Author: David Geiss [Institute of Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT)]
Lithium-ion batteries (LIB) are an indispensable part of our everyday lives. The application ranges from smartphones and laptops to electric cars and stationary energy storage systems. In the course of the rapidly increasing demand for electric cars, also in connection with the fulfilment of climate targets in many countries worldwide, the recycling of batteries will also pose a major economic and ecological challenge. Around half a million tonnes of LIB already have to be recycled. (1) As the demand for raw materials for accumulators is increasing rapidly, a shortage of resources is predicted before 2050. Because currently used recycling methods such as pyrometallurgy and hydrometallurgy have numerous disadvantages, a technology for ecologically and economically efficient recycling is urgently needed.
In the recycling approach used in this work, the chemical conversion of the cathode material is initiated mechanochemically by ball milling. This is solvent-free and, in contrast to commercial methods, also takes place without the addition of large amounts of acid. The use of aluminum foil, which is already present as a power collector in accumulators, also allows cathode waste to be recycled with waste when contaminated aluminum foil from the shredded accumulators is used.
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The recent exponential growth in the Li ion batteries (LIB) market, is largely driven by the demand for electric vehicles and the general transition to a green and digital economy. It is therefore imperative to develop more effective and economic processes for recovering battery raw materials such as Li, Co, Cu and Ni. Moreover, these materials are all classified as critical or strategic (Cu, Ni) raw materials by the European Commission, and for Europe, it is of great importance to build a sustainable European supply chain for Li and other battery raw materials to decrease its dependency on import. In this work, we have studied the possibility to recover Li, Ni, Cu and Co from secondary raw materials like black mass (cathode and anode fraction from shredded end- of-life Li ion batteries), as well as Li from spodumene concentrate, spodumene being an important and available Li mineral. The approach has been to convert the metals in the raw materials to metal chlorides, by chlorination in LiCl-KCl (58 : 42) melts at 470 °C and CaCl2-NaCl-KCl (35 : 30 : 30) at 727 °C. With this method, the metals could potentially be reduced from the chloride matrix by subsequent sequential electrodeposition, utilizing their difference in nobility. Regarding black mass, the highest chlorination yields were obtained from uncalcined material (Li 64 %, Co and Ni 22–24 %, Cu 83 %, and Mn 49 %) in LiCl-KCl at 470 °C, the carbon in the black mass probably enhancing the chlorination rate. For spodumene concentrate, a high yield for Li (100 %) was obtained with Cl2 in CaCl2-NaCl-KCl at 727 °C, this melt composition being more oxoacidic and the higher temperature helping the chlorination kinetics.
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The protonated product of lithium titanate (H2TiO3, HTO) is a promising adsorbent for lithium recovery from alkaline aqueous streams due to its high selectivity and cycling stability. This study investigates how precursor pretreatment influences the solid-state synthesis of its parent phase, monoclinic Li2TiO3 (LTO), and the resulting lithium adsorption performance of HTO. Multiple commercial TiO2 sources and pre-synthesis methodologies, including grinding, ball-milling, and ultrasonication in water, isopropanol, or ethanol, were evaluated for their impact on phase formation and textural properties. X-ray diffraction analysis revealed that high-energy ball-milling results in α-LTO after calcination, a phase that fails to produce effective Li-adsorbing HTO. In contrast, ultrasonication and conventional mixing preserve the desired monoclinic β-LTO structure. HTO derived from monoclinic LTOs exhibited superior performance, with adsorption capacities up to 25.84 mg g−1 and kinetic constants more than twice as high compared to untreated controls. All monoclinic HTOs followed pseudo-second-order kinetics and fit the Langmuir isotherm model, confirming monolayer adsorption. High lithium selectivity was maintained, as demonstrated by selectivity factors such as = 660, and = 2927 for HTOs obtained via ultrasonication in water. In contrast, materials derived from cubic LTO showed negligible lithium selectivity. Notably, HTO prepared via ultrasonication in water matched or exceeded solvent-based methods in performance, offering a more sustainable and scalable processing route. Repeated adsorption-desorption cycles using synthetic brines demonstrated consistent lithium recovery of approximately 30 % per cycle, and minimal titanium leaching. These findings underscore the critical role of precursor pre-treatment in tailoring the properties of lithium sorbents via solid-state synthesis, and identify ultrasonication in water as a scalable, eco-friendly approach to produce high-performance HTO.
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Lithium manganese oxides (LMO) are highly promising sorbents for lithium extraction from Li
-containing brines with high salt contents due to their high sorption capacity and high selectivity toward lithium. However, conventional synthesis routes are limited in scale. Therefore, a novel spray-drying method is presented herein, enabling a scalable synthesis of LMO sorbents for Li
extraction. The ion-exchange material is studied in both synthetic LiCl solutions and two different geothermal brines from the Upper Rhine Valley, demonstrating improved Li selectivity and extraction capabilities compared to materials from hydrothermal synthesis approaches. The extraction behavior in relevant mildly acidic environments is studied in detail. Further material improvements are achieved by substituting a fraction of Mn by Ti, which greatly reduced the dissolution of manganese during acid treatment in the first 5 extraction cycles from 5.6% to only 1.8%. In addition, the maximum sorption capacity of the Ti-substituted LMO (LMTO) can be further increased from 5.05 mmol g
for LMO (35.1 mg g
) to 5.66 mmol g
for LMTO (39.3 mg g
) under optimized m/V ratios. Hence, the results reported herein present a pathway toward LMO-based ion-exchange materials for the direct lithium extraction on an industrial scale.
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The Upper Rhine Graben (URG) is a highly promising area for geothermal lithium (Li) extraction. Li concentration in deep geothermal brine circulating in naturally fractured Visean and Triassic reservoirs exceed 150 mg/L and are combined with significant water flows exploited by geothermal plants. However, there are still a lack of knowledge in the fluid-rock interactions leading to present high Li concentration in the geothermal brine. To address the behavior of Li in the crystalline reservoir during hydrothermal alteration, 36 granite rock samples were selected from 3 deep geothermal wells at Soultz-sous-Forêts (GPK-1, GPK-2 and EPS-1) in France. These samples were analyzed both chemically and mineralogically to assess the impact of dissolution/precipitation on major elements together with Li precipitation in mineral phases or solubilization in the brine. In total, 4 different main alteration facies from low to high alteration grades were identified in the 36 granite samples (fresh granite, propylitic alteration, argillic alteration, argillic alteration and fractured) that displayed significant chemical, mineralogical and textural changes. The Li concentration of the total rocks range from 18 to 1938 ppm and could be attributed to secondary mineral precipitation (illite, illite/smectite and chlorite/smectite mixed layers, quartz, carbonates, barite) and hydrothermal alteration by partial dissolution of the main minerals (biotite, chlorite, feldspars) present in the granite. These results highlight the importance of fluid-rock interactions due to hydrothermal circulation in the mobilization of Li in the reservoir and refine the story behind high Li concentration in the URG brine.
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In order to mitigate the risks associated with cobalt supply, a safe and affordable LiFePO4-based (LFP) cathode for Li-ion batteries can be a significant solution to meet the rapidly growing battery market. However, economical and environmentally friendly recycling of LFP is impossible with currently available recycling technologies. In this study, an acid-free mechanochemical approach is applied to reclaim Li from LFP using Al as a reducing agent. The reaction mechanism involved in reductive ball-milling followed by water leaching has been elucidated through the examination of various milling times and molar ratios of components, fostering a deeper understanding of the process. Assessing the yield and purity of the final products provides insights into potential enhancements for this technology. Utilizing Al as the material of the current collector eliminates the need for additional external additives, thereby simplifying the recycling workflow. Continued research into this process has the potential to facilitate efficient and economical recycling of LFP materials.
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The conventional lithium extraction method involves the calcination of a-spodumene at 1050 °C so that it can be converted to the more-reactive b-spodumene and then a sulfuric acid roasting step at 250 °C. Lithium is finally extracted via leaching with water. This method is energy-intensive, leading to high capital and operational costs. In this study, the direct calcination of a-spodumene with the use of sodium carbonate and calcium oxide was examined, aiming to significantly reduce the calcination temperature and completely omit the sulfuric acid roasting step, thereby radically redesigning the lithium extraction process. The calcination product was then leached with different leaching agents, such as water and sulfuric acid, and at different temperatures. The efficiency of the additives was evaluated through the results of lithium extraction achieved during the leaching step. Different leaching agents and temperatures were investigated. The maximum lithium extraction achieved was 96%, obtained after calcination using a sodium carbonate/spodumene mixture and leaching with sulfuric acid at 90 °C. High lithium extractions, up to 83%, can also be achieved under the same calcination conditions and after leaching with sulfuric acid at lower temperatures, such as 40 °C, and for shorter leaching times.
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The poster is available in German and was presented at the German geothermal conference in Essen (October, 2023). Its summary is available in English in the article New membrane-free technique for the selective separation of lithium and sodium.