Rechargeable natural nanobatteries : diving into nanomagnetites on an atomic scale

Scientists from Université Grenoble Alpes, using a unique geo-spectro-chemical combined analysis at the Institut des sciences de la Terre de Grenoble (ISTerre - CNRS/IRD/UGA/UGE/USMB), have made a significant discovery that challenges previous theories. Their research reveals that a nano-battery, magnetite, is discharged not starting from its outside, but from its inside, while it is recharged by ferrous iron. Rhenium, a critical metal used in high temperature turbines, is also used to reconstruct paleoenvironment dynamics.
Cross section of the recharged nano magnetite battery showing the discharge/oxidized layer in yellow, the recharging ion in green and the recharged magnetite in red (Figure 1a), and the single rhenium atom sitting on Fe atom raws (Figure 1b) have been analyzed using in situ techniques, combined to innovative analytical developments at the ISTerre geochemical and mineralogical analytical platform (GMP). [1]

Researchers from Université Grenoble Alpes, drawing on the geo-spectro-chemical platform at ISTerre and spectro-microscopic analyses conducted at ESRF, ALS, IMMM, and LPS, have revealed a previously unknown discharge/recharge mechanism in magnetite nanoparticles. Contrary to the conventional core-shell model focused on external oxidation, they show that discharge occurs at the core of the particle, while recharge takes place through the insertion of Fe²⁺ ions at the periphery.

Furthermore, this work reveals that the Re(VII) anion is reduced to Re(IV) atoms or polynuclear clusters directly on the surface of magnetite, offering a new perspective on the trapping and transport of critical (or radioactive) elements in natural environments. The pre-oxidized and then recharged nanoparticles exhibit a maghemite “core” surrounded by a conductive magnetite shell, through which electrons travel to reach and discharge the core.

This research was conducted at :
  • ISTerre Grenoble, ESRF Grenoble, ALS Berkeley, IMMM Le Mans, and LPS Orsay as part of the CNRS-MITI and METSA projects.
  • The results of this study will be published in the journal Science Advances on May 16, 2025.

Bibliography

Single rhenium atoms on nanomagnetite : Probing the recharge process that controls the fate of rhenium in the environment
R. R. Ding, C. Guida, C. I. Pearce, E. Arenholz, J. M. Grenèche, A. Gloter, A. C. Scheinost, K. O. Kvashnina, K. F. Wang, A. Fernandez-Martinez, Y. Mu, K. M. Rosso, L. Charlet,
Science Advances 2025.
DOI : https://doi.org/10.1126/sciadv.adq3650

Scientific contacts

[1] The GMP platform has been co-funded by the CNRS, the French Agency for Nuclear waste (ANDRA) and the Auvergne-Rhône-Alpes Region. It is part of the French Geochemical & Experimental Network (RéGEF).