Energy Diffusion Research Articles

In situ-Induced Crystal Facet Engineering to Enhance the Rate Performance of Zn2+ Storage.

In recent years, aqueous zinc-ion batteries (ZIBs) have shown considerable promise in the energy storage sector, attributed to their inherent high safety and cost-effectiveness. Zn3V2O7(OH)2·2H2O (ZVO) has emerged as a promising candidate for Zn2+ storage in recent years, owing to its exceptional structural stability that endows it with an excellent cycle life. However, an unsatisfactory rate performance is a limiting factor for its development in ZIBs. Crystal facet engineering can be employed to rationally adjust the number of exposed diffusion channel entrances, thereby effectively enhancing the rate performance of ZIBs. Here, theoretical calculations are employed to analyze the diffusion energy barrier of Zn2+, providing guidance for selecting the optimal crystal facet. The obtained ZVO via electrochemical in situ conversion (e-ZVO) with increased exposed diffusion channel entrances of Zn2+ was proposed to enhance the rate performance. The modulation of ZVO crystal facet orientation and exposed diffusion channel entrances is achieved by manipulating the adsorption-induced surface energy of (CF3SO3)- on crystal facets. As a result, the e-ZVO achieves a high-rate performance of 57 mAh g-1 at 50 A g-1 and a capacity output of 41 mAh g-1 at 40 A g-1 even at -20 °C.

Theoretical Study of Halogen Anion Batteries With Ultra‐Thin InSe

ABSTRACTWe systematically explored the adsorption, diffusion, thermodynamics stability, and electrochemical performance of halogen anions (F−, Cl−, Br−, I−) on monolayer InSe using first‐principles calculations. F−, due to its strong electronegativity, has a destructive effect on the surface. The rank of the adsorption ability of other three anions is Cl− > Br− > I− according to the value of adsorption energy, which is agreement with their electronegativity strength. It was found that the halogen anions exhibited excellent diffusion performance with low diffusion energy barriers. Cl− can adsorb up to three layer showing an excellent theoretical capacity of 415 mA h g−1, while Br− and I− cannot obtain a stable structure when the coverage exceeds 1 and (2/3) layer. In summary, this study evaluates a prospective electrode material and establishes a theoretical foundation for the development of novel rechargeable batteries.

Epitaxial Electrodeposition of Zinc on Different Single Crystal Copper Substrates for High Performance Aqueous Batteries.

The aqueous zinc metal battery holds great potential for large-scale energy storage due to its safety, low cost, and high theoretical capacity. However, challenges such as corrosion and dendritic growth necessitate controlled zinc deposition. This study employs epitaxy to achieve large-area, dense, and ultraflat zinc plating on textured copper foil. High-quality copper foils with Cu(100), Cu(110), and Cu(111) facets were prepared and systematically compared. The results show that Cu(111) is the most favorable for zinc deposition, offering the lowest nucleation overpotential, diffusion energy, and interfacial energy with a Coulombic efficiency (CE) of 99.93%. The study sets a record for flat-zinc areal loading at 20 mAh/cm2. These findings provide some clarity on the best-performing copper and zinc crystalline facets, with Cu(111)/Zn(0002) ranking the highest. Using a MnO2-Zn full cell model, the research achieved an exceptional cycle life of over 800 cycles in a cathode-anode-free battery configuration.

Diffusion behavior of cesium in graphite matrix for a high-temperature reactor pebble-bed module: a first-principles study

ABSTRACT Graphite is one of the main materials of the fuel element in High Temperature Reactor Pebble-bed Module (HTR-PM). Knowledge of the behavior of Cesium (Cs) in graphite is necessary for reliable source term analysis under normal and accidental conditions for HTR-PMs. In this study, the diffusion behavior of Cs atoms in graphite was calculated to estimate the diffusivity of Cs using the first-principles density functional theory. The results show that the energy barriers for vacancy and interstitial diffusion are significantly different (2.257 eV and 0.051 eV, respectively), suggesting that interstitial diffusion is more likely to occur in high-temperature graphite. However, experimental data in literatures indicate that the activation energy for Cs diffusion in graphite falls between 1.5 to 3.3 eV, aligning with the migration energy for vacancy diffusion identified in this study. It is hypothesized that experimental observations of diffusion may be primarily influenced by vacancies. The results may help designers to select appropriate parameters or make physical assumptions and to consider the radiation risks caused by the residual fission product (Cs) in graphite.

Analysis of borehole strain anomalies before the 2017 Jiuzhaigou Ms 7.0 earthquake based on a graph neural network

Abstract. On 8 August 2017, a strong earthquake of magnitude 7.0 occurred in Jiuzhaigou, Sichuan Province, China. To assess pre-earthquake anomalies, we utilized variational mode decomposition to preprocess borehole strain observation data and combined them with a graph WaveNet neural network model to process data from multiple stations. We obtained 1-year data from four stations near the epicenter as the training dataset and data from 1 January to 10 August 2017 as the test dataset. For the prediction results of the variational mode decomposition–graph WaveNet model, the anomalous days were extracted using statistical methods, and the results of anomalous-day accumulation at multiple stations showed that an increase in the number of anomalous days occurred 15–32 d before the earthquake. The acceleration effect of anomalous accumulation was most obvious 20 d before the earthquake, and an increase in the number of anomalous days also occurred in the 1 to 3 d post-earthquake. We tentatively deduce that the pre-earthquake anomalies are caused by the diffusion of strain energy near the epicenter during the accumulation process, which can be used as a signal of pre-seismic anomalies, whereas the post-earthquake anomalies are caused by the frequent occurrence of aftershocks.

Understanding the influence of hydrogen on BCC iron grain boundaries using the kinetic activation relaxation technique (k-ART)

Abstract Hydrogen embrittlement (HE) poses a significant challenge to the mechanical integrity of iron and its alloys. This study explores the influence of hydrogen atoms on two distinct grain boundaries (GBs), $\Sigma37$ and $\Sigma3$, in body-centered-cubic (BCC) iron. Using the kinetic activation relaxation technique (k-ART), an off-lattice kinetic Monte Carlo approach with an EAM-based potential, extensive catalogs of activated events for atoms in both H-free and H-saturated GBs were generated.
Studying the diffusion of H, we find that, for these systems, while GB is energetically favorable for H, this element diffuses more slowly at the GBs than in the bulk. The results further indicate that the $\Sigma 3$ GB exhibits higher stability in its pure form compared to the $\Sigma 37$ GB, with notable differences in energy barriers and diffusion behaviors. Moreover, with detailed information about the evolution landscape around the GB, we find that the saturation of a GB with hydrogen both stabilizes the GB by shifting barriers associated with Fe diffusion to higher energies and reducing the number of diffusion events. For the $\Sigma 37$ GB, the presence of hydrogen causes elastic deformation, affecting the diffusion of Fe atoms both at the GB and in adjacent positions. This results in new diffusion pathways but with higher diffusion barriers, unlike for the $\Sigma 3$ GB. These results indicate that the presence of hydrogen rigidifies the direct GB interface layers while allowing more atoms to be active for the $\Sigma 37$ GB. This provides a microscopic basis to support the existence of competing mechanisms compatible with either plasticity (such as hydrogen enhanced localized plasticity --- HELP) or energy-dominated (hydrogen enhanced decohesion mechanism ---HEDE) embrittlement, with the relative importance of these mechanisms determined by the local geometry of the GBs.

Synergistically Boosted Na+ Migration and Deep Desodiation Stability of NASICON Cathode via High Entropy Regulation.

Mn-containing sodium superionic conductor (NASICON) compounds have shown considerable potential as cathode for sodium-ion batteries (SIBs) owing to higher working voltage (V5+/V4+: 3.9V), lower cost, and lower toxicity compared to full vanadium-based NASICON Na3V2(PO4)3. Taking Na3.3V1.7Mn0.3(PO4)3 (NVMP) as an example, its practical application is still restricted by poor electronic conductivity, sluggish intrinsic Na+ diffusion, and poor high-voltage stability. In this work, a high entropy strategy is proposed to develop Na3.3V1.613Mn0.3(Cr, Fe, Co, Ni, Zr)0.1(PO4)3 (HE-NVMP) cathode for not only enabling more and rapid Na+ migration but also significantly improving deep desodiation stability. Based on theoretical calculations and experimental findings, such high entropy modification can efficiently alter the coordination environments of both V/Mn and Na sites for reducing Na+ diffusion energy barrier, increasing the occupancy of Na+ at Na(2)sites, and consolidating the structure stability. Thus, the obtained HE-NVMP delivers superior high-rate capability (91.7 mAh g-1) up to 50 C and excellent cycling performance (capacity retention: 81.2%) after 10000 cycles at 20 C at the cutoff voltage of 4.1V. More importantly, such cathode also exhibits superior sodium storage properties at a higher cutoff voltage (4.5V) with electrochemical polarization with 75% reduction at 1 C and higher capacity retention of 80.3% after 2000 cycles at 20 C compared to pristine counterpart, indicating a great potential for practical rechargeable batteries with excellent overcharge resistance capability.

Layer-by-layer growth, apparent instability, and mound coarsening in thin film deposition controlled by thermally activated surface diffusion

Thin film deposition from vapor with adsorbate diffusion and Ehrlich-Schwoebel (ES) barriers at step edges is studied by kinetic Monte Carlo (KMC) simulations and scaling approaches. Mound coarsening with slope selection is shown at the largest thicknesses, where roughness (W) and correlation length (ξ) scale in time with exponents β≈n≈0.25, consistently with theoretical works but contrasting with previous simulations that systematically showed temperature-dependent exponents. At a given film thickness, we show that the mounded morphology is independent of the ES barrier, so that interlayer transport is suppressed, while the temperature increase of W and ξ is consistent with intralayer transport limited by adatom detachment from flat terrace borders. Initial layer-by-layer (LBL) growth occurs above a characteristic temperature that increases with the activation energies of terrace diffusion and of ES barrier, but weakly depends on the external flux. Subsequently, as the surface roughness is near the atom/molecule size, there is rapid roughening where, counterintuitively, larger effective growth exponents (β>0.5, suggesting unstable growth) are correlated with longer LBL regimes. Similar LBL-rough transitions were reported in organic film deposition and the model application to diindenoperylene films suggests a large ES barrier ∼0.4eV. In the mound coarsening regime, W/ξ and θ1/2/Wξ converge to constant values dependent on surface diffusion coefficients (θ is the film thickness). This convergence suggests mound coarsening with slope selection in SnTe films whose effective β is anomalously large, showing how film morphology can be interpreted beyond exponent measurements.

Adsorption and diffusion behavior of CO2/N2 in coking coal matrix based on molecular simulation: Considering the effects of moisture and temperature

The moisture content and temperature of coal has a significant impact on the efficacy of inert gases (CO2/N2) in inhibiting coal spontaneous combustion (CSC). Therefore, this study explores the changes in microporous structure, adsorption capacity, heat of adsorption as well as energy distribution and diffusion of CO2/N2 at varying moisture contents (1%–5%) and temperatures (303–343 K). The results demonstrate that water molecules gradually transform large pores in the microporous structure into multiple smaller pores, thus reducing the volume proportion of free pores. The adsorption of CO2/N2 is constrained by the pre-adsorbed water molecules occupying the adsorption sites. Both temperature and moisture exert similar effects on gas adsorption capacity, with higher levels of both reducing the adsorption capacity. Notably, temperature rise is associated with an increased heat of adsorption for the gas molecules. Under moisture effects, there is an observable positive relationship between the gas diffusion coefficient and the adsorption capacity. Conversely, there is a negative correlation with temperature. At low moisture content, CO2/N2 injection is enhanced. High temperatures reduce the effectiveness of CO2/N2 in preventing CSC, while heat can only be exchanged by diluting the oxygen concentration. These results provide crucial insights into the adsorption behavior of CO2/N2 at different temperatures and moisture contents.

Impact of partial regeneration method on the reduction of CO2 desorption energy

Amine-functionalized solid materials have shown efficacy for low-concentration CO2 environments; however, their regeneration is often hindered by slow desorption kinetics at low temperatures. To address this, an innovative approach termed “The Partial Regeneration Method” is introduced as a driving method to enable low-temperature regeneration of CO2 adsorbents at low concentration levels. Analysis of desorption kinetics mechanisms reveal that at low temperatures, CO2 molecules exhibit reduced kinetic energy and intraparticle diffusion coefficients. Furthermore, as it approaches chemical equilibrium temperature, the re-adsorption reaction rate increases. The partial regeneration method which selectively targets CO2 molecules with low re-adsorption rates could be more effective in a such low temperature conditions. This method involves intentionally halting regeneration midway and proceeding to the next adsorption process. Experimental application of specific energy requirements and scenario analysis demonstrated a 50.7% decrease in energy consumption compared to the conventional methods. By optimizing amine loading to reduce excessive re-adsorption, the shortened cycle period compensates for the decreased adsorption per cycle. Increasing the number of cycles led to a 97.5% improvement in CO2 adsorption capacity over a one-month period. Thus, when faced with unavoidable inefficient low-temperature regeneration conditions, the proposed partial regeneration method emerges as a promising solution for minimizing energy consumption.

First principles density functional theory study of tritium species adsorption on Ni(111) surface and diffusion in nickel-sublayer for tritium storage.

The nickel-plated zircaloy-4 is used as a tritium (3H) getter in the tritium-producing burnable absorber rods (TPBARs) to capture 3H produced in the 6Li-riched annular γ-LiAlO2 pellet under neutron irradiation. The experimental data and our previous theoretical results showed that the 3H species produced from the γ-LiAlO2 pellet were mainly 3H2 and 3H2O. These 3H species diffuse from the surface of the LiAlO2 pellet across vacuum to the nickel-plated zircaloy-4 getter and then further diffuse into the getter to chemically form metal hydrides. While a number of studies show that oxygen binds strongly as compared to 3H on the nickel (Ni) layer, the detailed mechanism of 3H species absorption and diffusion across the Ni plate and Ni/Zr interface are still unclear. By employing density functional theory calculations, here we explored the 3H2 and 3H2O species adsorption and dissociation on the Ni(111) surface and diffusion into the Ni sublayer. Our results indicated that the 3H2 and 3H2O dissociate on the Ni(111) surface. The NiOx and Ni(O3H)x could be formed in the Ni layer due to the higher oxygen (O) diffusion energy barrier and formation of Ni vacancy defects. The oxygen was found to be retained in the Ni layer from diffusing across the Ni-Zr interface. This was revealed by comparing the diffusion barriers for 3H with O. 3H was found to have nearly three times smaller diffusion barrier than for O, making 3H comparatively easier to diffuse through the Ni layer. The obtained results provide guidelines for experimental measurements on 3H retention behavior in TPBARs and may open further avenues to explore the impurity effects on 3H diffusion and storage at the Ni/zircaloy interfaces.

In situ oxidized Mo2CTx MXene film via electrochemical activation for smart electrochromic supercapacitors.

Mo2CTx MXenes have great potential for multifunctional energy storage applications because of their outstanding electrical conductivity, superior cycling stability, and high optical transmittance. In this study, we fabricate Mo2CTx film electrodes (referred to as Mo2C) on fluorine-doped tin oxide (FTO) substrates using the layer-by-layer (LbL) self-assembly technique. To improve the energy-storage performance of Mo2CTx film electrodes, we develop a convenient electrochemical activation process to prepare in situ oxidized Mo2CTx/MoO3 film electrodes (referred to as EA-Mo2C). The Mo2CTx/MoO3 hybrid film benefits from the addition of MoO3, which introduces extra redox sites and enhances the charge-storage capacity. Furthermore, the unique layered structure of Mo2CTx significantly reduces the diffusion energy barrier for cations. The synergistic interaction between Mo2CTx and MoO3 results in superior electrochemical performance, and the EA-Mo2C displays a remarkable increase in areal specific capacitance, achieving 23.29 mF cm-2 at a current density of 1.5mA cm-2, which is 518% higher than that of Mo2C. The electrochromic supercapacitor, assembled using EA-Mo2C as the ion-storage layer and polyaniline (PANI) as the electrochromic layer, enables power visualization and quantitative display. In summary, this study utilizes in situ electrochemical activation to derive high-performance electrode materials, offering an innovative strategy for advancing MXene-based energy-storage materials.

Improvement of oxidation resistance of the Ti-modified Cr-based coating on Zry-4 by Cr2O3/Cr2TiO5 double oxide layer with coherent interface

The loss of coolant accident (LOCA) has brought great threat to the safety of nuclear power plant. The oxidation resistance of Zircaloy-4(Zry-4) cladding must be improved to prevent the leakage of nuclear fuel. The Ti-modified Cr-based coating with excellent oxidation resistance was deposited on the Zry-4 by magnetron sputtering. The oxidation kinetics and microstructure evolution of the coatings were investigated via isothermal oxidation experiments at 900–1200 °C, respectively. The results of oxidation kinetics shows that the oxidation resistance of the Ti-modified Cr-based coated Zry-4 is significantly improved and the activation energy of the coated Zry-4 is increased by about 25 %. After steam oxidation at 1200 °C, the coating formed a three-layer structure, Cr2TiO5, Cr2O3 and residual Cr layer. The first-principles calculation shows that the diffusion energy of O in Cr2TiO5 is higher than that in Cr2O3. Furthermore, the formed Cr2TiO5 layer is connected to the underlying Cr2O3 layer via a coherent interface, which both improves the bonding of the oxide layer and dissipates the stresses generated during the oxidation.

Experimental studies on the effect of moisture content and temperature on moisture effective diffusivity and activation energy of bagasse

ABSTRACT Determining bagasse’s moisture effective diffusivity & activation energy requires examining the complex interactions between temperature and moisture content. Identifying these complexities is crucial in order to optimize bagasse applications in various scenarios. Traditional jaggery plants in rural India use a lot of their residual bagasse as fuel after extracting juice from sugarcane. Rural regions sun-dry residual wet bagasse having 45%–50% moisture. Moisture affects bagasse calorific value. Drying is crucial for bagasse heat content. The quantity of fuel fired in combustion chamber, currently reliant on open sun drying, is unpredictable. This study analyzes the role of fuel preparation, characteristics, and drying kinetics of bagasse of size 3.35 mm. Two types of samples, of which one is only a crushed one (wet sample-As Received Basis-ARB) and the other is a crushed and sundried sample (As Dried Basis-ADB). The study found effective diffusivity for crushed sample (ARB) and ADB at 50–100°C, with three models showing good predictions for drying bagasse at different temperatures, except for the Wagh-Singh model. The activation energy for bagasse of size 3.35 mm was determined as 23.19 kJ/mol for ARB and 13.13 kJ/mol for ADB. It was found that the fuel preparatory work and drying have a considerable effect on both the fuel’s activation energy and the moisture content. The fuel preparation and drying could reduce the consumption of bagasse to the tune of 3.7 million metric tons per annum at the energy source and also reduce carbon dioxide emission of 6.8 million TCO2/annum in India from jaggery units.

Vacancy Engineering on MnSe Cathode Enables High‐Rate and Stable Zinc‐Ion Storage

AbstractManganese selenide (MnSe), as a newly emerged manganese‐based chalcogenide, has recently been considered as a potential cathode for aqueous Zn‐based energy storage due to its many merits. Nevertheless, its unsatisfactory kinetic performance and cycling stability, along with its controversial energy storage mechanism, hinder its commercial application. Herein, the MnSe microspheres with Se‐rich vacancies (VSe‐MnSe) are synthesized, and employed as a cathode for Zn‐ion batteries/capacitors (ZIBs/ZICs) for the first time. Density functional theory (DFT) calculations and kinetic analyses illustrate that vacancy engineering of MnSe enhances the active sites, improves the electronic conductivity and ion transport, and reduces the adsorption energy and diffusion energy barriers of H+ and Zn2+, endowing the VSe‐MnSe cathode of ZIBs with significantly enhanced specific capacity, rate capability, and cycling stability. Interestingly, ex situ tests confirm the stable existence of VSe‐MnSe during the whole charge/discharge process and store energy with the first H+ insertion and subsequent H+/Zn2+ co‐insertion. More encouragingly, the VSe‐MnSe//porous carbon (PC) ZICs exhibit an ultrahigh energy density (178.0 Wh kg−1), a high power density (10 kW kg−1), and eminent cyclic stability (up to 10000 cycles). This research offers an efficient strategy for designing and developing high‐performance manganese‐based chalcogenides and sheds new insights into their energy storage mechanisms.

Triplet Energy Migration in Cytoskeletal Polymers.

Dexter energy transfer (DET) of triplet electronic states is used to direct energy in photovoltaics, quench reactive singlet oxygen species in biological systems, and generate them in photodynamic therapy. However, the extent to which repeated DET between aromatic residues can lead to triplet energy migration in proteins has not been investigated. Here, we computationally describe DET rates in microtubules, actin filaments and the intermediate filament, vimentin. We discover instances where interaromatic residue Dexter couplings within individual protein subunits of these polymers are similar those of small molecules used for organic electronics. However, interaromatic residue coupling is mostly weak (<10-3 eV), limiting triplet energy diffusion lengths to 6.1, 0.5 and 1.0 Å in microtubules, actin filaments and vimentin, respectively. On the other hand, repeated förster resonance energy transfer (FRET) between aromatic residues leads to singlet energy diffusion lengths of 12.4 Å for actin filaments and about 8.6 Å for both microtubules and vimentin filaments. Our work shows that singlet energy migration dominates over triplet energy migration in cytoskeletal polymers.

Reversing Surface Charge for Highly-Active Organic Photovoltaic Catalysts.

Organic photovoltaic materials typically exhibit low charge separation and transfer efficiency and severe exciton/carrier recombination due to high exciton binding energy and short exciton diffusion lengths, limiting the enhancement of photocatalytic hydrogen evolution performance. Here, we introduce a surface charge reversal strategy to regulate charge characters of organic photovoltaic catalyst (OPC). Compared to OPC nanoparticles (NPs) stabilized by anionic surfactant ((-) NPs), NPs stabilized by cationic surfactant ((+) NPs) exhibit a raised Fermi level, larger surface band bending and Schottky barrier, thereby enhancing charge separation and transfer efficiency while suppressing charge carrier recombination. As result, (+) NPs demonstrate better photocatalytic performance than (-) NPs, independent of the chemical structure of OPCs and surfactant molecules. Under illumination of AM1.5G, 100 mW cm-2, the PM6: 2FBP-4F NPs stabilized by cationic surfactant (dodecyltrimethylammonium bromide, DTAB) exhibit much higher photocatalytic activity for hydrogen evolution (up to 946.1±15.76 mmol h-1 g-1) than that of PM6: 2FBP-4F NPs stabilized by anionic surfactant, among the best results reported so far for photocatalytic hydrogen evolution under simulated sunlight.

How does ICT Diffusion and Renewable Energy Consumption affect CO2 Emissions?

This study investigates the impact of renewable energy consumption (REC), information and communication technology (ICT), and gross domestic product (GDP) on CO2 emissions in Saudi Arabia over the period 1990-2020. Utilizing an ARDL (Autoregressive Distributed Lag) model, the results reveal that GDP exerts a positive and significant effect on emissions in both the short and long term, suggesting that economic growth is associated with higher emissions. In contrast, REC has a negative impact, indicating that increased renewable energy consumption contributes to reducing emissions over time. However, the negative effect of REC on emissions in the short term suggests that transitioning to renewable energy may involve initial costs or disruptions that temporarily affect emissions. ICT also shows a negative influence on emissions in the long term, but its short-term effects are less consistent, reflecting the potential environmental costs associated with rapid technological expansion, such as increased energy consumption and electronic waste. The interaction terms between GDP and REC, as well as GDP and ICT, reveal that higher levels of renewable energy and technological development moderate the positive relationship between GDP and emissions, highlighting the complex trade-offs between economic growth, energy transition, and technological advancement. The findings emphasize the importance of expanding renewable energy infrastructure and fostering sustainable technological innovation to mitigate emissions while sustaining economic growth in Saudi Arabia.

Enhanced Oxidation Resistance of Pt‐Containing Inconel 718 Alloy through Facilitated Formation of Protective Chromia

This study investigates the influence of Pt addition on the oxidation behavior of a Cr2O3‐forming superalloy. Inconel 718 (IN718) alloys with varying Pt content were prepared and subjected to isothermal oxidation tests. The results demonstrate that Pt significantly enhances the oxidation resistance of IN718, as evidenced by reduced weight gain, thinner oxide layers, and smaller oxide particles. Pt addition also increases the activation energy for both initial interface oxidation and ion diffusion during long‐term oxidation. Furthermore, Pt promotes the formation of a Cr2O3 layer while suppressing the formation of other undesirable oxides, resulting in a more cohesive and stable oxide layer. The improved oxidation resistance is attributed to two key factors: during the initial oxidation stage, Pt, as a noble element, reduces the activity of the primary oxide‐forming element Cr to oxidative environments, thereby lowering its susceptibility to initial oxidation at the metal–oxidant interface. During long‐term oxidation, Pt preferentially substitutes for Ni in major phases such as γ‐Ni(Cr,Fe) and γ′‐Ni3(Al,Ti), locally increasing the Cr composition. This promotes Cr oxidation, effectively suppressing the oxidation of Ni or Fe. These findings suggest that Pt addition is a promising approach for enhancing oxidation resistance in alloy design.

Atomistic Transport Mechanisms in Lithium Salt‐Doped Ionic Covalent Organic Framework Electrolytes

Ionic covalent organic frameworks (iCOFs) have garnered significant attention as potential single‐ion conductive solid‐state electrolytes, where researchers have made great efforts in designing iCOF‐based composites, aiming to improve their intrinsic low conductivity. One successful case is to fill iCOF channels with lithium salts, such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). However, the ion transport mechanisms in these composite electrolytes are still largely unknown, hindering their further improvement. Here molecular dynamics simulations were employed to systematically predict the ion diffusivity in iCOF (e.g., TpPa‐SO3Li COF)‐LiTFSI composite electrolytes with varying LiTFSI compositions at different temperatures. A positive correlation was seen between Li+ diffusivity and LiTFSI:iCOF ratio, which was also verified by our experiments. Interestingly, the Li+ diffusion energy barrier obtained by the Arrhenius equation exhibited nearly no dependency on the LiTFSI concentration, indicating the importance of temperature insensitive microstructural related factors. Radial distribution functions show that with a higher LiTFSI proportion, the coordination number of SO3‐ decreases, while that of TFSI‐ increases, suggesting a competition between these two species in the Li+ solvation shell. Furthermore, configurational entropy and bond orientational order parameter calculations examined the degree of disorder in the Li+ solvation structure. These results should improve our mechanistic understandings of iCOF‐based electrolytes.