Spent Lithium Iron Phosphate Batteries Research Articles

Environment-friendly technology for recovering cathode materials from spent lithium iron phosphate batteries.

The consumption of lithium iron phosphate (LFP)-type lithium-ion batteries (LIBs) is rising sharply with the increasing use of electric vehicles (EVs) worldwide. Hence, a large number of retired LFP batteries from EVs are generated annually. A recovery technology for spent LFP batteries is urgently required. Compared with pyrometallurgical, hydrometallurgical and biometallurgical recycling technologies, physical separating technology has not yet formed a systematic theory and efficient sorting technology. Strengthening the research and development of physical separating technology is an important issue for the efficient use of retired LFP batteries. In this study, spent LFP batteries were discharged in 5 wt% sodium chloride solution for approximately three hours. A specially designed machine was developed to dismantle spent LFP batteries. Extending heat treatment time exerted minimal effect on quality loss. Within the temperature range of 240°C-300°C, temperature change during heat treatment slightly affected mass loss. The change in heat treatment temperature also had negligible effect on the shedding quality of LFP materials. The cathode material and the aluminium foil current collector accounted for a certain proportion in a sieve with a particle size of -1.25 + 0.40 mm. Corona electrostatic separation was performed to separate the metallic particles (with a size range of -1.5 + 0.2 mm) from the nonmetallic particles of crushed spent LFP batteries. No additional reagent was used in the process, and no toxic gases, hazardous solid waste or wastewater were produced. This study provides a complete material recovery process for spent LFP batteries.

Recycling of cathode from spent lithium iron phosphate batteries

We demonstrate the concept of fabricating new lithium ion batteries from recycled spent 18650 lithium ion batteries (LIB). LiFePO4 cathode was extracted from these spent LIB using combined approach of pre-treatment, mechanical treatment and hydrometallurgical process wherein weak organic acids, such as methyl sulfonic acid (MSA) and p-toluene sulfonic acid (TSA), were employed for the first time for leaching at room temperature of metal ions instead of conventional strong acids. High leaching efficiencies (95%) were obtained for extraction of Li and Fe using these acids from black mass. Reuse of these extracted metal ions is also demonstrated by precipitating them and synthesizing LiFePO4 cathode. Structural characterization showed the formation of single-phase LiFePO4 and electrochemical evaluation of this cathode in a LiFePO4/Li half-cell exhibited a capacity of 93 mA h/g and 80 mA h/g at 0.2C and 1C rate respectively with good cycle stability.

Theoretical-molar Fe3+ recovering lithium from spent LiFePO4 batteries: an acid-free, efficient, and selective process

In spent lithium iron phosphate batteries, lithium has a considerable recovery value but its content is quite low, thus a low-cost and efficient recycling process has become a challenging research topic. In this paper, two methods about using the non-oxidizing inorganic iron salt - Fe2(SO4)3 to recover lithium from LiFePO4 are proposed. The method-1 is theoretical-molar Fe2(SO4)3 (Fe2(SO4)3 : LiFePO4 =1:2) dosage is added and more than 97% of lithium can be leached in just 30 min even under a pretty high solid-liquid ratio of 500 g/L. Spectrophotometry provides the evidence of Fe2+/Fe3+ substitution in the leaching process. In the method-2, the generated Fe2+ originating from LiFePO4 is fully utilized with the addition of H2O2, and the dosage of Fe2(SO4)3 is decreased by two thirds (Fe2(SO4)3 : LiFePO4 =1:6). Several sulphates (CuSO4, NiSO4, MgSO4) are employed to explore the leaching mechanism. All the results reveal that the reaction of Fe3+ substituting Fe2+ has a powerful driving force. In addition, these two leaching processes simultaneously present superior selectivity for the impurities. The Fe2(SO4)3 in two methods does not cause pollution and is easily regenerated by adding H2SO4. The proposed rapid, efficient and selective leaching thought would be a competitive candidate for recycling spent LiFePO4 batteries.

A paired electrolysis approach for recycling spent lithium iron phosphate batteries in an undivided molten salt cell

A molten salt paired electrolysis, installed with dual LiFePO4 electrodes, employs electrons as both reducing and oxidizing agents and the molten salt as the solvent to efficiently reclaim end-of-life LiFePO4 batteries.

A new model of trajectory in eddy current separation for recovering spent lithium iron phosphate batteries

Eddy current separation (ECS) is an environment-friendly technology for separating nonferrous metallic particles whose size was from 2 mm to 10 mm. No wastes are generated in ECS. ECS quality of nonferrous metals from solid wastes is rather low in the production practice of spent lithium iron phosphate (LFP) batteries recovering. Repeating separation even manual sorting is required in the production. The traditional method of falling point prediction based on eddy current mechanics uses equivalent acceleration to replace separation motion curves. These curves have low precision and are unsuitable for predicting the motion trajectory of small particle size of sorted materials. In this work, eddy current separation of positive and negative plates in a crushed product of spent lithium iron phosphate battery is used as an example to establish the force and kinematics models of different materials in the eddy current separation. An iterative method, rather than average speed method, is used to improve the accuracy of the model. Displacement interval replaces disengagement angle as a separating index to improve the model’s intuitiveness and practical guidance. In the range of 2–20 mm, test results are consistent with simulation results. The copper and aluminium foils at a magnetic roller speed of 800r/min can be separated to a maximum particle size ratio of 1.72, and the maximum particle size ratio of copper and positive electrode sheets can be large. This paper provided an environmental-friendly and effective technology for separating nonferrous metals from crushed spent LFP batteries.

A facile recycling and regeneration process for spent LiFePO4 batteries

In response to the potential environment pollution and energy waste caused by the increasing spent lithium iron phosphate batteries (LFPs), many recycling methods have been developed. Among previous studies, the physical recycling method has attracted numerous attention due to its uncomplicated process and high efficiency. This work provides a regeneration mechanism of that the organic carbon layer is in situ coated on the surface of LiFePO4 particles by the decomposition of binder so that improves the conductivity and rate capability. When serving as cathode material for lithium ion battery, the 3 h-regenerated lithium iron phosphate battery delivers an excellent electrochemical performance which shows a discharge specific capacity of 151.55 mAh g−1 at 0.2C and delivers a discharge capacity of 120.44 mAh g−1 even at 10C compared with pristine spent LFPs. It delivers a discharge capacity of 124.35 mAh g−1 in first cycle and maintains 103.12 mAh g−1 with a high capacity retention rate of 82.93% after 2000 cycles at 0.5C through 18,650 battery testing. Meaningfully, a facile and sustainable regeneration process has been demonstrated to re-synthesize LiFePO4 from spent LFPs by our study which can be reused as cathode materials for lithium-ion batteries, indicating an economical and facile method to recycle spent LiFePO4 materials in large scale.

Acid-Free and Selective Extraction of Lithium from Spent Lithium Iron Phosphate Batteries via a Mechanochemically Induced Isomorphic Substitution.

Lithium (Li) is the most valuable metal in spent lithium iron phosphate (LiFePO4) batteries, but its recovery has become a challenge in electronic waste recovery because of its relatively low content and inconsistent quality. This study proposes an acid-free and selective Li extraction process to successfully achieve the isomorphic substitution of Li in LiFePO4 crystals with sodium (Na). The method uses low-cost and nontoxic sodium chloride (NaCl) as a cogrinding reagent via a mechanical force-induced solid-phase reaction. X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), and X-ray photoelectron spectroscopy (XPS) characterizations demonstrated the evidence of Li/Na isomorphic substitution, while XPS spectra of Fe 2p, P 2p, and O 1s revealed that the coordination environment of these elements was not significantly altered. Density functional theory calculations further provided evidence that Na and Li share similar outer electron arrangements and coordination environments, favoring Na over Fe as a replacement for Li in LiFePO4. Additionally, the regeneration of NaCl and the recovery of precipitated Li2CO3 were simultaneously achieved with Na2CO3 as the sole reagent. This concise and efficient acid-free mechanochemical process for Li extraction is a promising candidate for feasible recycling technology of Li from spent LiFePO4 batteries. The proposed process is particularly appealing because of its high selectivity, considerable economic advantages, and environmental benefits.

Combined mechanical process recycling technology for recovering copper and aluminium components of spent lithium-iron phosphate batteries

The recycling processes of spent lithium iron phosphate batteries comprise thermal, wet, and biological and mechanical treatments. Limited research has been conducted on the combined mechanical process recycling technology and such works are limited to the separation of metal and non-metal materials, which belongs to mechanical recovery. In this article the combined mechanical process recycling technology of spent lithium iron phosphate batteries and the separation of metals has been investigated. The spent lithium iron phosphate batteries monomer with the completely discharged electrolyte was subjected to perforation discharge. The shell was directly recycled and the inner core was directly separated into a positive electrode piece, dissepiment, and negative electrode piece. The dissociation rate of the positive and negative materials reached 100.0% after crushing when the temperature and time reached 300 °C and 120 min. The crushed products were collected and sequentially sieved after the low-temperature thermal treatment. Then, nonferrous metals (copper and aluminium) were separated from the crushed spent lithium iron phosphate batteries by eddy current separation with particle size -4 + 0.4. The optimised operation parameters of eddy current separation were fed at speeds of 40 r min-1, and the rotation speed of the magnetic field was 800 r min-1. The nonferrous metals of copper and aluminium were separated by the method of pneumatic separation. The optimal air speed was 0.34 m s-1 for the particle-size -1.6 + 0.4 mm and 12.85-14.23 m s-1 for the particle-size -4 + 1.6 mm. The present recycling process is eco-friendly and highly efficient and produces little waste.

Pneumatic separation and recycling of anode and cathode materials from spent lithium iron phosphate batteries.

A novel approach to recycling of copper and aluminum fragments in the crushed products of spent lithium iron phosphate batteries was proposed to achieve their eco-friendly processing. The model of pneumatic separation that determines the optimal airflow velocity was established using aerodynamics. The influence of the airflow velocity, and the density and thickness, and their ratios, of the aluminum and copper fragments on pneumatic separation were evaluated. The results show that the optimal airflow velocities of copper and aluminum fragments with and without the electrode materials are 3.27m/s and 1.67m/s, respectively. The accuracy and reliability of the present model was verified using a pneumatic separation experiment. It is concluded that graded pneumatic separation is unnecessary for the crushed particle size more than 9 mm. The experimentally determined optimal airflow velocity of the copper and aluminum fragments with and without the electrode materials is 3.3m/s and 1.7m/s, respectively. The mass fractions of the copper and aluminum fragments upon removal of the electrode materials after pneumatic separation are 97% and 96%, respectively, and both with the electrode material achieve 97.0%. The theoretically obtained optimal airflow velocities have good agreements with the experimentally obtained ones.

A facile recovery process for cathodes from spent lithium iron phosphate batteries by using oxalic acid

A simplistic and novel leaching process is developed to dispose spent lithium iron phosphate (LiFePO 4 ) batteries. In this paper, oxalic acid is selected as a leaching reagent to recover lithium as a resource and remove phosphorus from LiFePO 4 batteries, benefiting from its low natural effects. The physical properties of spent cathode materials (before leaching) and residues (after leaching) are identified by X-ray diffraction (XRD) and scanning electronic microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The total amounts of Li and Fe are analyzed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The process occurs under conditions of a 0.3 mol·L -1 oxalic acid concentration, a temperature of 80°C, a reaction time of 60 min and a solid/liquid ratio of 60 g· L -1 . It can effectively precipitate ~92% ferrum in terms of FeC 2 O 4 ·2H 2 O from LiFePO 4 , with the leaching efficiency of Li achieving up to 98%. This method demonstrates a new strategy for dealing with spent lithium iron phosphate batteries with a low cost and low environmental impact.

Regeneration cathode material mixture from spent lithium iron phosphate batteries

Cathode materials mixture (LiFePO4/C and acetylene black) is recycled and regenerated by using a green and simple process from spent lithium iron phosphate batteries (noted as S-LFPBs). Recovery cathode materials mixture (noted as Recovery-LFP) and Al foil were separated according to their density by direct pulverization without acid/alkali leaching for the first time. Subsequently, Recovery-LFP is further directly regenerated with solid state reaction and reused for lithium ion battery without adding acetylene black at the first time. Compared with recovery material, regeneration cathode materials mixture (noted as regeneration-LFP) displays excellent electrochemical performances, which delivers a discharge capacity of 129.43 mAh g−1 in the first and maintains 120.32 mAh g−1 with a high capacity retention rate of 92.96% after 1000 cycles at 0.5C through 18,650 battery testing. It is concluded that the regeneration material can be reused as cathode materials for lithium batteries.

Selective recovery of lithium from spent lithium iron phosphate batteries: a sustainable process

An effective and sustainable approach is demonstrated for selective leaching of lithium from spent lithium iron phosphate batteries.

A Closed-Loop Process for Selective Metal Recovery from Spent Lithium Iron Phosphate Batteries through Mechanochemical Activation

With the increasing consumption of lithium ion batteries (LIBs) in electric and electronic products, the recycling of spent LIBs has drawn significant attention due to their high potential of environmental impacts and waste of valuable resources. Among different types of spent LIBs, the difficulties for recycling spent LiFePO4 batteries rest on their relatively low extraction efficiency and recycling selectivity in which secondary waste is frequently generated. In this research, mechanochemical activation was developed to selectively recycle Fe and Li from cathode scrap of spent LiFePO4 batteries. By mechanochemical activation pretreatment and the diluted H3PO4 leaching solution, the leaching efficiency of Fe and Li can be significantly improved to be 97.67% and 94.29%, respectively. To understand the Fe and Li extraction process and the mechanochemical activation mechanisms, the effects of various parameters during Fe and Li recovery were comprehensively investigated, including activation time, cathode p...

Direct regeneration of cathode materials from spent lithium iron phosphate batteries using a solid phase sintering method

A direct regeneration of cathode materials from spent LiFePO4 batteries using a solid phase sintering method has been proposed in this article.