Search Results

Now showing 1 - 4 of 4
  • Item
    In situ Raman spectroscopy on silicon nanowire anodes integrated in lithium ion batteries
    (Pennington, NJ : Electrochemical Society Inc., 2019) Krause, A.; Tkacheva, O.; Omar, A.; Langklotz, U.; Giebeler, L.; Dörfler, S.; Fauth, F.; Mikolajick, T.; Weber, W.M.
    Rapid decay of silicon anodes during lithiation poses a significant challenge in application of silicon as an anode material in lithium ion batteries. In situ Raman spectroscopy is a powerful method to study the relationship between structural and electrochemical data during electrode cycling and to allow the observation of amorphous as well as liquid and transient species in a battery cell. Herein, we present in situ Raman spectroscopy on high capacity electrode using uncoated and carbon-coated silicon nanowires during first lithiation and delithiation cycle in an optimized lithium ion battery setup and complement the results with operando X-ray reflection diffraction measurements. During lithiation, we were able to detect a new Raman signal at 1859 cm−1 especially on uncoated silicon nanowires. The detailed in situ Raman measurement of the first lithiation/delithiation cycle allowed to differentiate between morphology changes of the electrode as well as interphase formation from electrolyte components.
  • Item
    Electrochemically deposited nanocrystalline InSb thin films and their electrical properties
    (Cambridge : Royal Society of Chemistry, 2016) Hnida, K.E.; Bäßler, S.; Mech, J.; Szaciłowski, K.; Socha, R.P.; Gajewska, M.; Nielsch, K.; Przybylski, M.; Sulka, G.D.
    We present an electrochemical route to prepare nanocrystalline InSb thin films that can be transferred to an industrial scale. The morphology, composition, and crystallinity of the prepared uniform and compact thin films with a surface area of around 1 cm2 were investigated. The essential electrical characteristics such as conductivity, Seebeck coefficient, the type, concentration and mobility of charge carriers have been examined and compared with InSb nanowires obtained in the same system for electrochemical deposition (fixed pulse sequence, temperature, electrolyte composition, and system geometry). Moreover, obtained thin films show much higher band gap energy (0.53 eV) compared to the bulk material (0.17 eV) and InSb nanowires (0.195 eV).
  • Item
    Correction: Electrochemically deposited nanocrystalline InSb thin films and their electrical properties (Journal of Materials Chemistry C (2016) 4 (1345-1350) DOI: 10.1039/C5TC03656A)
    (London : RSC Publ., 2019) Hnida, K.E.; Bäßler, S.; Mech, J.; Szaciłowski, K.; Socha, R.P.; Gajewska, M.; Nielsch, K.; Przybylski, M.; Sulka, G.D.
    There was an error in eqn (3) which was reproduced from the literature and used for the interpretation of the results. The calculations (using the equations from an original work from 1987) were done according the correct version of eqn (3) presented below:. (Table Presented). © 2019 The Royal Society of Chemistry.
  • Item
    Systematic tuning of segmented magnetic nanowires into three-dimensional arrays of 'bits'
    (London : RSC Publishing, 2017) Bochmann, S.; Fernandez-Pacheco, A.; Mačković, M.; Neff, A.; Siefermann, K.R.; Spiecker, E.; Cowburn, R.P.; Bachmann, J.
    A method is presented for the preparation of a three-dimensional magnetic data storage material system. The major ingredients are an inert nanoporous matrix prepared by anodization and galvanic plating of magnetic and non-magnetic metals in wire shape inside the cylindrical pores. The individual nanomagnets consist of a nickel-cobalt alloy, the composition of which is tuned systematically by adjusting the electrolytic bath composition at one optimal applied potential. The lowest magnetocrystalline anisotropy is obtained at the composition Ni60Co40, as quantified by superconducting quantum interference device magnetometry. Wires of this composition experience a pinning-free propagation of magnetic domain walls, as determined by single-wire magneto-optical Kerr effect magnetometry. Adding copper into the electrolyte allows one to generate segments of Ni60Co40 separated by non-magnetic copper. The segment structure is apparent in individual nanowires imaged by scanning electron microscopy, UV-photoelectron emission microscopy, and transmission electron microscopy. The single-domain structure of the wire segments is evidenced by magnetic force microscopy.