Batteries

24 pages, 20675 KiB

Open AccessReview

Cathodes for Zinc-Ion Micro-Batteries: Challenges, Strategies, and Perspectives

by Ling Deng, Qunfang Lin, Zeyang Li, Juexian Cao, Kailing Sun and Tongye Wei

Batteries 2025, 11(2), 57; https://doi.org/10.3390/batteries11020057 (registering DOI) - 2 Feb 2025

The sustainable development of high-performance micro-batteries, characterized by miniaturized size, portability, enhanced safety, and cost-effectiveness, is crucial for the advancement of wearable and smart electronics. Zinc-ion micro-batteries (ZIMBs) have attracted widespread attention for their high energy density, environmental friendliness, excellent safety, and low [...] Read more.

The sustainable development of high-performance micro-batteries, characterized by miniaturized size, portability, enhanced safety, and cost-effectiveness, is crucial for the advancement of wearable and smart electronics. Zinc-ion micro-batteries (ZIMBs) have attracted widespread attention for their high energy density, environmental friendliness, excellent safety, and low cost. The key to designing high-performance ZIMBs lies in improving their volumetric capacity and cycle stability. This review focuses on material design, electrode fabrication, and the structural configuration of micro-batteries, providing a comprehensive analysis of the challenges and strategies associated with cathodes in ZIMBs. Additionally, the application of ZIMBs, which provide energy for electronics such as wearable devices, tiny robots, and sensors, is introduced. Finally, future perspectives on cathodes for ZIMBs are discussed, offering key insights into their design and fabrication in order to facilitate the successful integration of ZIMBs into practical applications. Full article

(This article belongs to the Special Issue Emerging Materials and Technologies for Post-Lithium-Ion Batteries—2nd Edition)

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16 pages, 3545 KiB

Open AccessArticle

Effects of Ultrasonic Pretreatment on the Discharge for Better Recycling of Spent Lithium-Ion Batteries

by Weichen Yang, Zheng Tong, Hezhan Wan, Shuangyin Jiang, Xiangning Bu and Lisha Dong

Batteries 2025, 11(2), 56; https://doi.org/10.3390/batteries11020056 (registering DOI) - 2 Feb 2025

Abstract

Discharge treatment is a vital process in the pretreatment of spent lithium-ion batteries (LIBs). This paper focuses on the effects of ultrasonic pretreatment on the discharge of spent LIBs from the perspective of electrolyte concentration and ultrasonic power. By integrating characterizations such as [...] Read more.

Discharge treatment is a vital process in the pretreatment of spent lithium-ion batteries (LIBs). This paper focuses on the effects of ultrasonic pretreatment on the discharge of spent LIBs from the perspective of electrolyte concentration and ultrasonic power. By integrating characterizations such as pH measurement and X-ray fluorescence (XRF), the effect of ultrasonic pretreatment on the discharge of spent LIBs is evaluated. Experimental results show that sodium chloride (NaCl) solution and potassium chloride (KCl) solution have a more significant and better discharge efficiency (DE) under ultrasonic treatment, while organic electrolyte solutions which mainly contain formate and acetate generally show a less ideal DE. Under experimental conditions of using electrolyte discharge solutions with various electrolyte concentrations with the same ultrasonic power of 300 W, the DE generated from the experimental condition with KCl solution in 30 g/200 mL deionized water is the highest, 64.9%; under different ultrasonic powers in the same electrolyte solutions, the DE of 10 wt.% HCOONa solution is the highest at ultrasonic power of 500 W, at 4.7%. This work provides a reference for the efficient and cost-effective pretreatment of spent LIBs and the discharge mechanism in different electrolyte solutions with ultrasonic treatment is also explored to support the recycling of spent LIBs. Full article

(This article belongs to the Special Issue Advances in Recycling and Upcycling of Spent Lithium-Ion Batteries)

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22 pages, 7318 KiB

Open AccessArticle

One-Dimensional Electro-Thermal Modelling of Battery Pack Cooling System for Heavy-Duty Truck Application

by Mateusz Maciocha, Thomas Short, Udayraj Thorat, Farhad Salek, Harvey Thompson and Meisam Babaie

Batteries 2025, 11(2), 55; https://doi.org/10.3390/batteries11020055 - 31 Jan 2025

Abstract

The transport sector is responsible for nearly a quarter of global CO₂ emissions annually, underscoring the urgent need for cleaner, more sustainable alternatives such as electric vehicles (EVs). However, the electrification of heavy goods vehicles (HGVs) has been slow due to the [...] Read more.

The transport sector is responsible for nearly a quarter of global CO₂ emissions annually, underscoring the urgent need for cleaner, more sustainable alternatives such as electric vehicles (EVs). However, the electrification of heavy goods vehicles (HGVs) has been slow due to the substantial power and battery capacity required to match the large payloads and extended operational ranges. This study addresses the research gap in battery pack design for commercial HGVs by investigating the electrical and thermal behaviour of a novel battery pack configuration using an electro-thermal model based on the equivalent circuit model (ECM). Through computationally efficient 1D modelling, this study evaluates critical factors such as cycle ageing, state of charge (SoC), and their impact on the battery’s range, initially estimated at 285 km. The findings of this study suggest that optimal cooling system parameters, including a flow rate of 18 LPM (litres per minute) and actively controlling the inlet temperature within ±7.8 °C, significantly enhance thermal performance and stability. This comprehensive electro-thermal assessment and the advanced cooling strategy set this work apart from previous studies centred on smaller EV applications. The findings provide a foundation for future research into battery thermal management system (BTMS) design and optimised charging strategies, both of which are essential for accelerating the industrial deployment of electrified HGVs. Full article

(This article belongs to the Special Issue Battery Management in Electric Vehicles: Current Status and Future Trends: 2nd Edition)

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30 pages, 8165 KiB

Open AccessFeature PaperReview

A Review of Pnictogenides for Next-Generation Anode Materials for Sodium-Ion Batteries

by Sion Ha, Junhee Kim, Dong Won Kim, Jun Min Suh and Kyeong-Ho Kim

Batteries 2025, 11(2), 54; https://doi.org/10.3390/batteries11020054 - 29 Jan 2025

Abstract

With the growing market of secondary batteries for electric vehicles (EVs) and grid-scale energy storage systems (ESS), driven by environmental challenges, the commercialization of sodium-ion batteries (SIBs) has emerged to address the high price of lithium resources used in lithium-ion batteries (LIBs). However, [...] Read more.

With the growing market of secondary batteries for electric vehicles (EVs) and grid-scale energy storage systems (ESS), driven by environmental challenges, the commercialization of sodium-ion batteries (SIBs) has emerged to address the high price of lithium resources used in lithium-ion batteries (LIBs). However, achieving competitive energy densities of SIBs to LIBs remains challenging due to the absence of high-capacity anodes in SIBs such as the group-14 elements, Si or Ge, which are highly abundant in LIBs. This review presents potential candidates in metal pnictogenides as promising anode materials for SIBs to overcome the energy density bottleneck. The sodium-ion storage mechanisms and electrochemical performance across various compositions and intrinsic physical and chemical properties of pnictogenide have been summarized. By correlating these properties, strategic frameworks for designing advanced anode materials for next-generation SIBs were suggested. The trade-off relation in pnictogenides between the high specific capacities and the failure mechanism due to large volume expansion has been considered in this paper to address the current issues. This review covers several emerging strategies focused on improving both high reversible capacity and cycle stability. Full article

(This article belongs to the Special Issue Two-Dimensional Materials for Battery Applications)

20 pages, 4450 KiB

Open AccessArticle

Fluorination Strategies for Mn₃O₄ Nanoparticles: Enhancing Reversibility and Capacity in Li-Ion Batteries

by Régis Porhiel, Batiste Clavier, Taylan Karakoç, Sergey Pronkin, Dominique Foix, Elodie Petit, Malika El-Ghozzi and Katia Guérin

Batteries 2025, 11(2), 53; https://doi.org/10.3390/batteries11020053 - 28 Jan 2025

Abstract

Transition metal oxides (TMOs) occupy an increasing share in the search for new electrode materials for Li-Ion batteries. Despite promising electrochemical performances (up to 1000 mAh g⁻¹ in the case of conversion), these materials have poor cyclability linked primarily to hysteresis phenomena. [...] Read more.

Transition metal oxides (TMOs) occupy an increasing share in the search for new electrode materials for Li-Ion batteries. Despite promising electrochemical performances (up to 1000 mAh g⁻¹ in the case of conversion), these materials have poor cyclability linked primarily to hysteresis phenomena. To improve their electrochemical performance, one strategy consists of reducing the particle size. A second strategy relies on the incorporation of fluorine directly into electrode materials to limit the solid–electrolyte interface (SEI). Our study focuses on the impact of fluorination on the electrochemical performance of manganese oxide obtained by solid combustion synthesis (SCS). Two fluorinating agents were used: pure gaseous molecular fluorine F₂ and radical fluorine F^• through xenon difluoride XeF₂ decomposition. The use of F₂ results in strong fluorination localized primarily at the particle surface while XeF₂ diffuses deeper into the particle, resulting in the removal of residual carbon from the synthesis by combustion. The electrochemical performance of the oxide fluorinated with XeF₂ reaches more than 750 mAh g⁻¹ after 160 cycles, whereas that of the oxide fluorinated by F₂ barely exceeds that of the non-fluorinated oxide, less than 200 mAh g⁻¹ after 200 cycles. Full article

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

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14 pages, 3751 KiB

Open AccessArticle

Li-Ion Mobility and Solvation Structures in Concentrated Poly(ethylene carbonate) Electrolytes: A Molecular Dynamics Simulation Study

by Wei Tan, Kento Kimura and Yoichi Tominaga

Batteries 2025, 11(2), 52; https://doi.org/10.3390/batteries11020052 - 28 Jan 2025

Abstract

With the rapid global increase in the use of digital devices and electric vehicles, solid polymer electrolytes (SPEs) have emerged as promising candidates for all-solid-state batteries. They are expected to resolve safety concerns and overcome the limitations of energy density and charging speed [...] Read more.

With the rapid global increase in the use of digital devices and electric vehicles, solid polymer electrolytes (SPEs) have emerged as promising candidates for all-solid-state batteries. They are expected to resolve safety concerns and overcome the limitations of energy density and charging speed associated with traditional Li-ion batteries with liquid electrolytes. However, a limited understanding of ionic conduction mechanisms remains a significant barrier to their further development and practical application. In this study, we employed molecular dynamics simulations using the COMPASS II force field under NPT/NVT ensembles at 298 K to investigate the static and dynamic properties of poly(ethylene carbonate) (PEC) electrolytes at various salt concentrations. Key analyses included the radial distribution function, solvation free energy, and mean-square displacement (MSD) of individual Li cations. Based on their MSD data, Li cations were categorized into “faster” or “slower” groups, corresponding to conductivity levels above or below the average in each model. Our findings reveal that, at higher concentrations, a smaller fraction of faster Li cations contributes disproportionately more than slower Li cations to the overall mobility, highlighting that targeted manipulation of solvation structures could enhance ion transport efficiency in highly concentrated SPEs. Additionally, changes in coordination number and solvation free energy for both faster and slower Li cations suggest the existence of three different solvation patterns as salt concentration increases. These insights provide a deeper understanding of ionic transport and solvation structures in PEC electrolytes, with potential implications for the design of more efficient all-solid-state batteries. 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, 6468 KiB

Open AccessReview

Sustainable Extraction of Critical Minerals from Waste Batteries: A Green Solvent Approach in Resource Recovery

by Afzal Ahmed Dar, Zhi Chen, Gaixia Zhang, Jinguang Hu, Karim Zaghib, Sixu Deng, Xiaolei Wang, Fariborz Haghighat, Catherine N. Mulligan, Chunjiang An, Antonio Avalos Ramirez and Shuhui Sun

Batteries 2025, 11(2), 51; https://doi.org/10.3390/batteries11020051 - 28 Jan 2025

Abstract

This strategic review examines the pivotal role of sustainable methodologies in battery recycling and the recovery of critical minerals from waste batteries, emphasizing the need to address existing technical and environmental challenges. Through a systematic analysis, it explores the application of green organic [...] Read more.

This strategic review examines the pivotal role of sustainable methodologies in battery recycling and the recovery of critical minerals from waste batteries, emphasizing the need to address existing technical and environmental challenges. Through a systematic analysis, it explores the application of green organic solvents in mineral processing, advocating for establishing eco-friendly techniques aimed at clipping waste and boosting resource utilization. The escalating demand for and shortage of essential minerals including copper, cobalt, lithium, and nickel are comprehensively analyzed and forecasted for 2023, 2030, and 2040. Traditional extraction techniques, including hydrometallurgical, pyrometallurgical, and bio-metallurgical processes, are efficient but pose substantial environmental hazards and contribute to resource scarcity. The concept of green extraction arises as a crucial step towards ecological conservation, integrating sustainable practices to lessen the environmental footprint of mineral extraction. The advancement of green organic solvents, notably ionic liquids and deep eutectic solvents, is examined, highlighting their attributes of minimal toxicity, biodegradability, and superior efficacy, thus presenting great potential in transforming the sector. The emergence of organic solvents such as palm oil, 1-octanol, and Span 80 is recognized, with advantageous low solubility and adaptability to varying temperatures. Kinetic (mainly temperature) data of different deep eutectic solvents are extracted from previous studies and computed with machine learning techniques. The coefficient of determination and mean squared error reveal the accuracy of experimental and computed data. In essence, this study seeks to inspire ongoing efforts to navigate impediments, embrace technological advancements including artificial intelligence, and foster an ethos of environmental stewardship in the sustainable extraction and recycling of critical metals from waste batteries. Full article

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15 pages, 3262 KiB

Open AccessArticle

Thermal Safety Research of Lithium-Ion Batteries Based on Flame-Retardant Phase Change Materials

by Jiaxin Zhang, Jiajun Zhao, Yin Chen and Mingyi Chen

Batteries 2025, 11(2), 50; https://doi.org/10.3390/batteries11020050 - 26 Jan 2025

Abstract

Pure phase change materials (PCMs) have drawbacks such as low thermal conductivity and poor physical properties like flammability, which limit their further application in battery thermal management systems. This paper introduces an innovative flame-retardant composite phase change material (CPCM) made from paraffin, expanded [...] Read more.

Pure phase change materials (PCMs) have drawbacks such as low thermal conductivity and poor physical properties like flammability, which limit their further application in battery thermal management systems. This paper introduces an innovative flame-retardant composite phase change material (CPCM) made from paraffin, expanded graphite, chitosan (CS), ammonium polyphosphate (APP), and aluminum hypophosphite (AHP). The physicochemical properties and flame-retardant performance of CPCMs with five different flame-retardant ratios of 9%, 12%, 15%, 18%, and 21% are studied, and their application effects in battery thermal safety are revealed. The results show that the combination of flame retardants CS, APP, and AHP exhibits effective synergistic effects, and the prepared CPCM exhibits good flame-retardant properties and thermal management effects. The CPCM exhibits outstanding thermal management performance when the flame-retardant content is 12%. At a maximum discharge rate of 3C, compared to natural air-cooling conditions, the maximum battery temperature and temperature difference are controlled within the safe range of 41 °C and below 5 °C, respectively. The CPCM can play an important role in the thermal safety of lithium-ion batteries. Full article

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18 pages, 5805 KiB

Open AccessArticle

A Novel Method for Estimating the State of Health of Lithium-Ion Batteries Based on Physics-Informed Neural Network

by Yuxuan Deng, Changqing Du and Zhong Ren

Batteries 2025, 11(2), 49; https://doi.org/10.3390/batteries11020049 - 26 Jan 2025

Abstract

An accurate state of health (SOH) assessment of lithium-ion batteries is essential for ensuring the reliability and safety of electric vehicles (EVs). Data-driven SOH estimation methods have shown promise but face challenges in generalizing across diverse battery types and variable operating conditions. To [...] Read more.

An accurate state of health (SOH) assessment of lithium-ion batteries is essential for ensuring the reliability and safety of electric vehicles (EVs). Data-driven SOH estimation methods have shown promise but face challenges in generalizing across diverse battery types and variable operating conditions. To address this, this study integrates physical information into data-driven approaches, enabling physically consistent inferences and a rapid adaptation to different battery chemistries and usage scenarios. Specifically, physical features correlated with battery degradation, such as the link between incremental capacity (IC) peaks and SOH, are used as constraints to guide model learning. A fully connected layer within a back-propagation neural network (BPNN) is employed to capture battery aging dynamics effectively. Experimental results on two datasets show that the proposed model outperforms traditional neural networks, reducing the RMSE by at least 1.1% and demonstrating strong generalizability in both single-dataset and transfer learning tasks. Full article

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33 pages, 2675 KiB

Open AccessArticle

Some Critical Thinking on Electric Vehicle Battery Reliability: From Enhancement to Optimization

by Jing Lin and Christofer Silfvenius

Batteries 2025, 11(2), 48; https://doi.org/10.3390/batteries11020048 - 25 Jan 2025

Abstract

Electric vehicle (EV) batteries play a crucial role in sustainable transportation, with reliability being pivotal to their performance, longevity, and environmental impact. This study explores battery reliability from micro (individual user), meso (industry), and macro (societal) perspectives, emphasizing interconnected factors and challenges across [...] Read more.

Electric vehicle (EV) batteries play a crucial role in sustainable transportation, with reliability being pivotal to their performance, longevity, and environmental impact. This study explores battery reliability from micro (individual user), meso (industry), and macro (societal) perspectives, emphasizing interconnected factors and challenges across the lifecycle. A novel lifecycle framework is proposed, introducing the concept of “Zero-Life” reliability to expand traditional evaluation methods. By integrating the reliability ecosystem with a dynamic system approach, this research offers comprehensive insights into the optimization of EV battery systems. Furthermore, an expansive Social–Industrial Large Knowledge Model (S-ILKM) is presented, bridging micro- and macro-level insights to enhance reliability across lifecycle stages. The findings provide a systematic pathway to advance EV battery reliability, aligning with global sustainability objectives and fostering innovation in sustainable mobility. Full article

(This article belongs to the Collection Advances in Battery Energy Storage and Applications)

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21 pages, 7343 KiB

Open AccessArticle

Electrochemical Performance of Pre-Modified Birch Biochar Monolith Supercapacitors by Ferric Chloride and Ferric Citrate

by Ziyue Song, Tianjie Feng, Donald W. Kirk and Charles Q. Jia

Batteries 2025, 11(2), 47; https://doi.org/10.3390/batteries11020047 - 25 Jan 2025

Abstract

This study investigated the electrochemical properties of supercapacitors by pre-modifying thick birch biochar monoliths with FeCl₃ or C₆H₅FeO₇ solutions prior to wood pyrolysis. The pre-modification introduced iron species to the surface, promoting the specific surface area, charge-stored [...] Read more.

This study investigated the electrochemical properties of supercapacitors by pre-modifying thick birch biochar monoliths with FeCl₃ or C₆H₅FeO₇ solutions prior to wood pyrolysis. The pre-modification introduced iron species to the surface, promoting the specific surface area, charge-stored species, and surface functionalities, which enhanced the gravimetric capacitance. X-ray diffraction confirmed the successful loading of Fe₃O₄ and Fe. SEM implied the wider distribution of iron-rich particulates and porous carbon via self-pyrolysis on the biochar surface modified with 1.0 M C₆H₅FeO₇. Contact angle measurements demonstrated the enhanced wettability of the biochar surfaces following pre-modification, with the C₆H₅FeO₇-modified samples exhibiting superior wettability compared to the other groups. The gravimetric capacitance of the supercapacitor was dramatically promoted and reached 210 F/g and 219 F/g, respectively, when modified with 1.0M C₆H₅FeO₇ and 1.0 M FeCl₃ at a 5 mA/g current density. Compared to the birch biochar modified with 1.0 M FeCl₃, the 1.0 M C₆H₅FeO₇ had a higher current response peak and capacitive behavior in the CV analysis, demonstrated better ion diffusion capacity, and had lower charge-transfer resistance in the EIS results. But, a slight irreversible process on the electrode of the 1.0 M C₆H₅FeO₇ group led to a lower level of the supercapacitor capacitance retention. The results using ferric solution pre-impregnation show how iron species doping can improve capacitance behavior, providing a feasible scheme for the modification of thick biochar monolith. Full article

(This article belongs to the Special Issue High-Performance Super-capacitors: Preparation and Application)

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Graphical abstract

13 pages, 5950 KiB

Open AccessArticle

Nickel Stabilized Si/Ni/Si/Ni Multi-Layer Thin-Film Anode for Long-Cycling-Life Lithium-Ion Battery

by Yonhua Tzeng, Yu-Yang Chiou and Aurelius Ansel Wilendra

Batteries 2025, 11(2), 46; https://doi.org/10.3390/batteries11020046 - 25 Jan 2025

Abstract

Silicon-based anodes suffer from the loss of physical integrity due to large volume changes during alloying and de-alloying processes with electrolytes. By integrating electrochemically inert, physically strong, ductile nickel layers with a multi-layered thin-film silicon anode, the long-life cycling of the Si/Ni/Si/Ni anode [...] Read more.

Silicon-based anodes suffer from the loss of physical integrity due to large volume changes during alloying and de-alloying processes with electrolytes. By integrating electrochemically inert, physically strong, ductile nickel layers with a multi-layered thin-film silicon anode, the long-life cycling of the Si/Ni/Si/Ni anode was demonstrated. A capacity retention of 82% after 200 cycles was measured, surpassing the performance of conventional silicon thin-film anodes. This is attributed to the effective suppression of internal local stress induced by nonuniform volume expansion by the nickel layers. These findings offer a promising pathway towards the practical implementation of high-capacity silicon-based anodes in advanced lithium-ion batteries. Full article

(This article belongs to the Special Issue Lithium-Ion Batteries: Design, Preparation, Reaction Mechanisms of Electrode Materials, and Battery Life Evaluation)

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21 pages, 4141 KiB

Open AccessArticle

Ternary PEO/PVDF-HFP-Based Polymer Electrolytes for Li-Ion Batteries

by Hoang Bao Tran Nguyen, Ling Ding, Björn Pohle, Toni Schmeida, Hoang Bao An Nguyen and Daria Mikhailova

Batteries 2025, 11(2), 45; https://doi.org/10.3390/batteries11020045 - 25 Jan 2025

Abstract

The impetus to study and develop polymer electrolytes for metal-ion batteries is due to their enhanced safety compared to flammable organic liquid electrolytes, promising ionic conductivity, and broad electrochemical stability window, making them to viable candidates for battery application. In the current work, [...] Read more.

The impetus to study and develop polymer electrolytes for metal-ion batteries is due to their enhanced safety compared to flammable organic liquid electrolytes, promising ionic conductivity, and broad electrochemical stability window, making them to viable candidates for battery application. In the current work, we present a simple fabrication procedure and a comprehensive physico–chemical study of various PVDF-HFP-based electrolyte formulations with a sufficient addition of PEO polymer, LiTFSI conducting salt, and EMIMTFSI ionic liquid. The ionic conductivity, activation energy for ionic movement and thickness of the resulting polymer electrolyte show a non-linear dependency on the PVDF-HFP/PEO ratio. The electrolyte composition with a 0.35PEO-0.65PVDF-HFP/1LiTFSI/1EMIMTFSI mass fraction exhibits the highest ionic conductivity among the compositions, revealing

7.7 \times 10^{- 5} S {c m}^{- 1}

at 30 °C. Electrochemical tests in half full and full Li-ion batteries with a LiFePO₄ cathode and Li₄Ti₅O₁₂ anode also emphasized this composition as the most promising one, providing an initial capacity in full cells of 120 mAh g⁻¹ and a capacity retention of about 75% after 50 charge/discharge cycles at a 0.1 C current rate. In the PEO/PVDF-HFP polymer blend with EMIMTFSI as a plasticizer, the amount of crystalline parts, which are detrimental to a fast ionic diffusion, is significantly reduced. Full article

(This article belongs to the Special Issue Electrolyte and Electrode Design for Next-Generation Rechargeable Batteries)

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19 pages, 4882 KiB

Open AccessArticle

Density Modeling of Battery Electrolyte Mixtures

by Christian A. Landry, Jacob G. Bergeron, Olivier Mathieu, Kevin L. Gering and James C. Thomas

Batteries 2025, 11(2), 44; https://doi.org/10.3390/batteries11020044 - 23 Jan 2025

Abstract

Lithium-ion battery (LIB) electrolytes are generally composed of a mixture of organic hydrocarbons and lithium salt (e.g., LiPF₆). Experimental density data for basic and realistic multicomponent mixtures are scarce in the literature, and a predictive model for electrolyte solution density is [...] Read more.

Lithium-ion battery (LIB) electrolytes are generally composed of a mixture of organic hydrocarbons and lithium salt (e.g., LiPF₆). Experimental density data for basic and realistic multicomponent mixtures are scarce in the literature, and a predictive model for electrolyte solution density is not yet widely available. This work resolves to create a simple predictive method that can be used to estimate the density of these mixtures. A model that accounts for intermolecular forces in the electrolyte mixture was developed and fitted to density data available in the literature that was internally vetted for consistency. The model exhibited high accuracy for single-component electrolyte mixtures, with most predictions falling within 1% of measured values and all predictions falling within 5%. The model was further extended to more realistic, multi-solvent electrolyte mixtures that exhibited similar accuracy. In addition, a novel, accurate method for computing absolute molar and mass fractions of multi-solvent mixtures with specified volumetric concentrations (e.g., 1.2 M LiPF₆ in 1:1:1% vol. ethylene carbonate-EC/diethyl carbonate-DEC/dimethyl carbonate-DMC) is also described. The two separate approaches were combined to yield a modeling framework capable of computing molar concentrations and densities of all LIB electrolyte solutions based on LiPF₆ loaded in any combination of EC, EMC, DEC, DMC, and PC. Additional ionic salt data for NaPF₆ and LiFSI were also evaluated to illustrate the adaptability of the model to different salts and electrolytes. Once again, the model was successful, with most density predictions falling within 1% error and all falling within 5%. This work ultimately provides a simple, adaptable modeling framework for accurate prediction of electrolyte mixture densities. Full article

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12 pages, 3737 KiB

Open AccessArticle

Study on the Effect of Air Velocity and Duct Area on the Heat Dissipation of Lithium-Ion Batteries

by Zhiheng Pan, Maoyong Zhi, Lei Yuan, Qinrou Xu, Qiang Sun and Xiantao Chen

Batteries 2025, 11(2), 43; https://doi.org/10.3390/batteries11020043 - 22 Jan 2025

Abstract

With the growing adoption of lithium-ion batteries, the risk of battery thermal runaway is increasing, so effective temperature regulation for battery systems is essential. The air cooling system for battery thermal management offers advantages such as a simple structure and low cost, making [...] Read more.

With the growing adoption of lithium-ion batteries, the risk of battery thermal runaway is increasing, so effective temperature regulation for battery systems is essential. The air cooling system for battery thermal management offers advantages such as a simple structure and low cost, making it a promising solution for electric aircraft, electric vehicles, and other applications. In this work, the influence of inlet air velocity, inlet size, and inlet/outlet area ratio on the maximum temperature and maximum temperature difference in the battery pack was simulatively studied. When the inlet air velocity was 4 m/s, inlet size was 73 mm × 25 mm, and inlet/outlet area ratio was 1.25, the heat dissipation effect of battery pack was excellent, and the maximum temperature was 324.8 K. This research offers a crucial foundation for designing and setting the operational parameters of air cooling thermal management systems in lithium-ion battery packs. Full article

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24 pages, 5157 KiB

Open AccessArticle

Ceramic-Rich Composite Separators for High-Voltage Solid-State Batteries

by Kevin Vattappara, Martin Finsterbusch, Dina Fattakhova-Rohlfing, Idoia Urdampilleta and Andriy Kvasha

Batteries 2025, 11(2), 42; https://doi.org/10.3390/batteries11020042 - 21 Jan 2025

Abstract

Composite solid electrolytes are gaining interest regarding their use in Li-metal solid-state batteries. Although high ceramic content improves the electrochemical stability of ceramic-rich composite separators (C-SCE), the polymeric matrix also plays a vital role. In the first generation of C-SCE separators with a [...] Read more.

Composite solid electrolytes are gaining interest regarding their use in Li-metal solid-state batteries. Although high ceramic content improves the electrochemical stability of ceramic-rich composite separators (C-SCE), the polymeric matrix also plays a vital role. In the first generation of C-SCE separators with a PEO-based matrix, the addition of 90–95 wt% of Li_6.45Al_0.05La₃Zr_1.6Ta_0.4O₁₂ (LLZO) does not make C-SCE stable for cell cycling with high-voltage (HV) cathodes. For the next iteration, the objective was to find an HV-stable polymeric matrix for C-SCEs. Herein, we report results on optimizing C-SCE separators with different ceramics and polymers which can craft the system towards better stability with NMC622-based composite cathodes. Both LLZO and Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) were utilized as ceramic components in C-SCE separators. Poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDDA-TFSI) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were used as polymers in the “polymer/LiTFSI/plasticizer”-based matrix. The initial phase of the selection criteria for the separator matrix involved assessing mechanical stability and ionic conductivity. Two optimized separator formulations were then tested for their electrochemical stability with both Li metal and HV composite cathodes. The results showed that Li/NMC622 cells with LP70_PVDF_HFP and LZ70_PDDA-TFSI separators exhibited more stable cycling performance compared to those with LZ90_PEO300k-based separators. Full article

(This article belongs to the Special Issue Emerging Materials and Technologies for Post-Lithium-Ion Batteries—2nd Edition)

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19 pages, 1877 KiB

Open AccessReview

Comprehensive Assessment of Novel Technologies for Electrolyte Filling in Lithium-Ion Battery Production

by Michael Hinkers, Kristina Borzutzki, Oliver Krätzig and Florian Degen

Batteries 2025, 11(2), 41; https://doi.org/10.3390/batteries11020041 - 21 Jan 2025

Abstract

Electric vehicles play a pivotal role in the decarbonization of the mobility sector. However, their success depends on low-cost, high-performance batteries, requiring continuous optimization of their production processes. Electrolyte filling is a critical and costly bottleneck in the cell assembly and influences the [...] Read more.

Electric vehicles play a pivotal role in the decarbonization of the mobility sector. However, their success depends on low-cost, high-performance batteries, requiring continuous optimization of their production processes. Electrolyte filling is a critical and costly bottleneck in the cell assembly and influences the quality and safety of the cells, offering great potential for identifying process optimizations. The aim of this study is to complement existing studies by analyzing and evaluating novel technologies for electrolyte filling and thus to provide guidance for industry and science. A systematic literature and patent search led to the identification of sixteen relevant technologies. These were evaluated by a group of experts from the scientific community to identify the most promising technologies. As a result of this evaluation, five technologies emerged that were assessed as positive compared to the state of the art. Overall, the results of this study indicate that the dominating trend in electrolyte filling will be direct pressurization of the battery cells with increasing pressures. Apart from this trend, no other fundamentally new process technologies for industrial use are currently foreseeable. Our findings indicate that both academics and practitioners should focus future research and industrial efforts on optimizing and understanding the current process. Full article

(This article belongs to the Section Battery Processing, Manufacturing and Recycling)

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17 pages, 1931 KiB

Open AccessArticle

Lithium Tracer Diffusion in Li_xCoO₂ and Li_xNi_1/3Mn_1/3Co_1/3O₂ (x = 1, 0.9, 0.65)-Sintered Bulk Cathode Materials for Lithium-Ion Batteries

by Erwin Hüger, Daniel Uxa and Harald Schmidt

Batteries 2025, 11(2), 40; https://doi.org/10.3390/batteries11020040 - 21 Jan 2025

Abstract

The knowledge of Li diffusivities in electrode materials of Li-ion batteries (LIBs) is essential for a fundamental understanding of charging/discharging times, maximum capacities, stress formation and possible side reactions. The literature indicates that Li diffusion in the cathode material Li(Ni,Mn,Co)O₂ strongly increases [...] Read more.

The knowledge of Li diffusivities in electrode materials of Li-ion batteries (LIBs) is essential for a fundamental understanding of charging/discharging times, maximum capacities, stress formation and possible side reactions. The literature indicates that Li diffusion in the cathode material Li(Ni,Mn,Co)O₂ strongly increases during electrochemical delithiation. Such an increased Li diffusivity will be advantageous for performance if it is present already in the initial state after synthesis. In order to understand the influence of a varying initial Li content on Li diffusion, we performed Li tracer diffusion experiments on Li_xCoO₂ (LCO) and Li_xNi_1/3Mn_1/3Co_1/3O₂ (NMC, x = 1, 0.9, 0.65) cathode materials. The measurements were performed on polycrystalline sintered bulk materials, free of additives and binders, in order to study the intrinsic properties. The variation of Li content was achieved using reactive solid-state synthesis using pressed Li₂CO₃, NiO, Co₃O₄ and/or MnO₂ powders and high temperature sintering at 800 °C. XRD analyses showed that the resultant bulk samples exhibit the layered LCO or NMC phases with a low amount of cation intermixing. Moreover, the presence of additional NiO and Co₃O₄ phases was detected in NMC with a pronounced nominal Li deficiency of x = 0.65. As a tracer source, a ⁶Li tracer layer with the same chemical composition was deposited using ion beam sputtering. Secondary ion mass spectrometry in depth profile mode was used for isotopic analysis. The diffusivities followed the Arrhenius law with an activation enthalpy of about 0.8 eV and were nearly identical within error for all samples investigated in the temperature range up to 500 °C. For a diffusion mechanism based on structural Li vacancies, the results indicated that varying the Li content does not result in a change in the vacancy concentration. Consequently, the design and use of a cathode initially made of a Li-deficient material will not improve the kinetics of battery performance. The possible reasons for this unexpected result are discussed. Full article

(This article belongs to the Special Issue Electrolyte and Electrode Design for Next-Generation Rechargeable Batteries)

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26 pages, 4828 KiB

Open AccessFeature PaperArticle

Temperature-Dependent FTIRS Study of Manganese Oxide Spinel Obtained by Solution Combustion Synthesis (SCS) for Supercapacitor Applications

by Taylan Karakoç, Sécou Sall and Sergey N. Pronkin

Batteries 2025, 11(2), 39; https://doi.org/10.3390/batteries11020039 - 21 Jan 2025

Abstract

Solution combustion synthesis (SCS) is often utilized to prepare crystalline nanoparticles of transition metal oxides, in particular Mn oxides. The structure and composition of the final product depend on the conditions of the synthesis, in particular on the composition of metal precursors, its [...] Read more.

Solution combustion synthesis (SCS) is often utilized to prepare crystalline nanoparticles of transition metal oxides, in particular Mn oxides. The structure and composition of the final product depend on the conditions of the synthesis, in particular on the composition of metal precursors, its molar ratio to the fuel component, and the mode of heating. In the present work, the study of chemical phenomena that may occur in the SCS process has been studied for the conventional nitrate–glycine synthesis of Mn oxide, as well as for nitrate–citrate–glycine and nitrate–citrate–urea synthesis. In the case of nitrate–glycine synthesis at a 1:1 fuel-to-salt ratio, the formation of a weak complex of Mn(II) and glycine provides the conditions for an instantaneous SCS reaction upon heating, resulting in slight sintering of final oxide nanoparticles. Partial hydrolysis of the Mn precursor during slow solvent evaporation results in the formation of a mixture of oxides, namely MnO and Mn₃O₄. Formation of MnO is completely suppressed when ammonium citrate is added into the initial mixture. Pure Mn₂O₃ oxide is obtained from nitrate–citrate synthesis, while the pure Mn₃O₄ phase is obtained in the case of nitrate–citrate–glycine and nitrate–citrate–urea synthesis, due to the higher temperature generated in the presence of additional fuel. In the presence of citrate, the SCS reaction is slower, resulting in stronger sintering of the nanoparticles. The study of the electrochemical properties of synthesized oxides demonstrates that SCS with the nitrate–citrate–urea mixture provides the highest charge capacitance in 1 M NaOH: 130 F/g at 2 A/g. The impedance characterization of materials allows us to propose a tentative mechanism of degradation of electrode materials during galvanostatic cycling. Full article

(This article belongs to the Special Issue High Energy Density Supercapacitors: Acquisition, Characterization, and Application)

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