LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathodes in lithium-ion batteries have the advantages of high specific capacity and relatively low cost. However, long-term cycling at high voltage poses challenges to the cathode interface, leading to instability and a need for improved safety performance. Although the lithium fast ion conductor Li_1.2Ca_0.1Zr_1.9(PO₄)₃ ceramic separator can considerably enhance battery safety, it exhibits poor interface stability when paired with NCM811 cathode. Herein, a lithium fluoride (LiF) additive with a stable interface function is added to the ceramic separator to solve this problem. The LiF-modified ceramic separator was characterized using scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, mechanical tensile strength, thermal shrinkage, electrolyte uptake ability, electrochemical impedance spectroscopy, linear sweep voltammetry, and charge-discharge testing. The results show that the ceramic separator performs best when LiF accounts for 10% of the total mass of coated inorganic ceramic particles. It exhibits improved ionic transport properties, with room temperature ionic conductivity of 9.5×10^-4 S/cm and excellent interfacial stability. In a Li||LiNi_0.8Co_0.1Ni_0.1O₂ coin cell operating in the high-voltage range of 3.0—4.35 V, the discharge-specific capacity decreases from 195.2 to 119.9 mAh/g at a 0.3 C rate after 400 cycles, while maintaining 61.4% of the initial capacity when using LiF-contained ceramic separator. In contrast, the capacity retention of the cell without LiF is only 32.7%. The enhanced cycling stability of the battery using a LiF-contained ceramic separator can be ascribed to the formation of a high-quality, high-voltage cathode-electrolyte interface film, stabilizing the interface between the cathode and separator, thereby preserving the structural stability of the cathode material under high voltages. Therefore, the developed ceramic separator in this study provides a convenient method for commercializing NCM811 cathodes in high-voltage lithium-ion batteries by enhancing interfacial stability and cycling performance.

Na₃V₂O₂(PO₄)₂F(NVOPF) is a cathode material with potential application prospects in sodium-ion batteries. This is due to its suitably stable polyanion structure, high operating voltage, and high theoretical specific capacity. However, the intrinsic conductivity of the material is low, and it is prone to irregular agglomeration during the synthesis process, resulting in low actual specific capacity and unsatisfactory rate and cycling performances. Ion doping and micro/nanostructured materials have been found to benefit the intrinsic conductivity and stability of the material. This work, for the first time, reports the synthesis of Nb⁵⁺-doped NVOPF(NVNOPF, Na₃V_2-x Nb _x O₂(PO₄)₂F (0≤x≤0.15)) material with a hollow microspheric structure by the polyol-assisted hydrothermal method. The as-prepared NVOPF and NVNOPF materials were microspheres with sizes of 0.7-1.0 μm with hollow structures. The microspheres were found to be composed of nanoparticles of with sizes <100 nm. Nanoparticles shortened the diffusion distance between sodium ions, buffered the volume change caused by the intercalation/extraction of sodium ions, and improved the material cycling stability. Meanwhile, doping Nb⁵⁺ increased the lattice parameters of NVNOPF and enlarged the Na⁺ diffusion pathway. The solid-phase diffusion coefficient of Na⁺ in the material increased from 6.46×10^-16 for Na₃V₂O₂(PO₄)₂F to 3.52×10^-15 cm²/s for Na₃V_1.90Nb_0.10O₂(PO₄)₂F. The discharge specific capacity of Na₃V_1.90Nb_0.10O₂(PO₄)₂F was 126.4 mAh/g (0.1 C rate) and 98.1 mAh/g (10 C rate). After 500 cycles of charge and discharge at the 10 C rate, the capacity retention was 95.2%, which is better than that of the undoped material (66.8%). The results showed that Nb-doped and hollow spherical micro-/nanostructures could effectively improve the electrochemical performance and cyclic stability of NVOPF.

With the rapid development of technologies related to the power supply and energy storage in electric vehicles, Ni-rich layered oxides have become the most preferred cathode materials for application in power batteries owing to their high capacity and low cost. However, these layered oxides suffer from inferior cycling performance and poor rate capability, seriously impeding their practical application. Ni-rich single-crystalline can effectively mitigate the generation of particle cracking and improve the cycling stability of Ni-rich cathode materials; however, the severe preparation conditions of high nickel single crystals limit their development. Herein, polycrystalline Ni-rich LiNi_0.9Co_0.05Mn_0.05O₂ (NCM-PC) and single-crystalline LiNi_0.9Co_0.05Mn_0.05O₂ (NCM-SC) were prepared via coprecipitation combined with the high-temperature solid-state and molten-salt methods, respectively. The crystallographic structure, microstructure, electrochemical properties and Li⁺ diffusion kinetics of two cathode materials were systematically studied via scanning electron microscopy, x-ray diffractometry, constant current intermittent titration technique, and electrochemical tests. The results of this study demonstrate that NCM-PC possesses a relatively high lithium-ion diffusion coefficient, resulting in excellent rate performance. For instance, NCM-PC could deliver a discharge capacity of 164 mAh/g at 10 C. Although NCM-PC exhibits a low discharge capacity at a high C-rate, it exhibits an outstanding cycling performance with capacity retention of ～89 % after 100 cycles at 3 C. This study provides a theoretical basis for optimizing the particle size and electrochemical performance of single-crystalline/polycrystalline NCM materials having high-Ni content (≥90 %).

The effects of six electrolyte additives: vinylene carbonate (VC), ethylene sulfite (ES), ethylene sulfate (DTD), 1,3-propanediol cyclo-sulfate (PCS), 1,3-propylene sultone (PS), 1,3-propylene sultone (PST) on the electrochemical performance of lithium nickel cobalt manganese oxide (NCM111)//graphite lithium-ion batteries were investigated herein. Some conclusions were obtained by comparing the results of the first charging-discharging efficiency, discharged capacity, rate characteristics, low-temperature discharging capability, high-temperature storage performance and cycle life, etc. C＝C double bond can improve the film-forming property and promote the cycle life, making VC possess a relatively balanced performance in all aspects and can be used independently. The continuous gas production for ES in the formation, cycle, and storage processes can be observed because of the unstoppable decomposition of the electrolyte, making it impossible to use. Sulphate Additives (DTD and PCS) can significantly reduce the DCR and improve the low-temperature performance; however, their high-temperature performance is slightly restricted. Sulfonate additives (PS and PST) have outstanding effects in inhibiting high-temperature flatulence. Especially, PST with dual functional groups has better cycle performance and capability to suppress the voltage decay in high-temperature environments than PS but has higher impedance in low-temperature environments than other additives. A comprehensive comparison shows that the single-component sulfur-containing additive is equipped with unique characteristics in some properties but also has obvious defects, making it lonely and impossible. The problem of poor cycling performance of sulfur-containing additives can be solved by proportionally compounding them with VC, while their characteristics such as high initial coulombic efficiency, low internal resistance, excellent rate performance and high-temperature stability can be maintained. The comprehensive performance of binary combination is better than that of the single-component additive, making it a better choice for additive combination to improve the battery performance.

Polyepoxy-ethylene (PEO) polymer solid electrolyte has great prospects in all-solid-state lithium batteries owing to its high flexibility, excellent processability, and excellent interfacial compatibility. However, its effective application is hindered because of low ionic conductivity at room temperature and a narrow electrochemical window. Herein, a solution casting method was employed to disperse crown ether molecules (15-C-5) containing polar functional groups within PEO/LiTFSI matrix, thereby preparing PEO/15-C-5 polymer solid electrolyte. Moreover, the doping amount of crown ether, which affects the transfer behavior of Li ions within the all-solid-state electrolyte, was discussed. Additionally, the morphology, mechanical properties, and electrochemical performance of the polymerized solid electrolyte were systematically investigated. The results show that well-dispersed crown ether with a 10% doping amount effectively reduces the crystallinity of the PEO matrix and improves the motility of PEO chains, resulting in a good tensile strength of 1.83 MPa. Meanwhile, the strong complexation between 15-C-5 and Li ions promotes the dissociation of lithium salts and generates electrostatic repulsion against negative ions. Consequently, the ionic conductivity of the electrolyte and the migration number of lithium ions are substantially improved. Specifically, the ionic conductivity of PEO/10%15-C-5 solid polymer electrolyte reaches 1.00×10^-5 S/cm at 30 ℃, and the lithium-ion migration number reaches 0.42 at 60 ℃, which is 4.5 times and 1.9 times higher than those of PEO electrolyte, respectively. The formation of electrostatic repulsion centers between crown ethers and negative ions can easily trap lithium ions, creating relatively stable sites that reduce the possibility of O-Li complex active sites from the PEO chain segment, promoting the decomposition of the C-O-C structure. Therefore, the PEO electrolyte demonstrates a high decomposition voltage, increasing from 4.29 to 5.42 V. Additionally, when assembled into an assembled all-solid-state lithium battery with an NCM811 cathode, the PEO/10%15-C-5 electrolyte exhibits a favorable initial discharge specific capacity of 159 mAh/g at 60 ℃ and 0.5 C, along with a high retention rate of 89% after 100 cycles. Similarly, the all-solid-state lithium battery assembled with the lithium iron phosphate cathode shows excellent performance.

In recent years, sulfide solid-state electrolytes have attracted extensive attention from researchers due to their high safety, high ionic conductivity, wide electrochemical window, and several other advantages. Modification by doping is considered to be an effective approach to improve the electrochemical performance of sulfide solid-state electrolytes. Because of the unique electronic structure and functional properties of rare earth elements (REEs), doping these elements has emerged as one of the effective strategies to improve the ionic conductivity of solid electrolytes and reduce the grain boundary resistance. In this work, a series of modified sulfide solid electrolytes were synthesized using an REE compound, namely scandium oxide (Sc₂O₃), as a dopant. The doping of Sc₂O₃ was studied through X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. The electrical conductivity was determined by the AC impedance method. The results showed that when the Sc₂O₃ doping amount was x=0.04 (Li_6.08P_0.96Sc_0.04S_4.94O_0.06Cl), the sulfide solid-state electrolyte showed a high ionic conductivity of up to 3.17 × 10^-3 S/cm. A lithium-lithium symmetric battery was assembled using the as-prepared sulfide solid-state electrolyte. The battery showed a high critical current density of 0.95 mA/cm² and a stable cycling process over 300 h at a current density of 0.1 mA/cm². The Li_6.08P_0.96Sc_0.04S_4.94O_0.06Cl-based all-solid-state battery showed the first-cycle charge-discharge specific capacity of 249.0 and 191.2 mAh/g and the first-cycle charge-discharge efficiency of 76.78%. After 950 cycles, it could maintain a specific discharge capacity of 123 mAh/g. Even after exposure to the air for 90 min, the electrolyte exhibited good crystallinity and cycling performance for all-solid-state batteries. This work proposed a new dopant for improving the electrochemical performance of Li₆PS₅Cl-type sulfide solid-state electrolytes.

This research aimed to improve the heat storage performance of the composite phase-change unit filled with metal foam. The heat transfer performance of composite phase-change materials was significantly affected by the porosity distribution of metal foam. Therefore, a new gradient-porosity metal foam structure was established based on the energy storage system of the phase-change material (PCM) composite prepared from low-porosity metal foam. Then, the melting fraction, thermal energy storage rate, and thermal energy storage of the heat storage unit during the melting process were analyzed through numerical simulations. The effects of negative and positive gradient distributions of porosity along the heating direction on the melting rate and heat storage performance of the PCM composites were systematically studied. The results showed that the negative gradient porosity of the structure could further improve the thermal storage efficiency of the energy storage system. In addition, the enhancement effect was most significant when the porosity gradient was 0.12 (case S-6). For S-6, at 1000, 2000, and 2600 s, the melting rate increased by 0.67%, 2.31%, and 9.90%, respectively, compared with the uniform-pore structure. The complete melting time of the structure with the improved gradient pore could be shortened by up to 7.32%, and the thermal energy storage rate could be increased by 8.02% compared with the uniform-pore structure. The structure with the positive gradient porosity had no significant effect on the melting rate, but the thermal energy storage could be increased by 0.49%.

The application of single hydrated salts phase change materials is limited owing to disadvantages such as supercooling, phase separation, ease of leaking, and phase change temperature. To address these challenges, researchers must focus on developing composite phase change materials exhibiting high heat storage density, suitable phase change temperature, and high thermal conductivity properties. In this study, a eutectic salt having a mass ratio of 55 to 45 with respect to NH₄Al(SO₄)₂·12H₂O (AASD) to MgSO₄·7H₂O (MSH) eutectic phase change material was prepared. The phase change temperature was 76.4 ℃, and the latent heat of phase change was 189.4 J/g. The X-ray diffraction pattern and Fourier transform infrared spectra of the eutectic salt showed that the eutectic process was physical. 1% CaCl₂·2H₂O was used as a nucleating agent and 1% soluble starch was used as a thickening agent herein. This reduced the the supercooling degree from 34.9 ℃ to 28.0 ℃. Modified expanded graphite (MEG) and multiwalled carbon nanotubes (MWCNTs) were introduced to avoid leakage and improve the low thermal conductivity of the eutectic phase change materials. When the mass fraction of MWCNTs was 0.5%, the thermal conductivity of the composite phase change material (CPCM) reached 8.185 W/(m·K), which was 19.98 times that of the pure eutectic salt. The proportion of eutectic salt was 75.6%, the temperature and enthalpy of the CPCM were 74.3 ℃ and 133.5 J/g, and the supercooling was further reduced to 22.2 ℃. Thermogravimetric analysis showed that mixing the eutectic salt phase change material with MEG-MWCNTs increased the thermal stability of the material. The phase change enthalpy of the CPCM remained unchanged after 100 cycles of heating and cooling, indicating good cyclic stability. The CPCM based on AASD-MSH/MEG-MWCNTs developed in this study is a promising phase change material with suitable temperature, high enthalpy of phase change, large thermal conductivity, and good thermal cycle stability. This material has great potential for various applications.

The molten carbonate fuel cell (MCFC) is an efficient and sustainable power generation technology with high energy conversion efficiency and emission purification degree. Despite its immense potential, the development of MCFCs has been hindered owing to their high operating temperature and the unique properties of the molten carbonate electrolyte. Cathode dissolution is a severe issue that can lead to problems, such as Ni short circuits, negatively affecting fuel cell performance and lifespan. This review presents strategies for reducing cathode dissolution in MCFCs. It provides a brief overview of recent research on improving cathode dissolution from three aspects: alternative materials, coating modification, and additives. The review discusses the limitations of alternative NiO material and proposes the potential of coating technology to enhance the cathodic chemical performance of NiO and reduce cathode dissolution. The advantages and disadvantages of coating technology are also detailed, including research advancements and performance evaluations of methods, such as solution impregnation electroplating, sol-gel process, and atomic layer deposition. In addition, the article explores methods for reducing cathode dissolution by increasing the alkalinity of the electrolyte and incorporating alkaline oxides into NiO. However, it also highlights the risk of compromising cell performance by introducing excessive oxides. Overall, the article suggests that by developing new additives, leveraging coating technologies, compensating for the performance deficiencies of alloy cathode materials, and exploring new composite materials and other approaches, it is possible to obtain high-performance, low-cost cathode materials, thereby achieving large-scale commercialization of MCFC.

Conventional methods to test the battery materials' performance involve fabricating half/full cells and inferring material performance based on statistical results drawn from battery performance, such as energy density, rate capability, volume deformation, etc. These parameters are used to deduce material properties, including ionic/electronic conductivity, actual specific capacity, and exchange current density. However, such methods are marred by several issues. Firstly, significant errors are introduced as nonactive substances and the combined thermodynamic/kinetic processes influence individual material testing. These factors result in inaccurate and misleading performance reflections of active material. Secondly, testing the material performance on cells significantly wastes materials, energy, and time due to the far-exceeding cell capacity compared to individual particles. After comprehensively comparing different research objects for batteries, this paper proposed that direct electrochemical testing of single particles is currently the optimal approach for characterizing the kinetic performance of materials. This approach eliminated the influence of nonactive substances and pores in the porous electrode while retaining characteristics such as material defects, microstructure, etc. This paper reviewed various techniques for testing at the single-particle scale in lithium-ion batteries. In addition, a comparative analysis was conducted on aspects such as testing system, testing objects, object selectivity, lithiation state control, external stress, etc. Additionally, kinetic characterizations using contact-based and integrated single-particle microelectrodes were discussed, highlighting their effectiveness in performance characterization and parameter estimation. Finally, the paper discussed the combined use of single-particle kinetic characterization with other material characterization methods, as well as their future directions.

Sodium-ion batteries have emerged as a promising energy storage technology with global interest. However, the limited specific capacity of hard carbon, the primary anode material for sodium-ion batteries, restrains further improvement in energy density for full cells. In contrast, phosphorus-based anode materials have gained attention for high-performance sodium-ion batteries owing to their abundance and high theoretical specific capacity. The review summarizes some efficient strategies to improve structural stability and electrochemical performance by exploring the recent relevant literature. Black phosphorus can be easily prepared through mechanical methods and complexed with carbon materials such as graphene, multi-walled carbon nanotubes, and ketjen black. However, it is important to consider the formation of microscopic chemical bonds to enhance structural integrity and sodium storage reversibility. The chemical bonding between the surfaces of carbon material and black phosphorus plays a crucial role in achieving these advancements. In addition, the combination of conductive polymer and two-dimensional compounds with black phosphorus offers a pathway for optimizing material properties and electrode microstructures, further enhancing the electrochemical performance of sodium-ion batteries. Finally, the development prospect of black phosphorus-based anode material for sodium-ion batteries is proposed, highlighting their potential in advancing energy storage.

Lithium metal anodes have long been considered the "Holy Grail" in the field of energy storage batteries. However, the growth of dendrites on the anode surface and the continuous lithium metal loss make it impossible for lithium metal batteries to cycle stably, and even pose potential safety hazards, hindering their practical application. Researchers have proposed different interface modification methods to address these problems. Organic polymers with functional groups and diverse structures have advantages in inducing uniform lithium ion deposition and mitigating volume effects. They are favored by researchers in modifying lithium metal negative electrodes. This paper reviewed the strategies to improve the cycle stability of lithium metal batteries. Moreover, four major modification directions were introduced: electrolyte modification, current collector modification, separator modification, and artificial SEI membrane modification. The structural design criteria used for the interfacial modification of polymers were analyzed, and the methods of interfacial modification of polymers were discussed. Finally, the future research directions and development trends of metal lithium anode were prospected.

Ethylene carbonate (EC), an organic solvent with excellent performance, is widely regarded as an important component of electrolytes used in rechargeable lithium-ion batteries because of its high dielectric constant and good compatibility with graphite anodes. However, various problems related to EC, such as high melting point, high viscosity, and narrow electrochemical window, hinder the operation of lithium-ion batteries using EC-based electrolytes under various harsh operating conditions such as high temperature, high voltage, and low temperature. This study reviews recent literature with respect to EC-based electrolytes. First, this study reports the failure mechanisms related to conventional EC-based electrolytes under extreme operating conditions, including the reaction between EC and oxygen precipitated owing to cathode phase change under high voltage, the continuous consumption of electrolyte owing to the deterioration of the electrode-electrolyte interface, the decomposition of electrolyte under high-temperature conditions resulting in the generation of flammable radicals, and the uneven deposition of lithium under low-temperature conditions resulting in lithium dendrites. Secondly, the latest developments in research related to EC-free electrolytes are highlighted herein. This research includes the in situ construction of stable-electrode interface films, regulation of solvation structures, modulation of reaction paths, removal of reaction byproducts, and other optimization measures to redesign the electrolyte composition to improve the overall performance of Li-ion batteries through the design of electrolytes. Finally, the existing obstacles and possible development opportunities with respect to high-performance EC-free electrolytes are outlined in this study. This study provides a directional and theoretical guidance for developing lithium-ion batteries that can function under harsh operating conditions to meet demands from military and aviation industries.

The medium and high-temperature phase change heat storage and reuse is effectively achieve low-carbon economies and enhance industrial production. This study designs and tests a high-temperature phase change capsule step heat storage system to efficiently harness industrial high-temperature waste heat. The system uses polycarbonate materials with two different phase change temperatures as heat storage media and experimentally investigates the heat storage and release process under different inlet temperatures and inlet flow rates of the heat transfer air. The study mainly focuses on the temperature changes within the heat storage tank, the heat storage capacity, and the completion time of the heat storage and release processes. Experimental results show that the system can achieve a heat storage capacity of 30000 kJ when the inlet temperature is 500 ℃. Furthermore, increasing the inlet flow rate of the system reduces the heat storage time while having less influence on the total heat storage capacity of the system. The influence of the average liquid phase rate of the phase change material within the heat storage tank is analyzed about the total heat storage capacity of the system under different operating conditions. Meanwhile, the study highlights the air preheater installed in the system, which facilitates the heat exchange between high-temperature exhaust gas and the normal-temperature inlet gas, effectively enabling the waste heat utilization from the high-temperature exhaust gas. The results of the phase change experiment provide valuable insights into the influence law and optimization guidelines of the system operation parameters for the practical application of high-temperature phase change heat storage technology, which has a high reference value.

Internal short circuits (ISCs) in lithium-ion batteries (LIBs) lead to thermal runaway accidents. Therefore, diagnosing ISC faults in LIBs as early as possible is essential. However, the ISC resistance of LIBs in the early ISC fault stage is large, making it difficult to diagnose the microinternal short circuit (MISC) fault of LIBs. Herein, a fault diagnosis method is proposed for the MISC fault of LIBs based on the incremental capacity (IC) curve. When an MISC fault occurs in LIBs, a part of the charging current generates ohmic heat due to the presence of the short circuit resistance rather than participating in the electrochemical reaction of the LIB to increase the battery voltage. Consequently, the IC value of a short circuit battery is higher than that of a normal battery. Mean square error of the IC values of an MISC battery and a normal battery was calculated to evaluate the deviation, thereby diagnosing the MISC fault. Based on the differences between the charging capacities of MISC and normal batteries in the same voltage range, a quantitative calculation method was developed for MISC resistance. Simulation and experimental results showed that the proposed method could accurately detect MISC faults in batteries with a resistance of 710 Ω, and the maximum estimation error of the short-circuit resistance was 6.1%. Additionally, short-circuit experiments on aging batteries revealed that the proposed method was applicable for such batteries. The algorithm has low computational complexity and can be used for short-circuit fault diagnosis with just the charging data of low-rate batteries, which is easy for practical applications. The thermal effects of MISC faults in LIBs were also studied. The results demonstrated that the maximum temperature rise on the battery surface was 4.1 ℃ when the short circuit resistance was 100 Ω and 0.4 ℃ when it was 710 Ω. Temperature rise was not obvious when the MISC fault occurred in LIBs.

The heat-dissipation performance of lithium-ion batteries is related to the shape of the flow channel on a liquid cooling plate, flow direction, discharge rate, and temperature and velocity at the inlet. Using the maximum temperature, temperature difference, temperature standard deviation, and pressure drop with respect a lithium-ion battery (LIB) as evaluation indicators, a sine-function liquid-cooled plate channel is designed herein. The influences of the frequency and amplitude of the sine function on the heat-dissipation performance of LIBs are analyzed using the COMSOL finite element software. Herein, the influence of fluid-flow direction on the maximum temperature, temperature uniformity, and temperature consistency in LIBs under different discharge rates, inlet temperatures, and inlet velocities, respectively, are discussed. The results of this study show that the sine channel with low frequency and low amplitude is beneficial for heat dissipation from LIBs. It is beneficial of the flow direction change to improve the maximum temperature, temperature uniformity and temperature consistency of LIBs. The maximum temperature and temperature difference in LIBs decreases with the increasing number of staggered flow direction. The heat-dissipation performance of LIBs is improved more by fluid-flow direction at a high discharge rate than that at a low discharge rate. When the inlet temperature is 25 ℃, the effect of the heat dissipation of lithium-ion batteries is best by the variation of the flow direction.

A dual incentive adjustment strategy is proposed based on flexible energy storage of electric vehicles to address the problem of peak valley differences caused by the difficulty in orderly charging of electric vehicles under a single incentive, such as time-of-use electricity pricing, within the power system, which is difficult to cope with the supply and demand fluctuations caused by wind power generation and daily load patterns. To address this issue, our strategy incorporates several key elements. Firstly, the charging load of electric vehicles is predicted based on Monte Carlo simulations, and a battery loss model is established. On this basis, the optimization objectives are defined by considering the output of different power supply equipment in different periods, the proportion of carbon emissions, carbon quotas in the daily forecast, the cost of microgrid power generation, and the expected state of charge of users to minimize the mean square deviation of microgrid connected to power while maximizing user benefits. By dynamically adjusting the time-of-use electricity price and implementing a tiered carbon price, the optimized Grey Wolf algorithm is used to solve the model and formulate a reasonable charging and discharging plan to fully utilize the characteristics of electric vehicles as flexible loads, thereby suppressing the fluctuations in the load curve of the microgrid. Finally, simulation analysis is conducted to compare the proposed strategy with both non-incentive and single-incentive strategies, and the results showed that the peak-to-valley load difference decreases by 30.1% and 18.6%, respectively, verifying the effectiveness and superiority of our approach. Furthermore, the improvement of the owner-user benefits and the reduction of carbon emissions have verified that the environmental characteristics of electric vehicles require coordinated development with clean energy.

The extensive integration of distributed generation (DG) is one of the vital development trends in distribution networks. The reasonable configuration of energy storage systems is an essential means to enhance the ability of distribution networks to accept DG. This article considers the problem of power quality degradation caused by the high proportion of DG connected to the distribution network and establishes a multiobjective optimization configuration model for energy storage that minimizes voltage deviation, line loss rate, and optimal energy storage planning cost in the distribution network. Because of the shortcomings of the traditional optimization algorithms focusing on improving the performance of solving the multiobjective optimization of energy storage configurations, a method based on fast nondominated sorting and boundary crossing construction weight to set reference points is adopted to improve the marine predator algorithm and then solve multiobjective optimization model of energy storage in the distribution network to obtain the optimal grid connection position, rated capacity, and charging and discharging power of energy storage batteries in the distribution network during the scheduling period. By conducting numerical analysis on an IEEE-33 node system, the improved algorithm can effectively solve the energy storage configuration scheme that ensures stable operation of the distribution network at the optimal planning cost. Moreover, by comparing various intelligent optimization algorithms, the proposed improved algorithm has good convergence and distribution performance in solving multiobjective optimization configuration problems for energy storage.

Analyzing the characteristics of lithium batteries before failure is a complex task owing to their nature as electrochemical devices. Moreover, the limited number of failure samples in the production environment and the severe imbalance between positive and negative samples pose considerable challenges. To address these issues, this study proposes an improved online migration learning algorithm for early warning of high-voltage battery faults in batteries. First, to solve the problem of sample imbalance and reduce the use of computing resources, down-sampling technology is introduced. Specifically, a subsection down-sampling strategy is designed for the battery high-voltage fault early warning scenario. This strategy allows the algorithm model to learn more detailed features before the fault occurs. Second, an online transfer learning method based on batch incremental learning (homogeneous online transfer learning under incremental training, HomOTL-UIT) is proposed. This method addresses the need to update the offline classifier, which is trained in the source domain, at an appropriate time to adapt to the constantly changing data distribution in the target domain. Furthermore, it solves data distribution deviation issues and prevents the degeneration of online transfer learning into online learning. Batch incremental learning reduces the computing resource cost of multiple training, enabling continuous learning from the target domain and continuously improving the accuracy of offline classifiers over time. Then, a sliding window-based F₁-score scoring method is designed to solve the problem of the slow and unbalanced weight of the model to improve its accuracy. Finally, the validity and accuracy of the proposed method are verified using the operation data from an energy storage container. The results demonstrate its effectiveness, particularly when dealing with severely unbalanced positive and negative samples, thereby achieving an impressive F₁-score of 0.88.

Considering the increased energy density of the storage battery cabin, the proportion of thermal management energy consumption in the total auxiliary electricity consumption increases gradually. A thermal management control strategy based on an energy management system (EMS) planning curve is proposed in this study to achieve the desired low energy consumption and temperature difference with respect to the energy storage system. Moreover, the battery temperature is used to centrally control the air conditioning in the energy storage battery cabin. The effect of these strategies on cell temperature difference and air-conditioning power consumption was studied based on the experiment on the energy storage battery cabin with a capacity of 5.017 MWh. The results indicate that intrinsic cell inconsistency, module fan state, and air conditioning state all influence cell temperature difference. In the case of existing integration, using air conditioning has a negative effect on the temperature difference. Under the same charge and discharge power, compared with the experiment without control strategies, the cell temperature difference of battery stacks 1 and 2 decreased by 0.9 ℃ and 1.4 ℃, respectively. Benefited from the strategies, the total daily energy consumption of the air conditioning was reduced by 62% as there was no power consumption when on standby.

With the continuous application scale expansion of electrochemical energy storage systems, fire and explosion accidents often occur in electrochemical energy storage power plants that use lithium-ion batteries. This has become the main bottleneck restricting their safe and healthy development. The safety measures and placement spacing of energy storage containers have an essential impact on combustion and explosion development and diffusion. Herein, the impact of changes in shock wave pressure and flame propagation speed on the safety of energy storage containers was revealed by changing the ignition position and pressure relief plate strength. It was found that when the ignition point was located on the side near the inlet louver, the shock wave pressure and flame propagation speed increased, reaching 41.28 kPa and 557.0 m/s, respectively. It was also found that the pressure relief plate was crucial for safety design. When the pressure relief plate was only set at the inlet louver and the opening pressure was set to 30 kPa, the calculation area developed into detonation, causing a severe impact on surrounding safety. In addition, the results indicated that after a single energy storage tank underwent combustion and explosion, when the distance between the short sides reached 10 m, the impact on the surrounding area would be minimal. This study can provide a reference for fire accident warnings, container structure, and explosion-proof design of lithium-ion batteries in energy storage power plants.

Lithium titanate (LTO) batteries have potential applications in energy storage owing to their long cycling life and good thermal safety. However, limited studies have focused on the calendar aging of LTO batteries under high temperatures. The state of charge (SOC) and the environment temperature are generally recognized as the key parameters affecting the performance changes during the calendar aging process of LTO batteries. Herein, the evolution of electrochemical performance and the underlying mechanisms of commercial cylindrical LTO batteries were examined under high-temperature storage at different SOC levels (0%, 50%, and 100%) through accelerated aging experiments. The experimental results reveal a strong SOC dependence on the state of health of LTO batteries during high-temperature aging. Furthermore, the capacity evolution of batteries under various SOC levels shows different trends over time, driven by varying mechanisms. This study mainly reveals the influence of SOC on the performance of LTO batteries during high-temperature storage, providing valuable insights for future operation and maintenance of large-scale energy storage systems based on LTO batteries.

Understanding the thermal aspects of the battery electrochemical process is essential for managing the heat generated in lithium-ion batteries. Herein, an electrochemical-thermal coupled model was developed for an NMC lithium-ion battery. Experimental tests were conducted to validate the accuracy of the model in predicting voltage and temperature variations at different discharge rates and temperatures. Simulation studies were then conducted to estimate battery performance at different temperatures. At normal temperatures, regardless of the discharge rate, the NE heat generation was always smaller than the PE heat generation. While the NE polarization heat was higher than the PE polarization heat, the reversible heat absorption of NE was larger than that of PE. Consequently, the NE heat generation remained lower than that of PE. As the discharge rate increased, the proportion of PE heat generation decreased, whereas the proportion of NE heat generation increased first and then decreased. Simultaneously, the proportion of collector heat generation continued to rise. However, the heat generation characteristics differed when the battery discharge was discharged at subzero temperature compared to the normal temperature case. Firstly, subzero temperatures considerably increased the proportion of NE generation at low discharge rates. The reversible heat from NE became the primary contributor to the total reversible heat. Conversely, at high discharge rates, the NE heat generation rate decreased, while the PE heat generation rate exhibited the opposite trend. Secondly, the discharge time at subzero temperatures showed different trends with increasing discharge rates. At high discharge rates, the voltage rapidly decreased, leading to incomplete discharge and a phenomenon known as voltage rebound. At low discharge rates of 0.5—1 C discharge operation, the basic discharge process was completed, but the voltage rebound still occurred. The subzero temperature restricted the timely diffusion of lithium ions from the NE particles, leading to increased resistance and a rapid voltage drop. Meanwhile, a large amount of heat generation contributed to the temperature rise in the battery. Therefore, the battery exhibited the ability to rebound and maintain a continuous discharge at low rates.

The growing adoption of valley power and solar thermal utilization in civil construction has become crucial for the development and application of phase-change energy storage tanks. To address this need, this study focuses on the theoretical analysis of internal heat transfer in phase-change energy storage devices. It designed a phase-change energy storage tank for civil buildings, featuring a high-efficiency capillary heat exchanger as the core component. Furthermore, a performance testing experimental system was built to assess the thermal characteristics of the tank. Real-time temperature response data from industrial phase-change materials are recorded and analyzed to investigate the influence of the inlet temperature, flow rate, and flow direction of the hot and cold water on the thermal performance of the phase-change energy storage tank. The results show that compared to gravity flow at the same inlet temperature and flow rate, the heat transfer of the heat transfer fluid in counter-gravity flow is 1.1—1.2 times more efficient. Flow rate dominates the heat storage stage, while the inlet temperature considerably impacts the heat release stage. However, under the low flow rate condition, the outlet water temperature exhibits better continuous stability. For fulfilling the functional requirements of faster heat storage with a larger capacity and slower heat release with higher water temperature, it is recommended to set the inlet temperature of the working medium during the heat storage stage at 70—75 ℃. The recommended flow rate for the working medium in the capillary tube is 0.025—0.035 m/s. During the exothermic stage, the recommended flow rate in the capillary is within 0.020 m/s. In practical usage, a single unit of heat storage, operating twice under conditions of 30 ℃ and 85 L/h effluent, can meet the intermittent heating needs of a 20 m² room for one day and provide showering capacity for at least three people. This study provides valuable insights into the engineering application design and evaluation of domestic energy storage tanks.

The internal resistance of a battery affects its electrical performance and the temperature during its operation. Herein, the second-order equivalent circuit model (ECM) is established through the constant-current charge-discharge shelving test, which identifies the capacitance and resistance parameters of the cell under different currents, temperatures, and state-of-charge conditions, and calculates the electric performance of the cell. Additionally, Bernardi's heat generation model is introduced to account for the irreversible heat, and the combination of irreversible and reversible heat is calculated to determine the overall heat generation within the cell. By coupling the electric-thermal model in STAR-CCM+, the electrical and temperature responses of the battery are simulated under different working conditions. To overcome the shortcomings of the hybrid pulse power characterization test, such as short pulse time and incomplete characterization of internal resistance, this study adopts a constant-current charge-discharge shelving test to obtain the RC parameters and conducts an equivalent circuit simulation. The research results show that when the RC parameters obtained from the constant-current charge-discharge shelving test are imported into the electric-thermal coupling model, the simulation results have minimal deviation compared with the experimental results.

New energy systems have significant volatility and uncertainty, and the moment of inertia provided is limited. Large-scale grid connections of new energy systems lead to severe challenges in power system frequency regulation. Concurrently, in the asynchronous networking mode and with the continuous increase in DC scale, the system's moment of inertia is further reduced. Thus, energy storage and DC frequency limiting controllers (FLC) are required to improve the frequency control capability of the transmitting power grid under various disturbance scenarios. Therefore, a unified-frequency model was built based on the simulation data of a transmitting power grid to analyze the frequency modulation demand of the power grid under severe fault and conventional disturbance scenarios. On this basis, the joint optimization model for the energy storage controller and the DC FLC frequency modulation parameters was built for addressing frequency-related problems arising in various scenarios. By dynamically adjusting the frequency modulation parameters of the two, the system frequency modulation capability in different scenarios, the effect of frequency on the receiving power grid, and the frequency modulation economy were considered. Further, based on the model characteristics, a genetic algorithm was used to solve the optimization problem in a step-by-step manner and realize the comprehensive optimal design of the energy storage controller and the DC FLC frequency modulation parameters. Finally, the common disturbances pertaining to the transmitting power grid were simulated on the MATLAB simulation platform to verify the effect of optimization. The simulation results showed that the proposed method can not only take into account the frequency control of the transmitting and receiving power grids under various fault scenarios but also improve the frequency characteristics of the two power grids under conventional disturbance scenarios and the economy of frequency modulation.

In recent years, the electric vehicle industry in our country has developed rapidly, with emerging technologies such as vehicle-to-grid (V2G) gaining prominence in China's new electric power system and energy internet. V2G presents a future development trend owing to its low cost, scalability, and promising safety performance. Currently, the V2G technology is not fully developed, leading to a shortage of pilot projects, limited user engagement in V2G discharge behavior data, and insufficient analysis of V2G participation in the power market. To simulate electric vehicle discharge behavior more accurately and evaluate the economic and social benefits of V2G, electric vehicle (EV) users are further divided based on their idle time and willingness to accept discharge cutoff capacity. This allows us to establish discharge load curves for EV users with different preferences. Aiming at aggregator income, an optimization function model is established. Through the analysis of examples, we observed that different scheduling plans have varying demands for different types of EVs. Classification scheduling for different user groups is more beneficial than single-group modeling scheduling. Additionally, the optimization effect of different combinations of EV types is better than that of a single type. The carbon emission of EVs participating in V2G was evaluated and achieved a carbon reduction rate of 20% through optimization. Consequently, the optimized strategy enhances economic and social benefits compared with the original model.

The hydrogen sector has gained considerable attention in accelerating energy industry transformation owing to its zero pollution, high energy, rich resources, and versatile applications. However, the inherent instability and safety concerns of hydrogen, such as its susceptibility to burn and explode after leakage, pose challenges to its storage and transportation and overall cost-effectiveness. Efficient, economical, and safe hydrogen storage and transportation have become one of the main bottlenecks of the large-scale application of hydrogen technology. Among various storage and transportation technologies, high-pressure gaseous hydrogen storage technology is the most mature and widely used technology at present. By analyzing 2276 patents related to high-pressure gas hydrogen storage technology in 126 countries worldwide since 2003, we can know patent application trends, technological focus areas, monopolization tendencies, patent holders, market distribution, etc. This study aims to shed light on innovation heat, application trends, regional distribution, and the status of enterprises in the field, providing support for potential market entry, research directions, distribution points, etc. The analysis reveals that overall technological monopolies in this field are low. The technologies of considerable interest mainly revolved around high-pressure hydrogen storage containers, composite materials, aluminum alloys, etc. In the future, developing high-pressure gaseous hydrogen storage should focus on achieving lightweight, high-pressure solutions with low costs and stable quality. Although the number of new enterprises is increasing annually, the quantity of high-level technology patents remains limited. Therefore, expediting the technology application process and establishing technical barriers at the earliest opportunity is crucial. China has made substantial research and development investments in high-pressure hydrogen storage is large, indicating that the future domestic market competition is fierce.

The research and development (R&D) of electrochemical energy storage battery technology has attracted worldwide attention as a promising energy storage solution. However, a comprehensive and scientific analysis of its key technology topics, future R&D trends, and risk levels has been lacking owing to the complexity and extensiveness of this field. This study aims to bridge this gap using patent data to macroscopically analyze the application characteristics, identify technical topics using the latent Dirichlet allocation topic model, analyze topic evolution based on the post-discrete method, and assess the technology development risks using the Bayesian network model. The results show that there are 15 distinct technical topics within the field of electrochemical energy storage battery technology. The evolution trend of these topics is divided into ascending, stationary, and declining types. Analyzing patent quantities, industrial chains, and battery types, the global R&D efforts in this field show a continuous growth trend. Raw material-related technologies upstream of the electrochemical energy storage battery industry chain are the key field of R&D, although saturation or bottlenecks may be encountered. Meanwhile, processing-related technologies in the midstream field are gradually becoming a hot R&D direction. Furthermore, considering the industrial chain perspective, the assessment of technological development risks in the midstream processing field indicates a medium-level risk. Key risk factors include monopolizing key technologies, rising prices of upstream raw materials, lagging industry standards, and insufficient cooperation within the industrial chain. This study provides a useful reference for developing planning and R&D decision-making processes in electrochemical energy storage battery technology.