| 1. |
- Mathayan, Vairavel, et al.
(författare)
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Assessing the potential of ion beam analytical techniques for depth profiling Li in thin film Li ion batteries
- 2021
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 130:12
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Tidskriftsartikel (refereegranskat)abstract
- Depth resolution and probing depth for Li in lithium thin film batteries achievable using different ion beam analytical techniques were investigated. Experiments using protons for nuclear reaction analysis, He ions for time-of-flight (TOF) energy elastic recoil detection analysis (ERDA) in transmission geometry, as well as He and Li ions for coincidence ERDA in transmission geometry are performed. Experimental results are compared in terms of the obtained Li concentration in the separator layer. In coincidence ERDA experiments, significant loss of Li-Li and He-Li coincidence counts was observed due to multiple scattering of recoiled/scattered particles in the battery sample. The ideal achievable Li depth resolution was calculated for the ion beam techniques. A depth resolution of 750, 1030, 310, and 510 x 10(15) atoms/cm(2) could be achieved in the Nb2O5 cathode by nuclear reaction analysis (NRA) using 2 MeV H, TOF-ERDA using 8 MeV He, and coincidence ERDA using 8 MeV He and 8 MeV Li ions, respectively, upon optimization of the experimental setup. While a depth resolution of 120 x 10(15) ions/cm(2) could be achieved for Li by conventional TOF-ERDA using an solid-state detector energy detector and light primary ions such as O under gracing incidence, TOF-ERDA experiments are found to produce significantly higher beam damage in batteries than other techniques. The beam damage in NRA and coincidence ERDA as performed in this study is estimated to be of the order of 10(-4) dpa. (C)& nbsp;2021 Author(s).& nbsp; All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).
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| 2. |
- Mathayan, Vairavel, et al.
(författare)
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Determining the chronological sequence of inks deposited with different writing and printing tools using ion beam analysis
- 2021
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Ingår i: Journal of Forensic Sciences. - : John Wiley & Sons. - 0022-1198 .- 1556-4029. ; 66:4, s. 1401-1409
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Tidskriftsartikel (refereegranskat)abstract
- Determining the sequence of inks in a questioned document is important in forensic science. Conventional and micro beam-based ion beam analysis using Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission were employed to study the depth distribution of chemical elements in plain paper and inks/toner deposited by different pens as well as inkjet and laser printers. Composition depth profiling with high lateral resolution was performed with focus on areas where two different coloring agents overlapped. We identify under which conditions the sequence of inks deposited can be reconstructed, analyzing the continuity of characteristic contributions to the obtained signals, with a focus on the depth-resolved RBS data. The order of deposition was correctly determined for combinations of two different laser printers and in certain cases for pens. Results indicate a potential for analysis, depending on the composition of staining agent, that is, in particular if heavy species are present in sufficiently high concentration. In such cases, also characters obscured or modified by an agent of different composition can be revealed. Changing the probing depth by modifying the beam energy could yield additional information.
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| 3. |
- Mathayan, Vairavel, et al.
(författare)
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In-operando observation of Li depth distribution and Li transport in thin film Li ion batteries
- 2020
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 117:2
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Tidskriftsartikel (refereegranskat)abstract
- A quantitative assessment of Li transport is decisive for Li ion battery research. Here, we demonstrate in situ and in-operando depth profiling of the Li-inventory in lithium thin film batteries. We employ non-destructive coincidence elastic recoil detection analysis using different projectile ions in the MeV range to simultaneously quantify the lithium depth distribution in the whole stack with resolution better than 50nm by simulations of experimental data. Experiments were performed while charging and discharging the stack. 5MeV Li-7 primary ions were employed to extract the Li depth distribution in an similar to 3.6 mu m thick Ti/LMO/LIPON/NbO/Ti thin film battery. To show the versatility of the approach, a coincidence experiment was also performed using 4MeV He ions for an similar to 3.4 mu m thick Ti/LMO/LIPON/NbO/Ti battery. Our results illustrate, for example, lithium accumulation in the 90nm thick NbO layer upon charging with +3V. We could also show the transport of large amounts of Li from the LMO/LIPON interface to the LIPON/NbO interface upon overcharging with +5V. Altogether, these experiments demonstrate the potential of the employed technique, enabling in-operando high resolution composition depth profiling of Li and other light elements (e.g., H, He, C, N, and O) in ultrathin all-solid state batteries.
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| 4. |
- Mathayan, Vairavel, et al.
(författare)
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Oxygen trapping in defect clusters in Fe and FeCr alloy by ion channeling and ab-initio study
- 2020
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Ingår i: Journal of Nuclear Materials. - : ELSEVIER. - 0022-3115 .- 1873-4820. ; 532
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Tidskriftsartikel (refereegranskat)abstract
- Ion channeling experiment and ab-initio density functional theory (DFT) calculations are used to study O interactions with interstitial and vacancy clusters in Fe and FeCr alloy. Chromium and O-18 ions are implanted at the same depth in a Fe crystal and annealed at 400 degrees C. Lattice location of O-18 is found to be tetrahedral interstitial site by nuclear reaction analysis (NRA)/channeling and Cr is found at substitutional site with small displacement by particle induced X-ray emission (PIXE)/channeling experiment. DFT calculations predict similar sites of O-18 and Cr for trapping in self-interstitial clusters. On the other hand, O-18 is implanted in a Fe15at%Cr alloy and annealed at 400 degrees C. The O-18 is found to be displaced 0.6 A along <100> from the octahedral interstitial site in FeCr alloy. DFT calculations predict similar lattice location of O for trapping in vacancy clusters. The Cr atoms show strong influence on the O trapping at defects in FeCr alloy. (C) 2020 Elsevier B.V. All rights reserved.
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| 5. |
- Mathayan, Vairavel, et al.
(författare)
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Sensitive in-operando observation of Li and O transport in thin-film Li-ion batteries
- 2021
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- Thin-film batteries often contain oxides in the anode, cathode, and electrolyte materials. In-operando methods capable of Li and O depth profiling are relevant for battery research to study, e.g. diffusion and trapping of constituents. Here, we demonstrate ion beam-based analytical methods with high depth resolution and sensitivity for depth profiling Li and O in thin-film batteries using 10 MeV Li and He ions. Simultaneous depth profiling of Li and O was performed using combined coincidence elastic recoil detection analysis and Rutherford backscattering spectrometry measurements in the battery with 8 MeV He ions, and the Li and O transport was measured in operando. Reversible Li transport was observed from the LMO anode to the NbO cathode on charging and vice versa during discharging. O transport was observed from the LMO anode to the NbO cathode on first charging with 3.5 V but was not observed on further charging and discharging of the battery. Our in-operando measurements allow direct and quantitative observation of Li and O transport during charge-discharge cycles for thin-film batteries.
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| 6. |
- Zhu, Yuan, et al.
(författare)
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High Performance Full-Inorganic Flexible Memristor with Combined Resistance-Switching
- 2022
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:18, s. 21173-21180
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Tidskriftsartikel (refereegranskat)abstract
- Flexible memristors hold great promise for flexible electronics applications but are still lacking of good electrical performance together with mechanical flexibility. Herein, we demonstrate a full-inorganic nanoscale flexible memristor by using free-standing ductile alpha-Ag2S films as both a flexible substrate and a functional electrolyte. The device accesses dense multiple-level nonvolatile states with a record high 10 6 ON/OFF ratio. This exceptional memristor performance is induced by sequential processes of Schottky barrier modification at the contact interface and filament formation inside the electrolyte. In addition, it is crucial to ensure that the cathode junction, where Ag+ is reduced to Ag, dominates the total resistance and takes the most of setting bias before the filament formation. Our study provides a comprehensive insight into the resistance-switching mechanism in conductive-bridging memristors and offers a new strategy toward high performance flexible memristors.
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