| 1. |
- Agostini, Marco, 1987, et al.
(författare)
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Designing a Safe Electrolyte Enabling Long‐Life Li/S Batteries
- 2019
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 12:18, s. 4176-4184
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Tidskriftsartikel (refereegranskat)abstract
- Lithium–sulfur (Li/S) batteries suffer from “shuttle” reactions in which soluble polysulfide species continuously migrate to and from the Li metal anode. As a consequence, the loss of active material and reactions at the surface of Li limit the practical applications of Li/S batteries. LiNO3 has been proposed as an electrolyte additive to reduce the shuttle reactions by aiding the formation of a stable solid electrolyte interphase (SEI) at the Li metal, limiting polysulfide shuttling. However, LiNO3 is continuously consumed during cycling, especially at low current rates. Therefore, the Li/S battery cycle life is limited by the LiNO3 concentration in the electrolyte. In this work, an ionic liquid (IL) [N-methyl-(n-butyl)pyrrolidinium bis(trifluoromethylsulfonyl)imide] was used as an additive to enable longer cycle life of Li/S batteries. By tuning the IL concentration, an enhanced stability of the SEI and lower flammability of the solutions were demonstrated, that is, higher safety of the battery. The Li/S cell built with a high sulfur mass loading (4 mg cm−2) and containing the IL-based electrolyte demonstrated a stable capacity of 600 mAh g−1 for more than double the number of cycles of a cell containing LiNO3 additive.
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| 2. |
- 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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| 3. |
- Agostini, Marco, 1987, et al.
(författare)
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Stabilizing the Performance of High-Capacity Sulfur Composite Electrodes by a New Gel Polymer Electrolyte Configuration
- 2017
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 10:17, s. 3490-3496
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Tidskriftsartikel (refereegranskat)abstract
- Increased pollution and the resulting increase in global warming are drawing attention to boosting the use of renewable energy sources such as solar or wind. However, the production of energy from most renewable sources is intermittent and thus relies on the availability of electrical energy-storage systems with high capacity and at competitive cost. Lithium–sulfur batteries are among the most promising technologies in this respect due to a very high theoretical energy density (1675 mAh g?1) and that the active material, sulfur, is abundant and inexpensive. However, a so far limited practical energy density, life time, and the scaleup of materials and production processes prevent their introduction into commercial applications. In this work, we report on a simple strategy to address these issues by using a new gel polymer electrolyte (GPE) that enables stable performance close to the theoretical capacity of a low cost sulfur–carbon composite with high loading of active material, that is, 70 % sulfur. We show that the GPE prevents sulfur dissolution and reduces migration of polysulfide species to the anode. This functional mechanism of the GPE membranes is revealed by investigating both its morphology and the Li-anode/GPE interface at various states of discharge/charge using Raman spectroscopy.
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| 4. |
- Cavallo, Carmen, 1986, et al.
(författare)
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Effect of the Niobium Doping Concentration on the Charge Storage Mechanism of Mesoporous Anatase Beads as an Anode for High-Rate Li-Ion Batteries
- 2021
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 4:1, s. 215-225
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Tidskriftsartikel (refereegranskat)abstract
- A promising strategy to improve the rate performance of Li-ion batteries is to enhance and facilitate the insertion of Li ions into nanostructured oxides like TiO2. In this work, we present a systematic study of pentavalent-doped anatase TiO2 materials for third-generation high-rate Li-ion batteries. Mesoporous niobium-doped anatase beads (Nb-doped TiO2) with different Nb5+ doping (n-type) concentrations (0.1, 1.0, and 10% at.) were synthesized via an improved template approach followed by hydrothermal treatment. The formation of intrinsic n-type defects and oxygen vacancies under RT conditions gives rise to a metallic-type conduction due to a shift of the Fermi energy level. The increase in the metallic character, confirmed by electrochemical impedance spectroscopy, enhances the performance of the anatase bead electrodes in terms of rate capability and provides higher capacities both at low and fast charging rates. The experimental data were supported by density functional theory (DFT) calculations showing how a different n-type doping can be correlated to the same electrochemical effect on the final device. The Nb-doped TiO2 electrode materials exhibit an improved cycling stability at all the doping concentrations by overcoming the capacity fade shown in the case of pure TiO2 beads. The 0.1% Nb-doped TiO2-based electrodes exhibit the highest reversible capacities of 180 mAh g-1 at 1C (330 mA g-1) after 500 cycles and 110 mAh g-1 at 10C (3300 mA g-1) after 1000 cycles. Our experimental and computational results highlight the possibility of using n-type doped TiO2 materials as anodes in high-rate Li-ion batteries.
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| 5. |
- Celeste, Arcangelo, et al.
(författare)
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Enhancement of Functional Properties of Liquid Electrolytes for Lithium-Ion Batteries by Addition of Pyrrolidinium-Based Ionic Liquids with Long Alkyl-Chains
- 2020
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Ingår i: Batteries and Supercaps. - : Wiley. - 2566-6223. ; 3:10, s. 1059-1068
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Tidskriftsartikel (refereegranskat)abstract
- Three ionic liquid belonging to the N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imides (Pyr(1),nTFSI with n=4,5,8) have been added as co-solvent to two commonly used electrolytes for Li-ion cells: (a) 1 M lithium hexafluorophosphate (LiPF6) in a mixture of ethylene carbonate (EC) and linear like dimethyl carbonate (DMC) in 1 : 1 v/v and (b) 1 M lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI) in EC : DMC 1 : 1 v/v. These electrolyte formulations (classified as P and T series containing LiPF6 or LiTFSI salts, respectively) have been analyzed by comparing ionic conductivities, transport numbers, viscosities, electrochemical stability as well as vibrational properties. In the case of the Pyr(1,5)TFSI and Pyr(1,8)TFSI blended formulations, this is the first ever reported detailed study of their functional properties in Li-ion cells electrolytes. Overall, P-electrolytes demonstrate enhanced properties compared to the T-ones. Among the various P electrolytes those containing Pyr(1,4)TFSI and Pyr(1,5)TFSI limit the accumulation of irreversible capacity upon cycling with satisfactory performance in lithium cells.
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| 6. |
- Liu, Qiao, et al.
(författare)
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Enhanced ionic conductivity and interface stability of hybrid solid-state polymer electrolyte for rechargeable lithium metal batteries
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 23, s. 105-111
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Tidskriftsartikel (refereegranskat)abstract
- Compared to conventional organic liquid electrolyte, solid-state polymer electrolytes are extensively considered as an alternative candidate for next generation high-energy batteries because of their high safety, non-leakage and electrochemical stability with the metallic lithium (Li) anode. However, solid-state polymer electrolytes generally show low ionic conductivity and high interfacial impedance to electrodes. Here we report a hybrid solid-state electrolyte, presenting an ultra-high ionic conductivity of 3.27 mS cm −1 at room temperature, a wide electrochemical stability window of 4.9 V, and non-flammability. This electrolyte consists of a polymer blend matrix (polyethylene oxide and poly (vinylidene fluoride-co-hexafluoropropylene)), Li + conductive ceramic filler (Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 ) and a solvate ionic liquid (LiFSI in tetra ethylene glycol dimethyl ether, 1:1 in molar ratio) as plasticizer. The introduction of the solvate ionic liquid to the solid-state electrolyte not only improves its ionic conductivity but also remarkably enhances the stability of the interface with Li anode. When applied in Li metal batteries, a Li|Li symmetric cell can operate stably over 800 h with a minimal polarization of 25 mV and a full Li|LiFePO 4 cell delivers a high specific capacity of 158 mAh g −1 after 100 cycles at room temperature.
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| 7. |
- Liu, Yangyang, et al.
(författare)
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Insight into the Critical Role of Exchange Current Density on Electrodeposition Behavior of Lithium Metal
- 2021
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Ingår i: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Due to an ultrahigh theoretical specific capacity of 3860 mAh g−1, lithium (Li) is regarded as the ultimate anode for high-energy-density batteries. However, the practical application of Li metal anode is hindered by safety concerns and low Coulombic efficiency both of which are resulted fromunavoidable dendrite growth during electrodeposition. This study focuses on a critical parameter for electrodeposition, the exchange current density, which has attracted only little attention in research on Li metal batteries. A phase-field model is presented to show the effect of exchange current density on electrodeposition behavior of Li. The results show that a uniform distribution of cathodic current density, hence uniform electrodeposition, on electrode is obtained with lower exchange current density. Furthermore, it is demonstrated that lower exchange current density contributes to form a larger critical radius of nucleation in the initial electrocrystallization that results in a dense deposition of Li, which is a foundation for improved Coulombic efficiency and dendrite-free morphology. The findings not only pave the way to practical rechargeable Li metal batteries but can also be translated to the design of stable metal anodes, e.g., for sodium (Na), magnesium (Mg), and zinc (Zn) batteries.
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| 8. |
- Olsson, Martina, 1996, et al.
(författare)
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Multiscale X-ray imaging and characterisation of pharmaceutical dosage forms
- 2023
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Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 642
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Tidskriftsartikel (refereegranskat)abstract
- A correlative, multiscale imaging methodology for visualising and quantifying the morphology of solid dosage forms by combining ptychographic X-ray computed nanotomography (PXCT) and scanning small- and wide-angle X-ray scattering (S/WAXS) is presented. The methodology presents a workflow for multiscale analysis, where structures are characterised from the nanometre to millimetre regime. Here, the method is demonstrated by characterising a hot-melt extruded, partly crystalline, solid dispersion of carbamazepine in ethyl cellulose. Characterisation of the morphology and solid-state phase of the drug in solid dosage forms is central as this affects the performance of the final formulation. The 3D morphology was visualised at a resolution of 80 nm over an extended volume through PXCT, revealing an oriented structure of crystalline drug domains aligned in the direction of extrusion. Scanning S/WAXS showed that the nanostructure is similar over the cross section of the extruded filament, with minor radial changes in domain sizes and degree of orientation. The polymorphic forms of carbamazepine were qualified with WAXS, showing a heterogeneous distribution of the metastable forms I and II. This demonstrates the methodology for multiscale structural characterization and imaging to enable a better understanding of the relationships between morphology, performance, and processing conditions of solid dosage forms.
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| 9. |
- Rizell, Josef, 1996, et al.
(författare)
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Neutron Reflectometry Study of Solid Electrolyte Interphase Formation in Highly Concentrated Electrolytes
- 2023
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Ingår i: Small Structures. - : WILEY. - 2688-4062. ; 4:11
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Tidskriftsartikel (refereegranskat)abstract
- Highly concentrated electrolytes have been found to improve the cycle life and Coulombic efficiency of lithium metal anodes, as well as to suppress dendrite growth. However, the mechanism for these improvements is not well understood. Partly, this can be linked to the difficulty of accurately characterizing the solid electrolyte interphase (SEI), known to play an important role for anode stability and stripping/plating efficiency. Herein, in situ neutron reflectometry is used to obtain information about SEI formation in a highly concentrated ether-based electrolyte. With neutron reflectometry, the thickness, scattering length density (SLD), and roughness of the SEI layer formed on a Cu working electrode are nondestructively probed. The reflectivity data point to the formation of a thin (5 nm) SEI in the highly concentrated electrolyte (salt:solvent ratio 1:2.2), while a considerably thicker (13 nm) SEI is formed in an electrolyte at lower salt concentration (salt:solvent ratio 1:13.7). Further, the SEI formed in the electrolyte with high salt concentration has a higher SLD, suggesting that the chemical composition of the SEI changes. The results from neutron reflectometry correlate well with the electrochemical data from SEI formation.
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| 10. |
- Sadd, Matthew, 1994, et al.
(författare)
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Investigating microstructure evolution of lithium metal during plating and stripping via operando X-ray tomographic microscopy
- 2023
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Efficient lithium metal stripping and plating operation capable of maintaining electronic and ionic conductivity is crucial to develop safe lithium metal batteries. However, monitoring lithium metal microstructure evolution during cell cycling is challenging. Here, we report the development of an operando synchrotron X-ray tomographic microscopy method capable of probing in real-time the formation, growth, and dissolution of Li microstructures during the cycling of a Li||Cu cell containing a standard non-aqueous liquid electrolyte solution. The analyses of the operando X-ray tomographic microscopy measurements enable tracking the evolution of deposited Li metal as a function of time and applied current density and distinguishing the formation of electrochemically inactive Li from the active bulk of Li microstructures. Furthermore, in-depth analyses of the Li microstructures shed some light on the structural connectivity of deposited Li at different current densities as well as the formation mechanism of fast-growing fractal Li microstructures, which are ultimately responsible for cell failure.
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