Irreversible Processes Research Articles

New Non‐Invasive Method to Monitor and Reverse Faradaic Imbalance in Redox Flow Batteries

Aqueous Organic Redox Flow Batteries (AORFBs) have received much attention due to the accessibility of their active materials. However, among the key performance indicators that require improvement for AORFBs to become competitive against mature technologies, lifespan is especially critical for stationary energy storage. Faradaic imbalance driven by the occurrence of irreversible electrochemical processes decreases lifespan, so monitoring and correction of this parameter is required to prolong lifespan. This work presents a novel, simple and non‐invasive automatized method to monitor the Faradaic imbalance. This method is based on detecting the variation of the minimum derivative of the cell voltage upon cycling, and it is used as the activation criterion for a rebalancing device. The system is tested using an alkaline flow battery consisting of ferrocyanide and 2,6‐dihydroxyanthraquinone (2,6‐DHAQ), extending the cycle life of the battery to 400 cycles (235 h) without any capacity decay and without Ar‐filled glovebox. This demonstrates the feasibility of the proposed system to monitor the state‐of‐health (SOH) due to Faradaic imbalance and recover the capacity loss.

Electrochemical Performance of Pre-Modified Birch Biochar Monolith Supercapacitors by Ferric Chloride and Ferric Citrate

This study investigated the electrochemical properties of supercapacitors by pre-modifying thick birch biochar monoliths with FeCl3 or C6H5FeO7 solutions prior to wood pyrolysis. The pre-modification introduced iron species to the surface, promoting the specific surface area, charge-stored species, and surface functionalities, which enhanced the gravimetric capacitance. X-ray diffraction confirmed the successful loading of Fe3O4 and Fe. SEM implied the wider distribution of iron-rich particulates and porous carbon via self-pyrolysis on the biochar surface modified with 1.0 M C6H5FeO7. Contact angle measurements demonstrated the enhanced wettability of the biochar surfaces following pre-modification, with the C6H5FeO7-modified samples exhibiting superior wettability compared to the other groups. The gravimetric capacitance of the supercapacitor was dramatically promoted and reached 210 F/g and 219 F/g, respectively, when modified with 1.0M C6H5FeO7 and 1.0 M FeCl3 at a 5 mA/g current density. Compared to the birch biochar modified with 1.0 M FeCl3, the 1.0 M C6H5FeO7 had a higher current response peak and capacitive behavior in the CV analysis, demonstrated better ion diffusion capacity, and had lower charge-transfer resistance in the EIS results. But, a slight irreversible process on the electrode of the 1.0 M C6H5FeO7 group led to a lower level of the supercapacitor capacitance retention. The results using ferric solution pre-impregnation show how iron species doping can improve capacitance behavior, providing a feasible scheme for the modification of thick biochar monolith.

Relaxation dynamics of a mixed ferrimagnetic Ising system with random anisotropy

The relaxation dynamics of a mixed spin-1/2 and spin-1 ferrimagnetic Ising system with random anisotropy has been investigated using Onsager’s theory of irreversible thermodynamics. The magnetic Gibbs energy production, arising due to irreversible processes, is computed using the equilibrium mean-field Gibbs energy, based on the variational principle and the Gibbs–Bogoliubov inequality. In the framework of linear response theory, the time derivatives of the sublattice magnetizations are treated as fluxes conjugate to their corresponding generalized forces. Two relaxation times are computed, and their dependence on temperature and crystal field variances is examined near phase transition points for four distinct topologies, each corresponding to different phase diagrams. These phase diagrams emerge from random anisotropy drawn from a bimodal probability distribution: P(Δi)=12δ(Δi-Δ(1+α))+δ(Δi-Δ(1-α)). One of the relaxation times, denoted as τ1, increases rapidly and diverges near the critical and tricritical points separating the ferrimagnetic and paramagnetic phases. For α≥0, critical slowing down, characterized by the divergence of τ1, is observed near the isolated ordered critical points between the ferrimagnetic and disorder-induced ferrimagnetic phases. Finally, the variance of the relaxation times is analyzed across regions of crystal field and temperature, as well as the values of α at which re-entrant phenomena occur, due to the competing interactions in the random system.

Hidden domain boundary dynamics toward crystalline perfection

A central paradigm of nonequilibrium physics concerns the dynamics of heterogeneity and disorder, impacting processes ranging from the behavior of glasses to the emergent functionality of active matter. Understanding these complex mesoscopic systems requires probing the microscopic trajectories associated with irreversible processes, the role of fluctuations and entropy growth, and the timescales on which nonequilibrium responses are ultimately maintained. Approaches that illuminate these processes in model systems may enable a more general understanding of other heterogeneous nonequilibrium phenomena, and potentially define ultimate speed and energy cost limits for information processing technologies. Here, we apply ultrafast single-shot X-ray photon correlation spectroscopy to resolve the nonequilibrium, heterogeneous, and irreversible mesoscale dynamics during a light-induced phase transition in a (PbTiO3)16/(SrTiO3)16 superlattice. Such ferroelectric superlattice systems are a useful platform to study phase transitions and topological dynamics due to their high degree of tunability. This provides an approach for capturing the nucleation of the light-induced phase, the formation of transient mesoscale defects at the boundaries of the nuclei, and the eventual annihilation of these defects, even in systems with complex polarization topologies. We identify a nonequilibrium correlation response spanning >10 orders of magnitude in timescales, with multistep behavior similar to the plateaus observed in supercooled liquids and glasses. We further show how the observed time-dependent long-time correlations can be understood in terms of stochastic and non-Markovian dynamics of domain walls, encoded in waiting-time distributions with power-law tails. This work defines possibilities for probing the nonequilibrium and correlated dynamics of disordered and heterogeneous media.

Elucidating the degradation mechanism of beef myofibrillar proteins under hydroxyl radical oxidation through the lens of cysteine oxidation modifications.

The study aimed to assess the oxidative modification behavior of bovine myofibrillar proteins (MPs) cysteines (Cys) by hydroxyl radical (·OH) through the construction of an in vitr Fenton reaction system. The ·OH generated by the Fenton reaction induced large-scale oxidative modification of Cys, and redox proteomics identified a total of 1192 differential oxidation sites (Dos), 59 Dos were located in the MPs structure. The Cys of actin (17 Dos), myosin/myomesin (16 Dos), tenascin (12 Dos) and sarcomere (10 Dos) in the MPs structure showed active oxidative modification behavior towards ·OH, especially with the "-C-X-X-X-X-W-" structure amino acid sequence showed high sensitivity. Notably, the oxidative modification of Cys by ·OH was an irreversible process, as evidenced mainly by a significant decrease (p<0.05) in protein sulfhydryl groups and unfolding of protein secondary and tertiary structures. While the intermolecular forces of MPs were altered, with the most direct result being the degradation of MPs, which had a positive effect on beef tenderness and a negative effect on water-holding capacity.

Peak frequencies and relative peak heights of power spectra of stationary irreversible Markov processes

Peak frequencies and relative peak heights of power spectra of stationary irreversible Markov processes

Methacrylated gellan gum microgels: A further step in the gel-based cleaning system

Paper has been entrusted with a large portion of humanity's recorded knowledge in recent centuries, therefore its preservation is fundamental for maintaining cultural heritage. Indeed, cellulose—the primary material of these artifacts— goes through irreversible degradation processes as it ages, leading to a weakening of paper stability and color changes. In order to slow down ageing, several restoration strategies involving the use of wet cleaning by hydrogels can be found in literature. Multi-step treatments are often required to complete the cleaning procedure, as the properties of contaminants greatly vary from a chemical–physical point of view (i.e. hydrophilic, hydrophobic or, as for adhesives, polymeric compounds). In this article, we propose a cleaning strategy that accounts for the inherent roughness of paper by developing microgel particles made of methacrylated gellan gum. Microgel particles are smaller than their macroscopic counterparts, hydrogels, and as a result, they can clean paper more quickly, a few minutes as opposed to hours. Moreover, the chemical modification performed on deacylated gellan gum makes the polymer more hydrophobic, as compared to the unmodified one. In this way, the proposed microgels are able to interact with and adsorb not only hydrophilic by-products of cellulose degradation, as gellan gum-based microgels do, but also hydrophobic materials or synthetic adhesives. This procedure represents a valid strategy, safe for operators, for the cleaning of paper artworks as it avoids the use of potentially dangerous organic solvents for hydrophobic material removal.

Dietary supplementation and the role of phytochemicals against the Alzheimer's disease: Focus on polyphenolic compounds.

Alzheimer's disease is a complicated, multifaceted, neurodegenerative illness that places an increasing strain on healthcare systems. Due to increasing malfunction and death of nerve cells, the person suffering from Alzheimer's disease (AD) slowly and steadily loses their memories, cognitive functions and even their personality. Although medications may temporarily enhance memory, there are currently no permanent therapies that can halt or cure this irreversible neurodegenerative process. Nonetheless, fast progress in comprehending the cellular and molecular abnormalities responsible for neuronal degeneration has increased confidence in the development of viable prevention and treatments. All FDA-approved anti-AD medications have merely symptomatic effects and cannot cure the illness. This necessitates the pursuit of alternate treatments. Accumulating data shows that systemic neuroinflammation, oxidative stress and associated mitochondrial dysfunction play crucial roles in the etiology of AD and precede its clinical presentation. Therefore, innovative therapeutic approaches targeting these pathophysiological components of Alzheimer's disease are being explored aggressively in the present scenario. Phytochemicals such as resveratrol, curcumin, quercetin, genistein and catechins are prospective therapies owing to their capacity to alter key AD pathogenetic pathways, such as oxidative stress, neuroinflammation, and mitochondrial dysfunction. The use of new phytochemical delivery strategies would certainly provide the possibility to solve several issues with standard anti-AD medicines. In this review, the roles of phytophenolic compound-based treatment strategies for AD are discussed.

KINETICS AND THERMODYNAMICS STUDIES ON OIL EXTRACTION FROM SOUTHERN KADUNA PALM KERNEL SEEDS USING SUBCRITICAL WATER EXTRACTION TECHNOLOGY

Subcritical water has the potential to be highly efficient, non-toxic and low-cost alternative extraction solvent due to its unique properties under certain conditions. In this current study, we used the process variables (extraction temperature, time and particle size) to investigate the kinetics of palm kernel oil (PKO) extraction using subcritical water as solvent by considering the power law and Elovich’s kinetic law models. The laws of thermodynamics were employed to determine the spontaneity and nature of the PKO extraction process by evaluating thermodynamic parameters such as the Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS). The experimental result showed that the conditions for the optimum yield of PKO using subcritical water were established at 0.5 mm, 120 minutes and 493K (200 ◦C) where the highest oil yield was (49.02%). The experimental data was found to best fit the power law model compared to the Elovich’s model, as a result of its highest R2 and lowest SD and RMS values. Thermodynamics analysis showed that PKO extraction has positive enthalpy and entropy values of 7.23×10-4kJ/mol and 0.0304kJ/molK respectively, indicating an endothermic and irreversible process. The negative values of Gibbs free energy (– 12.56 to -14.99kJ/molK) indicated that the extraction process is spontaneous. Gas chromatography analysis showed that lauric acid (48.1%) appears as the predominant fatty acid in the extracted oil followed by myristic acid (16.0%) and linoleic acid (14.9%). The subcritical water technology was therefore, highly recommended for the extraction of PKO due to its high potentials as shown in the high oil yield obtained. The power law model was also recommended due to the overall comparative fitness to the experimental data while the thermodynamics specifications as verified in this work were also recommended to be used for process design of PKO extraction.

Internal model control based sliding mode controller design for unstable second order delayed processes with a case study on CSTR

Controlling the unstable processes is challenging since one or more poles are located on the right side of the s-plane. The existence of dead time in these systems makes control much more difficult. In this paper, internal model control based sliding mode control has been proposed for the control of unstable processes with dead time. Two sliding surfaces based on PID and PIDPI are used to design of the proposed controller. The parameters of continuous and discontinuous control law are obtained using differential evolution optimization technique. An objective function is constituted in terms of performance measure (integral absolute error) and control effort measure (total variation of controller output). Illustrative examples demonstrate the superiority of the proposed controller over earlier reported work in this realm, especially in terms of load disturbance rejection. A case study on temperature management of a continuous stirred tank reactor during an irreversible exothermic process also serves to highlight the applicability of the proposed system. Furthermore, robustness of the proposed controller is also investigated by inclusion of perturbations in the parameters. The obtained results clearly show how well the suggested controller works.

Dissipative disorder analysis of Homann flow of Walters B fluid with the applications of solar thermal energy absorption aspects

Encountering of entropy generation is meaningful while investigating the energy loss during the operational mechanical system. In particular, the flow of fluid experiencing friction drag and due to which a significant amount of heat transfer occurred. Thus, the thermodynamic system energy conversion is one of the measures of the lost available work and is known as irreversibility. Avoiding of such energy loss can be minimized by introducing the concept of hybridization during the liquid dynamics. This work is initiated to formally characterize and address the significance of irreversible process during the typical Homann flow of viscoelastic liquid. The flow with heat and mass balance aspects are further characterize with the inclusion of thermophoretic and Brownian motion factors. The flow configuration is interpreted in terms of gravitationally affected vertical cylindrical disk, for a better understanding of the impact of irreversible processes, more physical effects in terms of heating source/sink, chemical reaction and solar thermal radiation. New physical impacts are described numerically in terms of flow speed temperatures, nanoparticle volume fraction, displacement thicknesses and entropy generation. Perturbation method is utilized for the reduction of the fourth-order mathematical equation for reducing the problem in to well-posed from ill-posed status. The numerical analysis is carried out by applying one of the built-in commands while using MATLAB software. The buoyancy force factor enhanced the liquid speed, and the concentration of the liquid was determined with uplifted conduct for higher values of chemical reaction parameters. The overall entropy rate is reduced as the Brinkman number and magnetic parameter are increased. The heat transfer flow is increased by internal heat generation. Higher Prandtl and Schmidt numbers significantly affected the isotherms and volume fraction contours.

On the quantitative assessment of the thermal effect of heat transfer

Due to the constant rise in the cost of energy resources, as well as the tightening of rules for enterprises on environmental indicators, a thorough analysis of the operation of not only heat engines, but also auxiliary power equipment, including heat exchangers, is necessary. One of the criteria for the perfection of thermal processes in a heat exchanger can be the value of the irretrievably lost quality of energy [2]. The objective of this article is to estimate the maximum transferred thermal power, with known available thermal powers of heat carriers, using various methods: 1. arithmetic, using the logarithmic mean value of the difference in heat-exchanging media, 2. graphical arithmetic, using hyperbolas of constant power of heat-exchanging media, 3. calculating the minimum value of the total entropy loss as a result of irreversible heat exchange processes from a hot heat carrier to a wall, through a wall and from a wall to a cold heat carrier. The listed methods were developed by the authors and do not contradict similar developments by domestic and foreign authors [1- 4].

Why Does the Biosphere Interact with Earth's Climate, and How Do the Two-Way Interactions Work?

With the use of matter (carbon dioxide, nutrients, and water) and solar energy, phytoplankton produce oxygen and carbohydrates, which are transported to predators through the oceanic food web hierarchy. From the viewpoint of irreversible processes of non-equilibrium thermodynamics, oceanic photosynthesis gives a mechanistic picture of living things characterized by double sets of self-organizations supported by flows of energy and entropy discarded into the ocean environment. This produces biological, ocean circulation, and climate interactions.

Linear and Two-Dimensional Infrared Spectroscopy of the Multifunctional Vibrational Probe, 3-(4-Azidophenyl) Propiolonitrile. Deperturbing a Fermi Triad by Isotopic Substitution.

Infrared probes are chemical moieties whose vibrational modes are used to obtain spectroscopic information about structural dynamics of complex systems; in particular, of biomacromolecules. Here, we explore the vibrational spectroscopy and dynamics of a reagent, 3-(4-azidophenyl)propiolonitrile (AzPPN), for selectively tagging thiols in protein environments with a multifunctional infrared probe containing both, an azide and a nitrile chromophore. The linear infrared spectrum of AzPPN is heavily perturbed in the antisymmetric azide stretching region as a result of accidental Fermi resonances. Isotopically labeling the azide group at the β-position deperturbs the spectrum considerably and reveals two combination tones that mix with the antisymmetric stretching fundamental into a Fermi triad of hybrid vibrational excitations. Moreover, two-dimensional infrared (2DIR) spectra were recorded for 15Nβ-labeled AzPPN, which reveal waiting-time-dependent spectral shifts of diagonal peaks and dynamic buildups of cross peaks. The 2DIR-spectral evolution is indicative of intramolecular distribution of the pump-induced excess vibrational energy into low-frequency modes of the molecule that are coupled to either the azide or the nitrile stretching transition dipoles. Finally, IR-pump/IR-probe spectra with selective narrowband excitation reveal a time constant of 2.3 ps for intramolecular vibrational redistribution (IVR) and 18 ps for the final energy dissipation into the solvent. The cross-peak dynamics corroborate a notion in which IVR within the AzPPN-molecule is an irreversible process.

Disorder optimization in the mixed convective dynamics of nonlinear shear thinning materials with the significance of wavy surface amplitude and thermal resistance

A mixed convective driven wavy motion of the pseudo-plastic materials is very significant in different practical fields, like the production of paints and ketchup, etc. Blood flow through wavy vessels is another very practical aspect of this study. Energy conversion processes and effective resource use are one of the burning and hot topics when studying heat flow rate through materials. Main theme of this work is to optimize the heat energy conversion by introducing irreversible viscous dissipation and thermally radiative factors. In particular cases, the heat flow rate needs to be enhanced for low energy consumption. This is why, in such cases, the wavy surface flows are preferred by plane surfaces. The proposed problem is presented with highly non-linear mathematical equations. Some assumptions and variables address the mathematical equations in easily solvable forms. The findings are shown regarding the material's velocity, concentration, temperature, resistive forces, and heat-mass flow rates. A remarkable reduction in liquid velocity and enhancement in concentration and temperature is observed with the variation in amplitude of the wavy surface. The irreversible process is maximized due to the higher involvement of temperature ratio and thermal radiation factors, respectively. The ratio of infinite and zero shear rate viscosities reduced the concentration of the liquid. For method validation, a best-matched comparison is provided with literature.

TiO2 intercalated MWCNTs nanocomposite sensor for the detection and quantification of 5-Fluorouracil

The present analysis deals with the fabrication of novel electrochemical sensing platforms for the determination of the anti-cancer drug 5-Fluorouracil (5-FLU). Multiwalled carbon nanotubes/titanium dioxide nanoparticles (TiO2·MWCNTs) modified carbon paste electrodes were constructed and used to quantify 5-FLU in pH 7.0. TiO2·MWCNTs nanocomposite reveals a non-uniform distribution of agglomerated TiO2 nanoparticles over the smooth surface of MWCNTs At the TiO2∙MWCNTs/CPE, the 5-FLU molecule underwent an irreversible electro-oxidation process. The proposed electrode platform exhibited a high catalytic effect for the 5-FLU. The TiO2∙MWCNTs/CPE sensor shows the detection limits of 2.7nM for 5-FLU with sensitivity of 82.15µA·µM−1·cm−2. The sensor was employed to detect the desired drug moiety in the urine samples of pharmaceutical drugs along with spiked water and soil samples; the good recovery values demonstrating the applicability and selectivity of the sensor were supported by excipient interference investigation. Thus, the developed sensors and method makes them a promising alternative for future research to determine other bio-active molecules in pharmaceutical and clinical samples.

Endothelial Cell Aging and Autophagy Dysregulation.

Entropy is a natural process that affects all living cells, including senescence, an irreversible physiological process that impairs cell homeostasis. Age is a significant factor in disease development, and the pathogenesis of endothelial cell aging is multifactorial. Autophagy dysfunction accelerates endothelial cell aging and cell death, while autophagy preserves endothelial cell youthfulness through intracellular homeostasis and gene expression regulation. Sirt, mTORC1, and AMPK are youthfulness genes that induce autophagy by inhibiting mTOR and upregulating FIP200/Atg13/ULK1. Aged endothelial cells have decreased levels of Lamin B1, γH2AX, Ki67, BrdU, PCNA, and SA β-Gal. Maintaining healthy young endothelial cells can prevent most cardiovascular diseases. Autophagy targeting is a potential future therapeutic strategy to modify endothelial cell age and potentially slow or reverse the aging process. This article provides state-of-the-art research on the role of autophagy in endothelial cell aging. Hypothesizing that autophagy dysregulation is associated with early endothelial cell dysfunction and further clinical sequelae, including atherosclerosis formation, leading to various cardiovascular diseases.

Study of Insulin Electrochemical Reaction Mechanism on Modified Ni-Chit/SPCE Electrode

Insulin is the main hormone that regulates the glucose level in blood. Dysfunction in insulin production or action causes a serious disease called diabetes mellitus. Currently the glucose sensors are using for monitoring the course of the disease, but during treating diabetes, it is also necessary to know the concentration of insulin in body fluids. It offers information about the function of the pancreas and how much insulin was produced. A change in the concentration of glucose in the blood is the body's reaction to low insulin concentration or low sensitivity of cells to the presence of insulin [1].The insulin detection could be provided by immunoassay, chromatographic methods, electrochemical sensors etc. Among them electrochemical sensors display various advantages such as fast response, simple preparation, inexpensive instruments, and easy-to-use device. Modification of sensors working electrode improves electroanalytical properties of studied sensors. Various metal nanoparticles, metal oxide nanoparticles, and carbon nanomaterials are used for sensors modification. These nanomaterials are frequently fixed on the surface of electrode by using polymer film. Among polymer materials Nafion, chitosan, polypyrrole, and polyaniline are the most often used materials [2].Herein, we are focused on development of electrochemical sensor based on the nickel nanoparticles immobilised by chitosan film on the surface of screen printed carbon electrode (Ni-chit/SPCE). The mechanism of electrochemical reaction plays key role in the insulin electrochemical detection. There is the possibility to improve electrode material taking into consideration reaction mechanism and rate determining step. For studying of reaction mechanism was used cyclic voltammetry.The cyclic voltammograms for 2 μM insulin in 0.1 M NaOH and PBS at Ni-chit/SPCE are depicted in Figure 1. The cyclic voltammograms for the insulin solution display one anodic peak at approx. 0.7 V and a cathodic peak at approx. 0.4 V. According to the its shape and the distance between the oxidation and reduction peak, the electrochemical oxidation of insulin is irreversible process. Moreover, the oxidation peaks display a higher peak area compared to the reduction peak; it could indicate the EC mechanism of the electrochemical reaction. Upon analysis, Figure 1B presents a linear relationship (R2=0.92) between the current response and scan rate. Furthermore, Figure 1D reveals the relationship between the logarithmic peak current (I) and logarithmic scan rate (v). The derived equation log Ip = 0.606 log v – 1,787 (R2 = 0.92) with the slope value of 0.606 suggests that the insulin oxidation reaction is controlled by diffusion. The sluggish diffusion of the insulin molecules could be notch up to the size of insulin molecule. Therefore, the alkali solution displays a catalytic influence on the electrochemical detection of insulin. In alkali solution Ni nanoparticles will oxidise to Ni(OH)2 and following to NiOOH, as shown in Equations (1) and (2).Ni + 2 OH- ↔ Ni(OH)2 + 2e− (1)Ni(OH)2 + OH− ↔ NiOOH + H2O + e− (2)NiOOH + insulin ↔ Ni(OH)2 + product (3)The next step of the oxidation mechanism occurs after the oxidation of adsorbed insulin on the electrode surface. It could be expected, that NiOOH will reduce to Ni(OH)2, as shown in Equation (2). Simultaneously, the adsorbed insulin will be oxidized during the electrochemical reaction. Based on proposed mechanism of electrochemical reaction, the main role in the reaction mechanism plays presence of NiOOH and enhancement of insulin diffusion. Both processes are influenced by presence of NaOH in the studied solution because alkali solution promotes the NiOOH creation during the electrochemical reaction. These findings make it possible to significantly improve the properties of the tested sensor only by adding NaOH to the solution and thus improve sensor electroanalytical properties. Figure 1 Cyclic voltammograms of 2 µM insulin on Ni-chit/SPCE at different scan rates (A). The dependences of the peak current on scan rate (B), peak current on the square root of scan rate (C), and of logI on logv (D). Acknowledgement This research was sponsored by the NATO Science for Peace and Security Programme under grant id G6106 References [1] Šišoláková, I., Gorejová, R., Chovancová, F. et al.; Electrocatalysis 2023, 14, 697–707. https://doi.org/10.1007/s12678-023-00827-w[2] Shepa J, Šišoláková I, Vojtko M, et al.; Sensors (Basel). 2021 Jul 26;21(15):5063. doi: 10.3390/s21155063. Figure 1

Regulating Interfacial Chemistry with Amphiphilic Copolymer for Durable Zinc Metal Anodes

Although rechargeable aqueous zinc-metal batteries offer conspicuous advantages for grid-scale energy storage, their application is impeded by the insufficient reversibility of the Zn anode. Irreversible processes, such as dendrite growth and parasitic water-induced side reactions, contribute to the instability of the anode/electrolyte interface. In this study, we demonstrate amphiphilic Pluronic triblock copolymers comprising hydrophobic poly(propylene oxide) (PPO) and hydrophilic poly(ethylene oxide) (PEO) segments as a new class of electrolyte additives for stabilizing Zn metal anodes. Theoretical calculations reveal preferential affinity of PPO segments to the Zn metal surface and stronger interactions of PEO segments with Zn2+ ions than with PPO segments. This unique amphiphilic property of Pluronic copolymers establishes a hydrodynamic molecular interphase between the Zn metal and aqueous media, modulating Zn electrode interface chemistry. PPO segments adsorbed onto the Zn surface create a localized water-shielding environment, mitigating water-induced side reactions, while PEO segments ensure uniform Zn2+ ion flux within the interfacial region. The synergistic interfacial regulation by the Pluronic additive is related to its molecular structure, PEO/PPO composition, and block length. With its harmonized hydrophilic-hydrophobic attributes, Pluronic F127 demonstrates notably effective interface modulation. Impressively, the incorporation of F127 into the electrolyte results in a significantly enhanced lifespan of over 9300 h at 1 mA cm–2 and 3100 h at 5 mA cm–2 in Zn symmetric cells. Zn||VO2 full cells exhibit exceptional capacity retention after long-term cycling across a wide range of current densities. This study offers pivotal insights into realizing highly reversible Zn metal anodes through interfacial chemistry regulation.

Electrochemical Activity of Oxygen in Li-Ion Battery Cathodes from X-Ray Spectroscopic Modeling

As demand for better performance in energy storage increases, a clear understanding of the charge compensating mechanism in Li-ion battery cathodes is essential for developing next generation battery chemistries and materials. X-ray core level spectroscopies, e.g. x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS), allow for experimental measurement of the electronic structure of battery materials before and after charge, providing the clearest physical picture of electrochemical device operation.Here, we present numerical modeling of the XAS/RIXS of various battery chemistries compared to experimental measurements in situ. Modeling spectroscopic changes before and after discharge using not only density functional theory (DFT) based techniques but also exact diagonalization atomic multiplet formalisms prove crucial in these materials to accurately model correlation effects seen in their spectra, where reversible changes in the transition metal L3-edge spectroscopy may erroneously point to cationic redox. We address the common concept of transition metal redox, highlight the essential role of oxygen in both reversible and irreversible processes, and the break down in the standard paradigm of cationic/anionic redox.