Supercapacitors (SCs) stand out among various energy storage devices owing to their high power density and long-term cycling stability. As new two-dimensional material, MXenes have become a research hotspot in recent years owing to their unique structure and rich surface functional groups. Compared with other materials, MXenes are more promising for SCs owing to their tunable precursors, structural stability, and excellent electrical conductivity. However, the rate performance and electrochemical reaction activity of MXene materials are poor, and stacking severely limits their application. Therefore, various modification strategies are employed to improve the electrochemical performance of MXene materials. As the modification strategy of MXene electrode materials often involves increasing the number of ion transport channels to expose more active sites, the packing density is also affected to different degrees. Therefore, achieving a balance between high volumetric capacitance and rapid ion transport has become a key issue for the application of MXene-based SCs in wearable devices and microdevices. In this paper, the latest progress in the preparation methods and modification strategies of MXenes in recent years is reviewed with the aim of achieving both high volumetric capacitance and high ion transport for expanding the application of MXene-based SCs in microdevices and wearable devices.

Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries. However, achieving the balance among low cost, high waste recycling rates, and adequate strength remains a significant challenge for cemented rockfill. This study used a composite alkali activator to activate gangue cemented rockfill. The compressive strength, scanning electron microscopy, energy dispersive spectrometer, mercury intrusion porosimetry, X-ray diffraction, and thermogravimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength, microstructure, and composition of the cemented rockfill. The calcium silicate hydrate (C–S–H) molecular model of cemented rockfill was constructed to explore the fracture evolution of the nucleated molecular structure under tension. The results show that compressive strength initially increased and then decreased with the activator proportion, the optimal activator proportion of 1:2 resulted in a 31.25% increase in strength at 3 d. This reasonable activator proportion strengthens the pozzolanic effect of gangue, and consumes more calcium hydroxide to inhibit its agglomeration, ultimately achieving the densification of microstructure. The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model. The 12% substitution of calcium ions increases the adhesion between silicon chain layers, which is beneficial to the interlayer stress transfer. This work proposes a method for preparing low-cost cemented rockfill from alkali-activated gangue, which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.

Gold ores in the Jiaozhou region of China are characterized by their abundant reserves, low grade, fine dissemination, and challenges in upgrading. Froth flotation, with xanthate as the collector, is a commonly employed method for enriching auriferous pyrite from these ores. This study aimed to develop a more efficient flotation process by utilizing cavitation nanobubbles for a low-grade gold ore. Batch flotation tests demonstrated that nanobubbles significantly enhanced the flotation performance of auriferous pyrite, as evidenced by improved concentrate S and Au grades and their recoveries. The mechanisms underlying this enhancement were explored by investigating surface nanobubble (SNB) formation, bulk nanobubble (BNB) attachment to hydrophobic pyrite surfaces, and nanobubble-induced agglomeration using atomic force microscopy (AFM) and focused beam reflectance measurement (FBRM). The results revealed that nanobubble coverage on the pyrite surface is a critical factor influencing surface hydrophobicity and agglomeration. SNBs exhibited higher coverage on pyrite surfaces with increased surface hydrophobicity, flow rate, and cavitation time. Similarly, BNB attachment on pyrite surfaces was significantly increased with surface hydrophobicity and cavitation time. Enhanced surface hydrophobicity, along with higher flow rates and cavitation times, promoted pyrite particle agglomeration owing to the increased nanobubble coverage, ultimately leading to improved flotation performance.

The environment-friendly and efficient selective separation of chalcopyrite and molybdenite poses a challenge in mineral processing. In this study, gum Arabic (GA) was initially proposed as a novel depressant for the selective separation of molybdenite from chalcopyrite during flotation. Microflotation results indicated that the inhibitory capacity of GA was stronger toward molybdenite than chalcopyrite. At pH 8.0 with 20 mg/L GA addition, the recovery rate of chalcopyrite in the concentrate obtained from mixed mineral flotation was 67.49% higher than that of molybdenite. Furthermore, the mechanism of GA was systematically investigated by various surface characterization techniques. Contact angle tests indicated that after GA treatment, the hydrophobicity of the molybdenite surface significantly decreased, but that of the chalcopyrite surface showed no apparent change. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy revealed a weak interaction force between GA and chalcopyrite. By contrast, GA was primarily adsorbed onto the molybdenite surface through chemical chelation, with possible contributions from hydrogen bonding and hydrophobic interactions. Pre-adsorbed GA could prevent butyl xanthate from being adsorbed onto molybdenite. Scanning electron microscopy–energy-dispersive spectrometry further indicated that GA was primarily adsorbed onto the “face” of molybdenite rather than the “edge.” Therefore, GA could be a promising molybdenite depressant for the flotation separation of Cu–Mo.

Indigenous microbial communities were employed after subculture in stirred and column bioleaching experiments involving ion-adsorption type rare earth ore. The microbial eukaryotic communities exhibited dramatically varying diversity and structure across culture compositions. Compared with Czapek and sucrose medium, the community cultured in a nutrient broth (NB) medium had a higher diversity, and it was mainly composed of Zygosaccharomyces, Ustilago, Kodamaea, Malassezia, and Aspergillus. These microorganisms secrete organic acids, such as citric acid, malic acid, gluconic acid, and itaconic acid, which provide effective coordination electrons through hydroxyl and carboxyl groups. Stirred bioleaching experiments were conducted to investigate the effect of community, inoculum dosage, liquid–solid ratio, and time on the leaching efficiency. Stirred bioleaching resulted in a concentration limitation phenomenon. When the inoculum dosage of the community cultured in NB medium was 70vol%, the liquid–solid ratio was 5.0 mL·g⁻¹, and the time was 60 min, the upward trend of rare earths leaching rate has become very small. Specifically, the leaching rates of detectable La, Ce, and Y were approximately 92.49%, 92.42%, and 94.39%, respectively. The leaching efficiency and the three influencing factors all conformed to the Poly5 polynomial function, with variances above 0.99. Column bioleaching experiments were performed at a scale of 1 kg. The self-propelled low-pH environment increased the leaching efficiency, which resulted in a leaching rate of 98.88% for rare earths after 117 h. X-ray diffraction and scanning electron microscopy revealed that the samples mainly comprised quartz, kaolinite, orthoclase, muscovite, and zeolite, which were predominantly present in the form of lumps, flakes, rods, and small particles. After bioleaching, the wave intensity of quartz, kaolinite, orthoclase, and muscovite increased, and that of zeolite decreased considerably. A diminution in the number of fine particles indicated the dissolution of small quantities of clay minerals. Ultimately, the differentiated bioleaching mechanism of various forms of rare earths was discussed based on experimental phenomena.

Extracting lithium from coal measures can alleviate the shortage of strategic metal resources. However, the lattice substitution characteristics of lithium in carrier minerals and its extremely fine intercalation and entrainment behavior are the challenges that constrain the extraction efficiency of lithium from coal series. This study focuses on improving the separation efficiency between lithium-containing minerals and other minerals and the release behavior of lithium in the liquid phase. First, the feasibility of extracting lithium from carrier minerals is confirmed based on the occurrence state and the process mineralogy characterized by Bgrimm process mineralogy analyzing system (BPMA) and time of flight secondary ion mass spectrometry (TOF-SIMS). The optimal selective grinding behavior is achieved within 15 min, allowing Li carrier minerals, including chlorite, kaolinite, and halloysite, to deliver the best dispersion effect with other minerals. Thus, the enriched lithium carrier minerals have been preenriched through screening. The leaching efficiency of Li has reached 97.43% under 1 mol/L hydrochloric acid, 15 g/L pulp density, 70°C, and 20 min. Leaching kinetics studies indicate that the decrease in apparent energy validates the impact of grinding on metal leaching, aligning with the rate-controlling step of a chemical reaction. The process proposed in this study achieves the coordinated control of size and components in coal gangue and actualizes the effective selective enrichment of lithium through its low energy consumption and environmentally friendly nature.

The application of hydrogen gas in the pre-reduction of manganese ore may replace fossil carbon consumption and reduce CO₂ emissions in manganese ferroalloy production. The pre-reduction behavior of Nchwaning manganese ore was investigated using a fixed-bed reactor. The reduction rates at different temperatures and temperature programs were investigated, and the particles were sieved after reduction to measure the decrepitation. The reduction rate was measured by adding a tracer gas to the reducing gas and quantifying the off-gas. Samples with different particle-size distributions of the input material were reduced to investigate the effect of particle size on the reduction rate. Chemical analyses and X-ray diffraction were used to characterize the raw and reduced materials. The effects of particle size distribution and temperature on the oxygen removal rate were investigated. Manganese oxides were mostly reduced to MnO in the samples, whereas some iron oxides and carbonates remained. The degree of reduction was improved by using smaller particles and increasing the temperature.

Stainless steel, known for its exceptional properties and diverse applications, conventionally requires a multistage process that generates considerable CO₂ emissions by using fossil-based carbon reductants. This study investigated hydrogen plasma smelting reduction as a novel, sustainable, and efficient method for producing stainless steel directly from lateritic nickel and chromite ores. The research aimed to examine the effect of ore proportion on AISI 300 series stainless steel production and assess the reduction process over time through thermochemical calculations and experimental studies. Results showed that increasing the proportion of chromite ore in the feed raises Cr content and reduces Ni content in metals while increasing Cr₂O₃ and Al₂O₃ content in oxides. A briquette comprising 30wt% chromite ore and 70wt% calcined nickel ore yields better results for AISI 300 stainless steel, with Fe, Cr, Ni, and Si content of 62.95wt%, 19.37wt%, 11.83wt%, and 0.72wt%, respectively, after 180 s of hydrogen plasma exposure. Nearly all NiO compounds are converted into Ni after 60 s of smelting reduction, whereas FeO compounds are almost fully converted into Fe after 120 s of smelting reduction. AISI 300 series stainless steel is successfully produced after 120 s of reduction, achieving Fe, Cr, Ni, and Si content of 64.36wt%, 21.92wt%, 10.08wt%, and 0.61wt%, respectively. Process optimization remains promising because the Cr₂O₃ content in the slag is still relatively high at 15.52wt%. This ultrafast and direct production method holds considerable potential to transform stainless steel production by reducing environmental impact and enhancing process efficiency. Specifically, the method eliminates the use of an argon oxygen decarburization converter and vacuum oxygen decarburization in stainless steelmaking.

Tensile deformation and microvoid formation of quenched and tempered SA508 Gr.3 steel were studied using an in-situ digital image correlation technique and in-situ electron backscatter diffraction (EBSD) measurements. The quenched steel with a mixture of upper bainite and granular bainite exhibited a high ultimate tensile strength (UTS) of ∼795 MPa and an elongation of ∼25%. After tempering, long-rod carbides and accumulated carbide particles were formed at the interface of bainite–ferrite subunits and prior austenite grain boundaries (PAGBs), respectively. The UTS of the tempered steel decreased to ∼607 MPa, whereas the total elongation increased to 33.0% with a local strain of 191.0% at the necked area. In-situ EBSD results showed that strain localization in the bainite–ferrite produced lattice rotation and dislocation pileup, thus leading to stress concentration at the discontinuities (e.g., martensite–austenite islands and carbides). Consequently, the decohesion of PAGBs dotted with martensite–austenite islands was the dominant microvoid initiation mechanism in the quenched steel, whereas microvoids primarily initiated through the fracturing of long-rod carbides and the decohesion of PAGBs with carbides aggregation in the tempered steel. The fracture surfaces for both the quenched and tempered specimens featured dimples, indicating the ductile failure mechanism caused by microvoid coalescence.

In order to avoid poor machinability caused by excessive hardness under high-silicon conditions in the traditional free-cutting graphited steel, it is important to develop a suitable silicon-saving, aluminum-containing free-cutting steel. This study investigated the microstructure and graphite precipitation behavior of Fe–0.58C–1.0Al (wt%) steels with varying silicon contents (0.55wt%–2.67wt%) after tempering at different temperatures (680°C, 715°C). The tempering structure and the precipitation behavior of graphite and Fe₃C in Fe–0.58C–1.0Al steels were systematically studied by optical microscopy (OM), field emission scanning electron microscopy (FESEM), and electron microprobe analyzer (EPMA). The results showed that, at both tempering temperatures, the microstructure of 0.55wt% Si steel is ferrite + granular Fe₃C, and the microstructures of 1.38wt%–2.67wt% Si steels are ferrite + petaloid graphite + granular Fe₃C. With increasing Si content from 1.38wt% to 2.67wt% at constant tempering temperature, the number density of graphite particles increases, though their average size decreases. Meanwhile, the number density and average size of Fe₃C in experimental steels continuously decrease with the increase of Si content. For 0.55wt% Si steel without graphite precipitation, increasing tempering temperature promotes the accumulation and growth of Fe₃C. For 1.38wt%–2.67wt% Si steels with graphite precipitation, higher tempering temperature promotes graphite particles growth while accelerating the decomposition and refinement of Fe₃C. Furthermore, compared with the experimental steels containing 0.55wt% Si, 1.38wt% Si, and 2.67wt% Si, the 1.89wt% Si steel exhibits significantly lower hardness. Especially, when tempered at 715°C, Fe–0.58C–1.0Al steel with 1.89wt% Si exhibits enhanced graphitization behavior and reduced hardness, which is nearly HV 20 lower than previously reported Fe–0.55C–2.33Si steel.

The rust layer is a critical factor in determining the corrosion resistance performance of weathering bridge steel. Understanding the evolution mechanism of this rust layer is fundamental for the design and optimization of such steel. This study investigates the evolution of the rust layer on high-Cr-content weathering bridge steel, using an atmospheric corrosion monitoring (ACM) sensor and big data mining techniques in a simulated tropical marine atmosphere. Results reveal that the protective properties of the rust layer follow a periodic pattern of “ascending-constant” rather than a continuous ascending. Correlation analysis indicates that this phenomenon is attributed to the introduction of Cr, which promotes the formation of FeCr₂O₄ in the rust layer. FeCr₂O₄ helps prevent chloride ions from penetrating the rust layer, exerting a protective effect. These findings provide a strong scientific foundation for the design and improvement of new high-Cr-content weathering bridge steels.

The effect of aging precipitation on the stress corrosion cracking (SCC) mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture features of solid–solution and peak-aged steels. Aging precipitation exerts a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and other phases or interfaces. The strength of the martensite matrix is enhanced by abundant and evenly dispersed Ni(Fe,Al) precipitates, thereby reducing the possibility of splitting across martensite laths. Meanwhile, the Volta potential difference (VPD) between the matrix and primary NbC particles increases from 11.43 to 18.60 mV. Given that most of the primary NbC particles tend to be distributed along high-angle grain boundaries (HAGBs), anodic dissolution along HAGBs accelerates. Therefore, mechanical and electrochemical factors triggered by aging precipitation are involved in the variation in SCC behavior and mechanism. The SCC susceptibility of the steel increases along with the increasing tendency for intergranular cracking.

This study involved the development of an interpretable prediction framework to access the stretch formability of AZ31 magnesium alloys through the combination of the extreme gradient boosting (XGBoost) model with the sparrow search algorithm (SSA). Eleven features were extracted from the microstructures (e.g., grain size (GS), maximum pole intensity (I_max), degree of texture dispersion (μ), radius of maximum pole position (r), and angle of maximum pole position (A)), mechanical properties (e.g., tensile yield strength (TYS), ultimate tensile strength (UTS), elongation-to-failure (EL), and strength difference (ΔS)) and test conditions (e.g., sheet thickness (t) and punch speed (v)) in the data collected from the literature and experiments. Pearson correlation coefficient and exhaustive screening methods identified ten key features (not including UTS) as the final inputs, and they enhanced the prediction accuracy of Index Erichsen (IE), which served as the model’s output. The newly developed SSA-XGBoost model exhibited an improved prediction performance, with a goodness of fit (R²) of 0.91 compared with traditional machine learning models. A new dataset (four samples) was prepared to validate the reliability and generalization capacity of this model, and below 5% errors were observed between predicted and experimental IE values. Based on this result, the quantitative relationship between the key features and IE values was established via Shapley additive explanation method and XGBoost feature importance analysis. I_max, TYS, EL, r, GS, and ΔS showed a crucial influence on the IE of 10 input features. This work offers a reliable and accurate tool for the prediction of the stretch formability of AZ31 magnesium alloys and provides insights into the development of high-formable magnesium alloys.

The effect of cryogenic treatment (CT) and relaxation annealing on the average nearest neighboring distance of atom (d_m), thermodynamic stability, soft magnetic properties, microhardness (H_v), and corrosion resistance of as-spun (Fe_0.5Co_0.5)₇₅B₂₁Nb₄ metallic glasses (MGs) is studied. On the premise of maintaining a fully amorphous phase, appropriate CT and relaxation annealing are conducive to achieving the synergistic effect of increasing saturation magnetization (M_s) and reducing coercivity (H_c). Shallow CT at 213 K optimally enhances the soft magnetic properties of MGs. Given its low activation energy of nucleation and increased activation energy of growth, appropriate CT is beneficial for achieving uniform annealed nanocrystals in amorphous phases. The correlation between free volumes (FVs) and potential energy suggests that the variation in H_c depends on the expansion and contraction behavior of amorphous phases after different CT processes. The fitting formulas of H_c–d_m and M_s–H_v correlations demonstrate that soft magnetic parameters have a solid linear relationship with the contents of FVs and degree of dense random packing. Moreover, pitting resistance is improved by appropriate CT and relaxation annealing. This improvement is characterized by the promotion of the stability of the Nb-rich passive film formed during electrochemical corrosion in 3.5wt% NaCl solution.

Although the existence of glass–glass interfaces (GGIs) enables improved ductility of metallic nanoglasses (NGs), the excess free volumes at GGIs would cause the NGs to have a much-reduced mechanical strength. Herein, entropy-stabilized GGIs have been investigated in Co–Fe–Ni–Zn–P NGs, which have a large entropy of mixing (1.32R, where R is the gas constant) and could be in a new glass phase, different from that of glassy grain interiors. Through quantitatively determining the activation energy of glass transition separately for the GGIs and glassy grain interiors, the excess free volumes at GGIs are found to be reduced in comparison with those in the glassy grain interiors. The thermodynamically stable GGIs could be associated with increasing entropy of mixing in the GGI regions, which stabilizes the atomic structures of GGIs and enhances the glass forming ability of Co–Fe–Ni–Zn–P NGs. The influences of entropy-stabilized GGIs on the mechanical properties of Co–Fe–Ni–Zn–P NGs are further investigated by nanoindentation and creep tests under tensile deformation, demonstrating that there are notable enhancements in the ductility and mechanical strength for Co–Fe–Ni–Zn–P NGs. This work contributes to an in-depth understanding on the GGI phase in NGs and offers an alternative method for strengthening NGs through GGI engineering.

A series of high-entropy ceramics with the nominal composition (Mg_0.5Zn_0.5)_0.4+xLi_0.4(Ca_0.5Sr_0.5)_0.4−xTiO₃ (0 ≤ x ≤ 0.4) has been successfully synthesized using the conventional solid-phase method. The (Mg_0.5Zn_0.5)_0.4+xLi_0.4(Ca_0.5Sr_0.5)_0.4−xTiO₃ ceramics are confirmed to be composed of the main phase (Zn,Mg,Li)TiO₃ and the secondary phase Ca_0.5Sr_0.5TiO₃ by X-ray diffractometer, Rietveld refinement, and X-ray spectroscopy analysis. The quality factor (Q×f) of the samples is inversely proportional to the content of the Ca_0.5Sr_0.5TiO₃ phase, and it is influenced by the density. The secondary phase and molecular polarizability (α_T) have a significant impact on the dielectric constant (ε_r) of the samples. Moreover, the temperature coefficient of resonant frequency (τ_f) of the samples is determined by the distortion of [TiO₆] octahedra and the secondary phase. The results indicate that (Mg_0.5Zn_0.5)_0.4+xLi_0.4(Ca_0.5Sr_0.5)_0.4−xTiO₃ ceramics achieve ideal microwave dielectric properties (ε_r = 17.6, Q×f = 40900 GHz, τ_f = −8.6 ppm/°C) when x = 0.35. (Mg_0.5Zn_0.5)_0.4+xLi_0.4(Ca_0.5Sr_0.5)_0.4−xTiO₃ ceramics possess the potential for application in wireless communication, and a new approach has been provided to enhance the performance of microwave dielectric ceramics.

The development of stretchable conductors with high deformation, conductivity, and thermal conductivity using liquid metal (LM) has sparked widespread interest in the fields of flexible electronics, electromagnetic interference (EMI), and multifunctional materials. However, fabricating desirable shielding materials by directly coating LMs on soft polymer substrates remains a challenge because of the huge surface tension and weak wettability of LMs. In this study, Ga-based composite paste is prepared from a mixture of Ga and diamond nonmetallic particles through ultrasonic fragmentation. At various temperatures, the resulting LM composite putty (LMP) exhibits soft and hard properties and can thus be molded into specific shapes according to application needs. In addition, the composite can be easily coated onto polymer substrates, such as thermoplastic polyurethane (TPU) elastomer. The fabricated LMP–TPU exhibits an impressive shape deformation capacity of 1100%, demonstrating exceptional tensile properties and achieving electromagnetic interference–shielding effectiveness of up to 52 dB. Furthermore, it retains an ultrahigh conductivity of 20000 S/m, even under a strain of 600%. This feature further makes it a highly competitive multifunctional material.

Electrode materials that rely on conversion reactions for lithium-ion batteries (LIBs) possess high energy densities. However, a key issue in their design is bolstering their stability and minimizing volume variations during lithiation and delithiation. Herein, an effective strategy was devised to fulfill the fully reversible conversion reaction for lithium storage in CoMoO₄ through the hybridization of CoMoO₃. CoMoO₃/CoMoO₄ with a nanorod structure was synthesized via one-step annealing treatment after a solvothermal process. In such a structure, the CoMoO₃/CoMoO₄ nanorod can considerably boost mechanical robustness and offer ample space to counteract volume fluctuations throughout successive cycles owing to the cooperative interaction between CoMoO₃ and CoMoO₄. CoMoO₃/CoMoO₄ exhibited superior lithium-storage capacity (919.6 mAh/g at 0.1 A/g after 200 cycles) and cycling stability (683.4 mAh/g at 1 A/g after 600 cycles). CoMoO₃/CoMoO₄ showed a high potential as an anode material for LIBs.

To satisfy the demand for low-cost and long-range electric vehicles by the market, the commercialization of ultrahigh nickel cathode materials with high specific capacity and a wide electrochemical window is expected to facilitate the development of lithium-ion batteries. However, residual lithium compounds with a strong alkalinity cause difficulty in cathode preparation and indirectly affect the cycling stability of the cathode during cycling. Given the inevitability of the formation of residual alkali, a lithium-borate coating with an adjustable thickness was selected by controlling the formation of residual alkali. An additional lithium source was added to the synthesis process and converted into a thicker and more complete coating structure, which rendered the cathode with better cycle stability. As a result, the percentage of peak area of lithium carbonate on the surface-modified cathode surface exhibited a considerable decrease from 38.07% to 28.26%. The etching results show the formation of a uniform coating layer after boric acid treatment. The initial capacity of the treated cathode was 214.6 mAh·g⁻¹ owing to the favorable effect of the surface coating, and the capacity retention raised from 59.35% to 90.75% and from 63.81% to 91.94% after cycling at 0.5 and 1 C current densities, respectively. The boric acid coating-modified strategy proposed in this paper considerably ameliorates the cycling stabilization of cathodes and provides superior commercial application value for ultrahigh nickel cathode materials.

Red phosphorus (RP) has been recognized as a promising anode candidate for sodium-ion batteries (SIBs) due to its high theoretical capacity and natural abundance. However, the electrochemical performance of RP is restricted by the critical issues of the large volume variation upon cycling and the low intrinsic electronic conductivity. Herein, a nanocomposite with the structure of well-dispersed RP nanoparticles intimately attached to the surface of two-dimensional Ti₃C₂ nanosheets (NRP/Ti₃C₂) is prepared by a facile chemical precipitation method. The introduction of Ti₃C₂ nanosheets can effectively prevent the RP nano-grains/clusters from agglomeration and growth in the synthesis process. Besides, the flexible Ti₃C₂ sheets can not only function as the mechanical support for accommodating the volume change of RP upon Na⁺ uptake/release process, but also provide an efficient conductive network for electron transportation. Moreover, the shortened ions diffusion distance enabled by the nano feature of RP further favors the electrode reaction kinetics. When employed as anode for SIBs, the synthesized NRP/Ti₃C₂ composite exhibits a reversible capacity of ∼862 and 576 mAh·g⁻¹ at 0.1 and 0.5 A·g⁻¹, respectively, as well as a maintained capacity of 525.2 mAh·g⁻¹ after 100 cycles at 0.1 A·g⁻¹. In addition, the fabricated free-standing NRP/Ti₃C₂ electrode with a capacity of ∼2.21 mAh·cm⁻² and stable electrochemical cycling provides a valid guide toward high-performance RP-based anodes for realizing SIBs with high energy density.

CoFe bimetallic hydroxides (CoFe BMHs) find wide applications as excellent catalysts in the field of water splitting. However, no study has systematically investigated the influence of the morphologies of CoFe BMHs on catalyst performance. In this study, CoFe BMH nanoflowers (CoFe BMH NFs), CoFe BMH nanosheets (CoFe BMH NSHs), CoFe BMH nanorods (CoFe BMH NRs), and CoFe BMH nanospheres (CoFe BMH NSPs) were prepared on nickel foam via a hydrothermal method. CoFe BMH NSHs exhibited the most beneficial catalytic activity. At a current density of 100 mA·cm⁻², its overpotential for oxygen evolution reaction (OER) was 282 mV, and the overall water splitting voltage was 2.05 V. The double-layer charging capacitance (C_dl) value of CoFe BMH NSHs was the largest in CoFe BMHs, which proves that CoFe BMH NSHs have the largest active area. Furthermore, the active site in the OER process was metal oxyhydroxide (MOOH) through in situ Raman characterization, and the generation of the active substance was an irreversible process. This work provides important insights into the design of catalyst morphologies and offers valuable guidelines for the enhancement of the performance of other catalysts.

An in-depth understanding of the hydration mechanism of tricalcium silicate is an important basis for optimizing cement strength development. In this study, the adsorption of water molecules onto the M3-C₃S(001) surface at different water coverage levels (θ = 1/5, 2/5, 3/5, 4/5, and 1) was investigated using first-principles calculations. The results demonstrate that the conclusions obtained for single water molecule adsorption cannot be fully applied to multiple water molecule adsorption. The total adsorption energies become more negative with increasing water coverage, while the average adsorption energy of each water molecule becomes more positive with increasing water coverage. The water–water interactions reduce the water-surface interactions and are responsible for the anticooperative adsorption of multiple water molecules onto M3-C₃S(001). The formation of Ca–OH (–Ca) bonds favors the detachment of Ca from covalent oxygen, which reveals the significant role of dissociative adsorption. This work aims to extend the water adsorption study on M3-C₃S(001) from single water molecule adsorption to multiple water molecule adsorption, providing more detailed insights into the initial water reaction on the C₃S surface.