| 1. |
- 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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| 2. |
- Tsurumaki, Akiko, et al.
(författare)
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Enhanced safety and galvanostatic performance of high voltage lithium batteries by using ionic liquids
- 2019
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 316, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the addition of 1-butyl-1-methylpyrrolidinium hexafluorophosphate ([Py-14]PF6) to 1.0 M LiPF6 in ethylene carbonate-dimethyl carbonate (LP30) widens the temperature range, in which the electrolyte mixtures are ion conductive and safe. Specifically, at the concentrations of [Py-14]PF6 above 50 wt%, the electrolyte mixtures exhibit a flash point higher than room temperature and fulfill the requirements of liquids having controlled flammability. In this concentration range, also crystallization of the mixtures is completely suppressed, and low temperature ionic conductivity is improved. With respect to the electrochemical properties at room temperature, electrochemical stability window is widened by the addition of [Py-14]PF6 to LP30. However, it comes at the cost of slightly increased overall impedance and overpotential in Li vertical bar Li symmetric cells. We utilize these mixed electrolytes in high voltage Li vertical bar LiNi0.5Mn1.5O4 cells. In the presence of 30 wt% and 50 wt% of [Py-14]PF6 in LP30, the cells exhibit high specific capacity of about 110 mAh g(-1) over 200 cycles and improved coulombic efficiency, suggesting [Py-14]PF6 is a promising additive for the electrolyte in high-voltage, stable and safe lithium batteries.
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