Browsing by Author "Ye, T"

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    Neutron diffraction study of the li-ion battery cathode Li2FeP2O7
    (American Chemical Society, 2013-03-18) Barpanda, P; Rousse, G; Ye, T; Ling, CD; Mohamed, Z; Klein, Y; Yamada, A
    With a combination of magnetic susceptibility measurements and low-temperature neutron diffraction analyses, the magnetic structure of Li2FeP2O7 cathode has been solved. This pyrophosphate Li2FeP2O7 compound stabilizes into a monoclinic framework (space group P2(1)/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 T-N = 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. © 2013, American Chemical Society.
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    A new polymorph of Na2MnP2O7 as a 3.6 V cathode material for sodium-ion batteries
    (Royal Society of Chemistry, 2013-01-01) Barpanda, P; Ye, T; Avdeev, M; Chung, SC; Yamada, A
    Exploring novel low-cost cathodes for sodium-ion batteries, here we unveil [small beta]-Na2MnP2O7, a new pyrophosphate cathode. Stabilizing into a triclinic structure, it was found to be electrochemically active, delivering a discharge capacity approaching 80 mA h g-1 along with the highest ever Mn3+/Mn2+ redox potential located at 3.6 V. © 2013, Royal Society of Chemistry