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- Martinelli, Anna, 1978, et al.
(författare)
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Phase behavior and ionic conductivity in LiTFSI doped ionic liquids of the pyrrolidinium cation and TFSI anion
- 2009
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 113:32, s. 11247-11251
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Tidskriftsartikel (refereegranskat)abstract
- The phase behavior and the ionic conductivity of ionic liquids (ILs) of the N-alkyl-N-alkylpyrrolidinium (PYR xy ) cation and the bis(trifluoromethanesulfonyl)imide (TFSI) anion are investigated upon addition of LiTFSI salt. We compare the case of two new ILs of the PYR 2y cation (where 2 is ethyl and y is butyl or propyl) with that of the PYR 14 (where 1 is methyl and 4 is butyl). We find that the addition of LiTFSI increases the glass transition temperature, decreases the melting temperature and the heat of fusion and, in the ILs of the PYR 2y family, suppresses crystallization. In the solid state, significant ionic conductivities are found, being as high as 10 -5 Scm -1 , strongly increasing with Li + concentration. The opposite trend is found in the liquid state, where the conductivity is on the order of 10 -3 -10 -2 Scm -1 at room temperature. A T g -scaled Arrhenius plot shows that the liquid-state ionic conductivity in these systems is mainly governed by viscosity and that the fragility of the liquids is slightly influenced by the structural modifications on the cation. © 2009 American Chemical Society.
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- Ahmed, Istaq, 1972, et al.
(författare)
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Proton conduction in Perovskite Oxide BaZr0.5Yb0.5O3-δ Prepared by Wet Chemical Route
- 2008
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 155:11, s. 97-102
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Tidskriftsartikel (refereegranskat)abstract
- A wet chemical route has been used to synthesize the oxygen deficient perovskite Ba Zr0.5 Yb0.5 O3-δ. Analysis of X-ray powder diffraction data showed that both dried and hydrated samples adopt cubic crystal structures of space group Pm 3- m. Dynamic thermogravimetric analysis showed a significant mass loss for the hydrated sample compared to the dried sample, indicating that ∼28% of the oxygen vacancies are filled by protonic defects. The strong O-H stretch band, 2500-3500 cm-1, in the IR absorbance spectrum also clearly manifests the presence of significant levels of protons in the hydrated material. Proton conductivity was investigated on prehydrated (under dry Ar) and as-prepared (under wet Ar) samples. The heating cycle of the prehydrated sample showed higher proton conductivity compared to the cooling cycle, especially in the intermediate temperature range (150-550°C). Finally, comparison with data for Ba Zr0.9 Yb0.1 O3-δ revealed that the more heavily doped sample showed higher proton conductivity compared to the more lightly doped sample. © 2008 The Electrochemical Society.
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- Larsson Wexell, Cecilia, 1965, et al.
(författare)
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Electropolished titanium implants with a mirror-like surface support osseointegration and bone remodelling
- 2016
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8434 .- 1687-8442.
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Tidskriftsartikel (refereegranskat)abstract
- This work characterises the ultrastructural composition of the interfacial tissue adjacent to electropolished, commercially pure titanium implants with and without subsequent anodisation, and it investigates whether a smooth electropolished surface can support bone formation in a manner similar to surfaces with a considerably thicker surface oxide layer. Screw-shaped implants were electropolished to remove all topographical remnants of the machining process, resulting in a thin spontaneously formed surface oxide layer and a smooth surface. Half of the implants were subsequently anodically oxidised to develop a thickened surface oxide layer and increased surface roughness. Despite substantial differences in the surface physicochemical properties, the microarchitecture and the composition of the newly formed bone were similar for both implant surfaces after 12 weeks of healing in rabbit tibia. A close spatial relationship was observed between osteocyte canaliculi and both implant surfaces. On the ultrastructural level, the merely electropolished surface showed the various stages of bone formation, for example, matrix deposition and mineralisation, entrapment of osteoblasts within the mineralised matrix, and their morphological transformation into osteocytes. The results demonstrate that titanium implants with a mirror-like surface and a thin, spontaneously formed oxide layer are able to support bone formation and remodelling.
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- Agostini, Marco, 1987, et al.
(författare)
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Rational Design of Low Cost and High Energy Lithium Batteries through Tailored Fluorine-free Electrolyte and Nanostructured S/C Composite
- 2018
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 11:17, s. 2981-2986
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Tidskriftsartikel (refereegranskat)abstract
- We report a new Li–S cell concept based on an optimized F-free catholyte solution and a high loading nanostructured C/S composite cathode. The Li2S8present in the electrolyte ensures both buffering against active material dissolution and Li+conduction. The high S loading is obtained by confining elemental S (≈80 %) in the pores of a highly ordered mesopores carbon (CMK3). With this concept we demonstrate stabilization of a high energy density and excellent cycling performance over 500 cycles. This Li–S cell has a specific capacity that reaches over 1000 mA h g−1, with an overall S loading of 3.6 mg cm−2and low electrolyte volume (i.e., 10 μL cm−2), resulting in a practical energy density of 365 Wh kg−1. The Li–S system proposed thus meets the requirements for large scale energy storage systems and is expected to be environmentally friendly and have lower cost compared with the commercial Li-ion battery thanks to the removal of both Co and F from the overall formulation.
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- Ahmed, Istaq, 1972, et al.
(författare)
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Crystal structure and proton conductivity of BaZr0.9Sc0
- 2008
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Ingår i: Journal of the American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 91:9, s. 3039-3044
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Tidskriftsartikel (refereegranskat)abstract
- Solid-state sintering has been used to prepare the perovskite BaZr0.9Sc0.1O3-delta. Analysis of X-ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed after deuteration. Rietveld analysis of room-temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m). Dynamic thermogravimetric analysis indicates that the hydration process occurs below 335 degrees C and approximately 58% of the theoretical number of protonic defects can be filled. The presence of protons/deutrons is seen from the strong O-H/O-D stretch band in the infrared spectrum of the hydrated/deuterated samples. The proton conductivity of a prehydrated sample was investigated under dry and wet Ar atmospheres
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| 9. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Location of deuteron sites in the proton conducting perovskite BaZr0.50In0.50O3-y
- 2008
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 450:1-2, s. 103-110
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution neutron powder diffraction data have been collected on deuterated and dried samples of the perovskite BaZr0.5In0.5O2.75 at 5 K and room temperature, respectively. Inspection of Fourier nuclear density maps for the deuterated phase have allowed the deuteron position to be refined on a 12h (1/2, y, 0) crystallographic site, with y = 0.217(4) yielding a chemically reasonable O-D distance of 0.92(2) angstrom. Evidence for anisotropy of the deuteron position is also found consistent with a 24k crystallographic site (0.56, 0.21, 0) indicative of displacements of the ion towards neighbouring oxygen ions. The presence of static oxygen disorder in both the dried and deuterated samples is apparent from the structural analyses. Raman spectra confirm short range deviations from cubic symmetry for both dried and hydrated samples.
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| 10. |
- Atkins, Duncan, et al.
(författare)
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Accelerating Battery Characterization Using Neutron and Synchrotron Techniques: Toward a Multi-Modal and Multi-Scale Standardized Experimental Workflow
- 2022
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 12:17
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Tidskriftsartikel (refereegranskat)abstract
- Li-ion batteries are the essential energy-storage building blocks of modern society. However, producing ultra-high electrochemical performance in safe and sustainable batteries for example, e-mobility, and portable and stationary applications, demands overcoming major technological challenges. Materials engineering and new chemistries are key aspects to achieving this objective, intimately linked to the use of advanced characterization techniques. In particular, operando investigations are currently attracting enormous interest. Synchrotron- and neutron-based bulk techniques are increasingly employed as they provide unique insights into the chemical, morphological, and structural changes inside electrodes and electrolytes across multiple length scales with high time/spatial resolutions. However, data acquisition, data analysis, and scientific outcomes must be accelerated to increase the overall benefits to the academic and industrial communities, requiring a paradigm shift beyond traditional single-shot, sophisticated experiments. Here a multi-scale and multi-technique integrated workflow is presented to enhance bulk characterization, based on standardized and automated data acquisition and analysis for high-throughput and high-fidelity experiments, the optimization of versatile and tunable cells, as well as multi-modal correlative characterization. Furthermore, new mechanisms, methods and organizations such as artificial intelligence-aided modeling-driven strategies, coordinated beamtime allocations, and community-unified infrastructures are discussed in order to highlight perspectives in battery research at large scale facilities.
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