Search Results (438)

This study presents a hybrid method for state-of-charge (SOC) estimation of lithium-ion batteries using LSTM neural networks optimized with genetic algorithms (GA), combined with Coulomb Counting (CC) as an initial estimator. Experimental tests were conducted using medium-voltage (48–72 V) lithium-ion battery packs under standardized driving cycles (NEDC and WLTP). The proposed method enhances prediction accuracy under dynamic conditions by recalibrating the LSTM output with CC estimates through a dynamic fusion parameter $\alpha$. The novelty of this approach lies in the integration of machine learning and physical modeling, optimized via evolutionary algorithms, to address limitations of standalone methods in real-time applications. The hybrid model achieved a mean absolute error (MAE) of 0.181%, outperforming conventional estimation strategies. These findings contribute to more reliable battery management systems (BMS) for electric vehicles and second-life applications. Full article

Blasting is one of the most widely used and cost-effective techniques for rock excavation and fragmentation in open-pit mining, particularly for large-scale operations. However, repeated or poorly controlled blasting can generate excessive ground vibrations that threaten slope stability by causing structural damage, fracturing of the rock mass, and potential failure. Evaluating the effects of blast-induced vibrations is essential to ensure safe and sustainable mining operations. This study investigates the impact of blasting-induced vibrations on slope stability at the Saindak Copper-Gold Open-Pit Mine in Pakistan. A comprehensive dataset was compiled, including field-monitored ground vibration measurements—specifically peak particle velocity (PPV) and key blast design parameters such as spacing (S), burden (B), stemming length (SL), maximum charge per delay (MCPD), and distance from the blast point (D). Geomechanical properties of slope-forming rock units were validated through laboratory testing. Slope stability was analyzed using pseudo-static limit equilibrium methods (LEMs) based on the Mohr–Coulomb failure criterion, employing four approaches: Fellenius, Janbu, Bishop, and Spencer. Pearson and Spearman correlation analyses quantified the influence of blasting parameters on slope behavior, and sensitivity analysis determined the cumulative distribution of slope failure and dynamic response under increasing seismic loads. FoS values were calculated for both east and west pit slopes under static and dynamic conditions. Among all methods, Spencer consistently yielded the highest FoS values. Under static conditions, FoS was 1.502 for the east slope and 1.254 for the west. Under dynamic loading, FoS declined to 1.308 and 1.102, reductions of 12.9% and 11.3%, respectively, as calculated using the Spencer method. The east slope exhibited greater stability due to its gentler angle. Correlation analysis revealed that burden had a significant negative impact (r = −0.81) on stability. Sensitivity analysis showed that stability deteriorates notably when PPV exceeds 10.9 mm/s. Although daily blasting did not critically compromise stability, the west slope showed greater vulnerability, underscoring the need for stricter control of blasting energy to mitigate vibration-induced instability and promote long-term operational sustainability. Full article

This paper presents the electrical characterization of a flexible supercapacitor with a unique architecture incorporating a piezoelectric PVDF-TrFE film sandwiched between PEDOT:PSS:Graphene and LiTaO₃ as a charge-generating and charge-transferring layer. Impedance spectroscopy measurements reveal frequency-dependent capacitance behavior, reflecting the contributions of both piezoelectric and supercapacitor capacitances. Charge–discharge cycling tests demonstrate the device’s energy storage capabilities and indicate a potential enhancement through the piezoelectric effect. Supercapacitor cycling tests demonstrate the device’s energy storage capabilities, with an estimated specific capacitance of 10.14 F/g, a power density of 16.3 W/g, an energy density of 5.63 Wh/kg, and a Coulombic efficiency of 96.1% from an active area of 1 cm². The proposed structure can serve as an independent harvester and storage for low-power, wearable sensors. Full article

Lanthanide perovskite materials are promising candidates for supercapacitor applications. In this study, a series of La_1−xCa_xCrO₃ (x = 0–0.2) materials were prepared by sol-gel method, incorporating bivalent ions calcium at A-site. La_0.85Ca_0.15CrO₃ exhibited the lowest charge transfer resistance and highest specific surface area. At 1 A/g, La_0.85Ca_0.15CrO₃ achieved a maximum specific capacitance of 306 F/g, about 2.3 times higher than that of the LaCrO₃ (133 F/g). Based on the observed data, a mechanism involving oxygen anion charge storage during the charging-discharging process is proposed. After 5000 long cycle, the coulomb efficiency of the electrode remains above 94%. These results demonstrate that Ca-substituted compounds exhibit significant potential for A-site engineering in supercapacitor applications. Full article

Accurate State of Charge (SOC) estimation is critical for optimizing the performance and longevity of lithium-ion batteries (LIBs), which are widely used in applications ranging from electric vehicles to renewable energy storage. Traditional SOC estimation methods, such as Coulomb counting and open-circuit voltage measurement, suffer from cumulative errors and slow response times. This paper proposes a novel machine learning-based approach for SOC estimation by integrating Electrochemical Impedance Spectroscopy (EIS) with the SHapley Additive exPlanations (SHAP) method, Atom Search Optimization (ASO), and Light Gradient Boosting Machine (LightGBM). This study focuses on large-capacity lithium iron phosphate (LFP) batteries (3.2 V, 104 Ah), addressing a gap in existing research. EIS data collected at various SOC levels and temperatures were processed using SHAP for feature extraction (FE), and the ASO–LightGBM model was employed for SOC prediction. Experimental results demonstrate that the proposed SHAP–ASO–LightGBM method significantly improves estimation accuracy, achieving an RMSE of 3.3%, MAE of 1.86%, and R² of 0.99, outperforming traditional methods like LSTM and DNN. The findings highlight the potential of EIS and machine learning (ML) for robust SOC estimation in large-capacity LIBs. Full article

Inconsistencies in lithium-ion battery packs pose significant challenges for both electric vehicles and energy storage systems, causing diminished energy utilization and accelerated battery aging. This study investigates the characteristics and aging processes of 32 batteries, creating simulation models for cells and packs based on experimental data. Through a controlled single-variable approach, the decoupled analysis of multi-parameter inconsistencies is carried out. Simulation results demonstrate that parallel-connected packs can maintain charge consistency without the need for external balancing systems, thanks to their self-balancing mechanisms. On the other hand, series-connected packs experience accelerated capacity degradation primarily due to charge inconsistencies linked to differences in Coulombic efficiency (CE) and the initial state of charge (SOC). For packs with minor capacity variations and temperature inconsistencies, a passive balancing current of 0.001 C can effectively eliminate up to 3.8% of capacity loss caused by charge inconsistencies within 15 cycles. Active balancing systems outperform passive ones primarily when there is significant capacity inconsistency. However, for packs that have undergone capacity screening before assembly, both active and passive balancing systems prove to be equally effective. Additionally, inconsistencies in internal resistance have a minimal impact on overall pack capacity but limit the power of both series-connected and parallel-connected packs. These findings offer essential insights for the development of balancing systems within battery management systems. Full article

Lithium-ion batteries (LIBs) are widely deployed in electric vehicles due to their high energy density and long cycle life. Even after retirement, typically at around 80% of their rated capacity, LIBs can still be repurposed for second-life applications such as residential energy storage systems (ESSs). However, effectively grouping these heterogeneous cells is crucial to optimizing performance of the module. Retired LIBs can be effectively repurposed for numerous second-life applications such as ESSs, and other power backups. In this paper, we compare four clustering approaches including random grouping, equal-number Support Vector Clustering, K-means, and an equal-number Gaussian Mixture Model (GMM) to organize 60 retired cells into 48 V modules consisting of 15-cell groups. We verify the performance of each method via simulations of a 15S2P configuration, focusing on the standard deviation of final charge voltage, average charge throughput, delta capacity, and coulombic efficiency. Based on the evaluation metrics analyzed after regrouping the battery cells and simulating them for second-life ESS applications, the GMM-based clustering method demonstrates better performance. Full article

This study explores the feasibility of producing biohydrogen from winery wastewater using a dual-chamber microbial electrolysis cell (MEC). A mixed microbial consortium pre-adapted to heavy-metal environments and enriched with Geobacter sulfurreducens was anaerobically cultivated from diverse waste streams. Over 5000 h of development, the MEC system was progressively adapted to winery wastewater, enabling long-term electrochemical stability and high organic matter degradation. Upon winery wastewater addition (5% v/v), the system achieved a sustained hydrogen production rate of (0.7 ± 0.3) L H₂ L⁻¹ d⁻¹, with an average current density of (60 ± 4) A m⁻³, and COD removal efficiency exceeding 55%, highlighting the system’s resilience despite the presence of inhibitory compounds. Coulombic efficiency and cathodic hydrogen recovery reached (75 ± 4)% and (87 ± 5)%, respectively. Electrochemical impedance spectroscopy provided mechanistic insight into charge transfer and biofilm development, correlating resistive parameters with biological adaptation. These findings demonstrate the potential of MECs to simultaneously treat agro-industrial wastewaters and recover energy in the form of hydrogen, supporting circular resource management strategies. Full article

Na₂Ti₃O₇ (NTO), with low sodium insertion potential (~0.3 V vs. Na⁺/Na) and potential for high-energy-density batteries, is regarded as one of the most promising anode materials for sodium-ion batteries (SIBs). However, its practical application is hindered by poor electronic conductivity, sluggish Na⁺ (de)intercalation kinetics, and interfacial instability, leading to inferior cycling stability, low initial Coulombic efficiency, and poor rate capability. In this work, micron-sized rod-like NTO and Al-doped NTO (NTO-Al) samples were synthesized via a one-step high-temperature solid-state method. Al doping slightly reduced the size of NTO microrods while introducing oxygen vacancies and generating Ti³⁺, thereby enhancing electronic conductivity and reducing ionic diffusion resistance. H₂-TPR confirms that doping activates lattice oxygen and promotes its participation in the reaction. The optimized NTO-Al0.03 electrode delivered a significantly improved initial charge capacity of 147.4 mA h g⁻¹ at 0.5 C, surpassing pristine NTO (124.7 mA h g⁻¹). Moreover, it exhibited the best cycling stability (49.5% capacity retention after 100 cycles) and rate performance (36.3 mA h g⁻¹ at 2 C). Full article

Metal sulfides are promising anode candidates for sodium–ion batteries (SIBs) due to their high theoretical capacities. However, their practical application is limited by significant volume extension and sluggish Na⁺ diffusion during cycling, which lead to rapid capacity degradation and poor long-term stability. In this work, we report the rational design of a hollow triple-shelled high-entropy sulfide (NaFeZnCoNiMn)₉S₈, synthesized through sequential templating method under hydrothermal conditions. Transmission electron microscopy confirms its well-defined three-shelled architecture. The inter-shell voids effectively buffer Na⁺ insertion/desertion-induced volume extension, while the tailored high-entropy matrix enhances electronic conductivity and accelerates Na⁺ transport. This synergistic design yields outstanding performance, including a high initial Coulombic efficiency (ICE) of 94.1% at 0.1 A g⁻¹, low charge-transfer resistance (0.32~2.54 Ω), fast Na⁺ diffusion efficiency (10^−8.5–10^−10.5 cm² s⁻¹), and reversible capacity of 582.6 mAh g⁻¹ after 1600 cycles at 1 A g⁻¹ with 91.2% capacity retention. These results demonstrate the potential of high-entropy, multi-shelled architectures as a robust platform for next-generation durable SIB anodes. Full article

Accurate estimation of the state of charge (SOC) is important for the effective management and utilization of lithium-ion battery packs. While advanced estimation methods present in scientific literature commonly rely on detailed cell parameters and laboratory-controlled conditions, practical engineering applications often require solutions applicable to battery packs with unknown or limited internal characteristics. In this context, this study compares three different SOC estimation strategies—voltage-based, coulomb counting, and charge balance methods—implemented in an independent telemetry module (TIO) and their performance against a commercial battery management system (Orion BMS2). Experimental results demonstrate that the voltage-based method provides insufficient accuracy due to its inherent sensitivity to voltage thresholds and internal resistance under load conditions. Conversely, coulomb counting, with periodic recalibration through full charging cycles, showed significantly improved accuracy, closely matching the Orion BMS2 outputs when properly initialized. The results confirm the viability of coulomb counting as a pragmatic approach for battery packs lacking detailed cell data. Future research should address reducing dependency on periodic full-charge resets by incorporating adaptive estimation techniques, such as Kalman filtering or observers, and leveraging open-circuit voltage measurements and temperature compensation to further enhance accuracy while maintaining the simplicity and external applicability of the monitoring system. Full article

This study aims to develop high-performance nickel selenide (NiSe) electrodes via a controlled electrodeposition approach, optimizing the number of deposition cycles to enhance electrochemical energy storage capabilities. Nickel selenide electrodes were synthesized at varying electrodeposition cycles (2CY–5CY) and systematically evaluated in both three-electrode and asymmetric supercapacitor (ASC) configurations to determine the optimal cycle for superior performance. Among all, the NiSe-3CY electrode demonstrated the best electrochemical characteristics, delivering a high specific capacitance of 507.42 F/g in a three-electrode setup. It also achieved an energy density of 22.89 Wh/kg and a power density of 584.61 W/kg, outperforming its 2CY, 4CY, and 5CY counterparts. Notably, the 3CY electrode exhibited the lowest series resistance (1.59 Ω), indicative of enhanced charge transport and minimal internal resistance. When integrated into an ASC device (NiSe-3CY//activated carbon), it maintained a specific capacitance of 18.78 F/g, with an energy density of 8.45 Wh/kg and power density of 385.03 W/kg. Furthermore, the device exhibited impressive areal and volumetric capacitances of 351 mF/cm² and 1.09 F/cm³, respectively, with a corresponding volumetric energy density of 0.49 mWh/cm³. Long-term cycling tests revealed excellent durability, retaining 91% of its initial capacity after 10k cycles with a high Coulombic efficiency of 99%. These results confirm that the 3CY electrode is a highly promising candidate for next-generation energy storage systems, offering a balanced combination of high capacitance, energy density, and cycling stability. Full article

Pre-lithiation using Li–Si alloy-type additives is a promising technical approach to address the drawbacks of Si-based anodes, such as a low initial Coulombic efficiency (ICE) and inevitable capacity decay during cycling. However, its commercial application is limited by the air sensitivity of the highly reactive Li–Si alloys, which demands improved environmental stability. In this work, a protective membrane is constructed on Li₁₃Si₄ alloys using low-surface-energy paraffin and highly conductive carbon nanotubes through liquid-phase deposition, exhibiting enhanced hydrophobicity and improved Li⁺/e⁻ conductivity. The Li₁₃Si₄@Paraffin/carbon nanotubes (Li₁₃Si₄@P-CNTs) composite achieves a high pre-lithiation capacity of 970 mAh g⁻¹ and superb environmental stability, retaining 92.2% capacity after exposure to ambient air with 45% relative humidity. DFT calculations and in situ XRD measurements reveal that the paraffin-dominated coating membrane, featuring weak dipole–dipole interactions with water molecules, effectively reduces the moisture-induced oxidation kinetics of Li₁₃Si₄@P-CNTs in air. Electrochemical kinetic analysis and XPS depth profiling reveal the enhancement in charge transfer dynamics and surface Li⁺ transport kinetics (SEI rich in inorganic lithium salts) in P-SiO@C pre-lithiated by Li₁₃Si₄@P-CNTs pre-lithiation additives. Benefitting from pre-lithiation via Li₁₃Si₄@P-CNTs, the pre-lithiated SiO@C(P-SiO@C) delivers high ICE (103.7%), stable cycling performance (981 mAh g⁻¹ at 200 cycles) and superior rate performance (474.5 mAh g⁻¹ at 3C) in a half-cell system. The LFP||P-Gr pouch-type full cell exhibits a capacity retention of 83.2% (2500 cycles) and an energy density of 381 Wh kg⁻¹ after 2500 cycles. The Li₁₃Si₄@P-CNTs additives provide valuable design concepts for the development of pre-lithiation materials. Full article

We determine the interaction energy of electric monopole pairs, sources and sinks of a Coulombic field. These charges are represented by topological solitons of finite size and mass, described by a field of SO(3) rotations without any divergences. Such monopoles feel, at large distances, a pure Coulombic interaction. A crucial test for the physical interpretation of these monopoles is a classical running of the charge at small distances, expected from the finite soliton size. We investigate in detail a first observation of the increase in the effective charge at distances of a few soliton radii in this purely Coulombic system and compare it with the running of the coupling in perturbative QED. Full article

Battery energy storage systems (BESSs) are often used in partial-state-of-charge (PSOC) operation due to the desire for flexibility of charge and discharge. Lead–acid batteries are a good candidate to be used in battery energy storage due to their safety, recyclability, and long cycle life; however, the correct battery, cell, and regime should be chosen to ensure effective use. Manufacturers rarely publish data on PSOC performance of their batteries. During PSOC use, the charge acceptance of lead–acid batteries reduces both reversibly and, sometimes, irreversibly as the battery is cycled. Typical dynamic charge acceptance tests target the performance required in car batteries and do not adequately demonstrate the charge acceptance expected in BESS use. This paper demonstrates a representative charge acceptance degradation test which far more closely replicates the charge acceptance degradation seen in real-world PSOC BESS use using partial state of charge, coulomb control, and a charge-factor-controlled full charge. Full charges are shown to reverse the internal resistance associated with partial-state-of-charge operation. This is the case in the Leoch lead–carbon cells and 12 V battery tested. This shows that partial-state-of-charge operation degrades the charge acceptance and increases the internal resistance of a lead–acid battery, although with a charge-factor-based full-charge approach, the charge acceptance could be reset to baseline. Full article