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The demand for lithium-ion batteries (LIBs) is driven by environmental concerns and market growth, particularly in the transportation sector. The EU's push for net-zero emissions and the European Green Deal accentuates the role of battery technologies in sustainable energy supply. Organic acids, like gluconic acid, are explored for the eco-friendly leaching of valuable metals from spent batteries. This study investigates leaching kinetics using gluconic acid (hydrolyzed glucono-1.5-lacton), analyzing factors such as temperature, acid concentration, particle size, and reaction time. Results reveal the temperature's influence on leaching efficiency for cobalt, nickel, and lithium. The mechanism for Co follows a surface chemical reaction model with an activation energy of 28.2 kJ·mol−1. Nickel, on the contrary, shows a diffusion-controlled regime and an activation energy of 70.1 kJ·mol−1. The reaction of leaching Ni and Co using gluconic acid was determined to be first-order. The process within this environmentally friendly alternative leaching agent shows great potential for sustainable metal recovery. [ABSTRACT FROM AUTHOR]

Organic acids, such as gluconic acid, have been widely studied for their potential in the hydrometallurgical recycling of lithium-ion batteries. These organic alternative leachants offer several environmental and recycling-related benefits, including a high selectivity in terms of dissolving valuable metals, as well as a reduced environmental impact due to the application of non-toxic and biodegradable organic acids. Gluconic acid has previously been demonstrated in the oxidative degradation of glucose, either as an alternative reducing agent or in biometallurgical approaches, and has been described as an efficiency-supporting reagent. The results of this study demonstrate the effectiveness of using gluconic acid for the recovery of metals such as lithium, cobalt, nickel, and manganese from spent lithium-ion batteries. Recovery rates of above 98% for lithium, cobalt, and manganese, and a recovery rate of more than 80% for nickel could be reached by optimizing the leaching parameters, including an acid concentration of 1.2 M, the addition of hydrogen peroxide of 1.6 vol %, a solid-to-liquid ratio of 25 g/L, a leaching temperature of 75 °C, and a leaching time of 192 min. These results show that gluconic acid has the potential to become a viable and sustainable option for the hydrometallurgical recycling of lithium-ion batteries, as well as for opening a possible biohydrometallurgical route. Further investigations are required into the results obtained, to verify the existence of a new hydrometallurgical and sustainable process route involving gluconic acid. [ABSTRACT FROM AUTHOR]

The further development of lithium-ion batteries leads to an improvement in power densities as well as safety and thus requires an optimization of the materials used. For this purpose, among other approaches, the anode materials are doped with silicon oxide or metallic silicon is used as the anode. However, silicon is a semimetal and is known to lead to the formation of jelly-like fluids in hydrometallurgical processes under certain conditions. This publication evaluates which parameters are responsible for this viscosity change in the leaching solutions during the recycling of lithium-ion batteries and examines the corresponding reaction mechanism behind this phenomenon. Furthermore, the leaching efficiency for the valuable metals nickel, cobalt, lithium and manganese is evaluated and the influence of different silicon contents in the solution is investigated. It could be shown that, especially the simultaneous presence of H2SO4, H2O2 and Si or SiO2, lead to a significant viscosity increase due to the formation of metasilicic acid and, accordingly, the leaching efficiencies of the valuable metals are negatively influenced. [ABSTRACT FROM AUTHOR]

The need to recover critical elements from lithium-ion batteries is undisputed. The further development of cathode materials and the move towards cheaper alternatives make it necessary to adapt the corresponding hydrometallurgical recycling processes. In the best case, however, a process is so flexibly structured and designed that it can be used for a variety of cathode materials with different compositions. The leaching of nickel manganese cobalt oxide with sulfuric acid and a reducing agent has already been demonstrated and optimized in previous research work. Based on these data, an evaluation of the process as well as a parameter study for lithium iron phosphate cathode material, which has recently been used with increasing frequency but has a significantly lower valuable metal content, was carried out within the scope of this publication. By using the synergy effects that occur, an optimized parameter combination for the leaching of the critical element lithium could be found and further critical factors identified. [ABSTRACT FROM AUTHOR]