(Invited) Selective Cobalt Precipitation By Using Organic Linkers: New Close Loop Process for Cobalt Resource Sustainability
Authors: Peralta David , Lavergne-Bril Anna-Carolina , Billy Emmanuel , Colin Jean-Francois , Bloch Didier , Patoux Sebastien 
Published: December 2020

Cobalt is a critical material used in many applications such as steel alloys, catalysis and of course Li-Ion batteries. The massive market diffusion of electrified passenger vehicles expected in the next decades will most probably induce a considerable need of this scarce and expensive metal.1 The small number of locations where cobalt is produced may lead to several drawbacks such as geopolitical dependence, material shortage and also production capability. Consequently, it is necessary to identify new and efficient solutions to trap and reuse cobalt out of from various sources. Cobalt could be of course obtained by mining but it is also possible to recycle it from used batteries.
Here, we propose a disruptive and very efficient way to selectively precipitate cobalt from a solution by using Metal-Organic Frameworks (MOFs). MOFs belong to a particular class of porous hybrid materials.2 These hybrid materials are intensively studied for adsorption and catalysis applications. Recently, we discovered an organic ligand which is able to selectively precipitate cobalt based-MOFs from a mixture of nickel, manganese and cobalt.3–5

When a well-selected linker is put in contact with an equimolar solution of nickel, manganese and cobalt, at room temperature, a precipitate appears. The powder is recovered by filtration and characterized. In specific experimental conditions, we show that a hybrid material, belonging to the MOFs family, is synthesized. ICP-AES of the resulting material shows that the resulting compound contains up to 99% cobalt (molar percentage as a function of the metal contained in the MOF). This result may pave the way to the reuse of cobalt in many applications fields but the battery recycling field could reveal a critical case study. We introduce here the experimental results achieved when this new type of synthesis is used with a real, spent Li-ion battery leach solution. The resulting material has a cobalt content of 94.4 % (vs other metals) and contains a large part of the initial amount of cobalt initially present in the solution (figure 1).
The resulting material could be directly reused and implemented as positive electrode active material in a new Li-Ion battery. One other interesting aspect of this synthesis is the high value product obtained: the resulting MOF can indeed have many other uses such as catalyst or adsorbent
The results presented during the conference have been recently patented but have never been published and introduced before.
References
(1) Bloch, D.; Lefebvre, G.; Les matériaux requis par les batteries Li-ion. REE 2019-4
2019, 2019 (4).
(2) Férey, G. Hybrid Porous Solids: Past, Present, Future. Chem. Soc. Rev.
2007, 37 (1), 191–214. https://doi.org/10.1039/B618320B.
(3) Peralta, D.; Chaplais, G.; Simon-Masseron, A.; Barthelet, K.; Chizallet, C.; Quoineaud, A.-A.; Pirngruber, G. D. Comparison of the Behavior of Metal–Organic Frameworks and Zeolites for Hydrocarbon Separations. J. Am. Chem. Soc.
2012, 134 (19), 8115–8126. https://doi.org/10.1021/ja211864w.
(4) Peralta, D.; Chaplais, G.; Simon-Masseron, A.; Barthelet, K.; Pirngruber, G. D. Metal–Organic Framework Materials for Desulfurization by Adsorption. Energy Fuels
2012, 26 (8), 4953–4960. https://doi.org/10.1021/ef300762z.
(5) Chevalier, V.; Martin, J.; Peralta, D.; Roussey, A.; Tardif, F. Performance of HKUST-1 Metal-Organic Framework for a VOCs Mixture Adsorption at Realistic Concentrations Ranging from 0.5 to 2.5 Ppmv under Different Humidity Conditions. J. Environ. Chem. Eng.
2019, 7 (3), 103131. https://doi.org/10.1016/j.jece.2019.103131.

Figure 1: a/ Chart of the new close loop process presented, b/ ICP results of the starting solution and of the final precipitate, c/ electrochemical results obtained with a coin-cell using MOF

Figure 1