| 31. |
- Carboni, Marco, et al.
(author)
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Analysis of the Solid Electrolyte Interphase on Hard Carbon Electrodes in Sodium-Ion Batteries
- 2019
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In: ChemElectroChem. - : Wiley. - 2196-0216. ; 6:6, s. 1745-1753
-
Journal article (peer-reviewed)abstract
- The composition, morphology, and evolution of the solid electrolyte interphase (SEI) formed on hard carbon (HC) electrodes upon cycling in sodium‐ion batteries are investigated. A microporous HC was prepared by pyrolysis of d‐(+)‐glucose at 1000 °C followed by ball‐milling. HC electrodes were galvanostatically cycled at room temperature in sodium‐ion half‐cells using an aprotic electrolyte of 1 m sodium bis(trifluoromethanesulfonyl)imide dissolved in propylene carbonate with 3 wt % fluoroethylene carbonate additive. The evolution of the electrode/electrolyte interface was studied by impedance spectroscopy upon cycling and ex situ by spectroscopy and microscopy. The irreversible capacity displayed by the HC electrodes in the first galvanostatic cycle is probably due to the accumulation of redox inactive NaxC phases and the precipitation of a porous, organic‐inorganic hybrid SEI layer over the HC electrodes. This passivation film further evolves in morphology and composition upon cycling and stabilizes after approximately ten galvanostatic cycles at low current rates.
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| 32. |
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| 33. |
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| 34. |
- Carboni, Marco, et al.
(author)
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Unlocking high capacities of graphite anodes for potassium-ion batteries
- 2019
-
In: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 9:36, s. 21070-21074
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Journal article (peer-reviewed)abstract
- Graphite is considered a promising candidate as the anode for potassium-ion batteries (KIBs). Here, we demonstrate a significant improvement in performance through the ball-milling of graphite. Electrochemical techniques show reversible K-intercalation into graphitic layers, with 65% capacity retention after 100 cycles from initial capacities and extended cycling beyond 200 cycles. Such an affinity of the graphite towards storage of K-ions is explained by means of SEM and Raman analyses. Graphite ball-milling results in a gentle mechanical exfoliation of the graphene layers and simultaneous defect formation, leading to enhanced electrochemical performance.
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| 35. |
- Christiansen, Ane S., et al.
(author)
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Plasma properties during magnetron sputtering of lithium phosphorous oxynitride thin films
- 2015
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In: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 273, s. 863-872
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Journal article (peer-reviewed)abstract
- The nitrogen dissociation and plasma parameters during radio frequency sputtering of lithium phosphorus oxynitride thin films in nitrogen gas are investigated by mass appearance spectrometry, electrostatic probes and optical emission spectroscopy, and the results are correlated with electrochemical properties and microstructure of the films. Low pressure and moderate power are associated with lower plasma density, higher electron temperature, higher plasma potential and larger diffusion length for sputtered particles. This combination of parameters favors the presence of more atomic nitrogen, a fact that correlates with a higher ionic conductivity. Despite of lower plasma density the film grows faster at lower pressure where the higher plasma potential, translated into higher energy for impinging ions on the substrate, resulted in a compact and smooth film structure. Higher pressures showed much less nitrogen dissociation and lower ion energy with thinner films, less ionic conductivity and poor film structure with large roughness.
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| 36. |
- Colbin, Lars Olow Simon, et al.
(author)
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Anodic dissolution of aluminum in non-aqueous electrolyte solutions for sodium-ion batteries
- 2023
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In: Energy Advances. - : Royal Society of Chemistry. - 2753-1457. ; 3:1, s. 143-
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Journal article (peer-reviewed)abstract
- Anodic dissolution of aluminum (commonly called aluminum corrosion) is a potential issue in sodium-ion batteries. Herein, it is demonstrated how different sodium-ion battery electrolyte solutions affect this phenomenon. The type of electrolyte was critical for the presence of anodic dissolution, while the solvent appeared to alter the dissolution process.
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| 37. |
- Colbin, Lars Olow Simon
(author)
-
Developing Electrolyte Solutions for Sodium-Ion Batteries : Challenging the Use of Hexafluorophosphate
- 2024
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Doctoral thesis (other academic/artistic)abstract
- The ability to store energy will be critical for achieving a functioning electrified society largely based on renewable energy sources. Batteries are anticipated to be a vital part of the infrastructure required to facilitate this energy storage. Electrolyte solutions are an essential component of most batteries, including sodium-ion batteries, which are emerging as a potentially more sustainable alternative to lithium-ion batteries.This thesis critically assesses the use of sodium hexafluorophosphate as an electrolyte in sodium-ion batteries. Although widely used in lithium-ion batteries, the suitability of hexafluorophosphate for sodium-ion batteries needs re-evaluation. In this thesis, properties meriting the use of sodium hexafluorophosphate are explored, including its solubility in different organic solvents, conductivity, ability to prevent anodic aluminium dissolution, and cycling performance in battery cells. Sodium bis(oxalato)borate is investigated as an example of a fluorine-free alternative that may better align with the goal of increasing the sustainability of contemporary batteries. The main drawback of sodium bis(oxalato)borate is its significantly lower solubility compared to sodium hexafluorophosphate. However, at the same concentration in a given solvent, both electrolytes exhibit similar conductivities, challenging the notion that hexafluorophosphate enhances conductivity through low ion association.Both electrolytes also prevent anodic aluminium dissolution. However, the use of sodium hexafluorophosphate does not consistently ensure adequate passivation of the negative electrode, suggesting that solvents or additives are more central for this process in these systems. In contrast, sodium bis(oxalato)borate appear to significantly contribute to the passivation of the negative electrode, even when used as an additive. As a sole electrolyte, sodium bis(oxalato)borate enable promising cycling performance in both lab-scale cells and in cells close to commercial standards. This research indicates that sodium hexafluorophosphate can be replaced with a fluorine-free electrolyte without compromising battery performance. The findings highlight the potential for more sustainable sodium-ion batteries and represent a step towards reducing the environmental impact of an electrified society.
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| 38. |
- Colbin, Lars Olow Simon, et al.
(author)
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On the compatibility of high mass loading bismuth anodes for full-cell sodium-ion batteries
- 2022
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In: Dalton Transactions. - : Royal Society of Chemistry. - 1477-9226 .- 1477-9234. ; 51:44, s. 16852-16860
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Journal article (peer-reviewed)abstract
- Metallic bismuth is here studied as an anode material for sodium-ion batteries. The details of electrochemical redox reactions, rate performance and cycled life were investigated using relatively high mass loading electrodes in two- and three-electrode full-cells. It demonstrated that the rate capability of bismuth anodes with high mass loading are not as good as indicated in previous literatures where low mass loading electrodes were used. It also indicated that the resistances causing a faltering rate performance may be connected to a loss in particle contact during desodiation. Efforts were also made to study the different electrochemical processes that occur during early cycles. Less advantageous characteristics of bismuth electrodes are also discussed. For example, several different electrolyte solutions were tested for compatibility with the bismuth system, where only glyme-based solutions seemed to facilitate robust cycling.
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| 39. |
- Colbin, Simon, et al.
(author)
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A Halogen‐Free and Flame‐Retardant Sodium Electrolyte Compatible with Hard Carbon Anodes
- 2021
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In: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 8:23
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Journal article (peer-reviewed)abstract
- For sodium-ion batteries, two pressing issues concerning electrolytes are flammability and compatibility with hard carbon anode materials. Non-flammable electrolytes that are sufficiently stable against hard carbon have—to the authors’ knowledge—previously only been obtained by either the use of high salt concentrations or additives. Herein, the authors present a simple, fluorine-free, and flame-retardant electrolyte which is compatible with hard carbon: 0.38 m sodium bis(oxalato)borate (NaBOB) in triethyl phosphate (TEP). A variety of techniques are employed to characterize the physical properties of the electrolyte, and to evaluate the electrochemical performance in full-cell sodium-ion batteries. The results reveal that the conductivity is sufficient for battery operation, no significant self-discharge occurs, and a satisfactory passivation is enabled by the electrolyte. In fact, a mean discharge capacity of 107 ± 4 mAh g−1 is achieved at the 1005th cycle, using Prussian white cathodes and hard carbon anodes. Hence, the studied electrolyte is a promising candidate for use in sodium-ion batteries.
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| 40. |
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