Atomic Mass Research Articles

Oxygen isotope study of the Asuka-881020 CH chondrite II: Porphyritic chondrules

Oxygen isotope ratios and elemental compositions of porphyritic chondrules and olivine and pyroxene fragments in the Asuka-881020 CH chondrite were analyzed. The oxygen isotope ratios inside individual porphyritic chondrules are homogeneous within the uncertainty, except for relict grains of olivine and low-Ca pyroxene that have distinct oxygen isotope ratios. The average oxygen isotope ratios of the individual chondrules plot along and above the primitive chondrule mineral (PCM) line with Δ17O (=δ17O – 0.52 × δ18O) values from −4.7 ‰ to +4.1 ‰. The olivine and pyroxene fragments, which have Δ17O values ranging from −2.1 ‰ to +3.2 ‰, are likely to be fragments of the porphyritic chondrules.Unlike the non-porphyritic chondrules in CH and CB chondrites and chondrules in other carbonaceous chondrites, the type I and II chondrules do not show a systematic difference in the Δ17O values. Furthermore, the Δ17O values of the type I chondrules increase from −4.7 ‰ to +4.1 ‰ with increasing Mg# (=molar [MgO]/[MgO + FeO] × 100) from 96 to 99. We argue that the positive Δ17O-Mg# trend is explained by an addition of 16O-poor carbon-rich organics as a reducing agent to the relatively 16O-rich precursor silicate, which is a new environment for chondrule formation. This hypothesis is supported by the two lines of evidence observed in the present study. (1) The chondrules and fragments with higher Δ17O values show larger deviations from the PCM line towards low δ18O, suggesting oxygen isotope mass fractionation between the chondrule melt and CO or CO2. (2) Olivine phenocrysts in the chondrules with high Δ17O values contain Ni-poor Fe-metal particles surrounded by silica-rich glass, which may be reduction products during the chondrule formation. Thus, it is suggested that the porphyritic chondrules in CH and CB chondrites have different origins from chondrules in any other chondrite types, even from the non-porphyritic chondrules in CH and CB chondrites.

Precise modulation of surface lattice to reinforce structural stability of high-nickel layered oxide cathode by hafnium gradient doping

The quest for high-energy lithium-ion batteries has intensified interest in high-nickel layered oxide cathode materials, while the rise in nickel content adversely impacts structural stability and cycling performance. Herein, Hafnium (Hf) anchored at nickel (Ni) site precisely modulates the surface crystal lattice of high-nickel cathode (LiNi0.9Co0.05Mn0.05O2, NCM90) that is confirmed by Rietveld refinement of neutron powder diffraction. Notably, the strengthened structural stability thanks to Hf gradient doping is firmly substantiated by in-situ X-ray diffraction and in-situ X-ray adsorption spectroscopy. This enhancement can be ascribed to the substantial atomic mass of Hf and large radius of Hf4+, facilitating the minimization of potential alterations of interlayer or intralayer. The intensified Hf-O bond significantly increases the formation energy of oxygen vacancies and efficiently restrains the detrimental Li+/Ni2+ disorder, thereby mitigating lattice oxygen loss and enhancing both cycling and thermal stability of high-nickel cathode. Consequently, the 0.3 % Hf-doping cathode exhibits considerable improvement in electrochemical performance, delivering superior capacity retention of 95.0% after 100 cycles at 1C (1 C = 200 mA g−1) and 83.9 % after 500 cycles at 1C/5C in the voltage range of 3.0∼4.3 V. This work highlights the benefits of precise modulation strategy for high-nickel cathodes, offering a viable approach to enhance structural stability and electrochemical performance of high-nickel cathodes.

Fractional and Unitary Electric Charges I: Classical Foundations of Quantum Effects

Numerical value of the atom’s electrical/electromotive charge emerges naturally upon expressing its definitive e-m oscillation frequency ν as an exponent of eight, 8ν  (‘octave quantum’). This simple procedure realizes, for each element, accurate values of the established quantum numbers. It is revealed that unlike others, the spin quantum number ±½ is not an ‘octave quantum’, it actually turns out an exponent of a field coupling that manifests atomic mass. Octave quanta of frequencies of atoms of the second and third (invisible unknown) elements of nature’s chemical periodicity, “blackton” Bl and “boston” Bs, (8⅓, 8⅔)  manifest observational fractional one-third 1/3  and two-third 2/3  electrical charges normally associated with ‘quarks’. Based on the concept of ‘octave quantum’ the author uses periodic arrangement of the chemical elements to present a unique account of established quantum numbers, it facilitates a deeper insight into factors responsible for unusual valences commonly encountered among transition elements. It is concluded that the ease with which the procedure reproduces established quantum numbers strongly suggests an intrinsic classical origin of observational quantum characteristics.

Contact-Electro-Catalysis for Direct Oxidation of Methane under Ambient Conditions.

The conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo- and electro- chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact-electro-catalysis, initiating chemical reactions through charge exchange at a solid-liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat -1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas-phase catalytic reactions, underscore a significant advance in catalysis.

Contact‐Electro‐Catalysis for Direct Oxidation of Methane under Ambient Conditions

AbstractThe conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo‐ and electro‐ chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact‐electro‐catalysis, initiating chemical reactions through charge exchange at a solid–liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat−1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas‐phase catalytic reactions, underscore a significant advance in catalysis.

Discrimination of geographical origin of Korean and Chinese red pepper paste via inductively coupled plasma atomic emission spectroscopy and mass spectrometry

BackgroundRed pepper paste is a common ingredient used in food in Korea. The discrimination of the geographical origin of agricultural products is important to protect the agricultural industry and customers from the misinformation regarding the product origin. Several studies have attempted to identify the geographical origin of red pepper based on its characteristic features using diverse methods, such as inorganic elemental analysis. However, similar studies on red pepper pastes have not been conducted thus far.ResultsIn, this study, we established methods based on inductively coupled plasma optical emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) for determining inorganic elements in red pepper pastes. The limit of detection (LOD) of ICP-AES was in the range of 0.006–0.531 mg∙kg−1 and the limit of quantification (LOQ) was 0.017–1.593 mg∙kg−1. In addition, LOD and LOQ ranges for ICP-MS were 0.001–1.553, and 0.002–5.176 μg∙kg−1, respectively. The concentrations of Ca, K, Mg, Na, P, S, Cr, Mn, Co, Ni, Cu, Ga, As, Sr, Zr, Mo, Pd, Cd, Sn, Sb, Ce, Pt, Pb, and U were high in the Korean red pepper paste. All the employed discrimination models could clearly distinguish between Korean and Chinese red pepper pastes. In particular, among the four different models, CDA showed the most accurate ability to discriminate the geological origin of Korean and Chinese red pepper paste compared to that achieved using the other models with 100% accuracy.ConclusionsBased on, the findings of this study, the use of ICP-AES and ICP-MS analyses for discriminating the inorganic elements in food products in combination with the aforementioned statistical analysis models could help the mitigation of issues associated with the misinformation of the geographical origin of agricultural products, aiding customer protection.Graphical

Tephra identification without pre‐separation in ashed peat

ABSTRACTCryptotephras in peat and sediment samples are traditionally separated for geochemical characterization using chemical or density floatation techniques following initial tephra identification and shard counting through analysis of ashed residue via light microscopy. However, these practices can be time consuming, subject to practitioner experience and material type, with a potential for sample loss. We present an alternative approach to identify cryptotephra in peat and sedimentary samples, where ashed material is mounted directly in epoxy resin and analysed through back‐scattered electron (BSE) imaging via scanning electron microscopy–energy dispersive X‐ray spectroscopy (SEM‐EDX). Semi‐quantitative, unsupervised chemical maps of epoxy mounts are created within 120 min using ‘Feature Analysis’ on AZtec software by Oxford Instruments. These maps locate grains of higher atomic mass and categorize phases based on geochemistry. We create a tephra identification method using an ombrotrophic peat sample doped with bimodal Vedde Ash, where recovery of the known tephra proportion in wet peat is 96%. We also propose an automated alternative to optical shard counting, whereby tephra counts identified via Feature Analysis can be ratioed to total grain counts acquired through ImageJ software and extrapolated to the inorganic fraction in wet peat. We apply the method to a minerotrophic peat from Brackloon Wood, Mayo, Ireland, where the Laki ad 1783–84 cryptotephra is successfully identified.

Thermal Transport in Pentagonal CX2 (X = N, P, As, and Sb).

Two-dimensional (2D) materials with a pentagonal structure have many unique physical properties and great potential for applications in electrical, thermal, and optical fields. In this paper, the intrinsic thermal transport properties of 2D pentagonal CX2 (X = N, P, As, and Sb) are comparatively investigated. The results show that penta-CN2 has a high thermal conductivity (302.7 W/mK), while penta-CP2, penta-CAs2, and penta-CSb2 have relatively low thermal conductivities of 60.0, 36.9, and 11.8 W/mK, respectively. The main reason for the high thermal conductivity of penta-CN2 is that the small atomic mass of the N atom is comparable to that of the C atom, resulting in a preferable pentagonal structure with stronger bonds and thus a higher phonon group velocity. The reduction in the thermal conductivity of the other three materials is mainly due to the gradually increased atomic mass from P to Sb, which reduces the phonon group velocity. In addition, the large atomic mass difference does not result in a huge enhancement of the anharmonicity or weakening of the phonon relaxation time. The present work is expected to deepen the understanding of the thermal transport of main group V 2D pentagonal carbons and pave the way for their future applications, also, providing ideas for finding potential thermal management materials.

Optimization of the microelectrochemical drilling response variables of Inconel 718 alloy by grey relational analysis

The Material Removal Rate (MRR) is a critical aspect of microelectrochemicaldrilling. Thistechnique relies on chemical processes. The pace of drilling is affected by the atomic mass, electrical supply, electrolytic solution, and drillingperiod. To understand more about the influence of MRR on Inconel 718 alloy, experimental observations have been carried out with stainless-steel electrodes and various input processsettings. The optimization in this study depends on the Taguchi technique with an Optimization by Grey Relational Analysis(GRA). Taguchi's concept was used to set up the testing operations, which included three input processing factors: electrolytic solution, voltage, and feed speed. In count to the MRR,Surface Roughness (SR)and overcut were utilized as response variablesin this study. Analysis of Variance (ANOVA)has been utilized to study the effect of input variables on microelectrochemical drillingoutput parameters. The results of this research demonstrate that voltage is the most important element in achieving the SR and overcut target performing qualities, and optimal settings are discovered. Regression equations aredesigned forprediction analysis. This study will assist industrialists in determining variables to get desired results.

Resting cells of Skeletonema marinoi assimilate organic compounds and respire by dissimilatory nitrate reduction to ammonium in dark, anoxic conditions.

Diatoms can survive long periods in dark, anoxic sediments by forming resting spores or resting cells. These have been considered dormant until recently when resting cells of Skeletonema marinoi were shown to assimilate nitrate and ammonium from the ambient environment in dark, anoxic conditions. Here, we show that resting cells of S. marinoi can also perform dissimilatory nitrate reduction to ammonium (DNRA), in dark, anoxic conditions. Transmission electron microscope analyses showed that chloroplasts were compacted, and few large mitochondria had visible cristae within resting cells. Using secondary ion mass spectrometry and isotope ratio mass spectrometry combined with stable isotopic tracers, we measured assimilatory and dissimilatory processes carried out by resting cells of S. marinoi under dark, anoxic conditions. Nitrate was both respired by DNRA and assimilated into biomass by resting cells. Cells assimilated nitrogen from urea and carbon from acetate, both of which are sources of dissolved organic matter produced in sediments. Carbon and nitrogen assimilation rates corresponded to turnover rates of cellular carbon and nitrogen content ranging between 469 and 10,000 years. Hence, diatom resting cells can sustain their cells in dark, anoxic sediments by slowly assimilating and respiring substrates from the ambient environment.

Organic and Inorganic Carbon Sinks Reduce Long‐Term Deep Carbon Emissions in the Continental Collision Margin of the Southern Tibetan Plateau: Implications for Cenozoic Climate Cooling

AbstractThis paper aims to update our understanding of the carbon cycle in the Himalayas, the most intense collisional orogeny globally, by providing new insight into its impact on Cenozoic climate cooling through the use of isotopic variations in both organic and inorganic carbon and an isotopic mass balance model. Our results from 20 selected hot springs show that the relative contributions of dissolved carbon from the mantle, metamorphic decarbonization, aqueous dissolution, and soil organic matter are approximately 2%, 82%, 6%, and 10%, respectively. Approximately 87% ± 5% of CO2 generated in the deep crust precipitates as calcite, while approximately 5.5% ± 1% of this carbon is converted to biomass through microbial chemosynthesis at depths less than 2 km. Our random forests approach yielded a metamorphic carbon flux from the entire Himalayan orogenic belt of approximately 2.7 ∼ 4.5 × 1012 mol/yr. The minor CO2 released into the atmosphere (2.5 ∼ 4.2 × 1011 mol/yr) is comparable to the carbon consumption driven by Himalayan weathering. This paper provides new insights into deep carbon cycling, notably that approximately 93% of deeply sourced carbon is trapped in the shallow crust, rendering orogenic processes carbon neutral and possibly acting as one of the major triggers of long‐term climate cooling in the Cenozoic.

Comprehensive theoretical and experimental study of plasma plume dynamics across magnetic field

Dynamics of laser-produced plasma plume in the presence of magnetic field has been investigated theoretically and experimentally. A mathematical model has been proposed to estimate the time variation of axial dimension, expansion velocity and effective deceleration of the plasma plume across the magnetic field. The numerical solutions are also verified with analytical solutions. In order to validate the theoretical model, two directional, time-resolved images of laser-produced nickel and tungsten plasmas have been recorded in different magnetic field. The simulated plasma dynamics is compared with experimental data for significantly different atomic masses of ablated species, expand in wide range of magnetic field, ranging from 0.1 to 0.5 T. Most of the dynamical features for the both, diamagnetic and beyond the diamagnetic region e.g., temporal variation of plume dimension, characteristic time duration of diamagnetic behaviour, bubble radius and plasma instability are well captured by theoretical model with reasonable agreement with experimental observations.

Commissioning of the ERDA-TOF beamline at the ion beam laboratory in Madrid

We report progress for the ERDA time-of-flight beamline at the Centre of Micro-Analysis of Materials in Madrid. This beamline experienced a long shut down and has recently gone through a re-commissioning process. The time stations, based on a twin mirror design, demonstrate a time resolution of 215 ps for 6 MeV He2+. Using a standard particle detector for the energy signal we find a mass resolution of 1.4 atomic mass units for 27Al and 28Si with 40 MeV Cl4+. Detection efficiency needs no corrections for elements heavier than 7Li. Analysis of a borosilicate reference showed good agreement with the known composition. Based on these results, the facility is considered operational and open for users.

Improving the reactor safety aspects by the implementation of (Th-U233-Pu) fuel in a PWR assembly

The aim of this work is not only to demonstrate how to introduce thorium as an alternative nuclear fuel into pressurized water reactors, but also to examine the several advantages that (Th, U233, Pu) has over (Th, U233) and (Th, Pu) fuels when (U233O2) is mixed with (Th-Pu)O2 fuel. To investigate these advantages, three thorium fuels, (Th, U233), (Th-U233-Pu) and (Th-Pu) are simulated and analyzed by the MCNPX 2.7 code. The reactor safety aspects of these fuels are compared with those of the reference UO2 fuel. The concentration of Th-233 and fissile isotopes is adjusted to obtain criticality (Keff = 1.03) at the same burnup value (35 GWd/tonne) for all fuel types. Based on the predicted results, the author revealed that: 1) 56 % of plutonium (238-242) is depleted in the case of (Th-U233-Pu), while 41 % of plutonium is depleted in the (Th-Pu) at 60 GWd/tonne. This result indicates that (Th-U233-Pu) is more proliferation-resistant than (Th-Pu). 2) In terms of improving the quantity of radioactive waste, (Th, U233, Pu) model produces 0.6 and 0.9 times the amount of Am (241-243) and Cm (242-244) in UO2, respectively. On the other hand, (Th, Pu) fuel produces about 7 times the amount of Am and 8 times the amount of Cm in UO2 fuel. 3) The fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC) of (Th-U233-Pu) are more negative than that of UO2 and (Th-U233) at the early stages of fuel burnup (0–5) GWd/tonne.4) the total mass of fissile isotopes in (Th-U233-Pu) is greater than that of UO2 and (Th-U233) and as a result, the fuel life time is longer in the case of (Th-U233-Pu). 4) The conversion ratio provided by (Th-U233-Pu) is greater than that provided by UO2 and (Th-U233).This behavior is expected owing to the hardening of neutron spectrum in (Th-U233-Pu). 5) The peaking factors are lower in the case of (Th-U233-Pu) compared to (Th-Pu). 6) The concentration of xenon and samarium is noticeably lower for (Th-U233-Pu) in comparison with (Th-Pu) and consequently, the time required for restarting the reactor is accelerated.

Predicting nuclear masses with product-unit networks

Accurate estimation of nuclear masses and their prediction beyond the experimentally explored domains of the nuclear landscape are crucial to an understanding of the fundamental origin of nuclear properties and to many applications of nuclear science, most notably in quantifying the r-process of stellar nucleosynthesis. Neural networks have been applied with some success to the prediction of nuclear masses, but they are known to have shortcomings in application to extrapolation tasks. In this work, we propose and explore a novel type of neural network for mass prediction in which the usual neuron-like processing units are replaced by complex-valued product units that permit multiplicative couplings of inputs to be learned from the input data. This generalized network model is tested on both interpolation and extrapolation data sets drawn from the Atomic Mass Evaluation. Its performance is compared with that of common neural-network architectures, substantiating its suitability for nuclear-mass prediction. Additionally, a prediction-uncertainty measure for such complex-valued networks is proposed that allows identifying nuclides of expected large prediction error. Within and beyond the experimentally explored domain, model predictions are evaluated by computing deviations from the Garvey-Kelson relations.

The origin of anomalous mass-dependence of thermal conductivity in Janus XBAlY (X = Se, S, Te; Y = S, Se, O; X ≠ Y) monolayers

Owing to the unique asymmetric geometry, Janus monolayer compounds exhibit various exotic thermal properties and have promising applications in thermal management. In this study, we combine machine learning potentials and the phonon Boltzmann transport equation to perform a comparative study of the thermal transport properties in Janus XBAlY (X = Se, S, Te; Y = S, Se, O; X ≠ Y) monolayers. Our findings unveil a thermal conductivity (κp) ranking as SeBAlS > TeBAlO > SBAlSe, contradicting the conventional expectation that a higher κp is typically observed when the average atomic mass is smaller. At room temperature, the κp of SeBAlS is 174 Wm−1 K−1, which is 4.8 times that of SBAlSe when considering three-phonon scattering processes. Moreover, the consideration of four-phonon scatterings does not alter such ranking. The anomalous κp phenomenon was explained through a detailed analysis of the phonon–phonon scattering mechanism, phonon bandgap, phonon anharmonicity, and chemical bond strength. This study highlights the intricate relationship between atomic mass, bonding characteristics, and thermal properties, offering insights for designing Janus materials with tailored thermal conductivity.

Phytochemicals Involved in Mitigating Silent Toxicity Induced by Heavy Metals.

Heavy metals (HMs) are natural elements present in the Earth's crust, characterised by a high atomic mass and a density more than five times higher than water. Despite their origin from natural sources, extensive usage and processing of raw materials and their presence as silent poisons in our daily products and diets have drastically altered their biochemical balance, making them a threat to the environment and human health. Particularly, the food chain polluted with toxic metals represents a crucial route of human exposure. Therefore, the impact of HMs on human health has become a matter of concern because of the severe chronic effects induced by their excessive levels in the human body. Chelation therapy is an approved valid treatment for HM poisoning; however, despite the efficacy demonstrated by chelating agents, various dramatic side effects may occur. Numerous data demonstrate that dietary components and phytoantioxidants play a significant role in preventing or reducing the damage induced by HMs. This review summarises the role of various phytochemicals, plant and herbal extracts or probiotics in promoting human health by mitigating the toxic effects of different HMs.

Physical, Mechanical, and ionizing radiation shielding properties of 10PbO–10Na2O-(80-x)B2O3-xBaO glasses

This research explored the mechanical, physical, and ionizing radiation shielding properties of 10PbO–10Na2O-(80-x)B2O3-xBaO glass samples, where x = 10, 15, 20, and 25. The conventional melt-quench technique was employed to prepare the samples. The elastic moduli were investigated using the Makishima–Mackenzie model. At the same time, the radiation shielding properties involved a comprehensive analysis of the effective atomic number, linear attenuation and mass attenuation coefficients, half-value and tenth-value layers, radiation protection efficiency, and transmission factors, as well as the buildup factors for different mean-free paths (mfp). The impact of BaO (mol%) on the parameters mentioned above was investigated across a range of photon energies (0.015–15 MeV). In addition, the effect of BaO on the physical and mechanical properties of current glasses was studied. The addition of BaO showed an inverse impact on mechanical and physical properties, gradually reducing the glass's stability. In contrast, adding BaO to the compound enhanced photon attenuation ability, which means the sample with 25% BaO had the optimum capacity for radiation shielding amongst all the prepared samples. Moreover, the results demonstrated the complex interplay of Compton scattering, pair production, and the photoelectric effect, influencing the attention of photons. This work provides beneficial intuition into designing and optimizing glass-based radiation shielding materials.

Interplay of stellar and gas-phase metallicities: unveiling insights for stellar feedback modelling with Illustris, IllustrisTNG, and EAGLE

ABSTRACT The metal content of galaxies provides a window into their formation in the full context of the cosmic baryon cycle. In this study, we examine the relationship between stellar mass and stellar metallicity (MZ*R) in the hydrodynamic simulations Illustris, TNG, and EAGLE (Evolution and Assembly of GaLaxies and their Environment) to understand the global properties of stellar metallicities within the feedback paradigm employed by these simulations. Interestingly, we observe significant variations in the overall normalization and redshift evolution of the MZ*R across the three simulations. However, all simulations consistently demonstrate a tertiary dependence on the specific star formation rate (sSFR) of galaxies. This finding parallels the relationship seen in both simulations and observations between stellar mass, gas-phase metallicity, and some proxy of galaxy gas content (e.g. SFR, gas fraction, and atomic gas mass). Since we find this correlation exists in all three simulations, each employing a subgrid treatment of the dense, star-forming interstellar medium (ISM) to simulate smooth stellar feedback, we interpret this result as a fairly general feature of simulations of this kind. Furthermore, with a toy analytic model, we propose that the tertiary correlation in the stellar component is sensitive to the extent of the ‘burstiness’ of feedback within galaxies.

Molten-Salt-Assisted Strategy Enables High-Rate Micron-Sized Single-Crystal Li-Rich, Mn-Based Layered Oxide Cathode Materials.

Li-rich Mn-based layered oxides (LMLOs) are expected to be the most promising high-capacity cathodes for the next generation of lithium-ion batteries (LIBs). However, the poor cycling stability and kinetics performance of polycrystalline LMLOs restrict their practical applications due to the anisotropic lattice stress and crack propagation during cycling. Herein, B-doped micron-sized single-crystal Co-free LMLOs were obtained by molten-salt (LiNO3 and H3BO3)-assisted sintering. The results reveal that the low-melting-point molten salt can serve as liquid-phase media to improve the efficiency of atomic mass transfer and crystal nucleation and growth. The modified single-crystal LMLO cathodes can resist the accumulation of anisotropic stress and strain during the cycling and reduce interface side reactions, thus achieving excellent high-voltage stability and kinetics performance. The reversible specific capacity of the single crystals is 210.8 mAh g-1 at 1C with a voltage decay rate of 1.95 mV/cycle and up to 161.1 mAh g-1 at 10C with a capacity retention of 81.06% after 200 cycles.