In order to resolve the limitation of the built-in catalyst database in Aspen simulations,a dual-rate kinetic model based on the Power Law (PL) formulation is proposed.The kinetic model is integrated into Aspen Plus for multi-process simulation of hydrogen production.By incorporating the influence of catalysts on the reactions during the simulation,a more realistic chemical process simulation is achieved.The dual-rate kinetic model accurately reflects actual hydrogen production conditions: increasing temperature and reducing liquid hourly space velocity (LHSV) both enhance methanol conversion and simultaneously increase CO selectivity.The steam-to-carbon molar ratio has a minor impact on the reaction.By considering energy consumption,the optimal range of the steam-to-carbon molar ratio is 1.0~1.4.Under the condition in which the reaction temperature is 280 °C and the feed flow rate is 1.5 mL/min,the multi-process simulation results demonstrate that the CO concentration in the product is reduced to only 6.89 μL/L after methanol steam reforming, water-vapor shift,and CO selective oxidation.This CO concentration meets the requirements for proton exchange membrane fuel cells(PEMFC).

Compared with clastic reservoirs,carbonate reservoirs have extremely strong heterogeneity,multiple types of storage spaces,and uneven development of pores,caves,and fractures.How to characterize the three-dimensional storage space of strongly heterogeneous carbonate gas reservoirs is the key to fine reservoir description.By integrating geological,logging,seismic,and production dynamic data with reservoir characterization insights,this study focuses on the Maokou Formation fracture-dong carbonate reservoir in Hechuan Block.Random modeling combined with deterministic modeling methods is used to gradually construct a detailed geological model of the reservoir with various attributes such as structure,sedimentary facies,reservoir classification,porosity,permeability,and gas saturation,quantitatively characterizing the distribution characteristics of reservoir attributes.By combining geostatistics with multi-attribute collaborative simulation technology,this paper establishes a multi-scale integrated fracture-hole model,quantitatively characterizes the spatial distribution characteristics of reservoirs,and forms a set of fine fracture-hole carbonate reservoir modeling methods based on sedimentary facies-reservoir type classification control and multi-scale information fusion.

During the shutdown period of the J-Y refined oil product pipeline, there is a significant difference between the temperature of the transported oil and the outside soil temperature, which leads to a pressure drop in the pipeline after the shutdown. When the pressure at the high point of the pipeline drops below the saturated vapor pressure, air resistance occurs inside the pipeline, making it impossible to maintain pressure. This further poses a potential threat to the safe operation of the pipeline system. The SPS software was used to establish a pipeline model to simulate the equivalent soil temperature distribution along the pipeline. Through simulation and analysis, the inlet temperature error at the terminal station was effectively corrected, thereby obtaining the average soil temperature along the pipeline and the temperature drop range after shutdown. A fitting equation was utilized to reveal the relationship of equivalent soil temperature change over time. Combined with the pre-pump temperature measurement value and the equivalent soil temperature value obtained from the simulation, a shutdown operation was carried out after the system had been running for a period of time, and the trend of temperature and pressure changes after shutdown was simulated by the SPS model. The analysis shows that the temperature difference between oil and soil shows an exponential relationship with the pressure preservation time after shutdown. If the temperature difference between oil and soil before shutdown is small enough, vaporization is less likely to occur in the whole line after shutdown. If the temperature difference between oil and soil before shutdown is negative, the pressure in the pipe will increase after shutdown.

With the development of large-scale storage tanks,structural safety issues such as foundation settlement and structural deformation that affect the operation of large storage tanks have increasingly become the focus of equipment management and inspection personnel.Research on foundation settlement detection and structural integrity evaluation of large storage tanks is of practical significance for ensuring the safe operation.This article analyzes the types and typical damage forms of tank foundation settlement,and proposes requirements for tank foundation settlement detection based on the characteristics of different tank service stages such as design,construction,and regular inspection.It clarifies the detection and evaluation methods for different types of settlement,and focuses on the research of graded evaluation methods for uneven settlement around the tank.A 4-level evaluation method for basic uneven settlement,including settlement difference evaluation,deviation from the plane settlement amplitude evaluation,local non-uniform plane settlement evaluation,and stress analysis evaluation,is proposed to effectively support equipment management and inspection personnel in conducting structural suitability evaluation under tank foundation settlement conditions.

The characteristics and evolution of the imbibition front during spontaneous oil recovery in mixed wetting capillaries are critical for predicting imbibition efficiency in tight oil reservoirs with complex wettability. By establishing a spontaneous imbibition model under mixed wetting conditions, this study investigates the influence of spatially heterogeneous wettability distribution and the degree of mixed wettability on the spontaneous imbibition front distance and the interfacial deformation behavior. The critical condition for achieving efficient spontaneous imbibition in mixed wetting capillarie is identified. A higher water-wetting fraction results in smaller differences in the stabilized static suction front edge distance, achieving optimal oil recovery time more efficiently. Conversely, a larger cosine difference in contact angles between wet and dry sidewalls leads to greater disparities in this critical parameter. By combining simulation data with a fitting formula for static suction front edge distance variations, combined with analytical solutions for the front distance, we can quantitatively characterize the dynamic patterns of front distance changes and interfacial deformation characteristics in mixed-wetting capillary systems. These findings provide theoretical support for efficient and low-carbon development strategies in mixed-wet tight oil reservoirs.

To ensure the effect of several rounds of profile control in Bohai oilfield, the adaptability of a drag-increasing in-situ gel profile control agent was investigated specifically in the study. The gelation property, thermal stability and micromorphology after gelation were measured by viscosimetry, rheological analysis and scanning electron microscope respectively. The injectivity, plugging property, selectivity and enhanced oil recovery effect of the profile control agent were investigated by sand packing experiments. The results show that the profile control agent has low initial viscosity, excellent injectability and deep migration performance, and weak chromatographic separation behavior in the reservoir. At the reservoir temperature of 65 ℃, it has a long gelation time, high gelation viscosity and good thermal stability. After gelation, it has a three-dimensional network structure with microspheres as cross-linked nodes inside, and demonstrates shear thickening characteristic at a shear rate of 4~12 s?1. Additionally, the profile control agent possesses excellent selective plugging performance and preferentially enters the breakthrough area to form plugging, , while maintaining a low oil plugging rate in the oil layers. The profile control agent shows a significant effect on enhancing oil recovery and the increase in crude oil recovery rate reaches 15.0%~23.0% after injecting 1.000 pore volume (PV). Generally, the drag-increasing in-situ gel profile control agent can adapt to the reservoir characteristics of Bohai offshore oilfield well, and realize in-depth profile control in the reservoir.

In the process of offshore chemical drive, water drive well network and polydrive well network coexist after well network densification, which exerts a deep influence on oil development. To quantitatively characterize the perturbation degree of injected water and polymer, a water-polymer perturbation coefficient considering the dynamic changes of displacement volume of injected water and polymer is proposed. The production characteristics and laws under different displacement modes are analyzed based on the water-polymer perturbation coefficient, and the control strategies are discussed.The results show that the injected water would compress the polymer displacement area and exert an interference on the polymer front edge. Water-polymer perturbation coefficient has a good correlation with stage net oil increase curve, and water-polymer co-flooding process can be divided into five stages according to the water-polymer perturbation coefficient. In addition, water-polymer co-flooding has a better oil production than pure polymer flooding at the initial stage, but for a long period, development effect of pure polymer flooding is much better, and water-polymer alternating injection can balance the displacement front and improve the development effect. The result has a great significance to quantitatively characterize water-polymer perturbation degree and make adjustment measurements.

Polymer composites are the primary materials for water-lubricated bearings owing to their superior wear resistance, low friction coefficient, and resistance to water and corrosion. Their performance directly governs the safety, reliability, and operating costs of the bearing systems. This paper provides a systematic review of the properties of commonly used polymer composites for water-lubricated bearings and recent research progress. It focuses on analyzing the load-carrying capacity, wear resistance, and frictional behavior of different materials, while comparing their relative advantages and limitations. Finally, by addressing the current challenges with existing materials, the review proposes future research directions for high-performance water-lubricated bearing materials and suggests strategies for optimizing their design and engineering applications, aiming to offer valuable insights for further development.

As the global energy system accelerates its transition toward renewable energy,electrochemical energy storage devices play an increasingly vital role in ensuring power supply stability and promoting efficient energy utilization.However,low-temperature environments pose a significant challenge to the performance of electrochemical energy storage devices.Especially for widely used lithium-ion batteries,the problems such as significant decrease of charge and discharge capacity,increase of internal resistance and shortening of cycle life are particularly prominent,which seriously limits the commercialization development of lithium-ion batteries in cold regions and other scenarios.To address this challenge,this paper provides a systematic review of current research progress on the performance of electrochemical energy storage devices in low-temperature environments.First of all,focusing on the core research topic of modification and optimization of battery cathode materials and electrolyte systems.This study systematically elucidates the mechanism contributing to battery performance under low-temperature conditions,including changes in material resistivity,reduced reactivity of active materials,and increased viscosity of electrolyte materials.Then,the modification strategies of electrolyte to improve the performance of batteries under low temperature are reviewed and analyzed.In addition,other effective ways to optimize the low-temperature performance of energy storage devices and their mechanisms for improving the electrochemical performance are also expounded.

With the development of industrialization and modernization, water pollution has become increasingly serious, and the use of sunlight for water pollution degradation has become a future development trend. In this paper, flower?like BiOI photocatalyst was prepared via a solution route at room temperature without any template, and characterized by X?ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV?Vis diffuse reflectance spectra (UV?Vis DRS). As?synthesized flower?like BiOI showed better visible light photocatalytic activity for degrading Rhodamine B (RhB) than TiO₂. The experimental results of active species and electron spin resonance (ESR) measurement showed that ·O {}_{\mathrm{2}}^{-} was the main active species in the photocatalytic degraded process of organic pollutant over flower?like BiOI, and the possible degradation mechanism was speculated. This study provides a simple and convenient synthesis method for high activity photocatalysts.

For the reaction of catalytic dehydrogenation of ethanol to produce acetaldehyde, current catalysts face the challenge of limited selectivity, particularly exhibiting poor performance in the efficient generation of acetaldehyde. Some catalysts are hindered in the dehydrogenation process due to excessive acidity, which urgently needs to be addressed. Therefore, the development of novel catalysts with high?performance surface basicity is crucial.Two composite catalysts, La₂O₂CO₃/ZnO?a and La₂O₂CO₃/ZnO?b, were prepared using the co?precipitation method and the solution combustion method. The performance of the catalysts was evaluated by varying preparation conditions such as precipitation pH, aging time, calcination temperature, and calcination time to determine the optimal synthesis parameters. Advanced characterization techniques, including Scanning Electron Microscopy, Transmission Electron Microscopy, X?ray Diffraction, and CO₂ Temperature?Programmed Desorption, were employed to thoroughly investigate the catalyst's crystal phase, morphology, surface basicity, and their relationship with catalytic performance. The optimal process conditions for ethanol dehydrogenation to acetaldehyde were investigated on the best?performing catalyst. When the precipitation pH was 9.0, the aging time was 12.0 h, the ratio of n_La to n_Zn was 1.0, and the calcination temperature was 600 ℃, the optimal preparation conditions for the solution calcination method were determined as follows: calcination time of 5.0 h, calcination temperature of 550 ℃, and n_La/n_Zn of 1.0. Under the conditions of a volume space velocity of 1.0 h?1, a reaction pressure of 1.0 MPa, and a reaction temperature of 190 ℃, La?O?CO?/ZnO?a achieved the highest acetaldehyde yield of 57.60%.

To address the lack of specialized thermal?hydraulic calculation models for temperature?resistant polyethylene pipelines in oilfield gathering and transportation systems,this study conducted quantitative analysis on their hydraulic friction characteristics and thermal temperature drop patterns during oil transportation through field experiments.Based on multi?parameter experimental datasets,systematic investigations were performed to reveal the influence mechanisms of key variables including fluid properties, transportation temperature,rate of water content,and flow rate on pipeline pressure drop and temperature decline.For the first time,a calculation framework for the overall heat transfer coefficient applicable to temperature?resistant polyethylene (TRPE ) materials was established.Simulation model libraries were constructed using PIPEPHASE software,followed by comparative analysis of deviations between theoretical predictions and field measurements under varying boundary conditions.Through this process, friction calculation models and heat conduction models tailored for TRPE materials were selected and optimized,which provide valuable theoretical support for the process design and safety evaluation of TRPE pipelines in engineering applications.

In the process of heavy oil thermal recovery using SAGD (Steam?Assisted Gravity Drainage) technology, conventional thermal recovery boilers are mainly used for heat generation. When steam is used as the heat?carrying medium, problems such as a short water breakthrough time and low heat utilization efficiency are often encountered, resulting in low oil recovery. Changing the heat generation method to reduce water injection while ensuring heat injection is of great significance for thermal recovery.Based on the analysis of directional chemical reaction products and combined with large?scale three?dimensional physical simulation experiments, the feasibility of directional chemical reactions was verified, the expansion law of the temperature field in directional chemical reaction?assisted SAGD was clarified, and the characteristics of production curves at different mining stages were analyzed and evaluated.The results show that among the products of the directional chemical reaction, the liquid fluid is mainly C₅-C₂₀, and the gaseous substances are mainly CH₄ and CO₂; the final recovery degree of SAGD development assisted by directional chemical reaction products is 76.59%, which is 19.99 percentage points higher than that of pure SAGD. The research further verifies the mechanism of the directional chemical reaction?assisted SAGD efficiency?increasing technology, providing a theoretical basis and technical support for field applications.

Improper models of phase behavior are a major cause of many production problems faced by shale gas reservoirs. The phase behavior of oil?gas in micro?nano pores is crucial for shale oil and gas development. Considering the effects of capillary pressure and critical point shift on the thermodynamic phase equilibrium in micro?nano pores, a vapor?liquid equilibrium (VLE) model in the confined micro?nano pores was developed by using a volume?translated Peng?Robinson Equation of State(PR?EOS), and the relative error of prediction was less than 1.53%. Based on the improved VLE model, the phase behavior of hydrocarbon mixtures such as Bakken shale oil in the confined space was investigated. Results indicate that the nanopore confinement decreases the vapor?liquid density difference and equilibrium coefficient(K) of the light components and shrinks the phase envelope. As the pore size decreases, the interfacial tension (IFT) first decreases slowly and then drops sharply, particularly when the pore radius is less than 20 nm.This study can provide an important theoretical foundation to support the development of unconventional oil?gas resources.

In order to quickly define the dangerous distance of leakage in hydrogen?blended natural gas high?pressure pipelines, this study established a mathematical model of small hole jet leakage of hydrogen?blended natural gas high?pressure pipelines in open space by integrating the pipeline leakage model,nominal nozzle model and jet in cross?flow integration model,verified the applicability of the jet in cross?flow integration model under high?speed jet and analyzed the influence of hydrogen ratio,wind speed leakage hole diameter and pipeline pressure on the leakage jet trajectory and the influence of hydrogen ratio,wind speed and nominal diameter on the maximum explosion danger distance.The results shows that the JICF model is in good agreement with the experimental data and the numerical simulation data.The greater the hydrogen mixing ratio,the diameter of the leakage hole and the pipeline pressure are,the less the deflection degree of the leakage jet trajectory will be.The higher the wind speed is,the greater the deflection degree of the leakage jet will be.The relationship between the hydrogen ratio and the maximum dangerous explosion distance decreases linearly when the hydrogen ratio is lower than 44.4%,and increases linearly when the hydrogen ratio is higher than 44.4%.The relationship between the wind speed and the maximum dangerous explosion distance is approximately linear.The nominal diameter is directly proportional to the maximum explosive danger distance.

Carbon dioxide capture,utilization and storage(CCUS) is a crucial strategy for mitigating the greenhouse effect and reducing CO? emissions.As the predominant technology for large?scale commercial CO? capture,the high energy consumption of the absorption method seriously restricts the popularization and development of CCUS technology.This paper focuses on the energy?saving path in the CCUS process,and systematically reviews the latest research progress and achievements in three key directions: The research and development of new absorbents,design of new high?efficiency reactors,coupling of CO₂ capture and conversion process.The results show that the new absorbent reduces the energy consumption of the absorption reaction process,the high?efficiency reactor greatly enhances the mass transfer,and the integrated coupling technology realizes energy saving and consumption reduction from the process source.Future research needs to focus on the verification of the industrial application of new absorbents,the stability and cost control of long?term operation of reactors,and the further improvement of the economic efficiency of absorption and conversion integration technology,so as to promote the large?scale application of low?energy CCUS technology and help achieve the "double carbon" goal.

To address the issue of high steam consumption in the propane removal tower of the three tower gas fractionation process in refineries, it is proposed to use a high and low pressure dual tower propane removal process instead of the single tower propane removal process in the original process. The process was simulated under steady?state conditions using Unisim Design process simulation software. The steam load of the high?pressure depropanizer and the hot water load of the deethanizer were analyzed, and the main operating parameters were optimized. The results showed that under the operating conditions of n(top C₃ production)/n(total feed C₃)=0.6, top pressure of 1.81 MPa, feed tray position of the 10th plate, and feed positions of the 114th and 126th plates at the top of the propane removal tower and low?pressure propane removal tower respectively, using the high and low?pressure double tower propane removal process can save 56.12% of steam load compared to the original process, save 49.83% of hot water load in the ethane removal tower compared to before optimization, reduce total energy consumption by 235.4 kW, and save about 339.71 yuan in thermal utility costs per hour.

Under solvothermal conditions,Cu（CF₃COO）₂·xH₂O was used as a soluble copper salt, and thiophene?2,5?dicarboxylic acid （H₂tdc） as a linear ligand, which reacted with 1,10?phenanthroline （phen） and 2,2′?bipyridine （bipy） respectively,to synthesize two one?dimensional chain compounds:[Cu（tdc）（phen）] _n （1） and [Cu（tdc）（bipy）] _n ·DMF （2）.The structures of the synthesized compounds were characterized by single?crystal X?ray diffraction（SC?XRD）.The compositions of the compounds were analyzed by polycrystalline X?ray diffraction and Fourier infrared spectroscopy.The performances of the compounds were studied through photocurrent response tests and solution stability tests.The results show that the asymmetric structural unit of compound 1 is extremely similar to that of compound 2,with both containing the same [Cu(tdc)] structural unit. Both compounds exhibit photochemical stability,but they show different photocurrent response values,which is attributed to the different surface?modifying ligands (phen and bipy) in the two compounds.

To address the corrosion failure issues in hydrogenation reaction effluent air cooler (REAC)systems, a typical process simulation model was constructed using the reverse order deduction method. This study investigated the influence mechanisms of different oil flow rates on the distribution of corrosive components within the system, ammonium salt crystallization temperature, and erosion risks. The results indicate that variations in oil flow rate do not significantly affect the aqueous distribution of corrosive components or increase the system's erosion risk. Additionally, the oil flow rate has minimal impact on the crystallization temperature of ammonium salts, meaning higher flow rates do not elevate the risk of salt formation. However, increasing the flow rate of vacuum gas oil (VGO) markedly reduces the corrosion factor (K), thereby lowering the overall corrosion risk. The VGO flow rate also has a pronounced influence on the aqueous NH?HS concentration at the air cooler outlet, whereas the effect of naphtha flow rate differs from that of diesel and VGO. Notably, raising the flow rates of diesel and naphtha increases the system pH, while increasing VGO flow rate decreases it. To mitigate corrosion risks, it is recommended to moderately increase the VGO content during crude oil processing while simultaneously boosting either the diesel content or injection water volume.

During the process of water electrolysis,the "bubble effect" will significantly reduce the overall performance of the system.The classical nucleation theory (CNT model） fails to reveal the regulatory mechanism of the electrical double layer (EDL),surface microstructure,and mass transfer synergy on nucleation kinetics in actual electrochemical systems.This study develops an electrode interface bubble nucleation model with the synergistic effect of electrical double layer?mass transfer?surface microstructure,considering the synergistic regulation mechanism of ion migration diffusion behavior,electrode surface nano microstructure,and concentration boundary layer on the nucleation process.The research results show that the synergistic effect of EDL and microporous structurel generates significant potential gradients at the surface micropores,leading to an increase in local supersaturation and prioritizing bubble nucleation.At high overpotentials,the effect of the concentration boundary layer on nucleation energy barrier exhibits a nonlinear relationship.The thinner the concentration boundary layer is,the more significant the decreasing trend of the nucleation rate at high potential will be.The growth of bubbles is dominated by the net concentration flux near the three?phase contact line (TPCL),exhibiting a two?stage growth characteristic.The study provides a theoretical basis for optimizing the surface design of gas evolution electrodes.

The efficient production of hydrogen as a clean energy carrier relies on the performance optimization of electrocatalysts for the hydrogen evolution reaction (HER).Although platinum (Pt)?based catalysts exhibit exceptional HER activity,their high cost and stability issues can be mitigated through rational design of the support material.Nickel hydroxide (Ni(OH)?) has emerged as a promising support due to its unique proton conductivity,interfacial modulation properties,and stabilizing effects on Pt. However,a systematic understanding of the structure–activity relationship between Ni(OH)? supports and Pt nanoparticles,as well as the impact of synthesis parameters on catalytic performance,remains lacking.This study focuses on the regulation of Ni(OH)? support phase evolution and Pt interfacial growth behavior by hydrothermal synthesis temperature.By analyzing the structure–performance relationship through the synthesis parameter–microstructure–catalytic performance correlation mechanism),the synergistic effects of temperature on the crystallinity of the support,Pt particle size distribution,and interfacial electronic structure were elucidated.Experimental results indicate that the Pt@Ni(OH)? catalyst synthesized at 100 ℃ exhibits outstanding HER activity in 1 mol/L KOH electrolyte,with overpotentials of only 5 mV at 10 mA/cm2 and 62 mV at 100 mA/cm2,along with a Tafel slope of 70.0 mV/dec.After 50 hours of continuous operation,the electrode maintains nearly unchanged HER performance,demonstrating remarkable stability.

Sodium vanadium phosphate (Na₃V₂(PO₄)₃, abbreviated as NVP）, exhibits unique advantages in sodium?ion batteries due to its excellent thermal stability and broad sodium?ion transport channels. However, the expensive vanadium raw materials have diminished the attention on the commercial development of NVP. In this work, NVP was successfully synthesized using solid?state methods from NaVO₃, a byproduct from the upstream of the vanadium extraction industry, and compared with NVP synthesized from V₂O₅ and NH₄VO₃ at different calcination temperatures. The results indicate that the vanadium source has a significant impact on the structure and morphology of NVP, which further influences the battery capacity and rate performance. NVP prepared using NaVO₃ at 750 ℃ exhibits excellent electrochemical performance, achieving an initial high capacity of 105.6 mA·h/g at 0.1 C, and still obtaining high capacities of 101.5, 99.9, and 92.9 mA·h/g at subsequent rates of 1.0, 2.0, and 5.0 C, respectively. Moreover, it achieves a reversible capacity of 97.1 mA·h/g and a high capacity retention rate of 94.6% after 300 cycles at 1.0 C, and retains 94.0% capacity after 500 cycles at 5.0 C. This simple, efficient, and cost?effective synthesis strategy provides a reference for the scaled?up production of NVP.

Nickel?iron (NiFe)?based transition metal catalysts have garnered significant attention in recent years for their excellent electrocatalytic performance,particularly in the oxygen evolution reaction (OER).However, the catalytic efficiency of NiFe?based transition metal catalysts still has a certain gap compared with precious metal Ru or Ir, so it is necessary to modify it.Research has shown that defect engineering can effectively enhance the OER catalytic activity of NiFe?based transition metal catalysts.The types of defects in NiFe?based transition metal catalysts, the characterization methods, and the methods for constructing defect materials are summarized, and an overview the research progress of the OER study of defect?type NiFe?based transition metal catalysts is given; the challenges of defect engineering to improve the OER performance are discussed and prospects for future development are proposed.

Sodium?ion batteries are gradually becoming a powerful alternative to lithium?ion batteries in the low?speed two?wheeled electric vehicle market and large?scale energy storage applications due to their excellent low?temperature performance, significant cost?effectiveness,and high safety features.The potential of hard carbon with improved performance to substitute graphite in the sodium ion battery anode has attracted widespread attention.However,the high energy consumption and expensive cost still need to be overcome for commercialization of hard carbon anode.The key to developing anode materials for sodium?ion batteries that combine low cost,high sodium ion storage capacity,and excellent cycling stability will help to extend the application of hard carbon anodes in sodium?ion batteries.Biomass has become an attractive raw material for the preparation of hard carbon due to its renewable,low?cost,and environmentally friendly characteristics.It has been shown that the sodium storage properties of biomass?derived hard carbon are affected by multiple factors such as carbonization temperature,precursor variety,and microstructure.Hence,this review summarizes the relevant models proposed for the sodium storage mechanism in terms of the sodium storage behavior of hard carbon.The preparation of hard carbon anode materials,including the effect of electrochemical optimization procedures such as pyrolysis,activation, and doping is discussed.A further analysis of the sodium storage mechanism offers guidance for addressing the current issues such as the selection of precursors,the low initial Coulombic efficiency,and the limited means of closed pore regulation.

The high nickel cathode material LiNi _x Co _y Mn_1-x-y O₂(x≥0.6,NCM) is considered to be one of the most valuable cathode materials for lithium?ion batteries due to its low cost,high energy density and long service life.Although the high nickel content leads to a significant increase in the specific capacity and energy density of NCM,the increase in nickel content leads to poor cycling and thermal stability,which severely limits its practical application.Doping modification is an effective strategy to improve the structural stability and electrochemical performance of NCM.In this review,the common doping preparation methods of NCM are first described in detail.Subsequently,the effects of various doped elements on the lithium storage,rate performance and cycling performance of NCM were systematically analyzed.Finally,the development and future challenges of NCM are prospected,which is expected to provide an important reference for the application of NCM.

Sodium?ion batteries are considered a promising alternative to lithium?ion and lead?acid batteries, offering a balance between performance and cost?effectiveness for applications requiring moderate energy density and low cost. Hard carbon stands out as the most promising anode material for sodium?ion batteries, with the majority of scholars attributing its sodium storage capacity primarily to its porous structure. However, characterization techniques for this porous structure are currently very limited. This hinders in?depth analysis of the hard carbon pore structure and makes it more difficult to design performance enhancement strategies. This review provides an overview of current methods for characterizing the pore structure of hard carbon, including transmission electron microscopy, gas adsorption, X?ray small angle scattering, and helium true density testing. The combined use of these methods helps accurately characterize the pore structure of hard carbon and provides research ideas and technical support for the design of high?performance hard carbon anodes.

As the demand for energy storage escalates, sodium?ion batteries （SIBs） are increasingly in the spotlight due to their low cost and the plentiful availability of sodium resources. Particularly, hard carbon anode materials have emerged as a focal point of research, attributed to their superior cyclic stability and elevated energy density. This review delves into the advancements in hard carbon anode materials for SIBs, encompassing the screening and design of HCs precursors, surface modifications, pore structure adjustments, carbonization induction, heteroatom doping strategies, and additional tactics to augment the performance of HCs. By thoroughly examining the influence of HCs's pore structure, surface functional groups, and microstructure on the sodium storage mechanism, the review explores the potential for optimizing HCs performance through various fabrication processes. Furthermore, the article addresses the interfacial reaction mechanisms between HCs and electrolytes, along with possible avenues for enhancing HCs's cycling and rate capabilities through interface engineering. Ultimately, the review anticipates the future trajectory of HCs technology, including the design of nanostructures, surface modifications, and green manufacturing processes, underscoring the pressing need for the development of high?performance, cost?effective, and environmentally benign SIBs.