A green process for phosphorus recovery from spent LiFePO4 batteries by transformation of delithiated LiFePO4 crystal into NaFeS2

Recycling and Reuse of Spent LIBs: Technological Advances and Future Directions

Recovering valuable metals from spent lithium-ion batteries (LIBs), a kind of solid waste with high pollution and high-value potential, is very important. In recent years, the extraction of valuable metals from the cathodes of spent LIBs and cathode regeneration technology are still rapidly developing (such as flash Joule heating technology to regenerate cathodes). This review summarized the studies published in the recent ten years to catch the rapid pace of development in this field. The development, structure, and working principle of LIBs were firstly introduced. Subsequently, the recent developments in mechanisms and processes of pyrometallurgy and hydrometallurgy for extracting valuable metals and cathode regeneration were summarized. The commonly used processes, products, and efficiencies for the recycling of nickel-cobalt-manganese cathodes (NCM/LCO/LMO/NCA) and lithium iron phosphate (LFP) cathodes were analyzed and compared. Compared with pyrometallurgy and hydrometallurgy, the regeneration method was a method with a higher resource utilization rate, which has more industrial application prospects. Finally, this paper pointed out the shortcomings of the current research and put forward some suggestions for the recovery and reuse of spent lithium-ion battery cathodes in the future.

Ferrioxalate photolysis-assisted green recovery of valuable resources from spent lithium iron phosphate batteries

Recovering valuable resources from spent cathodes while minimizing secondary waste generation is emerging as an important objective for the future recycling of spent lithium-ion batteries, including lithium iron phosphate (LFP) batteries. This study proposes the use of oxalic acid leaching followed by ferrioxalate photolysis to separate and recover cathode active material elements from spent LFP batteries. The cathode active material can be rapidly dissolved at room temperature using appropriate quantities of oxalic acid and hydrogen peroxide, as determined through thermodynamic calculations. The dissolved ferrioxalate complex ion (Fe(C2O4)33-) is selectively precipitated through subsequent photolysis at room temperature. Depending on the initial concentration, the decomposition ratio can exceed 95 % within 1-4 h. Molecular mechanism analysis reveals that the decomposition of the Fe(C2O4)33- complex ion into water-insoluble FeC2O4·2H2O results in the precipitation of iron and the separation of metal elements. Lithium can be recovered as dihydrogen phosphates through filtration and water evaporation. No additional precipitant is needed and no other side products are generated during the process. Oxalic acid leaching followed by photolysis offers an environmentally friendly and efficient method for metal recovery from spent LFP cathodes. The photochemical process is a promising approach for reducing secondary waste generation in battery recycling.

Comprehensive Technology for Recycling and Regenerating Materials from Spent Lithium Iron Phosphate Battery

The lithium iron phosphate (LFP) battery has been widely used in electric vehicles and energy storage for its good cyclicity, high level of safety, and low cost. The massive application of LFP battery generates a large number of spent batteries. Recycling and regenerating materials from spent LFP batteries has been of great concern because it can significantly recover valuable metals and protect the environment. This paper aims to critically assess the latest technical information available on the echelon utilization and recycling of spent LFP batteries. First, it focuses on the progress of disassembly, evaluation and detection, regrouping, and application in echelon utilization. Then, the recycling technologies, including pretreatment, direct repair, and material regeneration, of spent LFPs are summarized. Finally, the paper proposes some challenges in the echelon utilization and recycling of spent LFP batteries, and concludes with recommendations for an intelligent, refined, and clean LFP battery circulation system that are required to ensure the sustainable development of spent LFP battery recycling.

Recovery of Li2CO3 from Spent LiFePO4 by Using a Novel Impurity Elimination Process

The large-scale implementations of lithium iron phosphate (LFP) batteries for energy storage systems have been gaining attention around the world due to their quality of high technological maturity and flexible configuration. Unfortunately, the exponential production of LFP batteries is accompanied by an annual accumulation of spent batteries and a premature consumption of the lithium resource. Recycling souring critical battery materials such as Li₂CO₃ is essential to reduce the supply chain risk and achieve net carbon neutrality goals. During the recovery of Li₂CO₃, impurity removal is the most crucial step in the hydrometallurgy process of spent LiFePO₄, which determines the purity of Li₂CO₃. By investigating and comparing the results of impurity elimination from the purified Li⁺-containing liquids with strong and weak alkalis under identical pH conditions, respectively, a strategy based on an alkali mixture has been proposed. The purified Li⁺-containing liquid was, thereafter, concentrated and sodium carbonate was added in order to precipitate Li₂CO₃. As a result, a high purity Li₂CO₃ (99.51%) of battery grade was obtained. LiFePO₄ prepared with the recovered Li₂CO₃ and FePO₄ as raw materials also displayed a comparative high capacity and stable cycle performance to the commercial product and further verified the electrochemical activity of the recovered materials.

A sustainable closed-loop method of selective oxidation leaching and regeneration for lithium iron phosphate cathode materials from spent batteries

A sustainable closed-loop method for recovering waste lithium iron phosphate batteries is developed in this paper. Li⁺ was selectively leached from cathode materials in a system of NaHSO₄ and H₂O₂. Under the optimal conditions of leaching temperature of 65 °C, 1.1 times molar quantity NaHSO₄, 2 vol% H₂O₂, solid-liquid ratio of 100 g/L and leaching time of 15 min, the leaching efficiency of Li can reach 99.84%, while Fe is only 0.048%. Meanwhile, XRD, FTIR, XPS and TEM analysis were carried out to explore the conversion mechanism in the oxidation leaching process of the original raw and leaching products. Li⁺ in the filtrate was precipitated with Na₂CO₃ and converted into Li₂CO₃. The precipitated salty wastewater can be converted into leaching agent for recycling by adding a certain amount of sulfuric acid. The recycled products are used to synthesize LiFePO₄ materials, and regenerated LiFePO₄ materials show good electrochemical properties. The discharge capacity displays 141.3 mAhg^-1 at 1C, with the capacity retention rate of 99.4% after 200 cycles. This study provides a sustainable closed-loop process for recycling and reuse of waste LiFePO₄ batteries, which promotes resource conservation and environmental protection.