Electrolyte Solution Research Articles

Investigation on the microstructure and compressive behavior of open-cell copper- Al2O3 composite foams

The objective of this study is to evaluate the mechanical behavior and energy absorption characteristics of open-cell copper- Al2O3 composite foams fabricated using polyurethane foam with an average pore size of 1.2 mm and a combination of electroless and electrodeposition methods. During electroplating process, the composite foams were fabricated with varying amounts of Al2O3 particles (0.1, 0.6, 0.8, and 1 g/l) in electrolyte solution. To assess mechanical properties of the fabricated foams, uniaxial compression test was conducted to determine the maximum compressive strength, energy absorption density, efficiency, and specific energy absorption. The content of Al2O3 in the fabricated composite foams was evaluated using energy dispersive X-ray (EDX) analysis, and the microstructure was examined using scanning electron microscopy (SEM). The results indicate that the incorporation of Al2O3 particles significantly improves the mechanical properties of the copper-Al2O3 composite foam. Specifically, in the composite foam with 9.34 vol% of Al2O3 particles, the maximum compressive strength, total energy absorption, specific energy absorption, and energy absorption efficiency reach 1.03 MPa, 6.48 MJ m−3, 1.9 J g−1, and 75%, respectively. This amount of alumina particles enhances the maximum compressive strength and total energy absorption of open-cell copper foam by approximately 30% and 100%, respectively. However, the mentioned parameters slightly decreased with an increasing amount of Al2O3 particles up to 16.32 vol%. These significant improvements in the mechanical properties of these foams make them well-suited for high-strength applications.

Synergistic advancements in battery-grade energy storage: Nb2C/MoTe2(PANI) hybrid electrode material as a enhanced electrocatalyst for hydrogen reduction reaction

The inherent stratified arrangement, narrow energy band gap, and similar electrical conductivity of two-dimensional (2D) molybdenum ditelluride (MoTe2) have attracted considerable interest for their use in supercapacitors. Integrating Niobium Carbide (Nb2C) into the MXene framework significantly improves self-aggregation and electrochemical activity. The current work, Nb2C/MoTe2 was synthesized via a cost-effective and simple hydrothermal technique. However, the Nb2C/MoTe2 nanocomposite shows pronounced self-stacking problems during electrode fabrication, which can significantly restrict the capacity for storing charge. PANI was incorporated as a dopant to address these challenges and enhance electrochemical activity, such as Nb2C/MoTe2(PANI). The performance of supercapacitors was assessed by electrochemical measurement in an aqueous electrolytic solution with a concentration of 2 M potassium hydroxide (KOH). Based on the GCD profile, the Nb2C/MoTe2(PANI) material demonstrates a notable specific capacity (Qs) of 270 C/g, energy density of 72.2 Wh/kg, and power density of 935 W/kg at a current density of 2 A g-1. In contrast, the composite material demonstrates a specific capacity of 185 C/g, as proven by CV conducted at 5 mV/s. In addition, the nanohybrid has a high level of capacitance retention of 87.6 % after undergoing 8500 consecutive cycles. The exceptional efficiency of supercapacitor applications can be ascribed to the enhanced mechanical flexibility, active cooperation, and synergistic impacts of Nb2C/MoTe2 and PANI. The Nb2C/MoTe2(PANI) nanocomposite possesses significant potential for eco-friendly energy generation and allows for a simple single-step fabrication procedure. Consequently, it can serve as an electrode for highly efficient supercapacitors.

The influence of salt concentration on the dissolution of microbubbles in bulk aqueous electrolyte solutions.

We study microbubbles (MBs) in aqueous electrolyte solutions and show that increasing the salt concentration slows down the kinetics of MB dissolution. We modified the Epstein-Plesset theory and experimented with NaCl aqueous solutions to estimate the MB effective surface charge and to compare it with predictions from the modified Poisson-Boltzmann theory. Our results reveal a mechanism responsible for the change in the dissolution of MBs in aqueous electrolyte solutions, with implications for emerging fields ranging from physics of solutions to soft and biological matter.

Phonon spectroscopy and features of low-temperature heat capacity of solid solutions of electrolytes

The kinetic characteristics of thermal frequency phonons in the region of helium temperatures in ceramic samples of the Ce1–xGdxO2–y electrolyte solid solution have been studied. To explain the temperature dependence of the phonon mean free path, we used the previously performed calculations of the energy of vacancy formation in the anion sublattice of a solid solution of zirconium dioxide stabilized by yttrium ZrO2:Y2O3 (YSZ) with a similar crystal structure. It is shown that in the Ce1–xGdxO2–y system under study, the formation of structural defects associated with the presence of vacancies in the anion sublattice with energy Δ = 8.53 K is possible. It has been established that analysis of the temperature dependences of the YSZ heat capacity allows one to trace the degree of disorder (amorphization) of the solid solution depending on its level of stabilization.

Differentiable modeling and optimization of non-aqueous Li-based battery electrolyte solutions using geometric deep learning

Electrolytes play a critical role in designing next-generation battery systems, by allowing efficient ion transfer, preventing charge transfer, and stabilizing electrode-electrolyte interfaces. In this work, we develop a differentiable geometric deep learning (GDL) model for chemical mixtures, DiffMix, which is applied in guiding robotic experimentation and optimization towards fast-charging battery electrolytes. In particular, we extend mixture thermodynamic and transport laws by creating GDL-learnable physical coefficients. We evaluate our model with mixture thermodynamics and ion transport properties, where we show improved prediction accuracy and model robustness of DiffMix than its purely data-driven variants. Furthermore, with a robotic experimentation setup, Clio, we improve ionic conductivity of electrolytes by over 18.8% within 10 experimental steps, via differentiable optimization built on DiffMix gradients. By combining GDL, mixture physics laws, and robotic experimentation, DiffMix expands the predictive modeling methods for chemical mixtures and enables efficient optimization in large chemical spaces.

Synthesis of chemical bath deposited Manganese oxide thin films for high performance supercapacitor

The present study addresses the growing need for high-performance supercapacitors, emphasizing the benefits of Manganese oxide (MnO2) thin film as a promising electrode material. Thin film deposition of MnO2 is achieved through Chemical Bath Deposition (CBD) method by varying the deposition time on the stainless steel substrate. In order to investigate impact of deposition time on various physico-chemical properties of MnO2 thin films, different characterizations were carried out like X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, cyclic voltammetry, Galvanostatic charge–discharge analysis. The deposited MnO2 thin films are subsequently studied for their electrochemical properties in a 1 M KOH electrolyte solution. Remarkably, the best specific capacitance is obtained about 296.5 F/g at current density of 0.5 A/g, with 86.42 % retention after 5000 cycles, highlighting the excellent electrochemical performance of the MnO2 thin films deposited at 6 hrs of reaction time. This work highlights valuable insights into the CBD deposited MnO2 thin films for supercapacitor applications, providing a foundation for the development of an efficient, low-cost, and scalable energy storage devices.

Effect of charge-discharge with higher capacitance performance of Ni-substituted CoFe2O4 magnetic nanoparticles for energy storage

In this work, we synthesized NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) magnetic nanoparticles (MNPs) by using ultrasonication-assisted reverse chemical co-precipitation method. The X-ray diffraction (XRD) patterns confirm the single-phase with mixed spinel structure of the NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs with the crystallite size range between 12 nm - 17 nm. The molecular dynamics and oleic acid coated Ni-substituted CoFe2O4 magnetic nanoparticles were confirmed by FTIR measurements. The surface composition of NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs (Ni, Co, Fe and O) and their oxidation states were estimated using X-ray photoelectron spectroscopy. The NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs are spherical in shape and polycrystalline in nature, confirmed by FESEM and HRTEM measurements. The Ni-substituted CoFe2O4 MNPs with higher zeta potential (ζ) from −24 mV to -41 mV with an increase in Ni concentration, signifies the stable colloidal stability due to the electrostatic repulsion between MNPs. The DC magnetization (M-vs-H) measurements reveal the ferrimagnetic behavior of NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs, which suppress the saturation magnetization (MS) from 48.6 emu/g to 5.3 emu/g with the enhanced coercivity (HC) from 335 Oe to 1700 Oe with the substitution of Ni2+ ions is in corroboration with electron paramagnetic resonance (EPR) measurements. The enhanced EPR resonance field (Hres = 2335 Oe - 3261 Oe) with the substitution of Ni2+ ions is attributed to the generation of oxygen vacancies and defects, which are predominant in Ni0.8Co0.2Fe2O4, resulting in significantly enhanced electrochemical performance. Therefore, the three-electrode system was utilized to investigate the electrochemical properties of NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs. The Ni-substituted CoFe2O4 MNPs have demonstrated significantly enhanced capacity retention of 77 % even after 5000 cycles in 1 M H2SO4 electrolyte solution. NixCo1-xFe2O4 (0 ≤ x ≤ 0.8) MNPs exhibit an excellent specific capacity (Cs) of 794.5 F/g at a current density of 1 A/g, signifies the rate of redox reaction at surface electrolyte interface (SEI) is greatly influenced by the surface to volume ratio. Thus, with the enhancement of Ni2+ ions, redox reaction kinetics might become more efficient resulting in the enhanced charge storage capacity.

Antioxidant Activity of Asphaltene and Resinous Components in the Magnetic Field

Using the voltammetric method of oxygen electroreduction, an analysis of the antioxidant activity of resin-asphaltene components isolated from 2 crude oils of different compositions before and after exposure to a magnetic field was carried out. For the studied asphaltenes, weakly polar and polar resins, an increase or decrease in antioxidant activity is observed with increasing sample concentration in the background electrolyte solution. Petroleum antioxidants are part of a complex colloidal structural system and are associated with it by associative interactions that arise as a result of changes in the size and activity of associates of the petroleum system as a whole.

Tailored copper doped indium sulfide nanostructures as electrode material for supercapacitor and nano photocatalyst for dye degradation

The unique copper-doped indium sulfide nanocrystals are synthesized by a gentle hydrothermal process. XRD, FTIR, XPS, FESEM/EDX, UV-DRS, and PL were used to characterize the final samples. Copper-doped indium sulfide nanostructures can be exploited as an active catalyst in photodegradation and as an electroactive material in supercapacitors due to their distinctive architecture. The copper-doped indium sulfide catalyst exhibits 85 percent photodegradation using methylene blue dye under natural sunlight irradiation, and the electrochemical test showed a capacitance of 668 Fg−1 at 1 Ag−1 in a 2 M KOH electrolyte solution. For future generations, photocatalyst and electrode can function as more desirable materials.

A nanofluidic chemoelectrical generator with enhanced energy harvesting by ion-electron Coulomb drag

A sufficiently high current output of nano energy harvesting devices is highly desired in practical applications, while still a challenge. Theoretical evidence has demonstrated that Coulomb drag based on the ion-electron coupling interaction, can amplify current in nanofluidic energy generation systems, resulting in enhanced energy harvesting. However, experimental validation of this concept is still lacking. Here we develop a nanofluidic chemoelectrical generator (NCEG) consisting of a carbon nanotube membrane (CNTM) sandwiched between metal electrodes, in which spontaneous redox reactions between the metal and oxygen in electrolyte solution enable the movement of ions within the carbon nanotubes. Through Coulomb drag effect between moving ions in these nanotubes and electrons within the CNTM, an amplificated current of 1.2 mA cm−2 is generated, which is 16 times higher than that collected without a CNTM. Meanwhile, one single NCEG unit can produce a high voltage of ~0.8 V and exhibit a linear scalable performance up to tens of volts. Different from the other Coulomb drag systems that need additional energy input, the NCEG with enhanced energy harvesting realizes the ion-electron coupling by its own redox reactions potential, which provides a possibility to drive multiple electronic devices for practical applications.

Effect of the indirect sonication on the plasma formation and energy parameters in the cathodic regime of the plasma-driven solution electrolysis

Effect of the indirect sonication on the plasma formation and energy parameters in the cathodic regime of the plasma-driven solution electrolysis

An Overview of Different Water Electrolyzer Types for Hydrogen Production

While fossil fuels continue to be used and to increase air pollution across the world, hydrogen gas has been proposed as an alternative energy source and a carrier for the future by scientists. Water electrolysis is a renewable and sustainable chemical energy production method among other hydrogen production methods. Hydrogen production via water electrolysis is a popular and expensive method that meets the high energy requirements of most industrial electrolyzers. Scientists are investigating how to reduce the price of water electrolytes with different methods and materials. The electrolysis structure, equations and thermodynamics are first explored in this paper. Water electrolysis systems are mainly classified as high- and low-temperature electrolysis systems. Alkaline, PEM-type and solid oxide electrolyzers are well known today. These electrolyzer materials for electrode types, electrolyte solutions and membrane systems are investigated in this research. This research aims to shed light on the water electrolysis process and materials developments.

A-340 Analysis of OrganOx Liver Perfusate at the Point-of-Care on the Abbott iSTAT and Nova Glucometer to Support Clinical Evaluations of Donor Livers Prior to Transplantation

Abstract Background The recently FDA-approved OrganOx Metra normothermic perfusion system for maintaining donor livers under physiologic conditions prior to transplantation comes equipped with a limited onboard blood gas analyzer for monitoring pO2, pCO2 and temperature. In clinical practice, however, additional biomarkers are used to assess the functional performance of the donor liver, including perfusate lactate clearance and glucose utilization. Liver perfusate contains a mixture of packed red blood cells, albumin, heparin, antibiotic, and solutions of amino acids and electrolytes and bile salts to support metabolic function, and is a specimen type that is not approved by the FDA. Implementation of the OrganOx Metra at Loyola University Medical Center (LUMC), a quaternary care transplant center, led to the validation of liver perfusate for the evaluation of glucose and lactate at the point-of-care (POC) using the Nova STATStrip Glucometer and Abbott iSTAT CG4 cartridge, respectively. Methods Lactate was measured on the Abbott iStat CG4 cartridge, and glucose which was measured using the Nova STATStrip Glucometer. Recovery studies were performed by mixing liver perfusate (non-centrifuged, n=16 independent specimen) with heparinized whole blood. Results The average recovery for the evaluation of lactate was 100% (range = 78 to 122%), and the average recovery for glucose was 109% (range = 93 to 112%). Conclusions Recovery studies evaluating matrix effect for the analysis of lactate (Abbott iSTAT, CG4) and glucose (Nova STATStrip) in liver perfusate indicate that the matrix of the perfusate does not affect the analytical accuracy, as compared to heparinized whole blood, the FDA-approved specimen type. Measurement of the OrganOx liver perfusate for lactate and glucose on these POC devices demonstrates reliable assessments to guide transplant teams in evaluating the viability of donor livers.

Disodium Malate Electrolyte Additive Facilitates Dendrite-Free Zinc Anode: Deposition Kinetics and Interface Regulation.

Due to the presence of H2O within the solvated sheath of [Zn(H2O)6]2+ as well as reactive free water in the electrolyte bulk phase, the extended cycling of aqueous zinc-ion batteries (AZIBs) is significantly affected by detrimental side reactions and the growth of Zn dendrites. This study significantly enhances the long-term cycling stability of AZIBs by introducing a small amount of disodium malate (DM) into a 2m ZnSO4 electrolyte solution. DM involvement in the solvation sheath of Zn2+ reduces the desolvation energy of Zn2+, thereby mitigating the corrosion and hydrogen evolution reaction (HER) of the negative electrode surface by [Zn(H2O)6]2+ ions. Additionally, DM adsorption on the zinc surface retards the reduction kinetics of Zn2+ at anode, promoting uniform distribution and predominant deposition on the flat (002) crystal plane, thus reducing dendrite formation. The assembled Zn||Zn symmetric cell exhibits stable cycling for over 500 h at 10mA cm-2 and 5 mAh cm-2. The Zn||VO2 full cells with DM additive exhibits an ultralong cycling lifespan without capacity loss.

Role of Acoustic and Volumetric Properties in View to Estimate the Intermolecular Interactions in the Solutions of Electrolytes and l‐Isoleucine

Abstractl‐Isoleucine is subjected to density and sound velocity measurements in aqueous solutions of potassium (KCl) and sodium chlorides (NaCl) as well as water, from 288.15 to 298.15 K. Through the use of these experimental data, a variety of volumetric and acoustical parameters are calculated, including values for molar volume (Vm), available volume (Va), adiabatic compressibility (β), nonlinear parameters (B/A), Wada constant (W), Rao's constant (R), and van der Wall's constant (a). The findings shed light on many electrostatic and hydrophobic interactions within the binary system involving electrolytes, water, and amino acids. The interactions between the electrolytes and l‐isoleucine are thoroughly examined under varying electrolyte concentrations and temperatures, revealing many interactions. Positive transfer quantities demonstrate the ion‐hydrophilic and solute–solvent interaction in the aqueous medium, particularly between l‐isoleucine and NaCl and KCl. The influence of electrolyte type and temperature on these interactions is discernible. The culmination of the study's outcomes is elaborated through analyzing solute–solvent and solute–solute interactions. In particular, the interaction hierarchy is identified as l‐isoleucine + water + KCl > l‐isoleucine + water + NaCl > l‐isoleucine + swater.

Effect of sodium tungstate concentration on surface morphology and hardness variation of 6063 aluminium alloy using by plasma electrolytic oxidation

Abstract The coatings were prepared on the surface of 6063 aluminium alloy using by plasma electrolytic oxidation in a sodium tungstate (Na2WO4) electrolyte solution with concentration varying from 0.017 to 0.068 mol/L. The power of plasma electrolytic oxidation is about 600 W, electrolysis time is 20 and 30 minutes, respectively. In this study using sodium tungstate as the main component of the electrolyte without any additives. The effects of Na2WO4 concentrations on the surface morphology and hardness variation of the 6063 aluminium alloys are investigated. These oxide films on aluminium were characterized by laser scanning confocal microscope, scanning electron microscopy (SEM) and Vickers microhardness indenter (Hv), respectively. The results reveal Na2WO4 electrolyte solution with concentration varying from 0.017, 0.034, 0.051 to 0.068 mol/L. When the electrolyte concentration is 0.034 mol/L, the maximum hardness value is 104 Hv after plasma electrolytic oxidation for 20 minutes. When the electrolyte concentration is 0.051 mol/L, the minimum surface roughness value obtained by plasma electrolytic oxidation for 30 minutes is Sa 0.324 μm.

Effect of charge inversion on the electrokinetic transport of nanoconfined multivalent ionic solutions

Understanding the effects of phenomena occurring at electrically charged interfaces, such as charge inversion (CI), is crucial for enabling electroosmosis as an efficient transport mechanism in nanodevices. Here, we employ molecular dynamics (MD) simulations to systematically analyze the effect of CI on the electrokinetic transport of multivalent ionic solutions confined in amorphous silica nanochannels. We employ mixtures of monovalent and multivalent counterions while fixing the total ionic concentration to establish correlations between observed phenomena and the amount of multivalent ionic species in the electrolyte solution. The results show that the development of CI is related to a decrease in the mobility of the fluid layers adjacent to the charged surface. In addition, we observe that interfacial overcharging disrupts the water molecular orientation in the fluid layers adjacent to the channel walls. From the non-equilibrium MD simulations of electro-osmotic flow, we disclose the influence of phenomena related to the presence of CI. In particular, flow reversal occurs in scenarios involving CI due to increased local viscosity and a higher concentration of coions within the hydrodynamically mobile and electrokinetically active region of the charged interface. We also find that the magnitude of the wall zeta (ζ) potential displays a monotonic increase with the development of CI in the system. Moreover, we explain why positioning the wall ζ potential at an imaginary (slip) plane, which separates the hydrodynamically mobile and immobile fluid, is misleading.

The Poisson–Boltzmann equation in micro- and nanofluidics: A formulary

The Poisson–Boltzmann (PB) equation provides a mean-field theory of electrolyte solutions at interfaces and in confinement, describing how ions reorganize close to charged surfaces to form the so-called electrical double layer (EDL), with numerous applications ranging from colloid science to biology. This formulary focuses on situations of interest for micro- and nanofluidics, and gathers important formulas for the PB description of a Z:Z electrolyte solution inside slit and cylindrical channels. Different approximated solutions (thin EDLs, no co-ion, Debye–Hückel, and homogeneous/parabolic potential limits) and their range of validity are discussed, together with the full solution for the slit channel. Common boundary conditions are presented, the thermodynamics of the EDL is introduced, and an overview of the application of the PB framework to the description of electrokinetic effects is given. Finally, the limits of the PB framework are briefly discussed, and Python scripts to solve the PB equation numerically are provided.

Composite electroforming of precision Ni-P-PTFE mold inserts with low internal stress and self-lubricating properties

An electrolyte solution incorporating sodium saccharin and an alkynyl compound was provided to electroform Ni-P-PTFE mold inserts with both low internal stress and good self-lubricating properties. The results showed that with 5 g·L−1 sodium saccharin and 1 mL·L−1 alkynyl compound, the internal stress reached a minimum of −114 MPa, an 82 % reduction from the −646 MPa observed without additives. The presence of sodium saccharin and alkynyl compound in the electrolyte solution reduced the hydrogen evolution reaction current from 15.2 to 12.9 mA at the operating cathode potential of −1 V and decreased the RTC(111) from 100 % to 90 %. The reduction of internal stress in the electrodeposited Ni-P-PTFE composites was attributed to the decreased hydrogenation strain, diminished Ni (111) texture intensity, and the partial incorporation of alkynyl compound reaction products into the cathode surface, which weakened the connections between crystallites. Finally, 5 g·L−1 sodium saccharin and 1 mL·L−1 alkynyl compound was applied to electroform Ni-P-PTFE mold insert with micro features. Only slightly pile-up defects at the corner of grooves were observed on the polymer chips demolded from Ni-P-PTFE mold insert, demonstrating its good self-lubricating property.

Unsupervised detection and mapping of sparks in the Electrochemical Discharge Machining (ECDM) process

Material removal in electrochemical discharge machining is caused by sparks generated in a tool immersed in an electrolytic solution. Being the primary machining agent in this non-contact machining process, mapping the locations of microscopic sparks is of great interest. The distribution of sparks around the tool surface could give insights into the machined hole properties like the size, surface finish, and depth as compared to the machining parameters such as applied voltage, tool size, rotation speed, and feed rate. This paper is focused on detecting sparks in photographs of the ECDM process captured using a high-speed camera. A novel approach of using a tri-planar reflective surface for capturing the location of sparks in 3D space using a 2D camera output is attempted. Traditional spark detection methods use neural network classifiers that need labeled data for training. This labeled data often comes from human intervention and contains inherent biases that could lead to misclassification. In this paper, an unsupervised spark detection methodology is demonstrated, which eliminates the need for human intervention and relies on the number of neighboring pixels detected in regions of interest (ROIs). The feasibility of using adaptive background modeling to classify thousands of images and identify the ones with sparks is demonstrated in this work. The masking technique combining effects of erosion followed by dilation is used to determine the exact boundaries of the spark contours in every image. Centroids for each of these contours are then transformed from the skewed coordinate system as observed in camera images, to a three-dimensional orthogonal coordinates system centered around the tool. The same procedure is repeated for various voltages to benchmark the distribution of sparks around a tool tip in an ECDM process.