Effect Of Electrolyte Composition Research Articles

Investigating the expansion behavior of silicon nanoparticles and the effects of electrolyte composition using a graphene liquid cell

Understanding the volume expansion behavior of Si anodes and their interaction with electrolyte environments is crucial for developing high-performance lithium-ion batteries (LIBs). This study utilizes a graphene liquid cell for in situ imaging to systematically investigate the volume expansion and etching behavior of Si anode nanoparticles in different electrolyte environments. Comparative experiments on Si@C core-shell nanoparticles assess their volume expansion dynamics. The findings reveal significant variation in the expansion rate of nano Si depending on the electrolyte environment, with chemical etching observed under specific conditions. Conversely, Si@C core-shell structures show mitigated expansion due to the confinement effect of the carbon matrix. Battery performance experiments validate these results, demonstrating the excellent cycling stability of Si@C anodes. Various coating agents are explored to optimize Si@C structures, with dopamine thin layer coating exhibiting the best cycling stability. This study offers fundamental insights into Si anode expansion, electrolyte effects, and carbon coating impacts, advancing LIB technology.

Enhancing protonic ceramic electrolysis cell performance through electrolyte composition optimization

Polarization resistance, chemical stability against high steam, and faradaic efficiency (FE) are important parameters for steam electrolysis using protonic ceramic electrolysis cells (PCEC) at an intermediate temperature range of approximately 500 °C. To investigate the effects of electrolyte composition on these parameters, PCECs were fabricated using two electrolyte compositions: one without Zr, Ba(Ce0.8Y0.1Yb0.1)O3-δ (BCYYb), and one with Zr, Ba(Ce0.3Zr0.5Y0.1Yb0.1)O3-δ (BCZYYb), as well as a double-layered electrolyte BCYYb/BCZYYb. Although Zr in BCZYYb is required for chemical stability, BCYYb without Zr can also be chemically stable against high steam at 500 °C. Additionally, BCYYb has a higher conductivity compared to BCZYYb, which contributes to lower ohmic resistance and the highest peak power density in H2 fuel at 700 °C (2.04 W/cm2) among the cells with three different electrolytes. However, the BCYYb electrolyte exhibits a slightly higher polarization resistance than BCZYYb. In PCEC operation at 500 °C, the electrolyte composition significantly affects the FE. At a high current density (0.8 A/cm2), the FE of the PCEC with the BCYYb electrolyte (85 %) is significantly larger than that with BCZYYb (68 %).

Cover Image, Volume 141, Issue 20

Wet spinning of chitin nanowhiskers: Effects of electrolyte composition in coagulation baths on mechanical properties and nanowhisker orientation by Jun Araki and Minami Nakajima. DOI: 10.1002/app.55335 image

Effect of Electrolyte Composition and Mass Transport on Electrochemical Hydrogenations of a Terminal Alkynol

AbstractElectrochemical hydrogenations (EChH) constitute a sustainable alternative to conventional thermocatalytic hydrogenation. Here, we explored the EChH of the vitamin E and A synthon 2‐methyl‐3‐butyn‐2‐ol in a scalable zero‐gap electrolyzer and revealed crucial effects of electrolyte composition and convection parameters to consider for optimization. We show that high Faraday efficiencies can be achieved with low to moderate concentrations of neutral or alkaline electrolytes. While the flow rate has a strong impact on performance, electrode compression and cell orientation can be used for fine tuning. We achieved a Faraday efficiency of up to 69 % for the targeted semi‐hydrogenated product at current densities of 80 mA cm−2 at 2.2 V cell voltage and a concentration of 1 M 2‐methyl‐3‐butyn‐2‐ol.

Electrochemical CO2 conversion in eutectic Li-Ba and Li-Ca carbonate mixtures

Here, the impact of electrolyte selection and electrolysis temperature on carbon morphology, energy consumption, and voltage efficiency in molten Li2CO3-BaCO3 and Li2CO3-CaCO3 electrolytes during 90 min 10 A constant current electrolysis are investigated. The scarcity of experimental investigations into these binary electrolytes, coupled with a lack of systematic investigation of temperature effects, necessitates further examination. The comprehensive analysis of the produced carbon reveals that both electrolyte composition and temperature influence carbon morphology. At lower temperatures the effect of electrolyte composition to the morphology is a more significant. The type and amount of metallic impurities mixed with the carbon vary depending on the electrolyte composition and electrolysis temperatures. The results from Li2CO3-CaCO3 electrolyte show more promising compared to results from Li2CO3-BaCO3 electrolyte in terms of product quality. Regarding electrolysis power and voltage efficiency, Li2CO3-CaCO3 proves equal or superior to other electrolytes, depending on temperature. Heat generation occurs in all the experiments, which emphasizes the importance maintaining a constant electrolysis temperature in industrial processes to manage heat generation effectively.

Wet spinning of chitin nanowhiskers: Effects of electrolyte composition in coagulation baths on mechanical properties and nanowhisker orientation

AbstractFibers composed solely of chitin nanowhiskers (ChNWs) with extreme uniaxial orientation can be successfully wet‐spun into coagulation baths containing 70% ethanol and various types of electrolytes (LiCl, HCl, NaCl, and MgSO4) with ionic strengths (J) of 0.075–0.3. The obtained fibers exhibited high ChNW orientation with degrees of orientation (S) ranging from 0.77 to 0.96. Fibers produced using NaCl‐containing coagulation baths contained residual NaCl crystals that were subsequently removed by rinsing. In contrast, LiCl and MgSO4, which originated from the corresponding baths and similarly remained within the fibers, did not crystallize due to hygroscopic deliquescence and the adaptation of SO42− ions for potential ionic crosslinking, respectively. Spinning with LiCl‐containing baths yielded fibers with maximum Young's modulus, stress at break, and strain at break of 7.9 ± 0.6 GPa, 58.8 MPa, and 1.13%, respectively. These mechanical properties of the unwashed fibers improved with J, while washing out the residual electrolytes and subsequent drying led to a decrease in the Young's modulus and an increase in the stress at break and strain at break. An increase in S was observed only in the fibers obtained using baths with J ≥ 0.3.

Optimizing composition of K4Fe(CN)6-based redox-active electrolyte as a key factor for improving electrochemical performance of rice-husk-derived activated carbon in supercapacitor electrode

Currently, the use of redox-active additives is an effective way to enhance the electrochemical performance of supercapacitors. Despite a lot of publications in the literature, the choice of redox-active electrolyte composition is still unclear. This work focuses on the study of the correlation between the K4Fe(CN)6 fraction (0–0.05 M) in 1 M Na2SO4 and electrochemical characteristics of rice-husk-derived activated carbon (AC). The effect of electrolyte composition was clarified by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy. The increase in the K4Fe(CN)6 fraction in the electrolyte significantly improved the specific capacitance of AC from 59 up to 288 F/g at a current density of 1 A/g. Nevertheless, despite the fact that the concentrated 0.05 M K4Fe(CN)6–1 M Na2SO4 electrolyte provided excellent capacitance, it led to a high self-discharge and charge transfer resistance, not beneficial for electrochemical applications.

The Effect of Electrolyte Composition on the Performance of a Single‐Cell Iron–Chromium Flow Battery

Flow batteries are promising for large‐scale energy storage in intermittent renewable energy technologies. While the iron–chromium redox flow battery (ICRFB) is a low‐cost flow battery, it has a lower storage capacity and a higher capacity decay rate than the all‐vanadium RFB. Herein, the effect of electrolyte composition (active species and supporting electrolyte concentrations), Fe/Cr molar ratio, and supporting electrolyte type (HCl and H2SO4) on the performance (current efficiency (CE), voltage efficiency (VE), energy efficiency, discharge capacity, and capacity decay) of an ICRFB is investigated. The storage capacity of the optimum electrolyte (1.3 m FeCl2, 1.4 m CrCl3, 5.0 mm Bi2O3 in 1.0 m HCl) is 40% higher (from 17.5 to 24.4 Ah L−1), while the capacity decay rate is tenfold lower (from 3.0 to 0.3% h−1) than the performance of the previously used 1.0 m FeCl2, 1.0 m CrCl3 in 3.0 m HCl. At the optimum Fe and Cr concentrations and ratio in 0.5 m HCl, a near constant CE (92.3%), VE (78.7%), and EE (72.6%) are obtained over 50 cycles. The significantly higher capacity decay when using 1.0 m H2SO4 (1.6% h−1) compared to 1.0 m HCl (0.3% h−1) confirms that HCl is the more suitable supporting electrolyte.

Effect of electrolyte composition on the formation of PEO coatings on AA2024 aluminium alloy

Since the electrolyte composition plays a crucial role in the plasma electrolytic oxidation (PEO) coating formation process, a systematic and in-depth study was proposed to identify an electrolyte composition for fast PEO coating growth on AA2024 alloy. Different concentration ratios of mixed alkaline electrolytes (hydroxide, silicate and phosphate) were investigated. PEO process was conducted at low constant current density of 50 mA/cm2, which is intended for lowering the energy consumption. Results demonstrated that the breakdown voltage of PEO coatings is directly proportional to the logarithm of electrolyte resistivity. The coating growth mechanism showed two main directions. The thickening of the coating mainly depends on the rapid deposition of electrolyte compounds in Si-based electrolyte, and the coating growth occurs mainly towards the electrolyte/coating interface. Contrary, in OH-, and P-based electrolytes, the inward coating growth was dominating mainly by substrate oxidation. A variety of phases as a function of different electrolyte compositions and final voltages were observed. With high final voltages (over 470 V) for coatings produced in mixed electrolytes with low concentrations of hydroxide, silicate or phosphate (2 and 6 g/L), γ-Al2O3 crystalline phase predominates in the PEO layer composition. However, only a low efficiency of coating growth can be reached. In the electrolytes with high silicate concentrations accompanied by an increase of phosphate concentration, the final voltage is around 455 V and the coating composition is dominated by an amorphous phase in combination with crystalline mullite and γ-Al2O3. High silicate-phosphate contents (18–24 g/L) in mixed electrolytes with low final voltages of about 360 V results in a fully amorphous PEO layer and significantly increases coating thickness. A combination of low content of hydroxide, high silicate with increasing content of phosphate in mixed electrolyte increases the coating thickness, and improves the density and uniformity of the overall PEO layers.

Effect of electrolyte composition on the structure and tribological properties of ceramic coatings obtained by microarc oxidation

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Electrochemical synthesis and characterization of Cu2O nanoparticles: Effect of electrolyte composition

Electrochemical synthesis and characterization of Cu2O nanoparticles: Effect of electrolyte composition

Effects of Electrolyte Composition on the Electrochemical Properties of an Aluminum Alloy Electrode for Al-Air Batteries

Aluminum-air batteries that use alkaline electrolytes have the advantage of a high operating voltage, but the aluminum alloy electrodes experience high corrosion rates. To address this issue, a promising solution is proposed, which involves mixing neutral electrolytes with the alkaline electrolyte. In this study, we analyzed the electrochemical characteristics of aluminum alloy electrodes in electrolyte solutions containing varying concentrations of NaCl added to a 1 M NaOH alkaline electrolyte solution to understand the effect of neutral electrolytes on the discharge performance of aluminum-air batteries. The results obtained from potentiodynamic polarization tests, electrochemical impedance spectroscopy, three-electrode discharge tests, and open-circuit potential tests confirmed that the corrosion reaction and discharge voltage of aluminum alloy electrodes are influenced by the concentration of NaCl in the alkaline electrolyte solution. The corrosion rates and discharge voltages decreased as the concentration of neutral electrolyte increased, indicating that the electrochemical properties of aluminum-air batteries are highly dependent on the electrolyte composition.

Alloying Element Depletion and Phase Transition in Stainless Steel 304 Induced by PEO Treatment in KOH- and TaOH-Rich Electrolyte

Due to their lower cost and good mechanical and corrosion properties, ferrous materials such as stainless steel (SS) are commonly used as bio-materials, mainly as surgical instruments and implants. Surface treatments such as plasma electrolytic oxidation (PEO) can be a valuable tool to increase corrosion resistance and enhance the bio-compatibility of metallic materials. In this scenario, the current study evaluated the effect of electrolyte composition on the surface of SS304 submitted to PEO treatment. The variation in the amount of KOH and Ta(OH)5 promoted significant changes in the surface characteristics, forming Fe-rich oxide plates, Ta-rich agglomerate particles, and an exposed substrate. The PEO-treated substrates were depleted of some alloying elements (Cr, Ni, and Mn), which, allied to the Ta-enrichment, affected the roughness, wettability, phase stability, micro-hardness, and corrosion resistance. All the PEO treatments presented a phase composition of single γ-Fe instead of a dual α + γ phase from the untreated substrate, which was understood in terms of the Nieq-Creq diagram. The corrosion tests indicated that the PEO treatment significantly affected the corrosion parameters, having the presence of a non-uniform oxide layer. The findings show that it is possible to control the chemical and phase composition of SS304 material employing PEO treatment.

Effect of electrolyte composition and deposition voltage on the deposition rate of copper microcolumns jet electrodeposition

Jet electrodeposition (Jet ECD) is widely recognized for its potential to achieve high deposition rates and adequate field fixation. Currently, the rapid deposition of microscale copper structures remains a significant challenge. In this study, we address this challenge by employing a custom-made microcapillary glass nozzle and optimizing key plating parameters, including H2SO4, CuSO4, KCl concentration, and applied voltage. Through systematic experimentation, we successfully deposited well-formed copper microcolumns with a diameter of 70 μm at a deposition rate of 19.8 μm/s. We discovered that higher concentrations of H2SO4, greater voltage, and the addition of Cl- ions were effective in increasing the deposition speed. Furthermore, a higher concentration of CuSO4 led to improved surface morphology. Additionally, we conducted COMSOL simulations to investigate the influence of voltage and conductivity on the deposition speed. Our research results contribute to the understanding and optimization of rapid fabrication processes for copper microstructures through jet electrodeposition at the microscale.

Cathode Dry Operation of Anion Exchange Membrane Water Electrolysis

The scale of hydrogen production from renewable energy sources is expected to increase worldwide in the future. Water electrolysis is a practical way to produce hydrogen from renewable energy sources. Water electrolyzers that use an anion exchange membrane (AEM) are expected to be new devices for hydrogen (H2) production that achieve high performance at low capital cost.In AEM water electrolysis, “cathode dry operation” is sometimes applied. In this operation mode, water (electrolyte solution) is supplied only to the anode, not to the cathode where water is consumed in the reaction, keeping the cathode dry. In this way, relatively dry hydrogen can be extracted directly from the cathode, simplifying the hydrogen drying process. When water electrolyzers are installed in large quantities (over 1000 units), the cost of balance of plants (BOPs) is expected to account for the majority of system costs [1], and simplifying the BOPs are important for reducing system costs. However, it was observed that cathode dry operation would cause concentration overpotentials due to water diffusion through the membrane [2], which may limit the current density and membrane thickness to prevent cathode dry-out.In this study, the effects of electrolyte composition and concentration on the water behavior in the membrane during cathodic dry operation on the electrolysis performance were quantitatively investigated.AcknowledgementThis work was supported partly by the New Energy and Industrial Development Organization (NEDO) through the Advancement of Hydrogen Technologies and Utilization Project (P 14021). The authors wish to express their gratitude to Tokuyama Corporation for their support and helpful advice.

(Best Student Presentation) Is Solid-Electrolyte Interphase Formation Affected by Electrode Conductivity?

Accurate analysis of the mechanism of interphase formation and its composition is imperative for the development of stable and efficient lithium/sodium-ion batteries. One of the most practically scalable ways to optimize interphase chemistry and morphology for reversible charge transport is electrolyte engineering and the application of formation protocol with specific current/voltage conditions. In this sense, the analysis of structure and dynamics within the electrode/electrolyte interface, i.e., the so-called electric-double layer, is essential to predicting the possible chemistry and mechanism of interphase formation.The latest was recently advanced by understanding the effect of electrolyte chemistry, e.g., the chemical structure of solvent and salt, their ratio, the presence of additives etc.1–4 Although, the role of electrode material is often neglected which creates an impression that both metallic and semiconductive electrodes form an identical electric-double layer within the same electrolyte, therefore, the mechanism of interphase formation should be very similar regardless of the chemical nature of the electrode.Here, we used examples of sodium-salt-containing ionic liquids and carbonate electrolytes to demonstrate that structural changes at the electrified interface are greatly affected by the dielectric nature of electrode material. The key observation is attributed to the different abilities of electrified electrodes to form van der Waals interactions with the electrolyte species. This affects the concentration of metal-anion complexes in relation to organic solvent near the electrode, therefore, different interphase chemistry will be formed (inorganic-rich vs. organic-rich), and different formation protocols must be used. For example, Fig. 1 shows the summary of this phenomenon for ionic liquid electrolytes with 50 mol% sodium bis(fluorosulfonyl)imide. Besides, metallic and semiconductive electrodes demonstrated different affinity toward polar organic solvent, i.e., ethylene carbonate, in 1.0 M NaPF6 in EC:DMC (1:1 by volume) electrolyte. This presentation will discuss the details of these fundings and introduce future applications. Fig. 1 | Schematic relationships between solid-electrolyte interphase (SEI) composition, applied current of preconditioning cycling, and dielectric nature of anode material.References Zheng, X. et al. Toward High Temperature Sodium Metal Batteries via Regulating the Electrolyte/Electrode Interfacial Chemistries. ACS Energy Lett. 7, 2032–2042 (2022).Rakov, D. A. et al. Engineering high-energy-density sodium battery anodes for improved cycling with superconcentrated ionic-liquid electrolytes. Nat. Mater. 19, 1096–1101 (2020).Rakov, D. A. et al. Polar Organic Cations at Electrified Metal with Superconcentrated Ionic Liquid Electrolyte and Implications for Sodium Metal Batteries. ACS Mater. Lett. 4, 1984–1990 (2022).Rakov, D. et al. Stable and Efficient Lithium Metal Anode Cycling through Understanding the Effects of Electrolyte Composition and Electrode Preconditioning. Chem. Mater. (2021). doi:10.1021/acs.chemmater.1c02981 Figure 1

Surface enlargement of tantalum capacitor foils by pulsed direct current etching and laser cladding

Electrochemical etching for the surface enlargement of tantalum capacitor foils has always been a challenge, due to the ultra-high chemical stability of tantalum foils. Herein, pulsed direct current etching of tantalum capacitor foils assisted by laser cladding was investigated and high surface area enlargement was achieved. The effects of electrolyte composition, power supply parameters and external environment on the etching process of tantalum foil were systematically studied, to screen out the best experimental conditions. Furthermore, iron particles with diameters of 3–5 μm were successfully laser cladded on the surface of tantalum foils. These particles will be easily etched in the electrochemical process to form more previous pores, which can serve as etching sites for further tantalum foil etching. Under the best conditions, high-specific capacitance tantalum foils with a capacitance of 155.1 nF/mm2 were obtained at a high forming voltage of 100 V, which were 8 times larger than the unetched light foils. The surface enlargement of tantalum capacitor foils is expected to realize the development of novel tantalum capacitors with both high operating voltage and high capacitance.

Effect of Electrolyte Composition on Plasma Electrolytic Polishing of Titanium Alloys

Effect of Electrolyte Composition on Plasma Electrolytic Polishing of Titanium Alloys

Effect of electrolyte composition on the surface characteristics of plasma electrolytic oxidation coatings over Ti[sbnd]40Nb alloy

The present work aims to develop corrosion-resistant and cytocompatible coatings on Ti40Nb alloy by the plasma electrolytic oxidation (PEO) process. Usually, PEO coatings on niobium substrate with superior surface characteristics are obtained using a silicate-based electrolyte system, and a phosphate-based electrolyte system is used for titanium substrate. Till date, electrolyte system composition is not optimised for the PEO coatings on Ti40Nb alloys. To study the influence of electrolyte composition on PEO coating properties over Ti40Nb alloy, three different concentrations of phosphate and silicate (75:25, 50:50, and 25:75) and a fixed amount of KOH were used, and their surface characteristics and corrosion properties were evaluated in this study. We found that coatings formed with an equal proportion of phosphate and silicate in an electrolyte system are dense, compact, thick and corrosion-resistant. A coating aimed for high bioactivity is also developed by adding hydroxyapatite (HA) nanoparticles to an equal proportion (50:50) electrolyte system. After the successful development of the PEO coatings over Ti40Nb alloy, its phase composition, surface morphological features, wettability, scratch resistance, and corrosion properties are examined. The cell viability and live/dead cell morphology of L-929 fibroblast cells were evaluated for untreated Ti40Nb alloy, PEO-treated Ti40Nb alloy, and Ti40Nb alloy PEO-treated with hydroxyapatite nanoparticles. All surface-modified samples exhibited better corrosion resistance than the untreated alloy. Ti40Nb alloy PEO treated with phosphate: silicate electrolyte system (50:50) exhibited better scratch resistance, higher wettability, bioactivity, favourable chemical composition, and surface morphological features than the other ratios of phosphate and silicate (25:75 and 75:25). Meanwhile, Ti40Nb alloy PEO treated with hydroxyapatite nanoparticles addition showed better cytocompatibility than without HA addition.

One-Step Electrochemical Synthesis and Surface Reconstruction of NiCoP as an Electrocatalyst for Bifunctional Water Splitting.

We adopted a simple one-step electrochemical deposition to acquire an efficient nickel cobalt phosphorus (NiCoP) catalyst, which avoided the high temperature phosphatization engineering involved in the traditional synthesis method. The effects of electrolyte composition and deposition time on electrocatalytic performance were studied systematically. The as-prepared NiCoP achieved the lowest overpotential (η10 = 111 mV in the acidic condition and η10 = 120 mV in the alkaline condition) for the hydrogen evolution reaction (HER). Under 1 M KOH conditions, optimal oxygen evolution reaction (OER) activity (η10 = 276 mV) was also observed. Furthermore, the bifunctional NiCoP catalyst enabled a high-efficiency overall water-splitting by applying an external potential of 1.69 V. The surface valence and structural evolution of NiCoP samples with slowly decaying stability under alkaline conditions are revealed by XPS. The NiCoP is reconstructed into the Ni(Co)(OH)2 (for HER) and Ni(Co)OOH (for OER) on the surface with P element loss, acting as real "active sites".