significantly more of its original activity after thermal regeneration (400 °C). Comprehensive characterization confirmed that the deactivation of the catalysts was governed by formation of stable metal sulfates, which only decomposed to a minor extent upon thermal treatment although Al doping lowered the thermal stability of the adsorbed sulfur species. Additionally, Fe doping was found to facilitate electron transfer between Mn and Fe ions and weaken the interaction between active sites and deposited sulfates during the heating procedure, which promoted re-oxidation of Mn2+ to catalytically active Mn3+/Mn4+. Altogether, the altered redox properties resulted in improved LT SCR performance, enhanced water stability, higher SO2 tolerance and superior regeneration of the MnFeOx catalyst.

Sorption of copper (II) ions by a composite sorbent based on chitosan and montmorillonite

A composite sorbent based on chitosan and montmorillonite has been developed for the extraction of heavy metal ions from aqueous solutions. The optimal chitosan / montmorillonite ratio for obtaining sorbent granules has been determined. Equilibriumkinetic studies of the process of copper (II) ions extraction in the heterophase system "aqueous solution of metal sulphate - modified sorbent" have been carried out.The treatment of sorption isotherms of copper (II) ions by the initial chitosan and a chitosan based composite according to the Langmuir equation made it possible to determine the maximum sorption capacities of these materials (А∞). It has been established that A∞ of the chitosan/montmorillonite composite sorbent exceeds the maximum sorption capacity for the original chitosan by more than two times.The effect of pH on the sorption of copper ions by chitosan-based sorbents is due to the competition of metal cations and protons for sorption sites. In the course of competitive chemisorption, protons deactivate amino groups - the main sorption centers, converting them into an inactive, H-salt form, which leads to a decrease in the sorption capacity of chitosan in relation to copper ions.Changes in the composition of the modified sorbent compared to the original chitosan are confirmed by infrared spectroscopy data. Microscopic studies using the method of scanning electron microscopy show the presence of changes in the surface structure of chitosan granules when montmorillonite is introduced into the composition of the sorbent.

Study on impregnation process optimization for regenerating the spent V2O5-WO3/TiO2 catalysts

It is of great economic value and environmental significance to extend the service life of commercial SCR catalysts. Water and acid wash as well as thermal regeneration were often used to remove toxic substances (such as dust, metal sulfates and metal chlorides) residual on catalyst surface so as to reduce the replacement frequency of catalyst, but easily lead to the loss of active components. In this paper, impregnation method was used to supplement the lost active components of the spent honeycombed V2O5-WO3/TiO2 (labeled as VW/Ti) catalyst, and the effects of drying duration and impregnation solution concentration on NH3-SCR performance of catalyst were studied. The results showed that the catalyst dried for 6 h at 110 °C exhibited the best deNOx activity and sulfur/water resistance. Further prolonging or shortening drying duration reduced the catalytic activity instead. It can be attributed that proper drying duration constructs abundant pore channels inside catalyst, optimizes active components dispersion, reduces diffusion resistance of reactants into the inner surface and provides more effective active sites on catalyst surface for adsorption and oxidation of reactants. With rise of V content in impregnation solution from 1.06 wt.% to 3.61 wt.%, deNOx activity as well as SO2/H2O resistance of catalyst improves at 150–300 °C. Besides, key influence factors are also discussed based on reaction kinetics analysis.

Influence of Organic and Inorganic Compounds of Various Metals on the Synthesis of Polysaccharides by the Medicinal Mushroom Trametes versicolor.

To date, basidiomycetes are considered to be promising objects of biotechnology, due to a number of biologically active compounds, such as polysaccharides and triterpenes. These compounds have a high therapeutic potential and demonstrate immunomodulatory, antiviral, and antifungal activities. The purpose of this study was to study the effect of various concentrations of metal citrates and sulphates on the content of exo- and endopolysaccharides of the fungus Trametes versicolor. The mycelium was grown by deep cultivation on a semisyntheticglucose-peptone-yeast medium with different contents of zinc, copper, and manganese salts, after which the extraction and measurement of the concentration of polysaccharides were carried out. The results obtained showed that copper citrate at a concentration of 4 mg/L had the greatest positive effect on biomass yield. The intensity of biomass growth on a nutrient medium with copper citrate increased by 80%. Zinc citrate increased the content of exopolysaccharides by 29% compared to the medium without metal salts. When manganese citrate was added to the medium, the productivity of synthesis decreased, but an increase in the growth rate of mycelium biomass was observed. Sulphates of these metals led to a decrease in the productivity of exopolysaccharide synthesis by 12% for zinc and 35% for manganese. The addition of both copper citrate and copper sulphate to the medium led to a decrease in the synthesis productivity by 66 and 24%, respectively. The introduction of both citrates and sulphates of these metals into the culture medium led to an increase in the percentage of endopolysaccharides in the mycelium of the fungus. Copper citrate enhances Trametes versicolor biomass by 80%. Zinc citrate increases exopolysaccharide content by 29%. Copper sulphate optimizes endopolysaccharide production.

Investigation of X-ray shielding effect of coated textile materials

The rapid development of technology has led to an increase in radiation sources. Electronic devices such as mobile phones, televisions, and computers, frequently used in daily life, are among the primary radiation sources. There are three principles for protection from radiation. These; are time, distance, and armor. Shielding is the most effective method for radiation protection.Radiation-shielding textile products containing lead are used to protect from radiation. Lead is the most used material in shielding due to its high atomic number and density. Lead's toxic, heavy, and brittle nature has led to the search for alternative shielding materials.This study aimed to develop textile materials that have shielding properties against X-rays. Within the scope of the study, three different dispersion preparations containing 60% by weight of Barium Sulfate, Bismuth Oxide, and Tungsten Oxide metal powders were made. Prepared dispersions were applied to four different fabrics with different constructions by a knife coating method. The radiation attenuation ratios of coated fabrics against X-rays at tube voltages of 40 kV, 60 kV, 80 kV, and 120 kV were investigated. As a result of the study, textile products with shielding properties against X-rays were obtained.

Contrasting Miscibility of Ionic Liquid Membranes for Nearly Perfect Proton Selectivity in Aqueous Redox Flow Batteries

AbstractIon‐selective membranes are widely used in various energy storage applications. However, conventional polymer‐based ion‐selective membranes, such as Nafion, are not perfectly ion‐selective, leading to a significant permeation of undesirable ionic species. As the imperfect ion‐selectivity of membranes leads to the failure of energy storage devices, much effort is devoted to improving membrane ion‐selectivity. Herein, an immiscible liquid‐state membrane is introduced for aqueous redox flow batteries. As hydrophobic ionic liquids are immiscible with aqueous catholyte and anolyte solutions, they separate the two without crossover. This property renders them suitable for use as a membrane for aqueous redox flow batteries. In addition, ionic liquids with long side alkyl chains, such as 1‐hexyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM‐TFSI), are miscible with sulfuric acid, whereas transition metal sulfates remain insoluble in HMIM‐TFSI. For this reason, HMIM‐TFSI is selectively permeable to protons and remains impermeable to transition metal cations. As a result, the HMIM‐TFSI membrane is almost perfectly proton‐selective, leading to negligible permeability of unfavorable ionic species, such as transition metal cations. Eventually, the HMIM‐TFSI membrane shows the excellent electrochemical performance of vanadium redox flow batteries, such as negligible self‐discharge over 2800 h, high Coulombic efficiency (≈99%), and stable capacity retention over 100 cycles.

(Invited) Structure and Dynamics of Interfacial Species in Electrical Double Layer

Understanding electrochemical processes is of importance for many industrial and scientific fields. Especially, interfacial species, such as electrolyte ions and solvent significantly affect electrochemical reaction activity. Surface oxide species also promote or inhibit various electrode reactions; therefore, the oxidation processes of metal electrode have been investigated using in situ vibrational spectroscopy. Infrared (IR) spectroscopy is an important tool because it can detect the complementary vibrational modes of surface oxide species. However, observation of the low-frequency mode is restricted by infusible IR windows such as CaF2, that are generally used in the IR reflection absorption spectroscopy (IRAS). We developed a complementary IR method that can be used to avoid contamination by dissolved ions from window material. The fusible low-pass IR window can be applied to in-situ IRAS measurements [1,2]. The adsorbed hydroxide was observed on the single crystal Pt electrodes depending on the surface orientation, its coverage was correlated with the decrease in oxygen reduction reaction activity [3]. Recent time resolved X-ray diffraction measurements revealed that there is a delay in the approach of alkali metal cations to surface because the interfacial water causes a blocking effect [4]. Therefore, the kinetics of approaching step in the EDL is significantly different from that of migration in the bulk phase, and the adsorption rate depends on the hydration structure, ionic valence, and ionic size. Although X-ray diffraction provides a distribution of interfacial species, it does not provide sufficient information about species identification and molecular orientation. We investigated the coadsorption dynamics of metal cation and (bi)sulfate anion using time resolved IR measurement [5]. Boron doped diamond (BDD) is a promising material of which properties are significantly different from those of metals and other carbon materials. However, the complex atomic arrangement and oxidation state of the polycrystalline BDD surface inhibit an atomic level study on the relationship between the electrochemical response and surface structure. More detailed surface analyses are necessary for the investigation of the electrode surface of BDD. We applied in situ ATR−IR spectroscopy to reveal the oxidative species and dopamine oxidation on the BDD electrode [6,7].[1] M. Nakamura, Y. Nakajima, N. Hoshi, H. Tajiri, O. Sakata, ChemPhysChem, 14, 2426 (2013).[2] M. Nakamura, Y. Nakajima, K. Kato, O. Sakata, N. Hoshi, J. Phys. Chem. C, 119, 23586 (2015).[3] T. Kumeda, H. Tajiri, O. Sakata, N. Hoshi, M. Nakamura, Nat. Commun., 9, 4378 (2018).[4] M. Nakamura, H. Kaminaga, O. Endo, H. Tajiri, O. Sakata, N. Hoshi, J. Phys. Chem. C, 118, 22136 (2014).[5] M. Nakamura, T. Banzai, Y. Maehata, O. Endo, H. Tajiri. O. Sakata, N. Hoshi, Sci. Rep., 7, 914 (2017).[6] T. Ogose, S. Kasahara, N. Ikemiya, N. Hoshi, Y. Einaga, M. Nakamura, J. Phys. Chem. C, 122, 27456 (2018).[7] R. Hosoda, N. Kamoshida, N. Hoshi, Y. Einaga, M. Nakamura, Carbon, 171, 814 (2021).

How Do Impurities in Electrolytes Affect the Electrochemical Performance of Oxides in Lithium-Ion Batteries?

The recovery and treatment of spent LIBs has already been studied extensively. On one hand, the hydrometallurgical recovery of cathode materials has aroused widespread attention because of its low energy consumption and benefit to the environment. On another hand, the purification of the materials reclaimed from spent batteries is a challenging process with high probability that, later, some remaining impurities such as transition metal carbonates and sulfates could be released into the electrolyte. In this way the impurity content will have a serious impact on the final performance of the battery. To this point different electrochemical and analytical measurements were conducted to elucidate the effects of impurities in the electrolyte formulation, specifically Li, Mn, Co, Ni, and Al carbonates, sulfates, and acetates. The base LP30 electrolyte was intentionally contaminated with a maximum concentration of selected impurity to study the effects of the contaminated electrolyte on the electrode. Different combinations and varieties were explored correspondingly. Test setups were based on both, NMC811 in half cells (vs. Li) and symmetrical Li||Li cells, and the influence of contaminations was thus exploited on the Li counter electrode and on the NMC811 in Li||NMC811 configuration. A number of standard and advanced electrochemical test techniques such as CC-CV, electrochemical impedance, rate capability tests, GITT, and CV was applied for a fully understanding of the electrochemical characteristics of standard cathode active materials such as NMC811 when electrolytes with (artificially downgraded) low purity levels are present. The presentation will focus on discussion of results regarding the presence of transition metals Ni, Co, and Mn as impurities in the electrolyte which showed a significant impact on the electrochemical performance of the tested cells. When the concentration of the impurities increases, both the overpotentials at the cathode and the rate of capacity decay during cycling increase as well. The data shown will be very helpful for the researchers to understand the impact of impurities on the performance of oxide-based LIB cathode materials.