Microwave synthesis of high-quality and uniform 4 nm ZnFe2O4nanocrystals for application in energy storage and nanomagnetics.
Magnetic nanocrystals with a narrow size distribution hold promise for many applications in different areas ranging from biomedicine to electronics and energy storage. Herein, the microwave-assisted sol-gel synthesis and thorough characterization of size-monodisperse zinc ferrite nanoparticles of spherical shape is reported. X-ray diffraction,57Fe Mössbauer spectroscopy and X-ray photoelectron spectroscopy all show that the material is both chemically and phase-pure and adopts a partially inverted spinel structure with Fe3+ions residing on tetrahedral and octahedral sites according to (Zn0.32Fe0.68)tet[Zn0.68Fe1.32]octO4±δ. Electron microscopy and direct-current magnetometry confirm the size uniformity of the nanocrystals, while frequency-dependent alternating-current magnetic susceptibility measurements indicate the presence of a superspin glass state with a freezing temperature of about 22 K. Furthermore, as demonstrated by galvanostatic charge-discharge tests and ex situ X-ray absorption near edge structure spectroscopy, the as-prepared zinc ferrite nanocrystals can be used as a high-capacity anode material for Li-ion batteries, showing little capacity fade - after activation - over hundreds of cycles. Overall, in addition to the good material characteristics, it is remarkable that the microwave-based synthetic route is simple, easily reproducible and scalable.
Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
Christian
C
Suchomski
Battery and Electrochemistry Laboratory, Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Ben
B
Breitung
Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Ralf
R
Witte
Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Michael
M
Knapp
Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Sondes
S
Bauer
Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Tilo
T
Baumbach
Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Christian
C
Reitz
Battery and Electrochemistry Laboratory, Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.|Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Torsten
T
Brezesinski
1-phenylethanol route; lithium-ion battery; nanomagnetism; nanoparticles; nonaqueous sol–gel synthesis; zinc ferrite