Lithium ion batteries are widely used in energy storage systems with high energy density, high power density and long service life. The accurate estimation of the usable capacity in the long-term operation state is the key for the energy storage system to participate in power regulation. In order to solve this problem, this paper proposes a method for estimating the usable capacity loss of lithium ion batteries based on Singular Value Decomposition-Double Adaptive Unscented Kalman Filter (SVD-DAUKF) algorithm, which firstly constructs the expression of battery usable capacity considering aging, and then uses the SVD-DAUKF algorithm combined with the equivalent circuit model to identify the model parameters and estimate the state of charge. Finally, combined with the parameter identification results and the definition of usable capacity, the estimation results of usable capacity loss are verified at 1 C, and the estimation error of usable capacity loss is less than 4%.

Lithium ion batteries (LIB) are widely used for mobile energy storage due to their high energy density and long cycle life. However, the limited resources of lithium severely limit its application in large-scale energy storage. In recent years, sodium ion batteries (SIB) have become a promising alternative to LIB due to their low cost and high safety. Hard carbon, with its low redox potential, stable structure, large layer spacing and relatively low cost, is widely used as an anode material for SIB. However, the poor multiplicative performance and low initial Coulomb efficiency of hard carbon anode limit the performance of SIB. This paper reviews the research progress of hard carbon anode for sodium ion batteries, including the mechanism of sodium storage in hard carbon, selection of precursors and the effect of preparation process on the performance of hard carbon.

Lithium ion battery dominates the market of portable electronic products and electric vehicles and energy storage. However, more and more attention has recently been paid to the cost and resource availability of lithium. Sodium ion batteries are considered to be the ideal choice for grid-level energy storage systems. There are still various challenges need to be overcome, however, before its commercial application. Among them, the low initial coulombic efficiency is a critical issue that seriously limits the improvement of practical energy density of the sodium ion full battery. This review analyzed the influence factors of low initial coulomb efficiency, such as the solid electrolyte interphase formed due to the decomposition of electrolyte during the first cycle, and the poor reversibility of sodium ion insertion/deintercalation process, as well as the defects and surface functional groups. Also, the paper summarized the emerging strategies to improve the initial coulomb efficiency of sodium ion batteries, such as electrolyte optimization, structure/morphology design, surface modification, and binder optimization, which is of great significance for promoting and realizing the practical application of high energy sodium ion batteries.

Silicon-based anode materials have problems of volume expansion, surface instability or low electron conductivity. In this paper, porous silicon-carbon composites are obtained by Si morphology control, conductive net-work design, porous structure construction and carbon coating. Si nanosheets can be obtained via balling based on different cleavage energies in different facets of Si. Spray drying of the well-distributed slurry containing silicon nanosheets, carbon nanotubes, and graphite yields porous structures. Liquid state carbon coating of the porous structures leads to the entire carbon coating on both the surfaces of the silicon nanosheets and the whole composites. Coin test shows the composite deliver a specific capacity of 1 000.8 mAh/g and a high initial coulombic efficiency of 93.9%. Full cell tests display high rate property at 1 C and good cycling behavior. These good performances are derived from the conductive net-work structure, the porous structure construction, and the dual-carbon coating of the composite.

This paper presents an original solution to the issue of the silicon-based negative electrode's high volume expansion and ease of detachment from the collector during battery cycling: a modified copper foil collector with graphene coating. The graphene coating makes the collector's surface rougher, which improves adhesion between the collector and the active material and prevents the phenomena of collector detachment from active material. The rate performance and cycle stability of batteries with modified collectors coated with graphene are significantly better than those with Cu foil collectors. At a high rate of 2 C, the silicon-based negative electrode with the improved collector covered with graphene had a discharge specific capacity of 467.2 mAh/g. After 80 cycles at 0.2 C, retention of capacity is still above 50%. In contrast, the one with normal copper foil collector only retained 18.2% of capacity.

Using high nickel ternary cathode material and silicon carbon anode material, 3.6Ah 18650 lithium ion battery was successfully prepared through the selection of anode material and optimization of electrode surface density parameters. The 18650 battery has a volumetric energy density of 751 Wh/L, can be discharged at 3 C multiplication rate, and has an operating temperature range of –40~60 ℃. The battery has good multiplicity performance, cycling performance, low temperature discharge performance and high temperature discharge performance, with good overall performance, which can meet the requirements of wide temperature range and long cycle use.

As the core energy storage component of flexible electronic devices, fiber shaped lithium ion batteries show the advantages of high flexibility, light weight and weaving. The electrode materials prepared by the traditional process usually use the metal current collector to coat the active material, which is easy to cause the active material to crack and fall off under various deformations. This method affects the stability of the energy storage performance. Carbon fiber (CF) has the advantages of high conductivity, good flexibility, strong mechanical properties, and weaving. It has received extensive attention as a conductive skeleton for flexible self-supporting electrodes. Carbon nanotubes (CNT) are conductive nanomaterials commonly used in the field of electrodes with large aspect ratio and large specific surface area. Arrayed carbon nanotubes (VACNTs) can also provide a highly ordered conductive structure and improve the mechanical strength of the electrode. Herein, VACNTs were grown in situ on CF as a flexible self-supporting conductive skeleton, and hydrothermally loaded lithium iron phosphate and lithium titanate as positive and negative electrodes respectively, and assembled into a fiber full battery. At a charge-discharge rate of 0.2 C, the initial discharge line specific capacity reaches 1.38 mAh/cm, and the line energy density is as high as 2.62 mWh/cm.

Anode-free lithium metal battery has become an academic hotspot due to its high theoretical capacity, energy density and low cost. However, due to the lithium-sparse property of copper foil and the high activity of lithium metal, the lithium deposition/stripping is not uniform, resulting in many problems such as lithium dendrites and excessive lithium consumption, which limits the practical application. In this paper, the advantages, challenges and solutions of anode-free lithium metal batteries were comprehensively reviewed. Four improvement strategies were discussed in detail, including modifying the current collector, constructing a stable solid electrolyte interface(SEI) film, introducing lithium supplementation technology and optimizing the electrolyte. The mechanism of the negative side affecting the deposition / stripping of lithium metal, the advantages of the positive side additional lithium source and the influence of the electrolyte on the reversibility of the anode-free lithium metal battery were discussed. The advantages and disadvantages of the four strategies and the future development direction were summarized.

Lithium metal anode has become a research hotspot in the field of rechargeable batteries due to its extremely high specific capacity (3 860 mAh/g) and low electrochemical potential (–3.04 V). However, the instability of lithium metal can promote the formation of dendrites, and the uncontrolled interface reaction during charge and discharge can cause the generated solid electrolyte interphase (SEI) to be unstable, affecting the battery cycling life. By introducing artificial SEI (ASEI), the mechanical and electrochemical properties are improved. The goal is to prepare lithium metal batteries (LMBs) with long cycle life and high energy density. Polymers are highly flexible and capable of designing their structures to meet specific needs, making them ideal materials for artificial SEI. In this paper, the properties and functions of artificial SEI are summarized. According to the types and functions of different functional groups of polymers, the research progress of artificial SEI is summarized, and the future research direction and development prospect are prospected.

Thermal runaway of lithium ion batteries is one of major problems hindering the development of higher energy density batteries and their large-scale application. The thermal safety of lithium ion batteries not only depends on the electrode material and battery design, but also varies by their aging modes and degrees. The degradation of electrochemical performance and thermal runaway behavior of aged lithium ion batteries during cyclic aging at high temperature were investigated in this work. The NCM lithium ion batteries were cyclic aged at 72 ℃ and 25 ℃ under 1 C current at CC-CV mode. The electrochemical performances of fresh and aged batteries were first compared, then ARC was used to perform thermal runaway test on fresh and aged batteries to explore the thermal safety variations of batteries after cyclic aging at high temperature, finally, the post analysis of aged batteries was carried out to investigate their aging mechanism. Related results have shown that the electrochemical performance of batteries deteriorated seriously due to the loss of large amounts of active materials in both positive and negative electrodes. During the ARC tests, both fresh and aged batteries occurred thermal runaway. However, the dynamic process of thermal runaway was slowed down due to the consumption of large amounts of electrolyte in aged batteries, thus the overall harm of thermal runaway by high-temperature aged batteries was alleviated.

In recent years, lithium ion batteries(LIBs) are the state-of-the-art battery technology, which has been widely used in portable electronic devices, electric vehicles, energy storage systems. However, there are still some problems that result the decay of energy and power density of LIB under low-temperature condition, restricting its application in extreme working condition for the following reasons: the diffusion of Li⁺ in the electrode material, the charge transfer and desolvation process at the interface are relatively slow. The increase of the viscosity of the electrolyte results in the deterioration of the wettability of the active material and separator. In addition, charging under low-temperature may lead to the growth of lithium dendrites, which trigger internal short circuit and thermal runaway accidents in the worst case. Based on years of experience in the development of low-temperature LIB and related literature reports, the strategies were reviewed to improve low-temperature performance from the perspective of electrolyte, focusing on the effects of co-solvents with low viscosity and wide liquid range, new lithium salts with high conductivity and low desolvation energy, and additives to form thin and dense SEI, and their challenges on low-temperature performance. Moreover, the future development direction of low temperature LIB was prospected.

Owning to the low cost and eco-friendliness, water-based processing for the preparation of electrode films is attractive in Li-ion battery industry. A composite binder suitable for water-based processing of Li-rich layered oxide cathodes(LLOs) was prepared by sodium alginate(SA) and polyacrylic acid(PAA). The result demonstrats that adjusting the mass ratio of SA and PAA can control the degree of cross-linking between the hydroxyl group of SA and the carboxyl group of PAA, thus regulating the electrode structure and improving the electrode kinetics. The LLOs electrode films prepared by the water-based processing has excellent electrochemical performance when the mass ratio of SA/PAA is 3∶1. The LLOs‖Li half-cells have a discharge specific capacity of 293.8 mAh/g(4.8 V), and 179.2 mAh/g at a high current density of 3 C. The study will help to design and optimize binders for 4.8 V high voltage LLOs.

Voltage reversal due to insufficient fuel supply severely restricts the lifespan of proton exchange membrane fuel cells (PEMFCs). In order to study and solve this problem, this work used bi-functional PtIr alloys as anode catalyst to fabricate membrane electrode assembly (MEA) and performed polarization performance, reversal tolerant performance and electrochemical impedance spectroscopy (EIS), etc. The results show that the peak power density of PtIr/C electrode can reach 1.49 W/cm², which is 2.1% higher than that of Pt/C-IrO₂ (50%) electrode (1.46 W/cm²). The reversal tolerant results show that PtIr/C electrode presents an anti-electrode time of 725 s, which is slightly worse than that of Pt/C-IrO₂ (50%) electrode, and lower absolute reversal voltage during the whole process, as well as higher structural stability which remained unchanged after reversal test. After the reversal, the peak power density of the PtIr/C electrode decreases to 1.18 W/cm² with an attenuation of about 20.80%, while the peak power density of the Pt/C-IrO₂ (50%) electrode decreases to 1.09 W/cm² with an attenuation of about 25.34%. In summary, compared with the Pt/C electrode doped with IrO₂, the PtIr electrode had better initial polarization performance and excellent anti-electrode ability. This research is of great significance for the design of high-performance and durable catalytic layers of fuel cell MEA.

The rapid development of renewable energy sources such as photovoltaic also brings great challenges to the frequency stability of microgrid system, in order to solve the frequency stability problems caused by the power imbalance between the source and load of microgrid, a two-layer multi-timescale frequency optimization scheduling model based on islanded photovoltaic microgrid has been established, and the optimal regulation of the system frequency has been considered comprehensively in terms of both system planning and operation, and a function of economic gain has been constructed in the upper-layer model. In the upper-layer model, a function with the economic return as the objective is constructed to optimize the long-term energy storage configuration of the microgrid system. In the lower-layer model, a multi-objective function with the operating cost and the root-mean-square of the frequency deviation is constructed to establish a day-ahead optimal dispatch model with the photovoltaic dynamic load shedding standby and the coordinated frequency regulation of the energy storage, and gold search algorithm is introduced to solve the double-layer multi-timescale optimization model, which gives the optimal energy storage configuration as well as the operating characteristics of each unit. Finally, the correctness and validity of the proposed model are verified by simulation example.

Power battery management technology is the core and key to ensuring the efficient, safe, and reliable operation of new energy vehicles. The State of Charge (SOC) of power batteries is the foundation of power battery management technology. However, there are too many uncertain factors affecting the SOC of power batteries, and how to accurately estimate the SOC of power batteries has become a key issue. Regarding the difficulty in accurately obtaining SOC for power batteries, this paper establishes a power battery testing platform, conducts routine performance testing and power battery life testing, establishes a fractional order model of power batteries based on fractional order theory, and then combines multiple innovation theory with fractional order model unscented Kalman filtering algorithm to propose fractional order model multiple innovation unscented Kalman filtering (FOMIUKF) algorithm, and uses this algorithm to estimate the SOC of power batteries. Comparative analysis was conducted on the estimation accuracy of power battery SOC based on different algorithms under different environmental temperatures, dynamic operating conditions, and initial SOC values. The results show that the average absolute error (MAE) and root mean square error (RMSE) of the power battery SOC estimation results are the smallest based on the FOMIUKF algorithm. Under different dynamic operating conditions, the maximum MAE of the power battery SOC estimation results using the FOMIUKF algorithm is about 1.04%, and the maximum RMSE of the power battery SOC estimation results is about 0.858 6%. This indicates that the accuracy of the FOMIUKF algorithm for power battery SOC estimation results is higher than that of the EKF, UKF, and FOUKF algorithms.

Long term peak shaving and frequency modulation of lithium iron phosphate energy storage batteries can lead to a decrease in electrode activity and a decrease in battery life. By conducting charging and discharging experiments on lithium iron phosphate energy storage battery modules under peak shaving and frequency modulation conditions, the relaxation behavior was analyzed, and the changes in relaxation voltage under different SOC, different charging and discharging methods, and different charging and discharging rates were compared. The voltage offset rate was proposed as an indicator to measure the voltage's recovery ability. The analysis of experimental results shows that the voltage recovery time of frequency modulation mode is greater than that of peak modulation mode, and the larger the current magnification, the longer the relaxation time. In peak shaving mode, after each charging and discharging cycle, intermittently soak for 540~660 s, while in frequency modulation mode, soak for 900~1 100 s after each cycle, which is beneficial for voltage's recovery.

Using FePO₄ as the iron source,the LiFePO₄ was prepared by carbothermaI reduction. By changing the feed rate and crushing pressure,the final product LiFePO₄ has different particle size distributions. The current collector made up the cell,which contains the final product LiFePO₄ conductive agents and binders. The results show that the D_max of final product LiFePO₄ is whthin 20 μm and the granularity of mixed liquids is within 35 μm. The compacting density of the coating layer is greater than 2.44 g/m³ and the 0.1 C discharge specific capacity exceeds 159 mAh/g. The final product LiFePO₄ has good performance in practicability.

With the increasing power demand of satellites, high-voltage and high-power equipment such as electric propulsion is widely used on satellites, which makes it difficult for the traditional 100 V bus electrical architecture to meet the increasing demand of satellites. This paper proposes a novel high-voltage conversion module for direct-driving Hall electric propulsion equipment. It adopts a two-stage circuit which can realize the functions of Maximum Power Point Tracking (MPPT), constant current charging for battery and bus voltage stabilization.

The flat potential platform (1.55 V) of lithium titanate battery can prevent the formation of SEI film and the generation of lithium dendrites more effectively, which is of great significance for portable electronics, energy vehicles, ecological environment and other applications. Due to the low intrinsic ion conductivity of lithium titanate battery, increasing the diffusion coefficient of lithium titanate is the main research direction at present. In this paper, the structural characteristics of lithium titanate batteries and the effects of synthesis methods on the electrochemical performance of lithium titanate materials were reviewed. The specific capacity, cycle performance and lithium ion diffusion coefficient of a series of lithium titanate batteries were obtained by different doping ions and surface coating modification. The addition of niobium has a higher lithium ion diffusion coefficient, and the coated LMSO has a higher capacity retention rate, which is helpful to further improve the electrochemical performance of lithium titanate batteries.

Due to high theoretical capacity, low redox potential, excellent safety features and economic benefits, aqueous zinc-ion batteries (AZIBs) have significant potential for applications in various fields, including portable electronic devices, energy storage devices and new energy vehicles. In the AZIBs system, optimizing electrolyte additives can enhance the stability of the electrolyte system, diminish the negative electrode dendrite growth, and prevent hydrogen evolution side reactions. Thus, comprehensively summarizing additive engineering and discovering new prospects to existing problems is necessary. The mechanism of the effect of electrolyte additives on the deposition behaviour of Zn²⁺ was summarised. Secondly, the challenges faced by negative electrode with an aim of finding ways of improving its performance through single or mixed additives were examined. The role of single additive in enhancing negative electrode was discussed and research on mixed additives was reviewed. Finally, possible strategies for the direction of development and the prospects for additive technology were suggested.

Solid-state lithium metal battery has become the most promising lithium battery technology for its outstanding safety and high theoretical specific capacity. For building a system with high specific energy density, the main obstacle is the interfacial issues and the compatibility between cathode and solid electrolyte. Through the introduction of modification strategies on film mechanical property, cathode/electrolyte interface properties and its integrated preparation technology, and theoretical calculation, etc, the progress of cathode/electrolyte interfacial modification techniques such as physical contact optimization, cathode/electrolyte permeability enhancement, interface compatibility improvement and cathode electrolyte interphase construction were reviewed. The development trend of interface modification technology for solid-state lithium metal batteries was also prospected.

Despite their wide range of applications, lithium-ion batteries (LIBs) are severely degraded in terms of capacity, rate capability and lifetime at low temperatures, which greatly limits their applications in low-temperature fields. A number of factors cause poor low-temperature performance of LIBs. The microscale processes occurring near the electrode/electrolyte interface, particularly the increased energy barrier for lithium ion (Li⁺) desolvation at the solid electrolyte interphase (SEI) and the slow transport of Li⁺ through the SEI, play a crucial role in the low-temperature performances of LIBs. Therefore, the improvement and development of electrolytes is of significant importance for the further exploration of low-temperature LIBs. This review started by examining the factors that limit the low-temperature kinetics of LIBs, and analyzed the low-temperature rate-determining steps. It then further explored how solvents, salts, and additives improve the low-temperature performances in different battery systems. This Review is expected to provide the informative outlook for the design of the next-generation low-temperature LIBs.

The cascading utilization of retired power lithium batteries (with a rated capacity of over 80%) can effectively alleviate the pressure of battery recycling and environmental pollution, and improve resource utilization efficiency and economic benefits. However, conducting rapid, non-destructive, and accurate state assessment of the retired batteries remains a challenge. Compared with other reported methods, electrochemical alternating current measurement of batteries and collecting data to draw impedance spectra are the core methods for studying battery states, which have two advantages: fast and non-destructive. The battery detected in this way can establish internal impedance and state correlation, and quickly complete battery state evaluation. The analysis methods of electrochemical impedance spectroscopy mainly include predicting impedance based on measurement data and machine learning methods, analyzing the changes in various equivalent components of the circuit based on equivalent circuit diagrams, and using integration algorithms to convert impedance spectroscopy into a more intuitive relaxation time distribution spectroscopy. These methods all provide analytical methods for the internal aging of batteries, providing an electrochemical basis for the relationship between the internal impedance and health status of batteries. Based on this, this article reviewed the latest research progress in combining electrochemical impedance spectroscopy with machine learning to evaluate the state of power lithium batteries both domestically and internationally, with a focus on summarizing and exploring the relationship between electrochemical impedance spectroscopy, equivalent circuit models, relaxation time distribution, and machine learning.

The efficient recycling and utilization of spent lithium-ion battery cathode materials aligns with China's new low-carbon development goals and promotes energy recycling. The capacity failure mechanism and pretreatment methods of spent lithium-ion batteries were introduced. The research status of traditional recycling methods such as pyrometallurgical recycling, hydrometallurgical recycling for the cathode materials obtained were analyzed. Direct recycling is the most ideal method for cathode materials of spent lithium-ion batteries. The characteristics of solid-phase regeneration, hydrothermal restoration, molten salts repairing, electrochemical regeneration methods were described, and the advantages and disadvantages of each method were summarized. Finally, the problems and challenges that recycling of spent lithium-ion batteries may face from multiple perspectives were discussed.

Coating machine is a device for lithium battery slurry to be coated on the surface of the substrate through the extrusion die head through the estimated amount feeding device, which is one of the key process equipment necessary for battery production. The key component of coating equipment is the oven. The reasonable design of the oven structure directly affects the production quality and productivity of positive and negative electrode pieces. This design is based on the reasonable layout of the wide coated air chamber and air nozzle structure, to optimize the uniformity of the transverse jet flow of the wide oven. Through simulation and experiment, the design improvement of air chamber and air nozzle of oven is verified, which provides experimental data for the design of ultra-wide oven and verifies the reliability and rationality of the design.

In order to predict the aging of proton exchange membrane fuel cells (PEMFCs) under dynamic operating conditions and improve the prediction ability of the gated recurrent unit network (GRU), this paper proposes a TCN-GRU-A prediction method that combines time convolutional network (TCN), attention mechanism, and GRU. By introducing the TCN layer to enhance the feature extraction ability of GRU, the attention mechanism is used to weight the output features of GRU to improve the accuracy of the prediction. Validated using a PEMFC dynamic durability test dataset, a comparison with various deep learning models' predictions indicates that the proposed method demonstrates lower prediction errors and better fitting, whether applied to full-current load data or constant-current load data.

Since the commercial application of lithium-ion batteries (LIBs), the capacity decline of lithium-ion batteries working in low temperature has attracted much attention from scholars. This paper analyzed and discussed the influencing factors of poor performance of LIBs in low temperature, and summarized the methods to improve the dynamics of low-temperature batteries in recent years from four aspects: electrolyte design, cathode material modification, anode material modification and battery heating technology. Finally, the methods to improve the performance of low-temperature LIBs were summarized and new insights and schemes were put forward to promote the sustainable development of high-performance low-temperature LIBs.

In order to solve the interfacial contact problem between solid-state electrolyte and electrode and realize the solid-state of lithium-sulfur battery, NASICON-type Li_1+xAl_xTi_2-x(PO₄)₃ oxide solid-state electrolyte (LATP) was prepared by sol-gel method, solid-state electrolyte membrane was prepared by water-based tape casting method, and quasi-solid-state lithium-sulfur batteries were assembled by using a small amount of electrolyte-wetted LATP solid-state electrolyte membrane. The ionic conductivity of the prepared LATP was 1.61×10^-4 S/cm, and the Li-symmetric battery could be stably cycled at 30 ℃ for more than 500 h. The quasi-solid-state battery was discharged at room temperature with a discharge specific capacity of 340 mAh/g at 5 C. The initial discharge specific capacity of the quasi-solid-state battery is 1 043 mAh/g at 30 ℃ with 0.1 C. The discharge specific capacity of the quasi-solid-state battery is 430 mAh/g after 100 cycles. After 100 cycles, the specific capacity is 430 mAh/g.

The high potential generated by the cell reversal causes irreversible carbon corrosion damage to the microporous layer, which greatly shortens the durability of PEMFC. So the study of carbon corrosion in the microporous layer caused by the cell reversal has important scientific significance to strengthen the durability of PEMFC. In this study, four kinds of commercial carbon black with different degrees of graphitization were selected to prepare microporous layer, and their properties before and after high-potential corrosion were analyzed. The results show that increasing the graphitization degree of carbon black and decreasing its specific surface area, the degradation degree of physical properties such as surface hydrophilicity, surface morphology and pore structure of GDL after corrosion was alleviated, and the degradation degree of cell performance was also alleviated. The corrosion resistance of the four kinds of carbon black is acetylene black>XC-72>Ketjen Black> BP2000. The physical properties of GDL prepared by acetylene black has almost no degradation after corrosion, and the performance of cell has a lower degradation degree. This provides an important theoretical basis for developing excellent reversal tolerant anode microporous layer and improving the durability of PEMFC.

The 120 Ah lithium iron phosphate battery was tested for thermal runaway in a sealed pressure chamber in an inert atmosphere. The body temperature and ambient temperature of the battery were recorded, the proportion of gas production components was analyzed, and the gas production, exhaust rate and flammability limit of the battery were calculated. As a control, experiments were carried out under the same conditions in the air atmosphere to investigate the influence of different atmospheres on the thermal runaway process of the battery. The process of battery thermal runaway goes through several stages of "temperature rise-valve opening-thermal runaway-cooling down". During thermal runaway, the ambient temperature above the battery decreases gradually. Compared with the inert atmosphere, the temperature of the battery in the air atmosphere is increased by 17.6%, the thermal runaway duration is extended by 14%, and the gas production is increased by 8.2%.

The SiO_x anode material was coated with sulfonated graphene by centrifugal spray drying method, and the pouch cell was prepared with sulfonated graphene coated SiO_x anode material (SGPE-SiO_x). The results show that the cycle life of the pouch cell prepared by SGPE-SiO_x is significantly improved, the impedance growth rate during cycling is significantly inhibited, and the thermal safety performance of the pouch cell is also improved. The cross-section morphology analysis of the anode electrode of the pouch cell after 100 cycles shows that the sulfonated graphene coating layer can inhibit the thickness growth of the SEI film on the surface of the SiO_x material during the cycling, which reduces from 800 nm of the uncoated anode to 200 nm of the coated anode.

This article uses three different types of acetylene black as raw materials, and characterizes and analyzes acetylene black through SEM, BET, laser particle size analyzer, etc. Test the stability and viscosity changes of slurries containing different types of acetylene carbon black. Prepare carbon coated aluminum foil through the gravure coating process and conduct electrical performance testing and analysis to evaluate the impact of three types of acetylene carbon black on the performance of carbon coated aluminum foil. The results show that the particle size distribution of acetylene carbon black particles used in the laboratory is about 8 µm, and the specific surface area is about 60 m²/g. The surface of SP-009 and Li-2060 is rough and has a fluffy pore structure, which is conducive to the embedding of active substances and increases the contact area between active substances and foil. After the slurry was prepared, SP-009 had the least sedimentation, better dispersion and stability among the three. The resistivity of carbon-coated aluminum foil of SP-009 is the smallest and more concentrated, with an average value of 1.95 mΩ. The smaller the resistance, the better the performance. Comparing the cycling performance of the batteries made of the three, SP-009 has the highest capacity retention rate after 100 cycles, at 84.46%. In summary, SP-009 acetylene black has good performance, improving the stability of the slurry and the conductivity of the coated aluminum foil.

In this paper, a lithium manganate material doped with lanthanum oxide was prepared by high temperature solid phase synthesis method. The influence of different doping ratio (mass ratio of La₂O₃ to MnO₂ was 0%, 0.5%, 1.0% and 1.5%, respectively) was investigated. The results showed that the maximum capacity of 1 C was 120.42 mAh/g, when the La₂O₃ doping amount was 1%. The first charge and discharge efficiency was the highest (96.76%). After 100 cycles, the 1 C volume retention rate was maximum (90.28%).

In order to achieve the specific energy increase of lithium ion batteries, the use of silicon-based materials to increase the capacity of the negative electrode is a common method for high specific energy lithium ion batteries. SiO_x has been used in power batteries because of its excellent cycling performance. However, in the process of charging and discharging, the volume expansion and contraction rate of the SiO_x particle is large, which often affects the cycle life of the battery. It is helpful to improve the cycle life of silicon-containing high specific energy system to investigate the relationship between particle pulverization and the transition growth of SEI film and the preloading force during the process of expansion and contraction of SiO_x particles. In this paper, the failure mechanism of SiO_x particles was analyzed by analyzing the failure state of silicon anode particles after high specific energy lithium ion battery cycling under different stress conditions.

Accurately and real-time monitoring the internal temperature of lithium batteries is crucial for preventing thermal runaway. However, there is currently no effective method for online monitoring of the internal temperature of batteries. Therefore, in this study, a miniaturized impedance testing system is utilized to perform impedance testing experiments on lithium ion batteries at various temperatures and state of charge (SOC) levels. The influence of battery temperature and SOC on impedance is investigated, aiming to identify characteristic frequencies strongly correlated with temperature and weakly correlated with SOC. On this basis, a lithium battery internal temperature estimation algorithm is proposed using the Support Vector Regression (SVR) technique, enabling non-destructive and accurate estimation of the internal temperature without the need for additional sensors.

The recycling of the substantial volume of retired batteries has emerged as one of the most pressing issues facing the electric vehicle (EV) industry due to the exponential rise of EVs. In order to maximize their economic benefits and utilization rate, retired batteries must be sorted according to the consistency of their performance before being used at the echelons utilization due to the inconsistent performance of retired batteries in terms of their capacity, internal resistance and other properties. Therefore, this article proposes a consistency sorting method for retired batteries based on discharge curves and improved fuzzy C-means algorithm. With this method, retired battery cells are used as the research subject. Discharge curves are selected through 1 C rate charging and discharging experiments, and feature parameters are then extracted. This information is used to build a high-precision sorting model of retired batteries, which is integrated with the improved fuzzy C-means algorithm. Based on the streamlined feature point extraction process, the efficiency of the sorting method is confirmed using retired batteries with various gradients in capacity.

It is of great practical significance of conducting experimental research on the safety of lithium ion battery modules under liquid cooling conditions considering their unique characteristics. In this study, the thermal runaway experiments on 280 Ah lithium iron phosphate batteries, induced by overcharge, external short circuit and overheating were performed on a submerged liquid cooling system test platform to explore the thermal behavior in both the thermal runaway process induced by liquid cooling of individual batteries and modules. Additionally, this study also scrutinized the distinctions in thermal runaway behavior between the conditions induced by liquid cooling and those governed by natural convection. It has revealed that submerged liquid cooling process can diminish the initial heating temperature, mitigates the temperature escalation triggered by overcharge-induced uncontrolled heating, lowers the peak temperature following such incidents, effectively dampens the rate of temperature increase during the process, and delays the onset of uncontrolled heating in the case of battery thermal runaway. Furthermore, in the thermal runaway experiment induced by overheat, utilizing submerged liquid cooling with a 2 kW heater plate attached to the heating, the battery reached a maximum temperature of 90 °C, indicating effective thermal control in preventing thermal runaway.

With the progress and development of hydrogen energy industry, the operating pressure and power density of proton exchange membrane fuel cell (PEMFC) are increasing. Based on FLUENT software package, a three-dimensional steady-state non-isothermal two-phase flow numerical model of PEMFC with trapezoidal channel is established by using the unsaturated flow theory (UFT). This study simulates and analyzes the two-phase flow of PEMFC under operating pressure, especially under high pressure and high power density. The results show that high operating pressure can significantly improve the power density, liquid water cooling rate, liquid water saturation and membrane water content. With the increase of pressure and current density, water condensation rate, electric drag and reverse osmosis demonstrate strong nonlinearity, which causes the accumulation position of liquid water to move to the inlet side.