| 1. |
- Liu, Yangyang, et al.
(författare)
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Promoted rate and cycling capability of Li–S batteries enabled by targeted selection of co-solvent for the electrolyte
- 2020
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 25, s. 131-136
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Tidskriftsartikel (refereegranskat)abstract
- Lithium sulfur (Li–S) batteries are considered as promising candidates for high-energy-density battery systems owing to the high theoretical capacity of sulfur (1675 mAh g−1) and low cost of raw materials. However, their practical application is hampered by low rate capability and rapid degradation of capacity, arising from the passivation of the cathode by lithium sulfides (Li2S2/Li2S) deposited during discharge and low interfacial stability of the Li anode. Herein, we report on a comprehensive strategy to select co-solvent to the electrolyte to regulate the deposition of lithium sulfides during charge-discharge process. We show that addition of a co-solvent with high solubility, and strong interaction with Li2S to a conventional electrolyte effectively mitigates the formation of a passivating layer on the sulfur cathode and dramatically improves the interfacial stability of the Li anode. We demonstrate that Sulfolane (SL) has these properties and that a Li–S cell with an electrolyte containing 6 vol% SL exhibits outstanding cyclic performance (0.083% decay per cycle) and rate capability (capacity density of 765 mAh g−1 at rate of 1.0C). Thus, we provide a facile strategy for the selection of co-solvent for improved performance of Li–S batteries, realizing their practical application for high-energy-density battery systems.
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| 2. |
- Xiong, Shizhao, et al.
(författare)
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Analysis of the solid electrolyte interphase formed with an ionic liquid electrolyte for lithium-sulfur batteries
- 2014
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 252, s. 150-155
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the formation of the solid electrolyte interphase (SEI) on lithium electrodes in the presence of an ionic liquid electrolyte with a particular focus on the influence of polysulfides present in the electrolyte on the SEI. The electrochemical performance of symmetric cells with lithium electrodes and electrolytes composed of N-Methyl-(n-butyl)pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14-TFSI) and LiTFSI, with and without the addition of polysulfides, were analyzed as well as the chemical composition of the SEI, before and after cycling. The cycling behavior of the symmetrical cells shows that the SEI films are relatively stable in the ionic liquid electrolyte, also in the presence of polysulfides. However, the presence of polysulfides results in a higher SEI layer resistance (R-SEI) and a higher activation energy. From X-ray photoelectron spectroscopy spectra (XPS), with argon-ion sputtering for depth profiling, we find that the SEI is formed by decomposition products from both cations and anions of the electrolyte. The XPS spectra show that the presence of polysulfides alters the decomposition process of the electrolyte, resulting in a SEI film with different chemical composition and structure, in line with the results from the electrochemical performance.
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| 3. |
- Xiong, Shizhao, 1985, et al.
(författare)
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Design of a Multifunctional Interlayer for NASCION-Based Solid-State Li Metal Batteries
- 2020
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 30:22
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Tidskriftsartikel (refereegranskat)abstract
- NASCION-type Li conductors have great potential to bring high capacity solid-state batteries to realization, related to its properties such as high ionic conductivity, stability under ambient conditions, wide electrochemical stability window, and inexpensive production. However, their chemical and thermal instability toward metallic lithium (Li) has severely hindered attempts to utilize Li as anode material in NASCION-based battery systems. In this work, it is shown how a tailored multifunctional interlayer between the solid electrolyte and Li anode can successfully address the interfacial issues. This interlayer is designed by creating a quasi-solid-state paste in which the functionalities of LAGP (Li1.5Al0.5Ge1.5(PO4)3) nanoparticles and an ionic liquid (IL) electrolyte are combined. In a solid-sate cell, the LAGP-IL interlayer separates the Li metal from bulk LAGP and creates a chemically stable interface with low resistance (≈5 Ω cm2) and efficiently prevents thermal runaway at elevated temperatures (300 °C). Solid-state cells designed with the interlayer can be operated at high current densities, 1 mA cm−2, and enable high rate capability with high safety. Here developed strategy provides a generic path to design interlayers for solid-state Li metal batteries.
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