LiFePO4 Research Articles

Investigate the changes of aged lithium iron phosphate batteries from a mechanical perspective

Investigate the changes of aged lithium iron phosphate batteries from a mechanical perspective

Thermal hazard comparison and assessment of Li-ion battery and Na-ion battery

Na-ion batteries are considered a promising next-generation battery alternative to Li-ion batteries, due to the abundant Na resources and low cost. Most efforts focus on developing new materials to enhance energy density and electrochemical performance to enable it comparable to Li-ion batteries, without considering thermal hazard of Na-ion batteries and comparison with Li-ion batteries. To address this issue, our work comprehensively compares commercial prismatic lithium iron phosphate (LFP) battery, lithium nickel cobalt manganese oxide (NCM523) battery and Na-ion battery of the same size from thermal hazard perspective using Accelerating Rate Calorimeter. The thermal hazard of the three cells is then qualitatively assessed from thermal stability, early warning and thermal runaway severity perspectives by integrating eight characteristic parameters. The Na-ion cell displays comparable thermal stability with LFP while LFP exhibits the lowest thermal runaway hazard and severity. However, the Na-ion cell displays the lowest safety venting temperature and the longest time interval between safety venting and thermal runaway, allowing the generated gas to be released as early as possible and detected in a timely manner, providing sufficient time for early warning. Finally, a database of thermal runaway characteristic temperature for Li-ion and Na-ion cells is collected and processed to delineate four thermal hazard levels for quantitative assessment. Overall, LFP cells exhibit the lowest thermal hazard, followed by the Na-ion cells and NCM523 cells. This work clarifies the thermal hazard discrepancy between the Na-ion cell and prevalent Li-ion cells, providing crucial guidance for development and application of Na-ion cell.

A non-isothermal kinetic study on the extraction of metals from spent lithium iron phosphate batteries using the NH2SO3H roasting process

A non-isothermal kinetic study on the extraction of metals from spent lithium iron phosphate batteries using the NH2SO3H roasting process

Applicability assessment of equivalent circuit-thermal coupling models on LiFePO4 batteries operated under wide-temperature and high-rate pulse discharge conditions

In military scenario, high-power lithium iron phosphate (LFP) batteries are frequently used under wide-temperature and high-rate pulse discharge conditions. An accurate electro-thermal coupling model (ETCM) is crucial for the safe operations. Equivalent circuit-thermal coupling model (ECTCM), which combines equivalent circuit model (ECM) and lumped thermal model, is the most widely used type of ETCM in applications. However, the applicability of ECTCM under wide-temperature and high-rate pulse discharge conditions is not clear. To assess the applicability of ECTCM under these special conditions, this study establishes six typical ECTCMs and accurately identify their corresponding model parameters. Then, these models are tested under high-rate pulse discharge conditions from -40oC to 50oC. The results indicate that ECTCMs are effective for pulse discharge at ambient and high temperatures, but not suitable for low-temperature conditions below 0oC. When the temperature is below 0oC, the pulse discharge voltage of the batteries can not be accurately simulated by ECTCMs. This work provides guidance for electro-thermal coupling modeling under high-rate pulse discharge conditions, and also points out the direction for the development of high-precision ETCM capable of handling wide-temperature and high-rate pulse discharge in the future.

Lithium‑sulfur batteries for next-generation automotive power batteries carbon emission assessment and sustainability study in China

The rise of electric vehicles has ushered in a revolution in the automotive industry, propelling the global automotive sector towards sustainable development. However, considerable controversy persists regarding the comprehensive performance of electric vehicle batteries and their environmental impact. The development of next-generation power batteries, aimed at enhancing energy storage performance while mitigating environmental consequences, has become a focal point of research in this field. Lithium‑sulfur batteries (LSBs), with their innovative structural design and environmentally friendly materials, not only enhance energy storage performance but also harbor significant environmental potential. When coupled with an all-solid-state battery structure, the all-solid-state lithium‑sulfur battery (A-LSB) demonstrates even more superior performance. This combination represents an ideal next-generation power battery for automotive applications, offering heightened efficiency and environmental sustainability. This study conducts a prospective life cycle assessment (LCA) to examine the environmental performance, particularly carbon emissions, during the production processes of LSBs and A-LSBs in the Chinese region. The primary objective is to uncover the potential for sustainable development in the future of lithium‑sulfur battery technologies. During the research process, we conducted comparative validation by comparing with traditional ternary lithium-ion batteries (NCM) and lithium iron phosphate batteries (LFP). Experimental setups were designed to simulate both laboratory and industrial production scenarios, with a primary focus on analyzing the sustainable performance of LSB and A-LSB. The results indicate that, compared to traditional lithium-ion batteries, both LSB and A-LSB exhibit lower carbon emissions and superior environmental performance, with A-LSB showing particular promise. However, A-LSB demonstrates higher sensitivity to environmental impacts, displaying significant variations before and after industrial production. Additionally, it exhibits a greater dependency on regional resources and energy structures. In contrast, LSB displays better regional adaptability.

Li+ Ion-Dipole Interaction-Enabled a Dynamic Supramolecular Elastomer Interface Layer for Dendrite-Free Lithium Metal Anodes.

The unstable lithium (Li)/electrolyte interface, causing inferior cycling efficiency and unrestrained dendrite growth, has severely hampered the practical deployment of Li metal batteries (LMBs), particularly in carbonate electrolytes. Herein, we present a robust approach capitalizing on a dynamic supramolecular elastomer (DSE) interface layer, which is capable of being reduced with Li metal to spontaneously form strong Li+ ion-dipole interaction, thereby enhancing interfacial stability in carbonate electrolytes. The soft phase in the DSE structure enables fast Li+ transport via loosely coordinated Li+-O interaction, while the hard phase, rich in electronegative lithiophilic sites, drives the generation of fast-ion-conducting solid electrolyte interface components, including Li3N and Li2S. Furthermore, the dynamically resilient DSE network composed of soft and hard phases protects Li anodes from electrolyte corrosion and accommodates volume changes during cycling. All features of the DSE layer synergistically facilitate uniform Li+ deposition and suppress Li dendrite propagation, ensuring a stable and dendrite-free Li anode. Consequently, the symmetric Li||Li cell incorporating the DSE layer achieves cycling stability exceeding 6000 h under 1 mA cm-2 and 1 mA h cm-2 conditions. Furthermore, full cell pairing DSE/Li anode with LiFePO4 (LFP) or high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes exhibits high-efficiency Li deposition and cycling stability, even under constrained conditions of limited Li (40 μm) and ultrahigh loading NMC811 cathode (21.5 mg cm-2). This study underscores the effectiveness of the ion-dipole interaction-enabled DSE network in developing stable, high-energy-density LMBs.

Facile Electrodeposition Method for Constructing Li2S as Artificial Solid Electrolyte Interphase for High-Performance Li Metal Anode.

Designing current collectors and constructing efficient artificial solid electrolyte interphase (SEI) layers are promising strategies for achieving dendrite-free Li deposition and practical applications in Li metal batteries (LMBs). Electrodeposition is advantageous for large-scale production and allows the direct formation of current collectors without binders, making them immediately usable as electrodes. In this study, an adherent Cu2S thin-layer on Cu foil is synthesized through anodic electrodeposition from a Na2S solution in a one-step process, followed by the generation of Li2S layers as artificial SEI layers via a conversion reaction (3DLi2S-Cu foil). The Li2S layers move from the 3D Cu surface to the deposited Li surface, facilitating uniform and dense Li deposition. The 3DLi2S-Cu foil structure demonstrates stable cycling performance over 350 cycles in an asymmetric cell, with a capacity of 1 mAh cm-2 at 1 mA cm-2. Moreover, symmetric cells with 5 mAh cm-2 of deposited Li exhibit a stable cycle life for over 1200 h. When paired with commercial LiFePO4 (LFP), the full cells show substantially enhanced cyclability, regardless of the amount of deposited Li. This study provides new insights into the construction of artificial SEIs for facilitating commercial applications.

Explosion characteristics of two-phase ejecta from large-capacity lithium iron phosphate batteries

When a thermal runaway accident occurs in a lithium-ion battery energy storage station, the battery emits a large amount of flammable electrolyte vapor and thermal runaway gas, which may cause serious combustion and explosion accidents when they are ignited in a confined space. With the gradual development of large-scale energy storage batteries, the composition and explosive characteristics of thermal runaway products in large-scale lithium iron phosphate batteries for energy storage remain unclear. In this paper, the content and components of the two-phase eruption substances of 340Ah lithium iron phosphate battery were determined through experiments, and the explosion parameters of the two-phase battery eruptions were studied by using the improved and optimized 20L spherical explosion parameter test system, which reveals the explosion law and hazards of the two-phase battery eruptions. Studies have shown that in a two-phase system explosion, EMC can make the two-phase system more explosive and more powerful, and the thermal runaway gas expands its explosion concentration range. The coupling explosion of the two enhanced the sensitivity and explosive power of the two-phase ejecta. Increasing the concentration of any combustible in a two-phase system will cause the explosion intensity parameters of the system to increase. However, when the combustible concentration exceeds the optimal explosion concentration, the explosion intensity parameters will decrease or even no explosion will occur. Both explosion intensity parameters and sensitivity parameters are more sensitive to EMC concentration, and the higher the EMC concentration, the stronger its dominant role in the explosion of the two-phase system. This work can lay the foundation for revealing the disaster-causing mechanism of explosion accidents in lithium-ion battery energy storage power stations, guide the safe design of energy storage systems and the prevention and control of explosion accidents, and provide theoretical and data support for the investigation of explosion accidents in energy storage power stations.

Sustainable Grease Lubrication Induced by Graphene Oxide and LiFePO4

This study investigates the possibility of modifying lubricating greases by 2D graphene oxide (GO) and lithium iron phosphate (LiFePO4) to enhance their tribological performance. GO's layered structure plays a crucial role in reducing friction by facilitating easy sliding between rubbing surfaces, making it an effective solid lubricant. The impact of these additives on friction reduction, wear resistance, and the tribolayer formation ability is evaluated by ball‐on‐disc tribometry with an emphasis on durability and sustainability. Comparative results reveal that unmodified greases exhibit a high susceptibility to wear, including oxide formation and severe plastic deformation. In contrast, greases with GO show a notable reduction in friction, while the addition of LiFePO4 contributes to the formation of a continuous protective layer that substantially reduces abrasive wear. The combination of GO and LiFePO4 results in a homogeneous, durable tribofilm that effectively protects surfaces against severe wear providing long‐term friction stability. Although lab‐scale LiFePO4 is used, the findings suggest a great potential for extending the useful life of recycled LiFePO4 from lithium‐ion batteries, similar to commercial LiFePO4 thus confirming significant improvements in the grease performance but also highlighting the potential to advance toward more sustainable solutions in industrial applications and electric vehicles.

The influence of iron site doping lithium iron phosphate on the low temperature properties and the diffusion mechanism of lithium ion

The influence of iron site doping lithium iron phosphate on the low temperature properties and the diffusion mechanism of lithium ion

Dendrite-Free Lithium Batteries Enabled by an Artificial High-Dielectric Biopolymer Interface Layer.

Lithium (Li) metal batteries face challenges, such as dendrite growth and electrolyte interface instability. Artificial interface layers alleviate these issues. Here, cellulose nanocrystal (CNC) nanomembranes, with excellent mechanical properties and high specific surface areas, combine with polyvinylidene-hexafluoropropylene (PVDF-HFP) porous membranes to form an artificial solid electrolyte interphase (SEI) layer. The porous structure of PVDF-HFP equalizes the electric field near metallic lithium surfaces. The high mechanical modulus of CNC (6.2 GPa) effectively inhibits dendrite growth, ensures the uniform flow of lithium ions to the lithium metal electrode, and inhibits the growth of lithium dendrites during cycling. The synergy of high polarity β-phase poly(vinylidene fluoride) (PVDF) and CNC provides over 1000 h of stability for Li//Li batteries. Moreover, Li//LiFePO4 (LFP) full cells with this artificial protective layer perform well at 5 C, showcasing the potential of this film in lithium metal batteries.

Estimating the tipping point for lithium iron phosphate batteries

Uncertainty surrounding NMC cathode chemistry prices have prompted increasing interest in less expensive alternative technologies. Chief among these is lithium iron phosphate (LFP), a chemistry that offers a cost advantage at the expense of energy density. We estimate which chemistry offers a lower cost at targeted vehicle ranges consistent with those consumers can expect from internal combustion engine vehicles. Our model – which considers tradeoffs between battery capacity and weight – enumerates a range ‘tipping point’ of 373.52 miles, beyond which NMC batteries consistently demonstrate a cost advantage over LFP batteries, despite the latter's reliance on less costly minerals. Using this tipping point as a benchmark, we leverage trip-level data from the National Household Travel Survey to explore which U.S. households may benefit from EVs equipped with LFP versus NMC batteries. Among multi-vehicle households, only 1 % of all trips taken exceed 160.53 miles, a figure analogous to our most conservative tipping point. To the extent that EVs may be utilized for relatively short commutes or as secondary or tertiary vehicles, our results suggest that LFP batteries can offer lower costs relative to NMC batteries while satisfying most households' travel demands. We subsequently discuss the policy implications of these findings.

Solid-State Lithium Batteries with In Situ Polymerized Acrylate-Based Electrolytes Capable of Electrochemically Stable Operation at 100 °C.

Solid polymer electrolytes (SPEs) typically consist of salts with mobile anions that could cause instabilities and parasitic side reactions in solid-state lithium (Li) batteries. To address this challenge, single-Li-ion conducting (SLIC) SPEs, where anions of Li salts are covalently attached to the polymer backbone, have been utilized to reduce the number of mobile anions. This approach improves the cationic transference number but is accompanied by a loss of ionic conductivity. In this work, we investigate a synergetic approach of using both a polymerizable SLIC salt and a conventional Li salt in a polymer matrix by in situ polymerization of the poly(propylene glycol) acrylate (PPGA) monomer. The synthesized hybrid SPEs show a high ionic conductivity of up to ∼2 × 10-4 S cm-1 and a relatively high Li-ion transference number of ∼0.4. With a significantly reduced fraction of mobile anions in the combined salt SPE, in situ polymerized SPE cells with a LiFePO4 (LFP) cathode achieve a stable performance for over 100 cycles at temperatures as high as 100 °C, which is unattainable with conventional Li salts or electrolytes. Furthermore, solid-state nuclear magnetic resonance spectra provide additional insights into differences in Li nucleus environments and emphasize a reduction in activation energy for hybrid SPEs due to their more open structure. This study opens the path for the fabrication of high-performance solid polymer Li batteries capable of operating at high temperatures using commercial battery fabrication equipment, as in situ polymerized acrylate-based polymers provide drop-in compatibility with conventional battery production, ease of acrylate polymerization, and inexpensive, facile SPE chemistry. We expect that further tuning of the acrylate-based SPE composition may allow further increases in its conductivity without sacrificing its electrochemical stability or mechanical properties.

Predictive pretrained transformer (PPT) for real-time battery health diagnostics

Modeling and forecasting the evolution of battery systems involve complex interactions across physical, chemical, and electrochemical processes, influenced by diverse usage demands and dynamic operational patterns. In this study, we developed a predictive pre-trained Transformer (PPT) model equipped with 1,871,114 parameters that enhance identification of both short-term and long-term patterns in time-series data. This is achieved through the integration of convolutional layers and probabilistic sparse self-attention mechanisms, which collectively enhance prediction accuracy and efficiency in diagnosing battery health. Moreover, the customized hybrid-model fusion supports parallel computing and employs transfer learning, reducing computational costs while enhancing scalability and adaptability. Consequently, this allows for precise real-time health estimations across various battery cycles. We validated this method using a public dataset of 203 commercial lithium iron phosphate (LFP)/graphite batteries charged at rates ranging from 1C to 8C. By using only partial charge data—from an 80 % state of charge to the maximum charging voltage (3.6 V for LFP batteries, 4.2 V for ternary batteries)—and avoiding complex feature engineering, error metrics were achieved below 0.3 % for root mean square error (RMSE), weighted mean absolute percentage error (WMAPE), and mean absolute error (MAE), with an R2 of 98.9 %. The generalization capabilities were further demonstrated across 36 different testing protocols, encompassing 23,480 cycles throughout the entire life cycle, with a total inference time of 9.88 s during the testing phases. Further experiments on 30 nickel cobalt aluminum (NCA) batteries and 36 nickel cobalt manganese (NCM) batteries, across different battery types and operational scenarios, resulted in RMSE, WMAPE, and MAE all below 0.9 %, with R2 values of 94.1 % and 94.4 %, respectively. These findings highlight the potential of our customized deep transfer neural networks to enhance diagnostic accuracy, accelerate training, and improve generalization in real-time applications.

Research on the Electrochemical Impedance Spectroscopy Evolution of Sodium-Ion Batteries in Different States.

Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion batteries (LIBs) due to the abundant availability of sodium, lower costs, and comparable electrochemical performance characteristics. A thorough understanding of their performance features is essential for the widespread adoption and application of SIBs. Therefore, in this study, we investigate the output characteristics and electrochemical impedance spectroscopy (EIS) features of sodium-ion batteries (SIBs) under various states. The research results show that, unlike conventional lithium iron phosphate (LFP) batteries, SIBs exhibit a strong linear relationship between state of charge (SOC) and open-circuit voltage (OCV) across various SOC and temperature conditions. Additionally, the discharge capacity of the battery remains relatively stable within a temperature range of 15 °C to 35 °C; when the temperatures are outside this range, the available capacity of the sodium-ion battery reduces significantly. Moreover, the EIS profiles in the high-frequency region are predominantly influenced by the ohmic internal resistance, which remains largely unaffected by SOC variations. In contrast, the low-frequency region demonstrates a significant correlation between SOC and impedance, with higher SOC values resulting in reduced impedance, indicated by smaller semicircle radii in the EIS curves. This finds highlights that EIS profiling can effectively monitor SOC and state of health (SOH) in SIBs, offering a clear correlation between impedance parameters and the battery's operational state. The research not only advances our understanding of the electrochemical properties of SIBs but also provides a valuable reference for the design and application of sodium-ion battery systems in various scenarios.

Characterization of Lithium-Ion Battery Fire Emissions—Part 2: Particle Size Distributions and Emission Factors

The lithium-ion battery (LIB) thermal runaway (TR) emits a wide size range of particles with diverse chemical compositions. When inhaled, these particles can cause serious adverse health effects. This study measured the size distributions of particles with diameters less than 10 µm released throughout the TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. The chemical composition of fine particles (PM2.5) and some acidic gases were also characterized from filter samples. The emission factors of particle number and mass as well as chemical components were calculated. Particle number concentrations were dominated by those smaller than 500 nm with geometric number mean diameters below 130 nm. Mass concentrations were also dominated by smaller particles, with PM1 particles making up 81–95% of the measured PM10 mass. A significant amount of organic and elemental carbon, phosphate, and fluoride was released as PM2.5 constituents. The emission factor of gaseous hydrogen fluoride was 10–81 mg/Wh, posing the most immediate danger to human health. The tested LFP cells had higher emission factors of particles and HF than the LCO cells.

Formulation and Recycling of a Novel Electrolyte Based on Bio-Derived γ-Valerolactone and Lithium Bis(trifluoromethanesulfonyl)imide for Lithium-Ion Batteries.

This work introduces a novel electrolyte comprising lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt dissolved in bio-based γ-valerolactone (GVL) for lithium-ion batteries (LIBs). Moreover, a simple and sustainable aqueous-based recycling approach for recovering the imide-based lithium salt is proposed. Beyond the sustainable origin of the GVL solvent, this electrolyte exhibits reduced flammability risk, characterized by a flash point of 136°C, along with favorable transport properties (conductivity of 6.2mScm-1 at 20°C) and good electrochemical stability (5.0V vs Li+/Li). Its good compatibility with graphite and lithium iron phosphate electrodes ensures remarkable cycling stability in LIB full-cells after 200 galvanostatic cycles at 1C. Furthermore, the proposed liquid-liquid phase electrolyte recycling method allows for a nearly complete recovery of the LiTFSI salt (97-99%) and the GVL solvent (78%). The feasibility of the recycling process is validated by the reutilization of the recovered LiTFSI salt in electric double-layer capacitors, achieving performances similar to that of the pristine salt with exceptional long-term stability.

Unraveling the contribution of nucleation to the intercalation energy barrier for phase-transforming Li-ion battery materials

Phase-transforming intercalation compounds, such as LiFePO4 (LFP) and Li4Ti5O12 (LTO), are widely utilized in Li-ion batteries, particularly for applications requiring high power and operation at low temperatures. However, the impact of phase transformation kinetics on energy density losses under extreme conditions has been largely unexplored. Specifically, the role of nucleation, the initial stage of phase transformation, in contributing to battery performance losses has not been previously investigated. In this study, we not only quantified the significance of material-level factors, such as interfacial charge transfer, in the low-temperature and high-rate performance of LFP and LTO materials, but also provided the first estimates of the apparent activation energies of nucleation. Our findings revealed that nucleation, particularly in the case of LFP, contributes significantly to overpotential, highlighting its pivotal role among material-level factors. Furthermore, our analysis allowed us to differentiate between material-level and particle-level limitations for the LTO/LFP cell, emphasizing the paramount importance of controlling the porosity of secondary particles to ensure high tolerance towards high-rate/low-temperature discharge.

Recycled lithium battery nanomaterials as a sustainable nanofertilizer: Reduced peanut allergenicity and improved seed quality

The rapidly increasing amount of end-of-life lithium iron phosphate (LiFePO4) batteries has raised significant environmental concerns. This study offers a strategy for a paradigm shift by transforming this growing waste into a valuable resource by recycling discarded LiFePO4 batteries and safely integrating the materials into sustainable agriculture. We used five types of LiFePO4 (10, 50 mg kg−1) applied to soil planted with peanuts in a full-culture experiment. Our results show that addition of <50 mg kg−1 of recycled nano-LiFePO4 (rn-LiFePO4) has a multifaceted positive impact on peanut because of sustainable release of nutrients and nano-specific effects, not only enhancing photosynthesis and root growth but also increasing yield by 22 %–34 % while simultaneously elevating seed nutritional quality. Moreover, a remarkable reduction (up to 99.78 % at 10 mg kg−1 rn-LiFePO4) in the expression of allergen genes was evident following exposure to LiFePO4, which showed a significant negative correlation with Fe content in the seeds. The decreased peanut allergen gene expression was mediated by a downregulation of metabolites associated with protein digestion and absorption. Furthermore, rhizosphere soil immune system enhancement may indirectly enhance immune responses to peanut allergy. This study suggests the significant potential of nanoscale LiFePO4 recycled from Li battery, including enhancing crop yield quality and mitigating peanut allergy concerns while simultaneously addressing a growing waste stream of concern.

Demonstration of MAX phases as triple functional artificial solid electrolyte interphase for ultralong life lithium metal anodes

Solid electrolyte interphase (SEI) has significant role in controlling lithium (Li) dendrites. However, lack of chemical stability, mechanical strength and self-perfection for conventional SEI cannot persistently suppress Li dendrites, leading to inferior cycling life. Herein, MAX phases (Ti2SnC and Ti2SC) as triple functional artificial SEI (ASEI) with high modulus, chemical stability and self-smoothing ability are introduced on Li foils (Ti2SnC@Li and Ti2SC@Li) for ultralong life Li metal anodes (LMAs). The high mechanical strength with lithiophilicity of the MAX can induce uniform Li deposition and suppress dendrite growth, while the excellent chemical stability and self-smoothing ability of the MAX guarantee the consistency of the ASEI, achieving ultralong life of the LMAs. As a result, the Ti2SnC@Li||Li@Ti2SnC half-cells demonstrate ultralong cycling performance of 5000 h at 5 mAh cm−2 and 5 mA cm−2. The Ti2SnC@Li||LiFePO4(LFP) full-cells demonstrate ultralong stability up to 3000 cycles at 5C. At harsh conditions including 24.3 mg cm−2 of LFP, 6.0 g (Ah)−1 of electrolyte and 2.6 of negative/positive ratio, the Ti2SnC@Li||LFP full-cells maintain 2.9 mAh cm−2 after 130 cycles at 0.3C. This work demonstrates the MAX phases with high modulus, chemical stability and self-smoothing ability as triple functional ASEI for metal anode protection.