Operando Electron Magnetic Measurements in Li-Ion Batteries

One of the challenges in the development of batteries consists in the investigation of new electrode materials and comprehension of the mechanism of lithium uptake. Herein, we report on the first in operando measurements of electron magnetism on a battery during cycling. We have succeeded in designing a non magnetic cell and have investigated the lithiation mechanism of FeSb₂, a high energy density anode material. The stepwise increase of the magnetic moment reveals an increase of amorphous Fe nanoparticle size, while Sb undergoes a reversible alloying with Li.¹

In operando electron magnetism brings macroscopic and quantitative data on the amorphous Fe nanostructures formed during cycling. The investigation of real time characterization techniques enables the collection of information at the nanoscale, required to elucidate electrochemical mechanism. Since most of the electrode materials are based on 3d transition metals with high electron magnetic moment, we believe in-situ electron magnetic measurements will bring valuable information on conversion or alloying mechanism to forecast more efficient electrodes.

[1] G. Gershinsky, E. Bar, L. Monconduit, D. Zitoun Energy and Environmental Sciences 2014, C4EE00490F