| Autor: |
Ulusoy S; Department Materials Science and Engineering, Uppsala University, P.O. Box 35, 751 03 Uppsala, Sweden., Feygenson M; Department Materials Science and Engineering, Uppsala University, P.O. Box 35, 751 03 Uppsala, Sweden.; European Spallation Source ERIC, SE-22100 Lund, Sweden.; Jülich Centre for Neutron Science (JCNS-1) Forschungszentrum Jülich, D-52425 Jülich, Germany., Thersleff T; Department Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden., Uusimaeki T; Department Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden., Valvo M; Department Chemistry, Uppsala University, 752 37 Uppsala, Sweden., Roca AG; Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra 08193, Barcelona, Spain., Nogués J; Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra 08193, Barcelona, Spain.; ICREA, Pg. Lluís Companys 23, Barcelona 08010, Spain., Svedlindh P; Department Materials Science and Engineering, Uppsala University, P.O. Box 35, 751 03 Uppsala, Sweden., Salazar-Alvarez G; Department Materials Science and Engineering, Uppsala University, P.O. Box 35, 751 03 Uppsala, Sweden. |
| Abstrakt: |
Due to their high potential energy storage, magnetite (Fe 3 O 4 ) nanoparticles have become appealing as anode materials in lithium-ion batteries. However, the details of the lithiation process are still not completely understood. Here, we investigate chemical lithiation in 70 nm cubic-shaped magnetite nanoparticles with varying degrees of lithiation, x = 0, 0.5, 1, and 1.5. The induced changes in the structural and magnetic properties were investigated using X-ray techniques along with electron microscopy and magnetic measurements. The results indicate that a structural transformation from spinel to rock salt phase occurs above a critical limit for the lithium concentration ( x c ), which is determined to be between 0.5< x c ≤ 1 for Fe 3-δ O 4 . Diffraction and magnetization measurements clearly show the formation of the antiferromagnetic LiFeO 2 phase. Upon lithiation, magnetization measurements reveal an exchange bias in the hysteresis loops with an asymmetry, which can be attributed to the formation of mosaic-like LiFeO 2 subdomains. The combined characterization techniques enabled us to unambiguously identify the phases and their distributions involved in the lithiation process. Correlating magnetic and structural properties opens the path to increasing the understanding of the processes involved in a variety of nonmagnetic applications of magnetic materials. |
