Side Reactions/Changes in Lithium-Ion Batteries: Mechanisms and Strategies for Creating Safer and Better Batteries

Electrolyte Chemistry Development for Sodium-Based Batteries: A Blueprint from Lithium or a Step Toward Originality?

Currently, electrolyte design for sodium-based batteries is largely inherited from their lithium-based counterparts, which often present critical challenges that hinder forging new perspectives and thus further improvements. This work delves into the key properties of representative sodium- and lithium-based electrolytes, encompassing prevailing salt anions. It aims to evaluate the impact of cation chemistry, including their nature and the degree of interactions with counter anions, thereby bridging the gap in effectively transferring the know-how accumulated in lithium batteries to sodium-based batteries. The results demonstrate that the unique impact of salt anions on the properties of metal-ion conducting electrolytes is tightly correlated with the nature of metal cations. By synchronizing the anionic structures with the critical features of sodium cations, the solvating dynamics and transport properties, chemical stability, aluminum corrosion behavior, and other key properties of the electrolytes could be finely tuned to fit the specific requirements of advanced sodium-based batteries. This work gives an in-depth insight into the chemical and physical features of sodium-based electrolytes, with a potential avenue to accelerate the deployment of high-performance sodium batteries and simultaneously inspire and guide the design of other electrolytes for emerging mono- and multivalent cation-based rechargeable batteries.

Progress and obstacles in electrode materials for lithium-ion batteries: a journey towards enhanced energy storage efficiency

This review critically examines various electrode materials employed in lithium-ion batteries (LIBs) and their impact on battery performance. It highlights the transition from traditional lead-acid and nickel-cadmium batteries to modern LIBs, emphasizing their energy density, efficiency, and longevity. It primarily focuses on cathode materials, including LiMn2O4, LiCoO2, and LiFePO4, while also exploring emerging materials such as organosulfides, nanomaterials, and transition metal oxides & sulfides. It also presents an overview of the anode materials based on their mechanism, e.g., intercalation-deintercalation, alloying, and conversion-type anode materials. The strengths, limitations, and synthesis techniques associated with each material are discussed. This review also delves into cathode materials, such as soft and hard carbon and high-nickel systems, assessing their influence on storage performance. Additionally, the article addresses safety concerns, recycling strategies, environmental impact evaluations, and disposal practices. It highlights emerging trends in the development of electrode materials, focusing on potential solutions and innovations. This comprehensive review provides an overview of current lithium-ion battery technology, identifying technical challenges and opportunities for advancement to promote efficient, sustainable, and environmentally responsible energy storage solutions. This review also examines the issues confronting lithium-ion batteries, including high production costs, scarcity of materials, and safety risks, with suggestions to address them through doping, coatings, and incorporation of nanomaterials.

High-Performance Alluaudite-Type Na2.54(Fe0.97Mg0.03)1.73(SO4)3 Microspheres Cathode for Sodium-Ion Batteries with an Ultrahigh Rate Capability and 9000 Cycle Life

Na2+2xFe2-x(SO4)3 (NFSO) is a promising cathode material for sodium-ion batteries (SIBs) due to its low cost and high operating potential (≈3.8 V). However, poor intrinsic electronic conductivity and sluggish kinetics are major drawbacks to its practical application. Herein, magnesium doped Na2+2xFe2-x(SO4)3 microspheres (Na2.54(Fe0.97Mg0.03)1.73(SO4)3) are synthesized via a designed spray-drying process. The optimized cathode material (NFSO@C-Mg0.02) possesses excellent rate performance up to 50C (50.8 mAh g-1 at 50C) and long-cycle stability (capacity retention of 78.3% even after 9000 cycles at 10C). Despite an increase in the mass loading to 10 mg cm-2, the electrode continues to represent a reversible capacity of 72.1 mAh g-1 at 3C. Furthermore, NFSO@C-Mg0.02║HC full cell demonstrates superior cycling stability (80% capacity retention over 8000 cycles at 5C) and high energy density (≈310 Wh kg-1, based on the cathode). In situ X-ray diffraction (XRD) results reveal that the Mg doping strategy successfully mitigates the variation in lattice volume. The density functional theory (DFT) calculations verify that the prominent rate performance is attributed to the enhanced Na+ diffusion kinetics and low ionic-migration energy barrier. This work provides an effective strategy and a fundamental understanding to enhance the electrochemical performance of cathode materials for SIBs.

Accidents involving lithium-ion batteries in non-application stages: incident characteristics, environmental impacts, and response strategies

With the rapid growth of electric vehicle adoption, the demand for lithium-ion batteries has surged, highlighting the importance of understanding the associated risks, particularly in non-application stages such as transportation, storage, assembly, and disposal. This review explores the types and causes of lithium-ion battery accidents, categorizing them into leakage, fire, and explosion, often resulting from electrical, thermal, and mechanical abuses. It examines the environmental impacts of such incidents, including the release of toxic substances that threaten public health and ecological systems. The research also outlines the need for effective risk assessment methods and compliance with safety standards. Furthermore, it evaluates current emergency response strategies, advocating for a unified approach to managing these incidents. By delving into the complexities of lithium-ion battery safety, this study aims to contribute to improved practices and regulatory frameworks, ultimately enhancing related accident responses.

Designing multifunctional artificial SEI layers for long-term stability of sodium metal anodes

Sodium metal batteries, which are low-cost and have great potential for large-scale energy storage, face challenges such as shortened battery life and safety issues due to the uncontrolled growth of sodium dendrites and extensive side reactions during the cycling of sodium metal anodes. In this work, we address these challenges by introducing SnF2 to the surface of the sodium metal, which in situ generates a stable composite interfacial layer (NaSn@NaF). This interfacial layer contains Na-Sn alloy with a potential gradient and electrically insulating NaF, which promotes uniform deposition of Na+ ions and effectively suppresses dendrite formation and side reactions. Additionally, In addition, the average Young's modulus of the modified artificial solid electrolyte interface layer (SEI) is about 6.9 Gpa, which is about 2.7 times higher than that of bare sodium (2.4GPa). This artificial/natural composite interfacial layer significantly enhances the performance of sodium electrodes. Symmetric battery cycling tests demonstrated that the electrode with the composite interfacial layer could sustain continuous charging and discharging for 870 h, a significant improvement compared to the 95 h achieved by the pristine sodium metal anode. Furthermore, the full-cell configuration (Na|NaSn@NaF||NVP) exhibited remarkable long-cycle stability, maintaining around 80 % capacity retention after 1100 cycles at a 2C rate, with minimal capacity degradation. This research presents a straightforward and efficient method that enhances the practical application potential of sodium metal anodes.

Recent Advances in Nanostructured Conversion-Type Cathodes: Fluorides and Sulfides

This review paper explores the emerging field of conversion cathode materials, which hold significant promises for advancing the performance of lithium-ion (LIBs) and lithium-sulfur batteries (LSBs). Traditional cathode materials of LIBs, such as lithium cobalt oxide, have reached their limits in terms of energy density and capacity, driving the search for alternatives that can meet the increasing demands of modern technology, including electric vehicles and renewable energy systems. Conversion cathodes operate through a mechanism involving complete redox reactions, transforming into different phases, which enables the storage of more lithium ions and results in higher theoretical capacities compared to conventional intercalation materials. This study examines various conversion materials, including metal oxides, sulfides, and fluorides, highlighting their potential to significantly enhance energy density. Despite their advantages, conversion cathodes face numerous challenges, such as poor conductivity, significant volume changes during cycling, and issues with reversibility and stability. This review discusses current nanoengineering strategies employed to address these challenges, including nano structuring, composite formulation, and electrolyte optimization. By assessing recent research and developments in conversion cathode technology, this paper aims to provide a comprehensive overview of their potential to revolutionize lithium-ion batteries and contribute to the future of energy storage solutions.

Non-rechargeable batteries: a review of primary battery technology and future trends

Primary batteries, or non-rechargeable batteries, are crucial for powering a diverse range of low-drain applications, from household items to specialized devices in medical and aerospace industries. Despite the growth of rechargeable battery technologies, primary batteries offer distinct advantages, including cost-effectiveness, reliability, and long shelf life. This review examines the current state of primary battery technology, exploring the major types, including alkaline, zinc-carbon, lithium, and silver oxide batteries, and discussing their significance in both everyday and specialized applications. Key challenges, such as the environmental impact of battery disposal, limitations in energy density, and performance optimization, are highlighted as areas of ongoing research. Advances in nanotechnology, materials science, and novel chemistries, such as biodegradable materials and high-performance lithium-based systems, promise to improve energy density and sustainability in the future. The review also outlines future trends, including increased miniaturization for medical devices, the development of robust batteries for extreme environments, and new battery chemistries that can replace or enhance current primary battery technologies. Addressing these challenges and gaps is essential for ensuring that primary batteries remain a viable and sustainable energy storage solution in the future.

Graph-Theory Algorithm for Prediction of Electrolyte Degradation Reactions in Lithium- and Sodium-Ion Batteries

The growing demand for sustainable energy storage devices requires the fabrication of novel materials for rechargeable metal-ion batteries. The stability of the materials incorporated in the electrochemical cells plays a crucial role in the specific capacity and cycling stability of energy storage devices. The processes that occur inside such systems are fairly complex; hence, the identification of unwanted side reactions affecting the electrochemical stability is not a trivial task. The present study combines cheminformatics and quantum chemistry approaches to create an algorithm that generates diverse viable side products of redox reactions that a given electrochemical system, e.g., different cathode or anode materials, electrolytes, solvents, etc., can undergo. Two case studies of electrolyte degradation are presented: namely, ethylene carbonate (EC) and diglyme (DG). The effect of the electrode surface is modeled by the dehydrogenation reactions of the electrolyte solvents. The predicted degradation products after reduction and oxidation are validated using previously reported experimental data. For EC, the predicted products are CO, CO2, ethene, ethylene oxide, [CO2]•-, and [CO2]•+, while for DG alkoxy anions are mainly anticipated. The number of gaseous products formed upon DG degradation is significantly smaller than the number of gaseous species formed by EC fragmentation. The proposed algorithm opens new avenues for the rapid deduction of degradation products of novel electrolyte solvents for which no experimental data are available and can easily be adapted to predict the degradation of other materials.

A bacterial cellulose composite separator with high thermal stability and flame retardancy for high-performance lithium ion batteries

Separators play a crucial role in enhancing the safety of lithium-ion batteries (LIBs); however, commercial polyolefin separators exhibit poor thermal stability and are flammable. This study investigates the use of green, environmentally friendly, and renewable bacterial cellulose as a substrate for developing a composite separator (BHM/5). The BHM/5 separator, comprising bacterial cellulose, an inorganic mineral nano-hydroxyapatite (HAP) and flame-retardant melamine polyphosphate (MPP), is fabricated via freeze drying and high-temperature pressing. The developed composite separator demonstrates superior thermal stability and excellent flame retardancy compared with commercial polyolefin separators while maintaining structural integrity at 200 °C and exhibiting self-extinguishing properties after ignition. Furthermore, the BHM/5 separator exhibits a high porosity of 74 % and a substantial electrolyte uptake of 459 %, achieving an ion conductivity of 1.44 mS/cm. As a result, the cell of the LiFePO4-Li system assembled demonstrates an initial discharge capacity of 131.35 mAh·g-1 at a current density of 1C and a capacity retention of 95.4 % after 150 cycles.

Using High-Entropy Configuration Strategy to Design Spinel Lithium Manganate Cathodes with Remarkable Electrochemical Performance

Owing to its abundant manganese source, high operating voltage, and good ionic diffusivity attributed to its 3D Li-ion diffusion channels. Spinel LiMn2O4 is considered a promising low-cost positive electrode material in the context of reducing scarce elements such as cobalt and nickel from advanced lithium-ion batteries. However, the rapid capacity degradation and inadequate rate capabilities induced by the Jahn-Teller distortion and the manganese dissolution have limited the large-scale adoption of spinel LiMn2O4 for decades. In this study, LiMn1.98Mg0.005Ti0.005Sb0.005Ce0.005O4 spinel positive electrode material (HE-LMO) with remarkable interfacial structural and cycling stability is developed based on a complex concentrated doping strategy. The initial discharge capacity and capacity retention of the electrode of HE-LMO are 111.51 mAh g-1 and 90.55% after 500 cycles at 1 C. The as-prepared HE-LMO displays favorable cycling stability, significantly surpassing the pristine sample. Furthermore, theoretical calculations strongly support the above finding. HE-LMO has a higher and more continuous density of states at the Fermi energy level and more robust bonded states of the electrons among the Mn─O atom pairs. This research contributes to the field of high-entropy doping modification and establishes a facile strategy for designing advanced spinel manganese-based lithium-ion batteries (LIBs).

Transforming Detrimental Crystalline Zinc Hydroxide Sulfate to Homogeneous Fluorinated Amorphous Solid-Electrolyte Interphase on Zinc Anode

The formation of non-ion conducting byproducts on zinc anode is notoriously detrimental to aqueous zinc-ion batteries (AZIBs). Herein, we successfully transform a representative detrimental byproduct, crystalline zinc hydroxide sulfate (ZHS) to fast-ion conducting solid-electrolyte interphase (SEI) via amorphization and fluorination induced by suspending CaF2 nanoparticles in dilute sulfate electrolytes. Distinct from widely reported nonhomogeneous organic-inorganic hybrid SEIs that exhibit structural and chemical instability, the designed single-phase SEI is homogeneous, mechanically robust, and chemically stable. These characteristics of the SEI facilitate the prevention of zinc dendrite growth and reduction of capacity loss during long-term cycling. Importantly, AZIB full cells based on this SEI-forming electrolyte exhibit exceptional stability over 20,000 cycles at 3 A/g with a charging voltage of 2.2 V without short circuits and electrolyte dry-out. This work suggests avenues for designing SEIs on a metal anode and provides insights into associated SEI chemistry.

Bio-Inspired Core-Shell Structured Electrode Particles with Protective Mechanisms for Lithium-Ion Batteries

Lithium-ion batteries (LIBs), as predominant energy storage devices, are applied to electric vehicles, which is an effective way to achieve carbon neutrality. However, the major obstructions to their applications are two dilemmas: enhanced cyclic life and thermal stability. Taking advantage of bio-inspired core-shell structures to optimize the self-protective mechanisms of the mercantile electrode particles, LIBs can improve electrochemical performance and thermal stability simultaneously. The favorable core-shell structures suppress volume expansion to stabilize electrode-electrolyte interfaces (EEIs), mitigate direct contact between the electrode material and electrolyte, and promote electrical connectivity. They possess wide operating temperatures, high-voltage resistance, and inhibit short circuits. During cycling, the cathode and anode generate a cathode-electrolyte interface (CEI) and a solid-electrolyte interface (SEI), respectively. Applying multitudinous coating approaches can generate multifarious bio-inspired core-shell structured electrode particles, which is helpful for the generation of the EEIs, self-healing the surface cracks, and maintaining the structural integrities of electrodes. The protected shells act as barriers to minimize unwanted side reactions and enhance thermal stability. These in-depth understandings of the bio-inspired evolution for electrode particles can inspire further enhancements in LIB lifetime and thermal safety, especially for bio-inspired core-shell structured electrodes possessing high-performance protective mechanisms.

Combining mechanical ball-milling with melt-polymerization to fabricate polyimide covalent organic frameworks towards high-performance sodium-ion batteries

Melt-polymerization and mechanical ball-milling were combined to achieve the facile mass production of polyimide covalent organic frameworks (COFs) towards high-performance sodium-ion batteries. The as-obtained COFs were demonstrated with high utilization of active sites (>83.0%) and COFs with smaller pore sizes were proved to deliver better performance with a specific capacity of 213.7 mA h g-1 at a current density of 0.1 A g-1.

PTHF/LATP Composite Polymer Electrolyte for Solid State Batteries

The novel crosslinked composite polymer electrolyte (CPE) was developed and investigated using polytetrahydrofuran (PTHF) and polyethyleneglycol diacrylate (PEGDA), incorporating lithium aluminum titanium phosphate (LATP) particles and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. Composite polymer electrolytes (CPEs) for solid-state lithium-ion batteries (LIBs) were synthesized by harnessing the synergistic effects of PTHF crosslinking and the addition of LATP ceramics, while systematically varying the film composition and LATP content. CPEs containing 15 wt% LATP (PPL15) demonstrated improved mechanical strength and electrochemical stability, achieving a high conductivity of 1.16 × 10-5 S·cm-1 at 80 °C, outperforming conventional PEO-based polymer electrolytes. The CPE system effectively addresses safety concerns and mitigates the rapid degradation typically associated with polyether electrolytes. The incorporation of PEGDA not only enhances mechanical stability but also facilitates lithium salt dissociation and ion transport, leading to a uniform microstructure free from agglomerated particles. The temperature-dependent ionic conductivity measurements indicated optimal performance at lower LATP concentrations, highlighting the impact of ceramic particle agglomeration onion transport pathways. These findings contribute to advancing solid-state battery systems toward practical application.

Boosting sodium storage performance of Na0.44MnO2 through surface modification with conductive polymer PPy utilizing sonication-assisted dispersion

The search for suitable electrode materials for sodium storage in sodium-ion batteries (SIBs) poses significant challenges. Na0.44MnO2 (NMO) has emerged as a promising candidate among various cathode materials due to its distinct three-dimensional tunnel structure, which facilitates Na+ diffusion and governs structural stress fluctuations during Na+ intercalation/deintercalation. However, NMO faces obstacles such as limited electronic conductivity, lattice distortion induced by the Jahn-Teller effect of Mn3+ during cycling, and Mn3+ disproportionation leading to material dissolution, which affects cycling durability. To overcome these problems, Na0.44MnO2/polypyrrole (NMO/PPy) composites were fabricated through surface modification of the conductive PPy using an ultrasonically assisted dispersion method. Experimental results show that NMO/PPy with a 7 wt% PPy content exhibits superior sodium storage capabilities. Specifically, at a current density of 0.5C, the initial specific discharge capacity reaches 135.2 mA h g-1, a 12.1% increase over pristine NMO, with a capacity retention of 94.5% after 100 cycles. Of particular note is a capacity retention of 82% after 500 cycles at 1C, attributed to the PPy coating, which suppresses Mn3+ side reactions, enhances the structural stability and electronic conductivity of NMO, and accelerates Na+ diffusion. These results suggest that the use of conductive polymer coatings represents a simple and effective strategy to improve the sodium storage capacity of NMO, paving the way for the further development of high-performance SIB cathodes.

Electrospun Lithium Porous Nanosorbent Fibers for Enhanced Lithium Adsorption and Sustainable Applications

Electrospun nanosorbent fibers specifically designed for efficient lithium extraction were developed, exhibiting superior physicochemical properties. These fibers were fabricated using a polyacrylonitrile/dimethylformamide matrix, with viscosity and dynamic mechanical analysis showing that optimal interactions were achieved at lower contents of layered double hydroxide. This meticulous adjustment in formulation led to the creation of lithium porous nanosorbent fibers (Li-PNFs-1). Li-PNFs-1 exhibited outstanding mechanical attributes, including a yield stress of 0.09 MPa, a tensile strength of 2.48 MPa, and an elongation at a break of 19.7%. Additionally, they demonstrated pronounced hydrophilicity and hierarchical porous architecture, which greatly favor rapid wetting kinetics and lithium adsorption. Morphologically, they exhibited uniform smoothness with a diameter averaging 546 nm, indicative of orderly crystalline growth and a dense molecular arrangement. X-ray photoelectron spectroscopy and density functional theory using Cambridge Serial Total Energy Package revealed modifications in the spatial and electronic configurations of polyacrylonitrile due to hydrogen bonding, facilitating lithium adsorption capacity up to 13.45 mg/g under optimal conditions. Besides, kinetics and isotherm showed rapid equilibrium within 60 min and confirmed the chemical and selective nature of Li+ uptake. These fibers demonstrated consistent adsorption performance across multiple cycles, highlighting their potential for sustainable use in industrial applications.