Neutron Diffraction Study of the Li-Ion Battery Cathode Li2FeP2O7

Prabeer Barpanda (1, 2) , Gwenaëlle Rousse (3) , Tian Ye (1) , Chris D. Ling (4) , Zakiah Mohamed (4) , Yannick Klein (3) , Atsuo Yamada (1, 2)

1 Department of Chemical System Engineering, The University of Tokyo
2 Unit of Element Strategy Initiative for Catalysts & Batteries, ESICB, Kyoto University
3 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
4 School of Chemistry, The University of Sydney

With a combination of magnetic susceptibility measurements and lowtemperature neutron diffraction analyses, the magnetic structure of Li2FeP2O7 cathode has been solved. This pyrophosphate Li2FeP2O7 compound stabilizes into a monoclinic framework (space group P21/c), having a pseudolayered structure with the constituent Li/Fe sites distributed into MO6 and MO5 building units. The magnetic susceptibility follows a Curie−Weiss behavior above 50 K. Li2FeP2O7 shows a long-range antiferromagnetic ordering at TN = 9 K, as characterized by the appearance of distinct additional peaks in the neutron diffraction pattern below TN. Its magnetic reflections can be indexed with a propagation vector k = (0,0,0). The magnetic moments inside the FeO6−FeO5 clusters are ferromagnetic, whereas these clusters are antiferromagnetic along the chains. The adjacent chains are in turn ferromagnetically arranged along the a-axis. The magnetic structure of Li2FeP2O7 cathode material is described focusing on their localized spin−spin exchange. The magnetic structure and properties have been generalized for Li2FeP2O7−Li2CoP2O7 binary solid solutions

Domaines: Physique Quantique [quant-ph]

Prabeer Barpanda, Gwenaëlle Rousse, Tian Ye, Chris D. Ling, Zakiah Mohamed, et al.. Neutron Diffraction Study of the Li-Ion Battery Cathode Li2FeP2O7. Inorganic Chemistry, 2013, 52, pp.3334-3341. ⟨10.1021/ic302816w⟩. ⟨hal-01056597⟩