| 1. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Designing High-Performant Lithium Battery Electrolytes by Utilizing Two Natures of Li+ Coordination: LiTDI/LiTFSI in Tetraglyme
- 2021
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Ingår i: Batteries and Supercaps. - : Wiley. - 2566-6223. ; 4:4, s. 205-213
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Tidskriftsartikel (refereegranskat)abstract
- Highly concentrated electrolytes (HCEs) based on glymes, such as tetraglyme (G4), are currently the focus of much battery research, primarily due to their unique properties - especially with respect to ion transport and electrochemical stability. While the LiTFSI-G4 and LiTDI-G4 systems both have been studied extensively, we here design their hybrid electrolytes to answer; will the resulting properties be averages/superpositions or will there be synergies created? We find the latter to be true and demonstrate that the most performant electrolytes are obtained by introducing a minor amount of LiTDI to an LiTFSI based electrolyte, which promotes the disproportionation and formation of "free" cations and at the same to avoid large aggregates - shown comprehensively both experimentally and by different modelling approaches and analyses combined. This electrolyte composition strategy can be generalized to other salts and solvents and thus a route towards a flora of novel battery electrolytes is here suggested.
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| 2. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Impact of Sulfur-Containing Additives on Lithium-Ion Battery Performance: From Computational Predictions to Full-Cell Assessments
- 2018
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1, s. 2582-2591
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Tidskriftsartikel (refereegranskat)abstract
- Electrolyte additives are pivotal for stabilization of lithium-ion batteries, by suppressing capacity loss through creation of an engineered solid-electrolyte-interphase-layer (SEI-layer) at the negative electrode and thereby increasing lifetime. Here, we compare four different sulfur-containing 5-membered-ring molecules as SEI-formers: 1,3,2-dioxathiolane-2,2-dioxide (DTD), propane-1,3-sultone (PS), sulfopropionic acid anhydride (SPA), and prop-1-ene-1,3-sultone (PES). Density functional theory calculations and electrochemical measurements both confirm appropriate reduction potentials. For a connection of the protective properties of the SEIs formed to the chemical structure of the additives, the decomposition paths are computed and compared with spectroscopic data for the negative electrode surface. The performance of full-cells cycled using a commercial electrolyte and the different additives reveals the formation of organic dianions to play a crucial beneficial role, more so for DTD and SPA than for PS and PES.
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| 3. |
- Fretz, Samuel Joseph, 1987, et al.
(författare)
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Amine- and Amide-Functionalized Mesoporous Carbons: A Strategy for Improving Sulfur/Host Interactions in Li-S Batteries
- 2020
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Ingår i: Batteries and Supercaps. - : Wiley. - 2566-6223. ; 3:8, s. 757-765
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-sulfur (Li-S) batteries are of great interest due to their potentially high energy density, but the low electronic conductivity of both the sulfur (S-8) cathode active material and the final discharge product lithium sulfide (Li2S) require the use of a conductive host. Usually made of relatively hydrophobic carbon, such hosts are typically ill-suited to retain polar discharge products such as the intermediate lithium polysulfides (LiPs) and the final Li2S. Herein, we propose a route to increase the sulfur utilization by functionalizing the surface of ordered mesoporous carbon CMK3 with polar groups. These derivatized CMK3 materials are made using a simple two-step procedure of bromomethylation and subsequent nucleophilic substitution with amine or amide nucleophiles. We demonstrate that, compared to the unfunctionalized control, these modified CMK3 surfaces have considerably larger binding energies with LiPs and Li2S, which are proposed to aid the electrochemical conversion between S-8 and Li2S by keeping the LiPs species in close proximity to the carbon surface during Li-S battery cycling. As a result, the functionalized cathodes exhibit significantly improved specific capacities relative to their unmodified precursor.
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| 4. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Anion amphiprotic ionic liquids as protic electrolyte matrices allowing sodium metal plating
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 55:83, s. 12523-12526
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Tidskriftsartikel (refereegranskat)abstract
- The sodium-ion battery (SIB) is proposed as a complementary technology to today's commercially dominant lithium-ion battery (LIB). While much know-how can be transferred from LIBs to SIBs, adjustments are still necessary, not the least for the electrolytes employed. Here the use of anion amphiprotic ionic liquid (AAIL) based electrolytes is proposed for SIB application. Two different AAILs, based on organic trifluoromethylsulfonylamide (TFSAm) and inorganic HSO4- anions, respectively, doped with NaTFSI salt have been studied, focusing on electrochemical stability and transport properties, complemented by studies of the ion-ion interactions, and final sodium-ion battery performance via stripping/plating vs. sodium metal electrodes.
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| 5. |
- 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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| 6. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Prospects for Improved Magnesocene-Based Magnesium Battery Electrolytes
- 2021
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Ingår i: Batteries and Supercaps. - : Wiley. - 2566-6223. ; 4:8, s. 1335-1343
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Tidskriftsartikel (refereegranskat)abstract
- Magnesium batteries are currently attracting a lot of interest as a next generation battery technology. One critical issue is to find a suitable electrolyte and herein we explore an electrolyte based on magnesocene (MgCp2) in tetrahydrofuran (THF), aiming for low-voltage Mg batteries, with respect to: Mg plating characteristics, electrochemical stability windows, electrolyte speciation, and electrolyte decomposition reactions; both experimentally and computationally. Overall, the electrolyte does not seem to decompose on a Mg metal anode and most likely reduced solvation of Mg2+ by the Cp- anion is important and species such as MgCp2THF2 may play an important role for Mg plating with small overpotential. The oxidation limit is largely determined by the Cp- anion and density functional theory predicted oxidation reactions point to polymerized end-products to be possible. Furthermore, in silico substitution studies enable us to establish the prospects of some Cp- anion derivatives to further improve the oxidative stability, but still the Mg2+ solvation must be monitored for ease of reduction and Mg plating.
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