Please use this identifier to cite or link to this item: doi:10.22028/D291-31385
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Title: Carbide-Derived Niobium Pentoxide with Enhanced Charge Storage Capacity for Use as a Lithium-Ion Battery Electrode
Author(s): Budak, Öznil
Geißler, Miriam
Becker, Dennis
Kruth, Angela
Quade, Antje
Haberkorn, Robert
Kickelbick, Guido
Etzold, Bastian J. M.
Presser, Volker
Language: English
Title: ACS applied energy materials
Volume: 3
Issue: 5
Startpage: 4275
Endpage: 4285
Publisher/Platform: ACS
Year of Publication: 2020
Publikation type: Journal Article
Abstract: Nb2O5 has been explored as a promising anode material for use as lithium-ion batteries (LIBs), but depending on the crystal structure, the specific capacity was always reported to be usually around or below 200 mAh/g. For the first time, we present coarse-grained Nb2O5 materials that significantly overcome this capacity limitation with the promise of enabling high power applications. Our work introduces coarse-grained carbide-derived Nb2O5 phases obtained either by a one-step or a two-step bulk conversion process. By in situ production of chlorine gas from metal chloride salt at ambient pressure, we obtain in just one step directly orthorhombic Nb2O5 alongside carbide-derived carbon (o-Nb2O5/CDC). In situ formation of chlorine gas from metal chloride salt under vacuum conditions yields CDC covering the remaining carbide core, which can be transformed into metal oxides covered by a carbon shell upon thermal treatment in CO2 gas. The two-step process yielded a mixed-phase tetragonal and monoclinic Nb2O5 with CDC (m-Nb2O5/CDC). Our combined diffraction and spectroscopic data confirm that carbide-derived Nb2O5 materials show disordering of the crystallographic planes caused by oxygen deficiency in the structural units and, in the case of m-Nb2O5/CDC, severe stacking faults. This defect engineering allows access to a very high specific capacity exceeding the two-electron transfer process of conventional Nb2O5. The charge storage capacities of the resulting m-Nb2O5/CDC and o-Nb2O5/CDC are, in both cases, around 300 mAh/g at a specific current of 10 mA/g, thereby, the values are significantly higher than that of the state-of-the-art for Nb2O5 as a LIB anode. Carbide-derived Nb2O5 materials also show robust cycling stability over 500 cycles with capacity fading only 24% for the sample m-Nb2O5/CDC and 28% for o-Nb2O5/CDC, suggesting low degree of expansion/compaction during lithiation and delithiation.
DOI of the first publication: 10.1021/acsaem.9b02549
URL of the first publication: https://pubs.acs.org/doi/abs/10.1021/acsaem.9b02549
Link to this record: hdl:20.500.11880/29393
http://dx.doi.org/10.22028/D291-31385
ISSN: 2574-0962
Date of registration: 7-Jul-2020
Faculty: NT - Naturwissenschaftlich- Technische Fakultät
Department: NT - Materialwissenschaft und Werkstofftechnik
Professorship: NT - Prof. Dr. Volker Presser
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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