| 1. |
- Barros Neves de Araújo, Rafael, 1985, et al.
(författare)
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Towards novel calcium battery electrolytes by efficient computational screening
- 2021
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 39, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- The development of Ca conducting electrolytes is key to enable functional rechargeable Ca batteries. The here presented screening strategy is initially based on a combined density functional theory (DFT) and conductor-like screening model for real solvents (COSMO-RS) approach, which allows for a rational selection of electrolyte solvent based on a set of physico-chemical and electrochemical properties: solvation power, electrochemical stability window, viscosity, and flash and boiling points. Starting from 81 solvents, N,N-dimethylformamide (DMF) was chosen as solvent for further studies of cation-solvent interactions and subsequent comparisons vs. cation-anion interactions possibly present in electrolytes, based on a limited set of Ca-salts. A Ca first solvation shell of [Ca(DMF) ] was found to be energetically preferred, even as compared to ion-pairs and aggregates, especially for PF and TFSI as the anions. Overall, this points to Ca(TFSI) and Ca(PF ) dissolved in DMF to be a promising base electrolyte for Ca batteries from a physico-chemical point-of-view. While electrochemical assessments certainly are needed to verify this promise, the screening strategy presented is efficient and a useful stepping-stone to reduce the overall R&D effort.
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| 2. |
- Forero-Saboya, Juan, et al.
(författare)
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Cation Solvation and Physicochemical Properties of Ca Battery Electrolytes
- 2019
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:59, s. 29524-29532
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Tidskriftsartikel (refereegranskat)abstract
- Divalent-cation-based batteries are being considered as potential high energy density storage devices. The optimization of electrolytes for these technologies is, however, still largely lacking. Recent demonstration of the feasibility of Ca and Mg plating and stripping in the presence of a passivation layer or an artificial interphase has paved the way for more diverse electrolyte formulations. Here, we exhaustively evaluate several Ca-based electrolytes with different salts, solvents, and concentrations, via measuring physicochemical properties and using vibrational spectroscopy. Some comparisons with Mg- and Li-based electrolytes are made to highlight the unique properties of the Ca2+ cation. The Ca-salt solubility is found to be a major issue, calling for development of new highly dissociative salts. Nonetheless, reasonable salt solubility and dissociation are achieved using bis(trifluoromethanesulfonyl)imide (TFSI), BF4, and triflate anion based electrolytes and high-permittivity solvents, such as ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (gBL), and N,N-dimethylformamide (DMF). The local Ca2+ coordination is concentration-dependent and rather complex, possibly involving bidentate coordination and participation of the nitrogen atom of DMF. The ionicity and the degree of ion-pair formation are both investigated and found to be strongly dependent on the nature of the cation, solvent donicity, and salt concentration. The large ion-ion interaction energies of the contact ion pairs, confirmed by density functional theory (DFT) calculations, are expected to play a major role in the interfacial processes, and thus, we here provide electrolyte design strategies to engineer the cation solvation and possibly improve the power performance of divalent battery systems.
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| 3. |
- Monti, Damien, et al.
(författare)
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Multivalent Batteries-Prospects for High Energy Density: Ca Batteries
- 2019
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 7:FEB
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Tidskriftsartikel (refereegranskat)abstract
- Batteries based on Ca hold the promise to leapfrog ahead regarding increases in energy densities and are especially attractive as Ca is the 5th most abundant element in the Earth's crust. The viability of Ca metal anodes has recently been shown by approaches that either use wide potential window electrolytes at moderately elevated temperatures or THE-based electrolytes at room temperature. This paper provides realistic estimates of the practical energy densities for Ca-based rechargeable batteries at the cell level, calculated using open source models for several concepts. The results from the Ca metal anode batteries indicate that doubled or even tripled energy density as compared to the state-of-the-art Li-ion batteries is viable if a practical proof-of-concept can be achieved.
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| 4. |
- 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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