| 1. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Chemically soft solid electrolyte interphase forming additives for lithium-ion batteries
- 2018
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 6:45, s. 22609-22618
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Tidskriftsartikel (refereegranskat)abstract
- The solid electrolyte interphase (SEI) layer is a key element of lithium-ion batteries (LIBs) enabling stable operation and significantly affecting the cycling performance including life-length. Here we present the concept of chemically soft SEI-forming additives, created by introducing aromatic ring based derivatives of already well-known SEI-formers to render them chemically soft, resulting in 1,3,2-benzodioxathiole 2,2-dioxide (DTDPh), 3H-1,2-benzoxathiole 2,2-dioxide (PSPh), and 1,4,2-benzodioxathiine 2,2-dioxide (PSOPh). A computational DFT based comparison predicts promise with respect to both early and controlled reduction processes. These predictions are verified by basic electrochemical studies targeting appropriate additive reduction potentials i.e. prior to any electrolyte solvent or salt decomposition. In addition, the decomposition paths of the SEI-formers are projected and the end products compared with spectroscopic data for the SEI-layers formed in LIB cells. The SEI-layers formed finally show very good properties in terms of improved capacity retention, improved coulombic efficiency, and reduced resistance for the graphite/electrolyte/LFP full cells made, especially observed for PSOPh. That is due to the preferred C-O bond breaking mechanism, observed also for DTDPh, and supported by the S-C bond breaking mechanism, together resulting in well conductive and good adhesion properties of the SEI-layers. This is expedited by higher softness, eventuating in a formation process stabilizing some of the radicals and/or lowering the kinetic barriers. These positive effects are confirmed both when applying a commercial style electrolyte and for a new generation electrolyte based on the LiTDI salt, where suppression of the TDI anion reduction is truly crucial.
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| 2. |
- Karlsmo, Martin, 1995, et al.
(författare)
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Le Chatelier's principle enables stable and sustainable aqueous sodium/magnesium-ion batteries
- 2024
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Ingår i: Journal of Materials Chemistry A. - 2050-7496 .- 2050-7488. ; 12:7, s. 4029-4036
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Tidskriftsartikel (refereegranskat)abstract
- Prussian blue analogue (PBA) based aqueous batteries assembled with organic materials are an up-and-coming and promising technology for less demanding applications. By avoiding scarce, costly, and toxic transition metals (e.g. Ni/Co/Cu), the technology may become low-cost, more environmentally benign, and also safer than today's alternatives. Here we rely on a PBA using the FeII/III redox pair together with aqueous low-to-medium concentrated fluorine/perchlorate-free electrolytes and organic materials to create long-term performant cells. The performance in terms of capacity, coulombic efficiency, cell voltage, and energy density are all comparable with previously reported aqueous PBA-based batteries, while the cycling performance is substantially improved by practically implementing Le Chatelier's principle. Additionally, we investigate the redox process(es) and find no proof for any proton storage, but that both Na+ and Mg2+ likely are active, why we classify it as an aqueous Na/Mg-ion battery. We present a new Prussian blue analogue based aqueous battery that by three salts in low-to-medium concentrations in the electrolyte substantially enhances the cycling performance and give promise for low-cost and sustainable energy storage.
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| 3. |
- Kim, Jae-Kwang, 1978, et al.
(författare)
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Nano-fibrous polymer films for organic rechargeable batteries
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:7, s. 2426-2430
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Tidskriftsartikel (refereegranskat)abstract
- We propose a nano-fibrous polymer (NFP) film, fabricated by electrospinning poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), as a key component in high performance organic batteries. The new strategy with a NFP film enables extraordinary rate capability and excellent cyclability, due to its special morphology. Moreover, the NFP film enhances the flexibility of the electrode at a low cost and prevents dissolution of PTMA into the electrolyte.
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| 4. |
- Le Pham, Phuong Nam, et al.
(författare)
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Prussian blue analogues for potassium-ion batteries: insights into the electrochemical mechanisms
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 11:6, s. 3091-3104
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Tidskriftsartikel (refereegranskat)abstract
- A comprehensive description of the electrochemical mechanisms of the Prussian Blue Analogue (PBA) K1.67Mn0.65Fe0.35[Fe(CN)6]0.92·0.45H2O is obtained by combining several complementary ex situ and operando physico-chemical characterisation techniques. This particular PBA, which shows very good electrochemical performance as a cathode material in potassium-ion batteries (PIBs), undergoes three successive redox reactions during the (de-)potassiation that are hereby identified by ex situ57Fe Mössbauer spectroscopy and operando Mn and Fe K-edge X-ray absorption spectroscopy. These reactions come along with notable modifications of the crystal structure, which are followed in real time by operando X-ray diffraction. The correlation of these results, interpreted with the support of chemometric methods, also reveals the limitations of this PBA, probably related to the deactivation of the Mn undergoing extensive reversible Jahn-Teller distortion during cycling as well as possible dissolution in the electrolyte. These results underline that optimisation of the chemical composition of PBAs is a crucial step towards the preparation of reliable and stable PBA-based cathodes for PIBs.
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| 5. |
- Loaiza, L. C., et al.
(författare)
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Understanding the lithiation/delithiation mechanism of Si1-xGex alloys
- 2017
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 5:24, s. 12462-12473
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Tidskriftsartikel (refereegranskat)abstract
- GexSi1-x alloys have demonstrated synergetic effects as lithium-ion battery (LIB) anodes, because silicon brings its high lithium storage capacity and germanium its better electronic and Li ion conductivity. Previous studies primarily focused on intricate nanostructured alloys with high costs of production, but here we studied the simpler Si0.5Ge0.5 alloy as a composite electrode. The electrochemical mechanism is explored by a combination of in situ and operando techniques such as powder X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Raman spectroscopy and Li-7 solid state nuclear magnetic resonance spectroscopy (NMR), all providing unique and complementary information about phase transformations during cycling. In this way amorphization of c-Si0.5Ge0.5 upon lithiation (discharging) and crystallization of a new phase at the end of the discharge have been identified. Additionally, an evolution of the refined cell parameters was observed and related to an overlithiation process. The crystallinity of Si0.5Ge0.5 was not restored upon charging (delithiation) and an amorphous phase was obtained. Lastly, an improved understanding of the electrochemical mechanism of Si1-xGex alloys is mandatory for assessing their viability as LIB anodes.
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| 6. |
- Mandai, Toshihiko, 1984, et al.
(författare)
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Al conductive haloaluminate-free non-aqueous room-temperature electrolytes
- 2015
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 3:23, s. 12230-12239
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Tidskriftsartikel (refereegranskat)abstract
- Al batteries are yet rather unexplored as a promising technology to respond to the growing electrochemical energy storage demands. Despite the outstanding electrochemical activity of haloaluminate-based electrolytes, no prospect of practical re-chargeable Al batteries has yet materialized, partly due to these electrolytes' extremely sensitive nature. Hence alternative aluminum conducting electrolytes with sufficient stability are strongly needed. Here a series of room-temperature ternary electrolytes consisting of aluminum trifluoromethanesulfonate (Al[TfO]3), N-methylacetamide (NMA), and urea are presented, which provide excellent ionic conductivities by selecting appropriate ratios. Compared to conventional organic electrolytes, unprecedented solvation ability for Al-salts and remarkable ion transport properties were observed. For the optimized composition, Al[TfO]3/NMA/urea = 0.05/0.76/0.19, physicochemical properties and vibrational spectroscopy data imply a decoupling of the Al conduction mechanism from viscosity limitations and furthermore that the dissociation state of the Al[TfO]3 salt drastically changes. These phenomena are likely due to the unique coordination environment of the Al3+ ions and the multiple functions of urea in these ternary mixtures. The electrochemical properties of the optimized ternary electrolyte were studied with respect to the electrochemical stability window and using cyclic voltammetry.
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| 7. |
- Ponrouch, A., et al.
(författare)
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Non-Aqueous Electrolytes for Sodium-Ion Batteries
- 2015
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428 .- 2050-7488 .- 2050-7496. ; 3:1, s. 22-42
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Forskningsöversikt (refereegranskat)abstract
- The first review of the various electrolytes currently used and developed for sodium-ion batteries (SIBs), both in terms of materials and concepts, is presented. In contrast to the Li-ion battery (LIB), which is a mature technology for which a more or less unanimously accepted "standard electrolyte" exists: 1 M LiPF6 in EC/DMC, the electrolyte of choice for SIBs has not yet fully conformed to a standard. This is true for both materials: salts, solvents, or additives, and concept, using the main track of organic solvents or aiming for other concepts. SIB research currently prospers, benefitting from using know-how gained from 30 years of LIB R&D. Here the currently employed electrolytes are emphasized and their effects on practical SIB performance are outlined, scrutinizing the rationale for specific choices made, salts, solvents, additives, concentrations, etc. for each specific cell set-up and usage conditions.
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| 8. |
- Rasheev, Hristo G., et al.
(författare)
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Fundamental promise of anthraquinone functionalized graphene based next generation battery electrodes: A DFT study
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:28, s. 14152-14161
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Tidskriftsartikel (refereegranskat)abstract
- Organic batteries are promising alternatives to the present rechargeable battery technologies, mainly due to projected lower fabrication costs, less environmental impact, more versatility, and chemical and mechanical flexibility. In this study we investigate potential organic battery electrodes composed of an electronically conductive graphene monolayer functionalized with redox-active anthraquinone (AQ). The combination overcomes common drawbacks of organic batteries: (i) the solubility of the organic redox-active materials in the electrolyte is mitigated by anchoring onto graphene and (ii) the need for a large amount of conductive additives in the composite electrode is circumvented by the high conductivity of graphene. The electrodes are modelled by various density functional theory (DFT) based approaches and their fundamental promise as part of Li, Ca, and Al based batteries are outlined. We model the design of the electrodes, such as AQ attachment and loading, the thermodynamics of accepting mono to trivalent ideal charge carriers from the electrolyte, i.e. Li+, Ca2+, and Al3+, and the kinetics of ion diffusion at the electrode surface by assessment of the activation barriers. From the calculated multi-step electrode potential profiles, the theoretical electrode energy densities, with respect to the redox-active part, are 570 and 512 W h kg-1 for Li and Ca, respectively, which is quite comparable to the active materials of inorganic medium voltage lithium-ion battery electrodes. As the average potentials are in the range 0.5-1.2 V vs. Mn+/M0 these materials are either to be used as negative electrodes, combined with a high or medium potential positive electrode, or as positive electrodes vs. metal electrodes, for low voltage battery application.
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| 9. |
- Shirshova, N., et al.
(författare)
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Polymerised high internal phase ionic liquid-in-oil emulsions as potential separators for lithium ion batteries
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:34, s. 9612-9619
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Tidskriftsartikel (refereegranskat)abstract
- In situ ionic liquid (IL) filled poly(merized) high internal phase emulsion monoliths and films were produced by polymerizing surfactant stabilized IL/monomer emulsion templates. The resulting in situ ionic liquid filled macroporous polymers have almost the ionic conductivity of the neat ionic liquid electrolyte. The effect of surfactant and lithium salt concentration, monomer to crosslinker ratio as well as internal phase volume ratio on the morphology and ionic conductivity were studied. It was found that the morphology of the resulting polyHIPEs affects significantly their ionic conductivity. PolyHIPEs with bigger pore throats have a higher ionic conductivity.
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| 10. |
- Shirshova, N., et al.
(författare)
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Structural supercapacitor electrolytes based on bicontinuous ionic liquid-epoxy resin systems
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:48, s. 15300-15309
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Tidskriftsartikel (refereegranskat)abstract
- 'Structural electrolytes' retain the desirable mechanical characteristics of structural (epoxy) resins whilst introducing sufficient ionic conductivity to operate as electrolytes in electrochemical devices. Here, a series of ionic liquid-epoxy resin composites were prepared to identify the optimum system microstructure required to achieve a high level of multifunctionality. The ionic conductivity, mechanical properties, thermal stability and morphology of the cured epoxy based structural electrolytes were studied as a function of phase composition for three fully formulated high performance structural epoxy systems. At only 30 wt% of structural resin and 70 wt% of ionic liquid based electrolyte, stiff monolithic plaques with thicknesses of 2-3 mm were obtained with a room temperature ionic conductivity of 0.8 mS cm-1 and a Young's modulus of 0.2 GPa. This promising performance can be attributed to a long characteristic length scale spinodal microstructure, suggesting routes to further optimisation in the future. © 2013 The Royal Society of Chemistry.
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