Batteries

12 pages, 1955 KB

Open AccessArticle

A MOF-Mediated Strategy for In Situ Niobium Doping and Synthesis of High-Performance Single-Crystal Ni-Rich Cathodes

by Yinkun Gao, Huazhang Zhou, Shumin Liu, Shuyun Guan, Mingyang Liu, Peng Gao, Yongming Zhu and Xudong Li

Batteries 2025, 11(10), 368; https://doi.org/10.3390/batteries11100368 (registering DOI) - 5 Oct 2025

Abstract

The development of single-crystal Ni-rich layered cathode materials (SC-NCMs) is regarded as an effective strategy to address the mechanical failure issues commonly associated with polycrystalline counterparts. However, the industrial production of SC-NCM faces challenges such as lengthy processing steps, high manufacturing costs, and [...] Read more.

The development of single-crystal Ni-rich layered cathode materials (SC-NCMs) is regarded as an effective strategy to address the mechanical failure issues commonly associated with polycrystalline counterparts. However, the industrial production of SC-NCM faces challenges such as lengthy processing steps, high manufacturing costs, and inconsistent product quality. In this study, we innovatively propose a metal/organic framework (MOF)-mediated one-step synthesis strategy to achieve controllable structural preparation and in situ Nb⁵⁺ doping in SC-NCM. Using a Ni–Co–Mn-based MOF as both precursor and self-template, we precisely regulated the thermal treatment pathway to guide the nucleation and oriented growth of high-density SC-NCM particles. Simultaneously, Nb⁵⁺ was pre-anchored within the MOF framework, enabling atomic-level homogeneous doping into the transition metal layers during crystal growth. Exceptional electrochemical performance is revealed in the in situ Nb-doped SC-NCM, with an initial discharge capacity reaching 176 mAh/g at a 1C rate and a remarkable capacity retention of 86.36% maintained after 200 cycles. This study paves a versatile and innovative pathway for the design of high-stability, high-energy-density cathode materials via a MOF-mediated synthesis strategy, enabling precise manipulation of both morphology and chemical composition. Full article

(This article belongs to the Section Battery Materials and Interfaces: Anode, Cathode, Separators and Electrolytes or Others)

13 pages, 2030 KB

Open AccessArticle

Electrode Capacity Balancing for Accurate Battery State of Health Prediction and Degradation Analysis

by Jianghui Wen, Yu Zhu and Shixue Wang

Batteries 2025, 11(10), 367; https://doi.org/10.3390/batteries11100367 - 3 Oct 2025

Abstract

Battery technology plays an increasingly vital role in portable electronic devices, electric vehicles, and renewable energy storage. During operation, batteries undergo performance degradation, which not only reduces device efficiency, but may also pose safety risks. The State of Health (SOH) is a crucial [...] Read more.

Battery technology plays an increasingly vital role in portable electronic devices, electric vehicles, and renewable energy storage. During operation, batteries undergo performance degradation, which not only reduces device efficiency, but may also pose safety risks. The State of Health (SOH) is a crucial indicator for assessing battery condition. Traditional SOH prediction methods face limitations in real-time adjustment and accuracy under complex operating conditions. By determining electrode capacity loss and identifying complex patterns that traditional methods struggle to detect, prediction accuracy can be improved. Based on electrode capacity matching and compensation relationships, this paper proposes an electrode capacity balance model to evaluate battery development trends and degradation during cycling. We use q_Li − q_p state assessment as a trend criterion, q_p to quantify aging, and Q_c to identify thermal runaway risk levels, developing more efficient SOH prediction indicators and methods to ensure battery safety and performance. Full article

(This article belongs to the Special Issue State-of-Health Estimation of Batteries)

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15 pages, 3687 KB

Open AccessArticle

Evaluating the Status of Lithium-Ion Cells Without Historical Data Using the Distribution of Relaxation Time Method

by Muhammad Sohaib and Woojin Choi

Batteries 2025, 11(10), 366; https://doi.org/10.3390/batteries11100366 - 2 Oct 2025

Abstract

In this paper, Distribution of Relaxation Time (DRT) analysis is presented as a powerful tool for understanding the aging mechanisms in lithium-ion batteries, with a focus on its application to estimating the State of Health (SOH). A novel parameter, the characteristic relaxation time, [...] Read more.

In this paper, Distribution of Relaxation Time (DRT) analysis is presented as a powerful tool for understanding the aging mechanisms in lithium-ion batteries, with a focus on its application to estimating the State of Health (SOH). A novel parameter, the characteristic relaxation time, derived from DRT analysis, is introduced to enhance SOH estimation. By analyzing the ratio of the central relaxation time (τ) between the charge transfer and diffusion peaks, the battery status can be determined without the need for historical data. Experimental data from lithium-ion batteries, including 18650 cells and LR2032 coin cells, were examined until the end of their life. Nyquist and DRT plots across various frequency ranges revealed consistent aging trends, particularly in the charge transfer and diffusion processes. These processes appeared as shifting and merging peaks in the DRT plots, signifying progressive degradation. A polynomial equation fitted to the τ ratio graph achieved a high accuracy (Adj. R² = 0.9994), enabling reliable battery lifespan prediction. Validation with a Samsung Galaxy S9+ battery demonstrated that the method could estimate its remaining life, predicting a total lifespan of approximately 2100 cycles (compared to 1000 cycles already completed). These results confirm that SOH estimation is feasible without prior data and highlight the potential of DRT analysis for accurate and quantitative prediction of battery longevity. Full article

(This article belongs to the Special Issue Toward Next-Generation Rechargeable Lithium-Ion Batteries: Current Status and Future Prospects)

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13 pages, 1846 KB

Open AccessArticle

Toward Circular Carbon: Upcycling Coke Oven Waste into Graphite Anodes for Lithium-Ion Batteries

by Seonhui Choi, Inchan Yang, Byeongheon Lee, Tae Hun Kim, Sei-Min Park and Jung-Chul An

Batteries 2025, 11(10), 365; https://doi.org/10.3390/batteries11100365 - 2 Oct 2025

Abstract

This study presents a sustainable upcycling strategy to convert “Pit,” a carbon-rich coke oven by-product from steel manufacturing, into high-purity graphite for use as an anode material in lithium-ion batteries. Despite its high carbon content, raw Pit contains significant impurities and has irregular [...] Read more.

This study presents a sustainable upcycling strategy to convert “Pit,” a carbon-rich coke oven by-product from steel manufacturing, into high-purity graphite for use as an anode material in lithium-ion batteries. Despite its high carbon content, raw Pit contains significant impurities and has irregular particle morphology, which limits its direct application in batteries. We employed a multi-step, additive-free refinement process—including jet milling, spheroidization, and high-temperature graphitization—to enhance carbon purity and structural properties. The processed Pit-derived graphite showed a much-improved particle size distribution (D50 reduced from 25.3 μm to 14.8 μm & Span reduced from 1.72 to 1.23), increased tap density (from 0.54 to 0.80 g/cm³), and reduced BET surface area, making it suitable for high-performance lithium-ion batteries anodes. Structural characterization by XRD and TEM confirmed dramatically enhanced crystallinity after graphitization (graphitization degree increasing from ~13 for raw Pit to 95.7% for graphitized Pit at 3000 °C). The fully processed graphite (denoted S_Pit3000) delivered a reversible discharge capacity of 346.7 mAh/g with an initial Coulombic efficiency of 93.5% in half-cell tests—comparable to commercial artificial graphite. Furthermore, when composited with silicon oxide to form a hybrid anode, the material achieved an even higher capacity of 418.0 mAh/g under high mass loading conditions. These results highlight the feasibility of transforming industrial coke waste into value-added electrode materials through environmentally friendly physical processes. The upcycled graphite anode meets industrial performance standards, demonstrating a promising route toward circular economy solutions in both the steel and battery industries. Full article

(This article belongs to the Section Battery Materials and Interfaces: Anode, Cathode, Separators and Electrolytes or Others)

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46 pages, 1449 KB

Open AccessReview

MXenes in Solid-State Batteries: Multifunctional Roles from Electrodes to Electrolytes and Interfacial Engineering

by Francisco Márquez

Batteries 2025, 11(10), 364; https://doi.org/10.3390/batteries11100364 - 2 Oct 2025

Abstract

MXenes, a rapidly emerging family of two-dimensional transition metal carbides and nitrides, have attracted considerable attention in recent years for their potential in next-generation energy storage technologies. In solid-state batteries (SSBs), they combine metallic-level conductivity (>10³ S cm⁻¹), adjustable surface [...] Read more.

MXenes, a rapidly emerging family of two-dimensional transition metal carbides and nitrides, have attracted considerable attention in recent years for their potential in next-generation energy storage technologies. In solid-state batteries (SSBs), they combine metallic-level conductivity (>10³ S cm⁻¹), adjustable surface terminations, and mechanical resilience, which makes them suitable for diverse functions within the cell architecture. Current studies have shown that MXene-based anodes can deliver reversible lithium storage with Coulombic efficiencies approaching ~98% over 500 cycles, while their use as conductive additives in cathodes significantly improves electron transport and rate capability. As interfacial layers or structural scaffolds, MXenes effectively buffer volume fluctuations and suppress lithium dendrite growth, contributing to extended cycle life. In solid polymer and composite electrolytes, MXene fillers have been reported to increase Li⁺ conductivity to the 10⁻³–10⁻² S cm⁻¹ range and enhance Li⁺ transference numbers (up to ~0.76), thereby improving both ionic transport and mechanical stability. Beyond established Ti-based systems, double transition metal MXenes (e.g., Mo₂TiC₂, Mo₂Ti₂C₃) and hybrid heterostructures offer expanded opportunities for tailoring interfacial chemistry and optimizing energy density. Despite these advances, large-scale deployment remains constrained by high synthesis costs (often exceeding USD 200–400 kg⁻¹ for Ti₃C₂T_x at lab scale), restacking effects, and stability concerns, highlighting the need for greener etching processes, robust quality control, and integration with existing gigafactory production lines. Addressing these challenges will be crucial for enabling MXene-based SSBs to transition from laboratory prototypes to commercially viable, safe, and high-performance energy storage systems. Beyond summarizing performance, this review elucidates the mechanistic roles of MXenes in SSBs—linking lithiophilicity, field homogenization, and interphase formation to dendrite suppression at Li|SSE interfaces, and termination-assisted salt dissociation, segmental-motion facilitation, and MWS polarization to enhanced electrolyte conductivity—thereby providing a clear design rationale for practical implementation. Full article

(This article belongs to the Collection Feature Papers in Batteries)

12 pages, 2321 KB

Open AccessCommunication

Intergranular Crack of Cathode Materials in Lithium-Ion Batteries Subjected to Rapid Cooling During Transient Thermal Runaway

by Siqi Li, Changchun Ye, Ming Jin, Guobin Zhong, Shi Liu, Yajie Liu and Zhixin Tai

Batteries 2025, 11(10), 363; https://doi.org/10.3390/batteries11100363 - 30 Sep 2025

Abstract

In metallurgy, the quenching process often induces changes in certain material properties, such as hardness and ductility, through the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids. Given that lithium-ion batteries operate under relatively benign conditions, conventional [...] Read more.

In metallurgy, the quenching process often induces changes in certain material properties, such as hardness and ductility, through the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids. Given that lithium-ion batteries operate under relatively benign conditions, conventional rapid cooling does not significantly affect the property variations in their internal electrode materials during normal use. However, thermal runaway presents an exception due to its dramatic temperature fluctuations from room temperature to several hundred degrees Celsius. In this study, we investigated NCM811 cathodes in 18,650 batteries subjected to transient thermal runaway followed by rapid cooling using several advanced analytical techniques. The results reveal a phenomenon characterized by intergranular cracking within NCM811 cathode materials when exposed to rapid cooling during transient thermal runaway. Furthermore, lithium-ion cells utilizing reused NCM-182.4 electrodes in fresh electrolyte demonstrate a reversible capacity of 231.4 mAh/g after 30 cycles at 0.1 C, highlighting the potential for reusing NCM811 cathodes in the lithium-ion battery recycling process. These findings not only illustrate that NCM811 particles may experience intergranular cracking when subjected to rapid cooling during transient thermal runaway, but also the rapidly cooled NCM811 electrodes exhibit potential for reuse. Full article

(This article belongs to the Special Issue Battery Interface: Analysis & Design)

26 pages, 1452 KB

Open AccessArticle

A Smart Evolving Fuzzy Predictor with Customized Firefly Optimization for Battery RUL Prediction

by Mohamed Ahwiadi and Wilson Wang

Batteries 2025, 11(10), 362; https://doi.org/10.3390/batteries11100362 - 30 Sep 2025

Abstract

Accurate prediction of system degradation and remaining useful life (RUL) is essential for reliable health monitoring of Lithium-ion (Li-ion) batteries, as well as other dynamic systems. While evolving systems can offer adequate adaptability to the nonstationary and nonlinear behavior of battery degradation, existing [...] Read more.

Accurate prediction of system degradation and remaining useful life (RUL) is essential for reliable health monitoring of Lithium-ion (Li-ion) batteries, as well as other dynamic systems. While evolving systems can offer adequate adaptability to the nonstationary and nonlinear behavior of battery degradation, existing methods often face challenges such as uncontrolled rule growth, limited adaptability, and reduced accuracy under noisy conditions. To address these limitations, this paper presents a smart evolving fuzzy predictor with customized firefly optimization (SEFP-FO) to provide a better solution for battery RUL prediction. The proposed SEFP-FO technique introduces two main contributions: (1) An activation- and distance-aware penalization strategy is proposed to govern rule evolution by evaluating the structural relevance of incoming data. This mechanism can control rule growth while maintaining model convergence. (2) A customized firefly algorithm is suggested to optimize the antecedent parameters of newly generated fuzzy rules, thereby enhancing prediction accuracy and improving the predictor’s adaptive capability to time-varying system conditions. The effectiveness of the proposed SEFP-FO technique is first validated by simulation using nonlinear benchmark datasets, which is then applied Full article

(This article belongs to the Special Issue Artificial Intelligence and Batteries: AI-Powered Innovations in Battery Technology)

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35 pages, 5230 KB

Open AccessArticle

Electrochemical Performances of Li-Ion Batteries Based on LiFePO₄ Cathodes Supported by Bio-Sourced Activated Carbon from Millet Cob (MC) and Water Hyacinth (WH)

by Wend-Waoga Anthelme Zemane and Oumarou Savadogo

Batteries 2025, 11(10), 361; https://doi.org/10.3390/batteries11100361 - 30 Sep 2025

Abstract

The electrochemical performance of Li-ion batteries employing LiFePO₄ (LFP) cathodes supported by bio-sourced activated carbon derived from millet cob (MC) and water hyacinth (WH) were systematically investigated. Carbon activation was carried out using potassium hydroxide (KOH) at varying mass ratios of KOH [...] Read more.

The electrochemical performance of Li-ion batteries employing LiFePO₄ (LFP) cathodes supported by bio-sourced activated carbon derived from millet cob (MC) and water hyacinth (WH) were systematically investigated. Carbon activation was carried out using potassium hydroxide (KOH) at varying mass ratios of KOH to precursor material: 1:1, 2:1, and 5:1 for both WH and MC-derived carbon. The physical properties (X-ray diffraction patterns, BET surface area, micropore and mesopore volume, conductivity, etc.) and electrochemical performance (specific capacity, discharge at various current rates, electrochemical impedance measurement, etc.) were determined. Material characterization revealed that the activated carbon derived from MC exhibits an amorphous structure, whereas that obtained from WH is predominantly crystalline. High specific surface areas were achieved with activated carbons synthesized using a low KOH-to-carbon mass ratio (1:1), reaching 413.03 m²·g⁻¹ for WH and 216.34 m²·g⁻¹ for MC. However, larger average pore diameters were observed at higher activation ratios (5:1), measuring 8.38 nm for KOH/WH and 5.28 nm for KOH/MC. For both biomass-derived carbons, optimal electrical conductivity was obtained at a 2:1 activation ratio, with values of 14.7 × 10⁻³ S·cm⁻¹ for KOH/WH and 8.42 × 10⁻³ S·cm⁻¹ for KOH/MC. The electrochemical performance of coin cells based on cathodes composed of 85% LiFePO₄, 8% of these activated carbons, and 7% polyvinylidene fluoride (PVDF) as a binder, with lithium metal as the anode were studied. The LiFePO₄/C (LFP/C) cathodes exhibited specific capacities of up to 160 mAh·g⁻¹ at a current rate of C/12 and 110 mAh·g⁻¹ at 5C. Both LFP/MC and LFP/WH cathodes exhibit optimal energy density at specific values of pore size, pore volume, charge transfer resistance (R_ct), and diffusion coefficient (D_Li), reflecting a favorable balance between ionic transport, accessible surface area, and charge conduction. Maximum energy densities relative to active mass were recorded at 544 mWh·g⁻¹ for LFP/MC 2:1, 554 mWh·g⁻¹ for LFP/WH 2:1, and 568 mWh·g⁻¹ for the reference LFP/graphite system. These performance results demonstrate that the development of high-performing bio-sourced activated carbon depends on the optimization of various parameters, including chemical composition, specific surface area, pore volume and size distribution, as well as electrical conductivity. Full article

(This article belongs to the Special Issue Advanced Carbon-Based Materials for Next-Generation Batteries and Supercapacitors)

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16 pages, 2423 KB

Open AccessArticle

Numerical Simulation Study and Stress Prediction of Lithium-Ion Batteries Based on an Electrochemical–Thermal–Mechanical Coupled Model

by Juanhua Cao and Yafang Zhang

Batteries 2025, 11(10), 360; https://doi.org/10.3390/batteries11100360 - 29 Sep 2025

Abstract

In lithium-ion batteries, the fracture of active particles that are under stress is a key cause of battery aging, which leads to a reduction in active materials, an increase in internal resistance, and a decay in battery capacity. A coupled electrochemical–thermal–mechanical model was [...] Read more.

In lithium-ion batteries, the fracture of active particles that are under stress is a key cause of battery aging, which leads to a reduction in active materials, an increase in internal resistance, and a decay in battery capacity. A coupled electrochemical–thermal–mechanical model was established to study the concentration and stress distributions of negative electrode particles under different charging rates and ambient temperatures. The results show that during charging, the maximum lithium-ion concentration occurs on the particle surface, while the minimum concentration appears at the particle center. Moreover, as the temperature decreases, the concentration distribution of negative electrode active particles becomes more uneven. Stress analysis indicates that when charging at a rate of 1C and 0 °C, the maximum stress of particles at the negative electrode–separator interface reaches 123.7 MPa, while when charging at 30 °C, the maximum particle stress is 24.3 MPa. The maximum shear stress occurs at the particle center, presenting a tensile stress state, while the minimum shear stress is located on the particle surface, showing a compressive stress state. Finally, to manage the stress of active materials in lithium-ion batteries while charging for health maintenance, this study uses a DNN (Deep Neural Network) to predict the maximum shear stress of particles based on simulation results. The predicted indicators, MAE (Mean Absolute Error) and RMSE (Root Mean Square Error), are 0.034 and 0.046, respectively. This research is helpful for optimizing charging strategies based on the stress of active materials in lithium-ion batteries during charging, inhibiting battery aging and improving safety performance. Full article

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15 pages, 1772 KB

Open AccessArticle

Towards a Porous Zinc Anode Design for Enhanced Durability in Alkaline Zinc–Air Batteries

by Sarmila Dutta, Yasin Emre Durmus, Eunmi Im, Hans Kungl, Hermann Tempel and Rüdiger-A. Eichel

Batteries 2025, 11(10), 359; https://doi.org/10.3390/batteries11100359 - 29 Sep 2025

Abstract

The commercialization of rechargeable alkaline zinc–air batteries has been constrained by critical challenges associated with the zinc electrode, including passivation, dendrite growth, and hydrogen evolution reaction. These issues severely limit the cycle life and pose a major barrier to large-scale industrial deployment. Integration [...] Read more.

The commercialization of rechargeable alkaline zinc–air batteries has been constrained by critical challenges associated with the zinc electrode, including passivation, dendrite growth, and hydrogen evolution reaction. These issues severely limit the cycle life and pose a major barrier to large-scale industrial deployment. Integration of porous anode structures and electrode additives—two widely investigated approaches for mitigating challenges related to zinc anode—shows significant promise. However, effectively combining these approaches remains challenging. This study introduces a method for fabricating zinc anodes that can combine the benefits of a porous structure and electrode additive. The polytetrafluoroethylene (PTFE) polymer binder used in fabricating the anode material resulted in a stable scaffold, providing the desired anode porosity of approximately 60% and effectively anchoring ZnO nanoparticles. The zinc anodes prepared using a nickel mesh current collector without any electrode additives demonstrated stable cycling performance, sustaining 350 cycles at a current density of 60 mA g_Zn⁻¹ with a coulombic efficiency of approximately 95%. Incorporating 2 wt.% Bi₂O₃ as an electrode additive further enhanced the cycling performance, achieving 200 stable cycles with 100% coulombic efficiency under an increased current density of 120 mA g_Zn⁻¹, signifying the effectiveness of the proposed fabrication strategy. Full article

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1 pages, 120 KB

Open AccessCorrection

Correction: Yadasu et al. Sensor Fusion-Based Pulsed Controller for Low Power Solar-Charged Batteries with Experimental Tests: NiMH Battery as a Case Study. Batteries 2024, 10, 335

by Shyam Yadasu, Vinay Kumar Awaar, Vatsala Rani Jetti and Mohsen Eskandari

Batteries 2025, 11(10), 358; https://doi.org/10.3390/batteries11100358 - 29 Sep 2025

Abstract

In the original publication [...] Full article

23 pages, 1147 KB

Open AccessArticle

Understanding Heat Generation of LNMO Cathodes in Lithium-Ion Batteries via Entropy and Resistance

by Kevin Böhm, Aleksandr Kondrakov, Torsten Markus and David Henriques

Batteries 2025, 11(10), 357; https://doi.org/10.3390/batteries11100357 - 28 Sep 2025

Abstract

The heat generation of lithium-ion batteries is a critical parameter, as it significantly affects cell temperature. Poor thermal management can lead to elevated cell temperatures, accelerating side reactions, reducing cell lifetime, and, in extreme cases, causing thermal runaway. Therefore, understanding heat generation is [...] Read more.

The heat generation of lithium-ion batteries is a critical parameter, as it significantly affects cell temperature. Poor thermal management can lead to elevated cell temperatures, accelerating side reactions, reducing cell lifetime, and, in extreme cases, causing thermal runaway. Therefore, understanding heat generation is crucial for the commercialization of emerging battery materials. Due to its high energy density, lithium–nickel–manganese–oxide (LNMO) is an attractive candidate for next-generation cathode materials; however, the composition of its heat generation is not yet fully understood. To address this, the state-of-charge (SoC)-dependent entropy coefficient and resistance of disordered LNMO cathodes are determined using the potentiometric method. The results show that both values are strongly influenced by the redox reactions of Ni and Mn. The entropy coefficient varies between 5.2 and −32.4 J

{mol}^{- 1} K^{- 1}

, depending on the SoC. Furthermore, the resistance exhibits a switching dependence on kinetics and mass transfer. The resulting heat flux calculations indicate that, at SoC < 20%, heat generation is dominated by the kinetic behavior of LNMO, leading to two exothermal peaks during discharge and one exothermal peak during charge. This behavior is validated through a comparison with a low-current calorimetric measurement. Full article

(This article belongs to the Section Battery Materials and Interfaces: Anode, Cathode, Separators and Electrolytes or Others)

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36 pages, 3877 KB

Open AccessReview

Swelling Mechanisms, Diagnostic Applications, and Mitigation Strategies in Lithium-Ion Batteries

by Sahithi Maddipatla, Huzaifa Rauf, Michael Osterman, Naveed Arshad and Michael Pecht

Batteries 2025, 11(10), 356; https://doi.org/10.3390/batteries11100356 - 28 Sep 2025

Abstract

Electrochemical processes within a lithium-ion battery cause electrode expansion and gas generation, thus resulting in battery swelling and, in severe cases, reliability and safety issues. This paper presents the mechanisms responsible for swelling, including thermal expansion, lithium intercalation, electrode interphase layer growth, lithium [...] Read more.

Electrochemical processes within a lithium-ion battery cause electrode expansion and gas generation, thus resulting in battery swelling and, in severe cases, reliability and safety issues. This paper presents the mechanisms responsible for swelling, including thermal expansion, lithium intercalation, electrode interphase layer growth, lithium plating, and gas generation, while highlighting their dependence on material properties, design considerations, C-rate, temperature, state of charge (SoC), and voltage. The paper then discusses how swelling correlates with capacity fade, impedance rise, and thermal runaway, and demonstrates the potential of using swelling as a diagnostic and prognostic metric for battery health. Swelling models that connect microscopic mechanisms to macroscopic deformation are then presented. Finally, the paper presents strategies to mitigate swelling, including materials engineering, surface coatings, electrolyte formulation, and mechanical design modifications. Full article

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15 pages, 3058 KB

Open AccessArticle

Hollow Carbon Nanorod-Encapsulated Eu₂O₃ for High-Energy Hybrid Supercapacitors

by Arslan Umer, Daniel W. Tague, Muhammad Abbas, John P. Ferraris and Kenneth J. Balkus, Jr.

Batteries 2025, 11(10), 355; https://doi.org/10.3390/batteries11100355 - 27 Sep 2025

Abstract

Carbon nanorods have been synthesized from acetylene and steam using europium oxide nanorods as a template. The resulting carbon exhibits a high conductivity of 4.66 × 10⁵ S/m and a surface area of 1226 m²/g. The Eu₂O₃ [...] Read more.

Carbon nanorods have been synthesized from acetylene and steam using europium oxide nanorods as a template. The resulting carbon exhibits a high conductivity of 4.66 × 10⁵ S/m and a surface area of 1226 m²/g. The Eu₂O₃ was partially or completely washed from the carbon, creating hollow nanorods. Hybrid supercapacitors were fabricated where the Eu₂O₃ contributes a redox pseudocapacitance. A gravimetric capacitance of 501.2 F/g for the hybrid cell and 202 F/g for the carbon-only cell was measured at 1 A/g using 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in propylene carbonate as an electrolyte. The hybrid supercapacitor exhibited an excellent energy density of 108 Wh/kg at 1 A/g compared to 43 Wh/g at 1 A/g for the carbon-only supercapacitor. Full article

(This article belongs to the Special Issue High-Performance Supercapacitors: Preparation and Application—2nd Edition)

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17 pages, 3364 KB

Open AccessArticle

Investigation of Pr³⁺ and Nd³⁺ Doping Effects on Sodium Gadolinium Silicate Ceramics as Fast Na⁺ Conductors

by Abinaya Sivakumaran, Shantel Butler, Samuel Reid and Venkataraman Thangadurai

Batteries 2025, 11(10), 354; https://doi.org/10.3390/batteries11100354 - 27 Sep 2025

Abstract

Sodium metal batteries (SMBs) with ceramic solid electrolytes offer a promising route to improve the energy density of conventional Na-ion batteries (SIBs). Silicate-based ceramics have recently gained attention for their favourable properties, including better ionic conduction and wider stability windows. In this study, [...] Read more.

Sodium metal batteries (SMBs) with ceramic solid electrolytes offer a promising route to improve the energy density of conventional Na-ion batteries (SIBs). Silicate-based ceramics have recently gained attention for their favourable properties, including better ionic conduction and wider stability windows. In this study, 10% Pr³⁺ and Nd³⁺ were doped into sodium gadolinium silicate ceramics to examine the effects on phase purity, ionic conductivity, and interfacial compatibility with sodium metal anodes. The materials were synthesized via solid-state methods and sintered at 950–1075 °C to study the impact of sintering temperature on densification and microstructure. Na₅Gd_0.9Pr_0.1Si₄O₁₂ (NGPS) and Na₅Gd_0.9Nd_0.1Si₄O₁₂ (NGNS) sintered at 1075 °C showed the highest room temperature total ionic conductivities of 1.64 and 1.74 mS cm⁻¹, respectively. The highest critical current density of 0.5 mA cm⁻² is achieved with a low interfacial area-specific resistance of 29.47 Ω cm² for NGPS and 22.88 Ω cm² for NGNS after Na plating/stripping experiments. These results highlight how doping enhances phase purity, ionic conductivity, and interfacial stability of silicates with Na metal anodes. Full article

(This article belongs to the Special Issue Advanced Electrode Materials for High-Performance Sodium-Ion Batteries—2nd Edition)

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12 pages, 2405 KB

Open AccessArticle

Impact of Inert Materials on Commercial Lithium–Ion Cell Energy Density

by William Yourey, Kayla Nong and Bhanu Babaiahgari

Batteries 2025, 11(10), 353; https://doi.org/10.3390/batteries11100353 - 27 Sep 2025

Abstract

With the goal of increasing energy density in lithium–ion cells, new active materials continue to be developed and evaluated. Similarly, in commercial lithium–ion cells, inert materials present in manufactured cells should also be evaluated. The impact of the thickness of inert materials on [...] Read more.

With the goal of increasing energy density in lithium–ion cells, new active materials continue to be developed and evaluated. Similarly, in commercial lithium–ion cells, inert materials present in manufactured cells should also be evaluated. The impact of the thickness of inert materials on EV-sized lithium–ion cells was evaluated. The impact of the thicknesses of the positive current collector, negative current collector, separator, and aluminum laminate package on cell properties is presented. The impact of these materials varies greatly over different cell designs, with one of the largest impacts being from a decrease in separator material thickness, especially in cells with a high number of electrode pairs, specifically, cells with a larger thickness or cells with low-capacity loadings. For high-capacity positive electrode loading, a decrease in separator thickness from 16 to 8 microns results in an increase in stack volumetric energy density from 502 to 531 Wh/L or an increase of 5.7%. Full article

(This article belongs to the Special Issue Battery Manufacturing: Current Status, Challenges, and Opportunities)

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18 pages, 10787 KB

Open AccessArticle

Experimental Investigations into the Ignitability of Real Lithium Iron Phosphate (LFP) Battery Vent Gas at Concentrations Below the Theoretical Lower Explosive Limit (LEL)

by Jason Gill, Jonathan E. H. Buston, Gemma E. Howard, Steven L. Goddard, Philip A. P. Reeve and Jack W. Mellor

Batteries 2025, 11(10), 352; https://doi.org/10.3390/batteries11100352 - 27 Sep 2025

Abstract

Lithium iron phosphate (LFP) batteries have become a popular choice for energy storage, electrified mobility, and plants. All lithium-based batteries produce flammable vent gas as a result of failure through thermal runaway. LFP cells produce less gas by volume than nickel-based cells, but [...] Read more.

Lithium iron phosphate (LFP) batteries have become a popular choice for energy storage, electrified mobility, and plants. All lithium-based batteries produce flammable vent gas as a result of failure through thermal runaway. LFP cells produce less gas by volume than nickel-based cells, but the composition of this gas most often contains less carbon dioxide and more hydrogen. However, when LFP cells fail, they generate lower temperatures, so the vent gas is rarely ignited. Therefore, the hazard presented by a LFP cell in thermal runaway is less of a direct battery fire hazard but more of a flammable gas source hazard. This research identified the constituents and components of the vent gas for different sized LFP prismatic cells when overcharged to failure. This data was used to calculate the maximum homogenous concentration of gas that would be released into a 1.73 m³ test rig and the percentage of the lower explosive limit (LEL). Overcharge experiments were conducted using the same type of cells in the test rig in the presence of remote ignition sources. Ignition and deflagration of the vent gas were possible at concentrations below the theoretical LEL of the vent gas if it was homogeneously mixed. Full article

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19 pages, 912 KB

Open AccessArticle

An Integrated Co-Simulation Framework for the Design, Analysis, and Performance Assessment of EIS-Based Measurement Systems for the Online Monitoring of Battery Cells

by Nicola Lowenthal, Roberta Ramilli, Marco Crescentini and Pier Andrea Traverso

Batteries 2025, 11(10), 351; https://doi.org/10.3390/batteries11100351 - 26 Sep 2025

Abstract

Electrochemical impedance spectroscopy (EIS) is widely used at the laboratory level for monitoring/diagnostics of battery cells, but the design and validation of in situ, online measurement systems based on EIS face challenges due to complex hardware–software interactions and non-idealities. This study aims to [...] Read more.

Electrochemical impedance spectroscopy (EIS) is widely used at the laboratory level for monitoring/diagnostics of battery cells, but the design and validation of in situ, online measurement systems based on EIS face challenges due to complex hardware–software interactions and non-idealities. This study aims to develop an integrated co-simulation framework to support the design, debugging, and validation of EIS measurement systems devoted to the online monitoring of battery cells, helping to predict experimental results and identify/correct the non-ideality effects and sources of uncertainty. The proposed framework models both the hardware and software components of an EIS-based system to simulate and analyze the impedance measurement process as a whole. It takes into consideration the effects of physical non-idealities on the hardware–software interactions and how those affect the final impedance estimate, offering a tool to refine designs and interpret test results. For validation purposes, the proposed general framework is applied to a specific EIS-based laboratory prototype, previously designed by the research group. The framework is first used to debug the prototype by uncovering hidden non-idealities, thus refining the measurement system, and then employed as a digital model of the latter for fast development of software algorithms. Finally, the results of the co-simulation framework are compared against a theoretical model, the real prototype, and a benchtop instrument to assess the global accuracy of the framework. Full article

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25 pages, 6367 KB

Open AccessArticle

Multiphysics Optimization of Graphite-Buffered Bilayer Anodes with Diverse Inner Materials for High-Energy Lithium-Ion Batteries

by Juan C. Rubio and Martin Bolduc

Batteries 2025, 11(10), 350; https://doi.org/10.3390/batteries11100350 - 25 Sep 2025

Abstract

This study presents a multiphysics simulation approach to optimize graphite-buffered bilayer anodes for enhanced energy density in lithium-ion batteries, assessing the electrochemical impact of diverse inner-layer materials, including silicon, hard carbon, lithium titanate (LTO), and metallic lithium, in pure and graphite-composite forms. A [...] Read more.

This study presents a multiphysics simulation approach to optimize graphite-buffered bilayer anodes for enhanced energy density in lithium-ion batteries, assessing the electrochemical impact of diverse inner-layer materials, including silicon, hard carbon, lithium titanate (LTO), and metallic lithium, in pure and graphite-composite forms. A coupled finite-element model implemented in COMSOL Multiphysics 6.2 was used to integrate spherical lithium diffusion, charge conservation, and the solid electrolyte interphase (SEI) formation kinetics. The evaluated anode structure consisted of a 60 µm-thick bilayer: a 30 µm graphite surface layer coupled with a 30 µm inner layer of alternative active materials. Simulations were performed using an NMC622 cathode, LiPF₆ in EC:EMC electrolyte, at room temperature, under a charge rate of 1 C, considering realistic particle sizes (graphite: 2.5 µm; Si: 0.1 µm; hard carbon: 2.5 µm; LTO: 0.2 µm; Li metal: 0.5 µm), and evaluated over 2000 cycles. The hard carbon/graphite configuration exhibited a capacity fade of 5.8% compared with 7.1% in pure graphite. Additionally, the SEI thickness decreased to 0.20 µm (from 0.25 µm), the overpotential dropped to −17 mV (from −59 mV), and the electrolyte consumption was reduced to 20.8% (from 42.9%). The analysis highlights hard carbon and LTO inner layers as optimal trade-offs between capacity and cycle stability, whereas silicon and lithium metal significantly increased the initial capacity but accelerated SEI formation and impedance growth. These findings demonstrate the graphite-buffered bilayer’s potential to decouple interfacial degradation from high-capacity materials, providing valuable guidelines for the design of advanced lithium-ion battery anodes. Full article

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