| 51. |
- Etman, Ahmed S., et al.
(författare)
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Molybdenum Oxide Nanosheets with Tunable Plasmonic Resonance : Aqueous Exfoliation Synthesis and Charge Storage Applications
- 2019
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 29:4
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Tidskriftsartikel (refereegranskat)abstract
- Herein, a simple aqueous‐exfoliation strategy is introduced for the fabrication of a series of MoO3−x nanosheets (where x stands for oxygen vacancies) using two commercial molybdenum oxide precursors, MoO2 and MoO3. The nanosheets offer a localized surface plasmon resonance (LSPR) effect which is dependent on the structure and local environment of the nanosheets. The LSPR can be efficiently tuned by changing the weight ratio between the molybdenum oxide precursor(s) and/or by solar light irradiation using a low‐energy UV lamp (36 W). For the pristine MoO3−x nanosheets, the highest LSPR signal is obtained for nanosheets prepared using 80% MoO2. On the contrary, after solar light irradiation, the nanosheets prepared using pure MoO3 offer the highest LSPR response. The nanosheets also show an outstanding rate capability when used as binder‐free supercapacitor electrodes in an acidified Na2SO4 electrolyte. The electrodes exhibit discharge capacities of 110 and 75 C g−1 at a scan rate of 20 and 1000 mV s−1, respectively. The MoO3−x nanosheets can likewise be used as a negative electrode material for lithium‐ion batteries. The efficient eco‐friendly synthesis and the ability to tune the photochemical and electrochemical properties of the nanosheets make this approach interesting to many energy‐related research fields.
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| 52. |
- Etman, Ahmed S., et al.
(författare)
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Simple and Green Method for Fabricating V2O5·nH2O Nanosheets for Lithium Battery Application
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the last few years, the synthesis of inorganic two dimensional (2D) materials tremendously increased, due to their promising surface area1,2. However, the synthesis of these 2D materials can significantly influence our environment, by the use of harmful chemicals and severe reaction conditions3,4.Herein, we report on a simple and green strategy for fabricating hydrated vanadium pentoxide (V2O5.nH2O) nanosheets from commercially available vanadium oxides precursors via water based exfoliation technique. Operando and ex situ X-ray diffraction (XRD) studies were conducted to track the structural changes during the exfoliation process. The vanadium oxidation states and the water content of the material were determined by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. Electron microscopy and atomic force microscopy (AFM) showed that the V2O5.nH2O is composed of a few nanometer thick nanosheets. A composite material of the V2O5∙nH2O nanosheets and multi-walled carbon nanotube (MW-CNT) were fabricated and then tested as a free standing electrodes (FSE) and conventionally casted electrodes (CCE) for lithium battery. Both electrodes showed promising capacities and rate capabilities for lithium-ion intercalation.References:(1) Nicolosi, V.; Chhowalla, M.; Kanatzidis, M. G.; Strano, M. S.; Coleman, J. N. Liquid Exfoliation of Layered Materials. Science (80-. ). 2013, 340 (6139), 1226419.(2) Etman, A. S.; Asfaw, H. D.; Yuan, N.; Li, J.; Zhou, Z.; Peng, F.; Persson, I.; Zou, X.; Gustafsson, T.; Edström, K.; Sun, J. A One-Step Water Based Strategy for Synthesizing Hydrated Vanadium Pentoxide Nanosheets from VO2 (B) as Free-Standing Electrodes for Lithium Battery Applications. J. Mater. Chem. A 2016, 4 (46), 17988–18001.(3) Wei, Q.; Liu, J.; Feng, W.; Sheng, J.; Tian, X.; He, L.; An, Q.; Mai, L. Hydrated Vanadium Pentoxide with Superior Sodium Storage Capacity. J. Mater. Chem. A 2015, 3, 8070–8075.(4) Zhou, K.-G.; Mao, N.-N.; Wang, H.-X.; Peng, Y.; Zhang, H.-L. A Mixed-Solvent Strategy for Efficient Exfoliation of Inorganic Graphene Analogues. Angew. Chem. Int. Ed. Engl. 2011, 50 (46), 10839–10842.
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| 53. |
- Etman, Ahmed, 1986-, et al.
(författare)
-
Simple and Green Method for Fabricating V2O5·nH2O Nanosheets for Lithium Battery Application
- 2017
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the last few years, the synthesis of inorganic two dimensional (2D) materials tremendously increased, due to their promising surface area1,2. However, the synthesis of these 2D materials can significantly influence our environment, by the use of harmful chemicals and severe reaction conditions3,4.Herein, we report on a simple and green strategy for fabricating hydrated vanadium pentoxide (V2O5.nH2O) nanosheets from commercially available vanadium oxides precursors via water based exfoliation technique. Operando and ex situ X-ray diffraction (XRD) studies were conducted to track the structural changes during the exfoliation process. The vanadium oxidation states and the water content of the material were determined by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. Electron microscopy and atomic force microscopy (AFM) showed that the V2O5.nH2O is composed of a few nanometer thick nanosheets. A composite material of the V2O5∙nH2O nanosheets and multi-walled carbon nanotube (MW-CNT) were fabricated and then tested as a free standing electrodes (FSE) and conventionally casted electrodes (CCE) for lithium battery. Both electrodes showed promising capacities and rate capabilities for lithium-ion intercalation.
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| 54. |
- Farhat, Douaa, et al.
(författare)
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Towards high-voltage Li-ion batteries : Reversible cycling of graphite anodes and Li-ion batteries in adiponitrile-based electrolytes
- 2018
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Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 281, s. 299-311
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Tidskriftsartikel (refereegranskat)abstract
- Due to their low vapor pressure and their promising electrochemical and thermal stability, N C- (CH2)n-C N dinitriles are proposed as an electrolyte solvent for Li-ion batteries. Adiponitrile (ADN) has substantial advantages, especially for applications requiring high potential cathodes, because it has high electrochemical/thermal stability (up to 6 V vs. Li/Li+, > 120 degrees C). However, to obtain very high voltage batteries, ADN electrolytes must also passivate the anode of the battery. In this work, reversible cycling of graphite in adiponitrile was successfully achieved by adding a few percent of fluoroethylene carbonate allowing the realization of Graphite/NMC Li-ion battery. The battery of specific capacity of 135 mAhh.g(-1) showed a cycling stability for more than 40 cycles. The composition of the solid electrolyte interphase (SEI) was determined as a function of the FEC concentration as well as the state of charge of the graphite anode using hard X-ray photoelectron spectroscopy (HAXPES) and XPS. With FEC, the SEI layer is thinner and depends on the SOC of the anode, but does not depend on the FEC concentration. SEM characterizations clearly showed that the surface of the anode is completely covered by the SEI layer, regardless of the concentration of FEC. Indeed, 2% of FEC is sufficient to suppress the reduction of adiponitrile which is explained by a specific adsorption of FEC on the graphite anode.
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| 55. |
- Fichtner, Maximilian, et al.
(författare)
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Rechargeable Batteries of the Future-The State of the Art from a BATTERY 2030+Perspective
- 2022
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 12:17
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Forskningsöversikt (refereegranskat)abstract
- The development of new batteries has historically been achieved through discovery and development cycles based on the intuition of the researcher, followed by experimental trial and error-often helped along by serendipitous breakthroughs. Meanwhile, it is evident that new strategies are needed to master the ever-growing complexity in the development of battery systems, and to fast-track the transfer of findings from the laboratory into commercially viable products. This review gives an overview over the future needs and the current state-of-the art of five research pillars of the European Large-Scale Research Initiative BATTERY 2030+, namely 1) Battery Interface Genome in combination with a Materials Acceleration Platform (BIG-MAP), progress toward the development of 2) self-healing battery materials, and methods for operando, 3) sensing to monitor battery health. These subjects are complemented by an overview over current and up-coming strategies to optimize 4) manufacturability of batteries and efforts toward development of a circular battery economy through implementation of 5) recyclability aspects in the design of the battery.
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| 56. |
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| 57. |
- Gond, Ritambhara, et al.
(författare)
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A Lignosulfonate Binder for Hard Carbon Anodes in Sodium-Ion Batteries : A Comparative Study
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society. - 2168-0485. ; 9:37, s. 12708-
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Tidskriftsartikel (refereegranskat)abstract
- An important factor in the development of sodium-ion batteries (SIBs) is the use of cheap and sustainable materials. Sodium lignosulfonate, a lignin derivative, is demonstrated here as an attractive, "green", water-soluble, and potentially cost-effective binder for use in hard carbon anodes for SIBs. A comparison of its battery cycling performance is made against other binders including sodium carboxymethyl cellulose and lignin, obtained from the kraft process, as well as sodium alginate, derived from algae. Apart from lignin, which requires processing in N-methyl-2-pyrrolidone, the other three binders are water-soluble. Lignosulfonate shows comparable or better performance, with high capacity retention and stability, when using 1 M NaPF6 in propylene carbonate or ethylene carbonate:diethyl carbonate electrolytes for both half- and full-cells (against a Prussian white cathode). Further improvements are observed when including styrene-butadiene rubber as a co-binder. X-ray photoelectron spectroscopy demonstrates similar solid electrolyte interphase compositions after the initial sodium insertion for both lignosulfonate and carboxymethyl cellulose binders. However, after subsequent cycling, the surface layer composition and thickness are found to be dependent on the binder. For the lignosulfonate-based electrode, the layer appears thicker but comprises a smaller fraction of carbon-oxygen species. © 2021 The Authors.
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| 58. |
- Hakim, Charifa, et al.
(författare)
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Anionic Redox and Electrochemical Kinetics of the Na2Mn3O7 Cathode Material for Sodium-Ion Batteries
- 2022
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 36:7, s. 4015-4025
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Tidskriftsartikel (refereegranskat)abstract
- Manganese-based layered oxides have gained wide attention as cathode materials for sodium-ion batteries due to their cost-effectiveness and nontoxicity. Among them, Na2Mn3O7, which shows promising electrochemical properties as a host material for sodium ions, has been extensively investigated recently. However, the charge compensation mechanisms during battery operation are still ambiguous. Herein, we investigate the electronic structure of Na2Mn3O7 using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering techniques. Mn L-II,L-III-edge XAS spectra show that manganese ions do not undergo any oxidation reaction during the first charge process, suggesting that sodium removal is instead charge compensated by oxygen-ion redox reactions. This, in turn, has an impact on the cycling performances delivered by the material, especially the capacity retention over cycles and also the electrochemical kinetics of sodium ions in Na2Mn3O7.
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| 59. |
- Hakim, Charifa, et al.
(författare)
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Development of P2 or P2/P3 cathode materials for sodium-ion batteries by controlling the Ni and Mn contents in Na0.7CoxMnyNizO2 layered oxide
- 2023
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 438
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Tidskriftsartikel (refereegranskat)abstract
- Layered oxide cathode materials with the general formula NaxTMO2 (TM = transition metals) have shown promises as electrode materials for future large-scale sodium-ion batteries. However, several challenges including capacity degradation at high voltage, phase transitions as well as structural sensitivity to minor changes in the sodium and transition metal contents during the synthesis process have hampered their development. Herein, we report a systematic investigation of the impact of replacing cobalt by either manganese or nickel on the structural and electrochemical properties of Na0.7CoxMnyNizO2 (x + y + z = 1) layered oxide materials using a variety of analysis and electrochemical techniques. Mixed phases of P2 and P3 cathode materials are obtained through a slight increase of the nickel content, while increasing the manganese content showed little effect on the P2-type structure. Increasing manganese content is shown to lead to lower discharge capacity but excellent capacity retention after 100 cycles, while nickel-rich electrodes exhibit higher discharge capacity approaching 120 mAh/g but poor rate capability performance.
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| 60. |
- Hakim, Charifa, et al.
(författare)
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P-doped Hard Carbon as Anode Material for Sodium-ion Batteries
- 2019
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Ingår i: Proceedings of 2019 7th international renewable and sustainable energy conference (IRSEC). - : IEEE. - 9781728151526 ; , s. 754-756
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Konferensbidrag (refereegranskat)abstract
- The P-doped hard carbon was synthesized using carboxymethyl cellulose and phosphoric acid as the carbon and phosphorus precursors, respectively. The X-ray photoelectron spectroscopy (XPS) analysis reveals that the doped phosphorus atoms can incorporate into the carbon framework and most of them are connecting with carbon atoms to form P-C bonds. When used as anodes in sodium ion batteries, the obtained un-doped and P-doped hard carbon show poor electrochemical performances. The results indicate further optimization of the synthesis process is required. However, this approach opens up new possibilities to improve electrochemical performance of hard carbon anodes.
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