CE05 - Une énergie durable, propre, sûre et efficace

Mg-Ion/Sulfur batteries with Alloying Electrodes – MISTRALE

Submission summary

In the quest for better energy management, "post-lithium" systems are emerging. The explosion in the production of Li-ion batteries can face sustainability problems (resources, recycling) and therefore cost fluctuations. It is important to study alternative devices, bringing together electrode materials and electrolytes that are cost-efficient, safe and highly performing.
Magnesium batteries have seen renewed interest in recent years. Nevertheless, the limited diffusion of ions in conventional host structures (lamellar oxides, polyanionic compounds) remains a brake on the development of such systems. The use of conversion electrode materials such as sulfur is an alternative solution. In addition, the combination of a magnesium anode and a sulfur cathode meets the criteria mentioned above. However, the particular chemical properties of these elements, and in particular the passivation of magnesium, induce the electrolyte design towards complex and/or corrosive formulations, which are therefore unsuitable for future industrialization. The concept of the MISTRALE project is to replace magnesium with MgxM alloys to allow the use of more conventional and safe electrolytes. In addition, electrode shaping starting from alloy powder is easier than with magnesium metal, which again makes possible a possible transfer to large scale production.
Indeed, some p-block elements can react electrochemically with magnesium to form alloys. Specific and/or volumetric capacities are often very important, and the large volume variations related to the alloy reaction can be minimized with an appropriate electrode formulation. Obviously, the theoretical energy densities of the MgxM/S batteries will be lower than for an ideal Mg/S system, but this drop remains low and can be accepted if an industrial transfer remains possible (which is not the case with Mg/S systems currently presented in the literature).

The organization of the MISTRALE project is based on an already proven methodology, firstly a review of MgxM alloys (syntheses, morphology, and electrode shaping) and simple electrolytic formulations (mainly a dissolved magnesium salt in an organic solvent). In a second step, the selected electrode materials and electrolytes will be integrated in complete batteries, with positive electrodes based on sulfur. The detailed characterization of the phenomena taking place within the electrode materials or at the electrode-electrolyte interfaces will be an important step in order to be able to evaluate the influence of the presence of an alloy instead of magnesium on the phenomena of dissolution and reduction of polysulfide species, which usually contribute to the gradual decline in performance in metal/sulfur systems.
If most electrochemical tests will be carried out in button cells, the transition to "pouch-cells" is planned at the end of the project, as an essential first step before a possible prototyping study.

Project coordination

Romain Berthelot (Institut de chimie moléculaire et des matériaux - Institut Charles Gerhardt Montpellier)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

ICGM Institut de chimie moléculaire et des matériaux - Institut Charles Gerhardt Montpellier

Help of the ANR 241,304 euros
Beginning and duration of the scientific project: - 36 Months

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