Structural Evolution Research Articles

Study on the performances of epoxy asphalt binders influenced by the dosage of epoxy resin and its application to steel bridge deck pavement

The concentration of epoxy resin can outstandingly affect the performance of hot-mixed epoxy asphalt binders. A standard measuring procedure of tensile performance for plastics is applied to investigate epoxy asphalt binders influenced by different dosages of epoxy. The rheological performances and microscope structure evolution process influenced by hot mixed epoxy dosage are investigated by dynamic shear rheometer and laser scanning confocal microscopy respectively. The consequences manifest that the flexibility and anti-rutting ability of epoxy asphalt binders is raised accompanied by raising the dosage of epoxy resin are founded by long time of creep, creep and recovery. Dynamic shear rheometer temperature scans showed that epoxy asphalt binders exhibited excellent thermal stability within the scope of -20 oC and 120oC, when the amount of epoxy resin is no less than 40%. It was observed by laser scanning confocal microscopy that the three-dimensional crosslinked network structure was gradually shaped when the epoxy resin concentration was no less than 40%. These experimental results demonstrated that the excellent performances of epoxy asphalt binders are obtained when the concentration of epoxy resin is no less than 40%. From the viewpoint of epoxy asphalt mixtures, the optimal mixture performances are acquired, when the concentration of epoxy resin is no less than 40%. Finally, when the concentration of epoxy resin is 40%, the excellent cost-performance of epoxy asphalt is obtained, which can be used in steel bridge deck pavement.

TEA+ : A Novel Temporal Graph Random Walk Engine with Hybrid Storage Architecture

Many real-world networks are characterized by being temporal and dynamic, wherein the temporal information signifies the changes in connections, such as the addition or removal of links between nodes. Employing random walks on these temporal networks is a crucial technique for understanding the structural evolution of such graphs over time. However, existing state-of-the-art sampling methods are designed for traditional static graphs, and as such, they struggle to efficiently handle the dynamic aspects of temporal networks. This deficiency can be attributed to several challenges, including increased sampling complexity, extensive index space, limited programmability, and a lack of scalability. In this article, we introduce TEA+ , a robust, fast, and scalable engine for conducting random walks on temporal graphs. Central to TEA+ is an innovative hybrid sampling method that amalgamates two Monte Carlo sampling techniques. This fusion significantly diminishes space complexity while maintaining a fast sampling speed. Additionally, TEA+ integrates a range of optimizations that significantly enhance sampling efficiency. This is further supported by an effective graph updating strategy, skilled in managing dynamic graph modifications and adeptly handling the insertion and deletion of both edges and vertices. For ease of implementation, we propose a temporal-centric programming model, designed to simplify the development of various random walk algorithms on temporal graphs. To ensure optimal performance across storage constraints, TEA+ features a degree-aware hybrid storage architecture, capable of adeptly scaling in different memory environments. Experimental results showcase the prowess of TEA+ , as it attains up to three orders of magnitude speedups compared to current random walk engines on extensive temporal graphs.

Enhanced energy storage performance, breakdown strength, and thermal stability in compositionally designed relaxor Eu3+ substituted Na0.2K0.3Bi0.5TiO3

Lead-free Eu3+ substituted NKBT ceramics (Na0.2K0.3Bi0.5-xEuxTiO3, x = 0 (Eu 0),0.02(Eu 2),0.04(Eu 4), and 0.06(Eu 6)) were strategically designed via a local random field approach. The structural evolution had been confirmed through X-ray diffraction analysis. The observation of a broad dielectric curve supported the enhanced relaxor nature and the phenomena reflected in the P-E and S-E loops. The diffuse phase transition transforms to the plateau-type feature with excellent thermal stability with ±20 % and ± 40 % variation in dielectric constant over the temperature range of 120 to 500 °C and 90 to 500 °C, respectively in Eu 4. A large recoverable energy density of 1.7 J/cm3 with a high breakdown strength of 188 kV/cm was achieved in the Eu 2 sample at room temperature, making it a potential candidate for energy storage application. Moreover, the frequency stability (0.1 to 500 Hz range), thermal stability (45 °C to 85 °C), and fatigue measurement (10−1 to 106 cycles) were performed from the application point of view. The highest efficiency (82 %) was also achieved in the Eu 6. The negligible Sneg of Eu-rich compositions proves the existence of a relaxor state when the field is removed, and it transforms into the ergodic relaxor state. Furthermore, the SRBRF model is exploited to understand and correlate the transformation from normal to relaxor ferroelectrics with their properties. The current study provides a novel idea for compositional design for energy density, efficiency, and thermal stability ceramics by modifying and creating weakly coupled polar phases with rare earth substitution.

Dynamical Tests of a Deep-Learning Weather Prediction Model

Abstract Global deep-learning weather prediction models have recently been shown to produce forecasts that rival those from physics-based models run at operational centers. It is unclear whether these models have encoded atmospheric dynamics, or simply pattern matching that produces the smallest forecast error. Answering this question is crucial to establishing the utility of these models as tools for basic science. Here we subject one such model, Pangu-Weather, to a set of four classical dynamical experiments that do not resemble the model training data. Localized perturbations to the model output and the initial conditions are added to steady time-averaged conditions, to assess the propagation speed and structural evolution of signals away from the local source. Perturbing the model physics by adding a steady tropical heat source results in a classical Matsuno–Gill response near the heating, and planetary waves that radiate into the extratropics. A localized disturbance on the winter-averaged North Pacific jet stream produces realistic extratropical cyclones and fronts, including the spontaneous emergence of polar lows. Perturbing the 500hPa height field alone yields adjustment from a state of rest to one of wind–pressure balance over ∼6 hours. Localized subtropical low pressure systems produce Atlantic hurricanes, provided the initial amplitude exceeds about 4 hPa, and setting the initial humidity to zero eliminates hurricane development. We conclude that the model encodes realistic physics in all experiments, and suggest it can be used as a tool for rapidly testing a wide range of hypotheses.

Experimental Study on Differential Thermal Response and Pore-Fracture Structure Evolution Characteristics of Coals under Microwave Irradiation: A Case Study of Five Different Rank Coals

Experimental Study on Differential Thermal Response and Pore-Fracture Structure Evolution Characteristics of Coals under Microwave Irradiation: A Case Study of Five Different Rank Coals

Structural evolution and electronic properties of the La-doped germanium clusters

The geometric structure, relative stability, and electronic properties of LaGe n − (n = 3–14) are systematically studied by density functional theory, and the results are compared with the experimental literature data. It is found that the structures of 10A-I, 11A-I, and 14A-I are clearly two-parted and have the potential to design molecular chains. Combined with the average binding energy and second-order differential energy analysis, it is speculated that LaGe 9 − is a magic number cluster. The density of states and natural population analysis indicate that electrons consistently transfer from the La atom to Ge atoms. Doped La atom increases the interaction with Ge atoms and improve the stability of pure germanium clusters. Interestingly, LaGe 9 − has a high transfer charge number, and its high stability can be further explained by the spherical jellium model. The investigation into LaGe 9 − magic number clusters offer valuable insights for the exploration of novel materials with superior stability and performance.

TP-PROFILE: Monitoring the Thermodynamic Structure of the Troposphere over the Third Pole

Ground-based microwave radiometers (MWRs) operating in the K- and V-bands (20–60 GHz) can help us obtain temperature and humidity profiles in the troposphere. Aside from some soundings from local meteorological observatories, the tropospheric atmosphere over the Tibetan Plateau (TP) has never been continuously observed. As part of the Chinese Second Tibetan Plateau Scientific Expedition and Research Program (STEP), the Tibetan Plateau Atmospheric Profile (TP-PROFILE) project aims to construct a comprehensive MWR troposphere observation network to study the synoptic processes and environmental changes on the TP. This initiative has collected three years of data from the MWR network. This paper introduces the data information, the data quality, and data downloading. Some applications of the data obtained from these MWRs were also demonstrated. Our comparisons of MWR against the nearest radiosonde observation demonstrate that the TP-PROFILE MWR system is adequate for monitoring the thermal and moisture variability of the troposphere over the TP. The continuous temperature and moisture profiles derived from the MWR data provide a unique perspective on the evolution of the thermodynamic structure associated with the heating of the TP. The TP-PROFILE project reveals that the low-temporal resolution instruments are prone to large uncertainties in their vapor estimation in the mountain valleys on the TP.

Understanding the Correlation between Electrochemical Performance and Operating Mechanism of a Co-free Layered-Spinel Composite Cathode for Na-Ion Batteries.

Compositing different crystal structures of layered transition metal oxides (LTMOs) is an emerging strategy to improve the electrochemical performance of LTMOs in sodium-ion batteries. Herein, a cobalt-free P2/P3-layered spinel composite, P2/P3-LS-Na1/2Mn2/3Ni1/6Fe1/6O2 (LS-NMNF), is synthesized, and the synergistic effects from the P2/P3 and spinel phases were investigated. The material delivers an initial discharge capacity of 143 mAh g-1 in the voltage range of 1.5-4.0 V and displays a capacity retention of 73% at the 50th cycle. The material shows a discharge capacity of 72 mAh g-1 at 5C. This superior rate performance by the material could be by virtue of the increased electronic conductivity contribution of the incorporated spinel phase. The charge compensation mechanism of the material is investigated by in operando X-ray absorption spectroscopy (in a voltage range of 1.5-4.5 V vs Na+/Na), which revealed the contribution of all transition metals toward the generated capacity. The crystal structure evolution of each phase during electrochemical cycling was analyzed by in operando X-ray diffraction. Unlike in the case of many reported P2/P3 composite cathode materials and spinel-incorporated cobalt-containing P2/P3 composites, the formation of a P'2 phase at the end of discharge is absent here.

Substrate-dependent structural evolution during the oxidation of SiNx thin films

Substrate-dependent structural evolution during the oxidation of SiNx thin films

Concentration effects on the local structures and electronic properties of Er x BaY2− x F8: a first-principles study

Er3+ doped barium yttrium fluoride (BaY2F8) crystal has gained long-term attention due to its great potential in laser and medical device applications. However, the local structures of Er3+ doped BaY2F8 system (Er:BYF) remain uncertain, and the effect of doping concentration on structures and properties is unknown. Therefore, in this study, the first-principles study of the structural evolution of Er x BaY2−x F8 (x = 0.125, 0.25) crystals was carried out. By means of density functional theory and particle swarm optimization algorithm, the stable structures of Er:BYF crystals with two different concentrations are shown as standard monoclinic structures with P2 symmetry for the first time. The impurity Er3+ ions successfully enter the main lattice, replacing the Y3+ ions, and forming a [ErF8]5− polyhedron with C 2 point group symmetry. By calculating the electronic properties, the band gap values of the two structures are significantly reduced compared with that of pure BaY2F8 crystal. However, the conduction band does not break through the Fermi level, and the crystals still maintain the insulation characteristic. According to the calculation of the electron local density function, we conclude that Er–F and Y–F in Er:BYF are connected by ionic bonds. These results fill a theoretical gap in the study of Er:BYF crystals and provide inspiration for structural evolution and material design at different doping concentrations.

Characterization of the evolution of thermal maturity and pore structure of continental organic-rich shales

To clarify the evolution of thermal maturity and pore structure in continental organic-rich shales, calcareous shales of the Liaohe Basin (China) were pyrolyzed, and examined using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nitrogen sorption isotherms, and nuclear magnetic resonance (NMR) spectroscopy. The increase in Raman G‒D band separation and decrease in Raman ID/IG ratio with increasing thermal maturity indicate that these parameters provide superior thermal maturity indicators. This is also confirmed by the good linear correlation of G‒D band shifts and ID/IG with vitrinite reflectance (VR) and maximum temperature (Tmax), respectively. The relative detection accuracy (DA), sampling requirements (SR), sample preparation (SP), detection time (DT), and equipment requirement (ER) of VR, G‒D band shifts, ID/IG, Tmax, FTIR, and XPS indicate that Raman analysis is a simple, quick, and robust method to evaluate thermal maturity. The moderate SR, complex SP, and long DT suggest that VR and Tmax are less widely applicable for characterizing thermal maturity. The FTIR and XPS techniques provide semi-quantitative maturity indicators with poor DA and high ER. Pores observed within organic matter and minerals under SEM indicate that an increase in thermal maturity not only affects the development of organic pores but is also beneficial for the formation of mineral dissolution pores, such as those formed during the transformation of Na0.95Ca0.16Al1.16Si2.84O8 to Na0.84Ca0.02Al1.02Si2.98O8, a process confirmed by XRD. The BET and NMR data also indicate that the development of pore structure is closely related to the evolution of thermal maturity in calcareous shale. During the initial stage, primary pores are filled by bitumen generated from kerogen; this leads to a decrease in transition pores, mesopores, and shale porosity, and reduced pore connectivity. Then, secondary nanoscale pores, transition pores, and mesopores increase with increasing thermal maturity. The peak in secondary porosity is consistent with the liquid hydrocarbon production rate peak, a process that increases shale porosity and leads to improved pore connectivity. The dissolution of minerals induced by organic acids may also contribute to this secondary porosity. With a further increase in thermal maturity, secondary porosity at the microscale is further developed, while transition pores and mesopores collapse, resulting in reduced pore connectivity. The poor pore connectivity that occurs at both low and high VR values may be more conducive to the preservation of shale oil and gas. This study is significant for research into the evolution of thermal maturity and pore structure in continental organic-rich shales.

The Rapid Evolution of De Novo Proteins in Structure and Complex.

Recent studies in the rice genome-wide have established that de novo genes, evolving from non-coding sequences, enhance protein diversity through a stepwise process. However, the pattern and rate of their evolution in protein structure over time remain unclear. Here, we addressed these issues within a surprisingly short evolutionary timescale (<1 million years for 97% of Oryza de novo genes) with comparative approaches to gene duplicates. We found that de novo genes evolve faster than gene duplicates in the intrinsic disordered regions (IDRs, such as random coils), secondary structure elements (such as α-helix and β-strand), hydrophobicity, and molecular recognition features (MoRFs). In de novo proteins, specifically, we observed an 8-14% decay in random coils and IDR lengths and a 2.3-6.5% increase in structured elements, hydrophobicity, and MoRFs, per million years on average. These patterns of structural evolution align with changes in amino acid composition over time as well. We also revealed higher positive charges but smaller molecular weights for de novo proteins than duplicates. Tertiary structure predictions showed that most de novo proteins, though not typically well-folded on their own, readily form low-energy and compact complexes with other proteins facilitated by extensive residue contacts and conformational flexibility, suggesting a faster-binding scenario in de novo proteins to promote interaction. These analyses illuminate a rapid evolution of protein structure in de novo genes in rice genomes, originating from non-coding sequences, highlighting their quick transformation into active, protein complex-forming components within a remarkably short evolutionary timeframe.

Thermally Controlled Synthesis of Cr2(NCN)3/CrN Heterostructured Composite Anodes for High‐Performance Li‐Ion Batteries

Cr2(NCN)3 features high specific capacity and fast electrical conductivity, making it a promising anode candidate for Li‐ion batteries. However, inherent chemical and structural metastability severely restrict its capacity output and cycle life, resulting in unsatisfactory battery performance. Here we use its thermal instability characteristic and propose a thermal controlled structural coordination strategy to in‐situ construct a Cr2(NCN)3/CrN heterostructure. Systematic studies reveal the thermodynamic structural evolution of Cr2(NCN)3 under precise temperature regulation, as well as the essential relevancy between electrochemical properties and crystalline structures. An optimal Cr2(NCN)3/CrN heterostructural composite obtained at 690 °C features uniform two‐phase recombination with abundant grain boundaries enables promising electrochemical performance, exhibiting a high reversible discharge capacity (760 mAh g−1) and a good cycle performance (75% retention after 100 cycles). It is worth noting that the above performance is significantly improved over unmodified pure transition metal carbodiimides or metal nitride anodes. This study provides a simple and universal structural regulation strategy for transition metal carbodiimides that utilizes their thermal sensitivity to synchronously construct synergistic transition metal carbodiimides/transition metal nitrides heterostructures, promoting their potential applications in Li‐ion batteries.

Strain and Electric Field Engineering of G-ZnO/SnXY (X, Y = S, Se) S-Scheme Heterostructures for Photocatalyst and Electronic Device Applications: A Hybrid DFT Calculation.

Using hybrid density functional theory calculations, we systematically study the biaxial strain and electric field modulated electronic properties of g-ZnO/SnS2, g-ZnO/SnSe2, and g-ZnO/SnSSe S-scheme van der Waals heterostructures (vdWHs). g-ZnO/SnS2 and g-ZnO/SnSSe are found to be promising photocatalysts for water splitting with high solar-to-hydrogen efficiencies, even under acidic, alkaline, and high-stress conditions. The strain effect on the bandgaps of g-ZnO/SnXY is explained in detail according to the correlation between geometry structure and orbital hybridization of SnXY, which could help understand the strain-induced band structure evolutions in other SnXY (X, Y = S, Se)-based vdWHs. It is surprising that under an external electric field, g-ZnO/SnS2, g-ZnO/SnSe2, and g-ZnO/SnSSe can offer the occupied nearly free-electron (NFE) states. In many materials, NFE states are usually unoccupied and is not conducive to the charge transport. The NFE state in g-ZnO/SnSe2 is the most sensitive to the electric field and might be promising electron transport channel in nanoelectronic devices. g-ZnO/SnSe2 might also have application potential in gas sensors and high-temperature superconductors.

The Quest for Two-Dimensional MBenes: From Structural Evolution to Solar-Driven Hybrid Systems for Water-Fuel-Energy Generation and Phototherapy.

The field of 2D materials has advanced significantlywith the emergence of MBenes, a newmaterial derived from the MAX phases family, a novel class of materials that originates from the MAX phases family. Herein, this article explores the unique characteristics and morphological variations of MBenes, offering a comprehensive overview of their structural evolution. First, the discussion explores the evolutionary period of 2D MBenes associated with the several techniques for synthesizing, modifying, and characterizing MBenes to tailor their structure and enhance their functionality. The focus then shifts to the defect chemistry of MBenes, electronic, catalytic, and photothermal properties which play a crucial role in designing multifunctional solar-driven hybrid systems. Second, the recent advancements and potentials of 2D MBenes in solar-driven hybrid systems e.g. photo-electro catalysis, hybrid solar evaporators for freshwater and thermoelectric generators, and phototherapy, emphasizing their crucial significance in tackling energy and environmental issues, are explored. The study further explores the fundamental principles that regulate the improved photocatalytic and photothermal characteristics of MBenes, highlighting their promise for effective utilization of solar energy and remediation of the environment. The study also thoroughly assesses MBenes' scalability, stability, and cost effectiveness in solar-driven systems. Current insights and future directions allow researchers toutilize MBenes for sustainable and varied applications. This review regarding MBenes will be valuable to early researchers intrigued with synthesizing and utilizing 2D materials for solar-powered water-energy-fuel and phototherapy systems.

Microstructural Evolution and Phase Transformation on Sn‐Ag Solder Alloys under High‐Temperature Conditions focusing on Ag3Sn phase

This study investigates the microstructural and phase transformations in Sn‐Ag solder alloys under high‐temperature conditions, utilizing X‐Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Electron Backscatter Diffraction (EBSD) analyses. The research addresses the shift from lead‐based solders to lead‐free alternatives, particularly the Sn‐3.5Ag variant, to meet environmental directives. Analytical techniques were employed pre‐ and post‐controlled thermal cycling from 30°C to 180°C, aimed at emulating solder reflow processes. The XRD analysis at room temperature demonstrated pronounced crystalline peaks, suggesting a preferred orientation within the crystal structure. Additionally, the stability in peak positions (2θ values) indicated low lattice strain in the material. Upon heating, peak broadening suggested grain growth and the onset of recrystallization. SEM and EDS analyses corroborated these findings, displaying a fine‐grained, well‐distributed microstructure with a homogenous composition of Sn and Ag elements. EBSD provided insights into the orientation and texture of grains, revealing a weak to moderate texture across the phases. Post‐experiment data indicated a dominant presence of larger grains and significant variation in grain size, with an area‐weighted mean grain size of 68.47 microns and a standard deviation of 8.68 microns, this suggests significant grain growth and coarsening of the Ag3Sn intermetallic compounds. These structural evolutions have crucial implications for the mechanical properties and reliability of the solder alloy in electronic assemblies, underscoring the need for further exploration of lead‐free solder materials in the electronics industry.This article is protected by copyright. All rights reserved.

Molecular dynamics study on the influence of thermal aging on the mechanical properties of epoxy resins for high voltage bushing.

Thermal aging significantly deteriorates the mechanical properties and service performance of epoxy resins used for the high-voltage bushing. Current studies on the thermal aging behavior of epoxy resins mainly focus on experimental observations. However, an in-depth understanding of the mechanism of thermal aging of epoxy resins requires the monitoring of structural evolution of epoxy resins during thermal aging at the molecular level. To thoroughly analyze the intrinsic factors affecting structural evolution and the effect of thermal aging on the mechanical properties of epoxy resin for high-voltage bushing, epoxy resin models with different crosslinking degrees were established and thermal aging treatments at various temperatures and time periods were carried out by molecular dynamics simulation. It was found that the tensile strength of the epoxy resin was enhanced with the increase of the crosslinking degree, which was related to the elevation of the proportion of C-N and O-H bonds in its structure. With the increase of thermal aging temperature, the tensile strength of the epoxy resin decreased, which was related to the formation of weak bonds. At the early stage of thermal aging and after a period of high-temperature thermal aging, the strength of epoxy resin significantly decreases. The thermal aging of the epoxy resin is accelerated under external loading. In addition, the crosslinking degree and curing agent also affect the thermal aging resistance of epoxy resins. The results of this study can provide guidance for predicting and improving the thermal aging resistance of epoxy resins. Materials Studio was used to construct molecular models and complete crosslinking reactions. DGEBA and 44DDS (or 33DDS) were mixed at a ratio of 2:1, followed by crosslinking reaction. During this process, the Nose method was used to control temperature, the Berendsen method was used to control pressure, and the polymer consistent force field (PCFF) was used to control the motion and force of atoms. Isobaric-isothermal ensemble (NPT ensemble) was used to heat up epoxy resin models to various thermal aging temperatures of 400K, 500K, 600K and 700K. The models were maintained at these temperatures for different thermal aging times of 100ps, 200ps, 300ps, 400ps, 500ps, 600ps, 700ps and 800ps. Afterwards, the models were cooled down to 300K and subjected to uniaxial tensile testing at this temperature with a strain rate of 1 × 109s-1. The structural configurations and stress-strain data during the tensile process were recorded. The flow stress of the material was derived by counting the average stress in the 20-50% strain interval.

Study on structure and viscosity evolution mechanism of titanium-containing iron liquid in full viscosity range

This study aims to investigate the relationship between the viscosity of Fe-4.5wt%C-0.2wt%Ti melt and its liquid structure. The actual experimental results of viscosity measurement reveal that the viscosity range of Fe-4.5wt%C-0.2wt%Ti melt can be segmented into three intervals. Through thermodynamically calculated equilibrium phases and high-temperature confocal experiments, it is observed that the abrupt change in viscosity in the lower temperature range is attributed to the precipitation of the graphite phase. Moreover, differential scanning calorimetry experiments exhibit a distinct phase transition in the liquid phase region. To delve into the atomic structure of the liquid phase region, molecular dynamics simulations are employed. The high-temperature liquid structure of Fe-4.5wt%C-0.2wt%Ti melt predominantly consists of vacancies, atomic clusters with Ti as the core, and atomic clusters with C as the core. Within the high-temperature liquid phase region, the conversion of Free-Fe and C1-Fe to Cx-Fe occurs, resulting in a reduction of free volume and enhanced stability of the cluster. Consequently, the inhomogeneity of the Fe-4.5wt%C-0.2wt%Ti melt increases, and the viscosity exhibits a significant increase with temperature, leading to a variation in the viscosity within the liquid phase interval.

Self-Limiting Phase Transition Enabling Reversible Overstoichiometric Li Storage in Ni-Rich Cathodes.

Ni-rich cathodes are some of the most promising candidates for advanced lithium-ion batteries, but their available capacities have been stagnant due to the intrinsic Li+ storage sites. Extending the voltage window down can induce the phase transition from O3 to 1T of LiNiO2-derived cathodes to accommodate excess Li+ and dramatically increase the capacity. By setting the discharge cutoff voltage of LiNi0.6Co0.2Mn0.2O2 to 1.4 V, we can reach an extremely high capacity of 393 mAh g-1 and an energy density of 1070 Wh kg-1 here. However, the phase transition causes fast capacity decay and related structural evolution is rarely understood, hindering the utilization of this feature. We find that the overlithiated phase transition is self-limiting, which will transform into solid-solution reaction with cycling and make the cathode degradation slow down. This is attributed to the migration of abundant transition metal ions into lithium layers induced by the overlithiation, allowing the intercalation of overstoichiometric Li+ into the crystal without the O3 framework change. Based on this, the wide-potential cycling stability is further improved via a facile charge-discharge protocol. This work provides deep insight into the overstoichiometric Li+ storage behaviors in conventional layered cathodes and opens a new avenue toward high-energy batteries.

Elevated Water Oxidation by Cation Leaching Enabled Tunable Surface Reconstruction

Water electrolysis is one promising and eco‐friendly technique for energy storage, yet its overall efficiency is hindered by the sluggish kinetics of oxygen evolution reaction (OER). In response, developing strategies to boost OER catalyst performance is crucial. With the advances in characterization techniques, an extensive phenomenon of surface structure evolution into an active amorphous layer was uncovered. Surface reconstruction in a controlled fashion was then proposed as an emerging strategy to elevate water oxidation efficiency. In this work, Cr substitution induces the reconstruction of NiFexCr2‐xO4 during cyclic voltammetry (CV) conditioning by Cr leaching, which leads to a superior OER performance. The best‐performed NiFe0.25Cr1.75O4 shows a ~1500% current density promotion at overpotential η = 300 mV, which outperforms many advanced NiFe‐based OER catalysts. It is also found that their OER activities are mainly determined by Ni:Fe ratio rather than Fe content in all metal elements. Meanwhile, the turnover frequency (TOF) values based on redox peak and total mass were obtained and analysed, and their possible limitations in the case of NiFexCr2‐xO4 are discussed. Additionally, the high activity and durability were further verified in a membrane electrode assembly (MEA) cell, highlighting its potential for practical large‐scale and sustainable hydrogen gas generation.