Spent Lithium Iron Phosphate Research Articles

Revealing role of oxidation in recycling spent lithium iron phosphate through acid leaching

Revealing role of oxidation in recycling spent lithium iron phosphate through acid leaching

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

Mechanism and process study of spent lithium iron phosphate batteries by medium-temperature oxidation roasting strategy

In this study, we determined the oxidation roasting characteristics of spent LiFePO4 battery electrode materials and applied the iso-conversion rate method and integral master plot method to analyze the kinetic parameters. The ratio of Fe (II) to Fe (III) was regulated under various oxidation conditions. The results showed that 95.50 % of LiFePO4 was oxidized to Li3Fe2(PO4)3 and Fe2O3 under the most cost-effective roasting conditions (500°C, 1000 mL/min, 30 min, air atmosphere) and only approximately 18 % graphite was involved in the reaction. More than 99 % of the lithium was leached under these roasting conditions, with minimal impurities. Medium-temperature selective oxidation roasting effectively avoided the high-temperature sintering phenomenon that affects the crystal structure of the product. Instead, a fine, uniform oxidized phase was formed, and the polyvinylidene fluoride impurity that typically persists throughout the recycling process was avoided. This study provides a sufficient theoretical basis and experimental prerequisites for selective, time-efficient, and economical lithium leaching or reductive regeneration of the cathode materials.

For elements-utilization regeneration of spent LiFePO4: Designed basic precursors for advanced polycrystal electrode materials

Spent lithium iron phosphate (LFP) is commonly recovered by hydrometallurgy to prepare Li2CO3 and FePO4, but suffering from long process and low value-added products. Hydrothermal method avoids element separation and regenerates LFP materials directly from leaching solution of spent LFP. However, it requires three-time the theoretical amount of lithium. In this study, using LiFePO4(OH) (LFPOH) as a medium, LFP materials were regenerated with theoretical amount of lithium in virtue of energetically favorable reaction of Li-ions into the internal structure. The formation mechanism of LFPOH and LFP materials were investigated, and advanced polycrystal LFP materials with fast ions-diffusion ability and high reversibility were obtained. The capacities of recovered LFP materials are 156.17 mAh g−1, 148.51 mAh g−1, 138.34 mAh g−1, 124.1 mAh g−1 at 0.2 C, 0.5 C, 1 C and 2 C, respectively and their capacity could be remained 139.92 mAh g−1 at 1 C with retention of almost 100 % after 200 cycles. Moreover, with the assistance of economic analysis, the designed regenerated path displayed considerable recycling value-potential, especially the reducing of Li-resources (from three-time to one-time). This study sheds light on designing polycrystal recovered LFP with help of basic medium, whilst provides an effective strategy for preparing high-performance LFP materials.

Recycling of Spent Lithium Iron Phosphate Cathodes: Challenges and Progress.

The number of spent lithium iron phosphate (LiFePO4, LFP) batteries will increase sharply in the next few years, owing to their large market share and development potential. Therefore, recycling of spent LFP batteries is necessary and urgent from both resource utilization and environmental protection standpoints. In this review, the significance of pretreatment for LFP recycling is first underscored, and its technical challenges and recent advancements are presented. Following that, the current recycling methods for spent LFP cathodes are outlined in terms of the respective treating processes, advantages, and disadvantages. Additionally, the preparation methods of LFP cathode material are reviewed to guide the resynthesis of LFP that uses salts obtained from spent LFP, which are beneficial for closed-loop recycling of LFP batteries. Lastly, we explore the future development direction of spent LFP battery recycling, highlighting the importance of technological innovation to advance the sustainable growth of the LFP battery industry.

Selective leaching of lithium from mixed spent lithium iron phosphate powder

In recent years, lithium iron phosphate (LFP) batteries have been widely used in the electric vehicle industry. The recycling of spent LFP will be propitious to conserving resources and alleviating the environmental risks it poses. In this study, a selective extraction method for lithium from spent LFP was proposed using nitric acid. Lithium leached into the liquid phase, while P and Fe remained in the leaching residue. Under the conditions of 120°C, HNO3/Li molar ratio of 2, and time of 2 h, the leaching efficiency of lithium reached 99.5 %, with a selectivity reaching 82.1 %. Initially, LFP was decomposed to liberate Li, Fe, and P in the liquid phase. Subsequently, ferrous ions were oxidized to trivalent, high-valent iron ions re-precipitated as FePO4·2 H2O. Thermodynamic calculations indicate that the temperature and pH value of the extraction system have significant influence on both the oxidation and reprecipitation steps. An imbalance of Fe/P ratio (<1) in the raw material hinders the selectivity of lithium extraction, and supplementing this portion of Fe can enhance the selectivity to over 90 %. Additionally, LiCO3 and anhydrous FePO4 were effectively regenerated from the leachate and residue. This study provides a novel approach for the recycling of spent LFP and probably contributes to the sustainability of the lithium ion battery industry.

Tailoring crystal plane of short-process regenerated LiFePO4 towards enhanced rate properties

Captured by the environmental and economic value, the recycling of spent lithium iron phosphate (LFP) batteries has attracted numerous attentions. However, hydrometallurgical method still suffers from complex process, and hydrothermal method is limited by morphology control, ascribed to the strong polarity of water. Herein, supported by ethanol as crystal surface modifier, the regular (010) orientation and short b-axis are effectively tailored for regenerated LFP. As Li-storage cathode, the capacities of as-optimized LFP could reach up to 157.07 mA h g−1 at 1 C, and the stable capacity of 150.50 mA h g−1 could be remained with retention of 93.48% after 400 cycles at 1 C. Even at 10 C, their capacity could be still kept about 119.3 mA h g−1. Assisted by the detail analysis of adsorption energy, the clear growth mechanism is proposed, the lowest adsorbing energy (−4.66 eV) of ethanol on (010) crystal plane renders the ordered growth along (010) crystal plane. Given this, the work is expected to shed light on the tailoring mechanism of internal plane about regenerated materials, whilst providing effective strategies for high-performance regenerated LFP.

Multi-perspective evaluation on spent lithium iron phosphate recycling process: For next-generation technology option

The recycling of spent lithium iron phosphate batteries has recently become a focus topic. Consequently, evaluating different spent lithium iron phosphate recycling processes becomes necessary for industrial development. Here, based on multiple perspectives of environment, economy and technology, four typical spent lithium iron phosphate recovery processes (Hydro-A: hydrometallurgical total leaching recovery process; Hydro-B(H2O2/O2): hydrometallurgical selective lithium extraction process; Pyro: Pyrometallurgical recovery process; Direct: Direct regeneration process) were compared comprehensively. The comprehensive evaluation study uses environment, economy and technology as evaluation indicators, and uses the entropy weight method and analytic hierarchy process to couple the comprehensive indicator weights. Results show that the comprehensive evaluation values of Hydro-A, Hydro-B (H2O2), Hydro-B (O2), Pyro and Direct are 0.347, 0.421, 0.442, 0.099 and 0.857, respectively. Therefore, the technological maturity of Direct should be further improved to enable early industrialization. On this basis, this study conducted a quantitative evaluation of the spent lithium iron phosphate recycling process by comprehensively considering environmental, economic and technical factors, providing further guidance for the formulation of recycling processes.

Direct Regeneration of Degraded LiFePO4 Cathode via Reductive Solution Relithiation Regeneration Process.

The rapid growth of electronic devices, electric vehicles, and mobile energy storage has produced large quantities of spent batteries, leading to significant environmental issues and a shortage of lithium resources. Recycling spent batteries has become urgent to protect the environment. The key to treating spent lithium-ion batteries is to implement green and efficient regeneration. This study proposes a recycling method for the direct regeneration of spent lithium iron phosphate (LFP) batteries using hydrothermal reduction. Ascorbic acid (AA) was used as a low-cost and environmentally friendly reductant to reduce Fe3+ in spent LiFePO4. We also investigated the role of AA in the hydrothermal process and its effects on the electrochemical properties of the regenerated LiFePO4 cathode material (AA-SR-LFP). The results showed that the hydrothermal reduction direct regeneration method successfully produced AA-SR-LFP with good crystallinity and electrochemical properties. AA-SR-LFP exhibited excellent electrochemical properties, with an initial discharge specific capacity of 144.4 mAh g-1 at 1 C and a capacity retention rate of 98.6% after 100 cycles. In summary, the hydrothermal reduction direct regeneration method effectively repairs the defects in the chemical composition and crystal structure of spent LiFePO4. It can be regarded as a green and effective regeneration approach for spent LiFePO4 cathode materials.

A green recyclable process for selective recovery of Li and Fe from spent lithium iron phosphate batteries by synergistic effect of deep eutectic solvent and oxygen

This work designs a new method for recovering spent LiFePO4 cathode materials, aiming to address issues with traditional hydrometallurgy processes such as complex operations, low lithium recovery rates, and high wastewater discharge. The method involves using a deep eutectic solvent (DES) composed of chloroacetic acid and ethanol, and oxygen as an oxidant, for the cooperative leaching of LiFePO4 powders. Based on the acidic nature of the DES and the oxidizing properties of oxygen, LiFePO4 was undergone an in-situ transformation into solid FePO4, while 100% of lithium was dissolved in the DES with high selectivity. The FePO4 product can be recovered by filtration, and the addition of oxalic acid to the filtrate allows for lithium recovery. Importantly, the structure of the DES remained unchanged after use, allowing for three recycling cycles without a significant decrease in LiFePO4 recovery efficiency. This process is environmentally friendly, with no generation of acidic or alkaline wastewater, and boasts high metal recovery rates, showcasing its huge potential for application.

Recovery of iron phosphate and lithium carbonate from sulfuric acid leaching solutions of spent LiFePO4 batteries by chemical precipitation

The recycling of lithium and iron from spent lithium iron phosphate (LiFePO&lt;sub&gt;4&lt;/sub&gt;) batteries has gained attention due to the explosive growth of the electric vehicle market. To recover both of these metal ions from the sulfuric acid leaching solution of spent LiFePO&lt;sub&gt;4&lt;/sub&gt; batteries, a process based on precipitation was proposed in this study. Since ferric and ferrous ions coexisted in the leaching solution, all the ferrous ions were first oxidized to ferric ions by adding H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; to the leaching solution. About 99% iron(III) was recovered as iron phosphate by adjusting the solution pH to 2 at 25 &lt;sup&gt;o&lt;/sup&gt;C for 30 mins. After the precipitation of iron phosphate, the remaining Li(I) in the filtrate was recovered as lithium carbonate by precipitation with Na&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; as a precipitant. Addition of acetone to the filtrate at room temperature greatly enhanced the precipitation percentage of Li(I). Moreover, solid Na&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; was better than Na&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; solution in precipitating Li(I). About 95% of lithium ions was recovered as carbonate precipitates under the optimum conditions: solution pH = 11, 3.0 molar ratio of solid Na&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; to Li(I), 7/5(v/v) volume ratio of acetone to the filtrate, 25 &lt;sup&gt;o&lt;/sup&gt;C, 300 rpm for 2 hrs.

Cyclic redox strategy for sustainable recovery of lithium ions from spent lithium iron phosphate batteries

The growth of spent lithium-ion batteries requires a green recycling method. This paper presents an innovative hydrometallurgical approach in light of redox flow batteries, which employed Fe3+/Fe2+ as regenerative redox mediator to selectively extract Li+ from LiFePO4. In contrast to the conventional method in which the oxidizer is disposable, the present scheme allows for the recycling of the oxidizer, which demonstrates the advantages of environmentally friendly, low cost and higher extraction rate, offering a novel approach to recycling spent batteries.

In-situ oxidation for selective lithium extraction from spent LiFePO4 cathodes by low acid dosage

Recovery of lithium from spent lithium iron phosphate batteries is crucial to alleviating the storage of lithium. This study proposes a method for the selective recovery of lithium from spent lithium iron phosphate battery cathodes using a leaching system of H2SO4 and H2O2. Efficient and selective lithium recovery was achieved through in-situ oxidation of lithium iron phosphate driven by a low acid dosage, and the mechanism of selective lithium recovery was investigated by precipitation experiments of Fe2+ and PO43−. The shrinking core model was used for the kinetic analysis of the leaching process, and the results suggested that the leaching process was controlled by the internal diffusion of the product layer. Moreover, essential leaching parameters such as acid concentration, H2SO4 dosage, H2O2 dosage, leaching time, and leaching temperature were systematically investigated. The results showed that the leaching rate of Li reached 97.95 % along with a selectivity of 99.60 %, which meets the standard of the battery-grade Li2CO3, while the leaching rate of both Fe and P was less than 1 %.

Regeneration of degraded lithium iron phosphate by utilizing residual lithium from spent graphite anode

With the fast development of lithium-ion batteries, there will be a lot of spent lithium iron phosphate (LFP) batteries in the near future. The loss of lithium in LFP leads to the capacity attenuation, while the lost lithium is mainly trapped in spent graphite anode. Herein, we proposed a closed-loop recycling method for spent LFP batteries, which utilizes the lithium from spent graphite to directly regenerate spent LFP through hydrothermal method. Compared with spent LFP, the repaired LFP displays enhanced electrochemical performance. This strategy tightly integrates the recycling of cathode and anode, which simplifies the recovery process and decreases the recovery cost.

Selective flotation separation mechanism of LFPs and graphite electrode materials using CMC as inhibitor

Economical and efficient separation and utilization of spent lithium iron phosphate powder is the key to lithium-ion battery recycling. Flotation, as a low-cost physical enrichment method, has attracted much attention due to its promising advantage of separating graphite before the metallurgical extraction of lithium iron phosphate. However, high-efficiency flotation separation reagent is still challenging. In this work, low-viscosity carboxymethyl cellulose (CMC) was used as a selective flotation inhibitor in the separation of graphite and lithium iron phosphate electrode materials (LFPs). With the addition of 100 mg/L 25 mPa·s CMC, the recoveries of graphite and LFPs were 96.37% and 3.47%, respectively, indicating excellent separation efficiency. The adsorption analysis and wettability measurement indicated that CMC is more favorable adsorbed on the surface of LFPs and graphite, and also greatly improved the wettability and hydrophilicity of LFPs. Meanwhile, the turbidity and particle size analysis showed that CMC could effectively disperse LFPs particles, reducing the particle entrapment caused by heterocoagulation. Furthermore, XPS and FT-IR studies confirmed that CMC could chemisorb on LFPs and physically adsorb on graphite electrode material. The study results could provide a promising physical enrichment method for the green and efficient recycling of spent lithium iron phosphate batteries.

Recovery of Li and Fe from spent lithium iron phosphate using organic acid leaching system

The valuable metals, lithium and iron, were recovered from spent LiFePO4 cathode powder by hydro- metallurgy, and the recycled products were used as raw materials for the preparation of lithium iron phosphate. By the optimization of the leaching process parameters, the leaching efficiency of Li reached 96.56% at pyruvic acid concentration of 3.0 mol/L, volume of H2O2 of 2 mL, solid-to-liquid ratio of 0.1 g/mL, reaction temperature of 80 °C, and reaction time of 20 min. The leached residue was characterized by XRD, XPS, and FE-SEM coupled with EDS, and the results showed that the leached residue was FePO4 with an Fe/P molar ratio of 0.974.After adjusting the pH of the leaching solution to 12.0 and stirring for 2 h at 80 °C, the recovery of Li from the leaching solution was enabled by in-situ precipitation in the form of Li3PO4 with a purity of 96.5 wt.%. The reaction kinetic data of Li leaching using the pyruvic acid/H2O2 solution were fit to the Avrami model with R2>0.95. The low activation energy of the Li leaching process indicated that diffusion step limited the reaction rate during the leaching process.

A chemical method for the complete components recovery from the ferric phosphate tailing of spent lithium iron phosphate batteries

After acid leaching of ferric phosphate tailings, the filtrate was used to synthesize hydrated ferric phosphate, while the filter residue served as a filler for natural SBR, achieving the resourceful utilization of solid waste materials.

Direct regeneration of spent LiFePO4 cathode materials assisted with a bifunctional organic lithium salt.

Direct regeneration is an effective strategy of spent lithium iron phosphate (S-LFP), with the principal aspect being the selection of the lithium source and reductant. Here, assisted with a thermodynamically favourable reaction involving a bifunctional organic lithium salt (lithium citrate), the single-step regeneration of S-LFP is successfully achieved. The structure and composition of the regenerated LFP are significantly restored, demonstrating excellent electrochemical performance (142.7 mA h g-1) with no degradation after 200 cycles.

Electrochemical selective lithium extraction and regeneration of spent lithium iron phosphate

In this paper, a green, efficient and low-cost process for the selective recovery of lithium from spent LiFePO4 by anodic electrolysis is proposed. The leaching rates of Li, Fe and P under different conditions were explored and the optimal conditions are obtained. In the optimal conditions, Li, Fe and P leaching rates were 96.31%, 0.06% and 0.62% respectively. The Li/Fe selectivity was over 99.9%. The product obtained is isostructural FePO4 and retains the original particle morphology. The FePO4 obtained can be synthesised into LiFePO4/C by direct regeneration process or impurity removal regeneration process. The material synthesized by the latter process has a better electrochemical performance, with a discharge specific capacity of 144.5 mAh/g at 1.0C and a capacity retention of 92.0% over 500cycles. The superior performance can be attributed to an impurity removal process that reduced agglomeration and improved particle morphology.

Regeneration of graphite anode from spent lithium iron phosphate batteries: Microstructure and morphology evolution at different thermal-repair temperature

Recycling of graphite anode from spent lithium ion batteries is critical to the sustainability of the Li-ion battery industry. In this work, the effect of temperature on the microstructure morphology of graphite is studied systematically and the correspondence between the structure morphology and electrochemical properties is elucidated for the first time. The results show that heat treatment leads to the carbonization of organic impurities in spent graphite and the formation of an amorphous carbon layer on the graphite surface. The evolution of the carbon layer from formation to disappearance occurs at different heat-treatment temperatures, which is why the optimal heat-treatment temperature is not the highest heat-treatment temperature. Under optimal conditions, the regenerated graphite exhibits a charging capacity of 339.5 mAh g−1 at 0.1C, and displays a high retention rate of 97.7% after 60 cycles. Our work promotes the regeneration and utilization of spent graphite anode in the industry.