| 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. |
- Calcagno, Giulio, 1990, et al.
(författare)
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Effect of Nitrogen Doping on the Performance of Mesoporous CMK-8 Carbon Anodes for Li-Ion Batteries
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:19
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Tidskriftsartikel (refereegranskat)abstract
- Designing carbonaceous materials with heightened attention to the structural properties such as porosity, and to the functionalization of the surface, is a growing topic in the lithium-ion batteries (LIBs) field. Using a mesoporous silica KIT-6 hard template, mesoporous carbons belonging to the OMCs (ordered mesoporous carbons) family, namely 3D cubic CMK-8 and N-CMK-8 were synthesized and thoroughly structurally characterized. XPS analysis confirmed the successful introduction of nitrogen, highlighting the nature of the different nitrogen atoms incorporated in the structure. The work aims at evaluating the electrochemical performance of N-doped ordered mesoporous carbons as an anode in LIBs, underlining the effect of the nitrogen functionalization. The N-CMK-8 electrode reveals higher reversible capacity, better cycling stability, and rate capability, as compared to the CMK-8 electrode. Coupling the 3D channel network with the functional N-doping increased the reversible capacity to similar to 1000 mAh center dot g(-1) for the N-CMK-8 from similar to 450 mAh center dot g(-1) for the undoped CMK-8 electrode. A full Li-ion cell was built using N-CMK-8 as an anode, commercial LiFePO4, a cathode, and LP30 commercial electrolyte, showing stable performance for 100 cycles. The combination of nitrogen functionalization and ordered porosity is promising for the development of high performing functional anodes.
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| 3. |
- Lee, Suyeong, et al.
(författare)
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Recent developments and future challenges in designing rechargeable potassium-sulfur and potassium-selenium batteries
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- The use of chalcogenide elements, such as sulfur (S) and selenium (Se), as cathode materials in rechargeable lithium (Li) and sodium (Na) batteries has been extensively investigated. Similar to Li and Na systems, rechargeable potassium-sulfur (K-S) and potassium-selenium (K-Se) batteries have recently attracted substantial interest because of the abundance of K and low associated costs. However, K-S and K-Se battery technologies are in their infancy because K possesses overactive chemical properties compared to Li and Na and the electrochemical mechanisms of such batteries are not fully understood. This paper summarizes current research trends and challenges with regard to K-S and K-Se batteries and reviews the associated fundamental science, key technological developments, and scientific challenges to evaluate the potential use of these batteries and finally determine effective pathways for their practical development.
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| 4. |
- Sadd, Matthew, 1994, et al.
(författare)
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Polysulfide Speciation and Migration in Catholyte Lithium−Sulfur Cells
- 2022
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Ingår i: ChemPhysChem. - : Wiley. - 1439-7641 .- 1439-4235. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- Semi-liquid catholyte Lithium−Sulfur (Li−S) cells have shown to be a promising path to realize high energy density energy storage devices. In general, Li−S cells rely on the conversion of elemental sulfur to soluble polysulfide species. In the case of catholyte cells, the active material is added through polysulfide species dissolved in the electrolyte. Herein, we use operando Raman spectroscopy to track the speciation and migration of polysulfides in the catholyte to shed light on the processes taking place. Combined with ex-situ surface and electrochemical analysis we show that the migration of polysulfides is central in order to maximize the performance in terms of capacity (active material utilization) as well as interphase stability on the Li-metal anode during cycling. More specifically we show that using a catholyte where the polysulfides have the dual roles of active material and conducting species, e. g. no traditional Li-salt (such as LiTFSI) is present, results in a higher mobility and faster migration of polysulfides. We also reveal how the formation of long chain polysulfides in the catholyte is delayed during charge as a result of rapid formation and migration of shorter chain species, beneficial for reaching higher capacities. However, the depletion of ionic species during the last stage of charge, due to the conversion to and precipitation of elemental sulfur on the cathode support, results in polarization of the cell before full conversion can be achieved.
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