Lithium salts for advanced lithium batteries: Li–metal, Li–O<sub>2</sub>, and Li–S

Younesi, Reza; Veith, Gabriel M.; Johansson, Patrik; Edström, Kristina; Vegge, Tejs

doi:10.1039/c5ee01215e

Cited by 500 publications

(394 citation statements)

References 186 publications

(363 reference statements)

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“…than the FSIbased analogs. 20 These values illustrate the crucial effect of the size and shape of the cation in combination with the size and shape of the anion on the packing and crystallization behavior of the salt. 21 It was also observed that P 1113 FSI was the only ionic liquid that showed extra peaks below melting that can be attributed to the presence of other phases/crystalline structures of lower melting points or due to a solid-solid transition corresponding to a regular crystalline to plastic crystalline phase.…”

Section: Resultsmentioning

confidence: 99%

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

Salem

Zavorine

Nucciarone

et al. 2017

J. Electrochem. Soc.

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In this work, three ionic liquids with two different cations and two different anions: trimethyl propyl phosphonium bis-fluorosulfonyl imide (P 1113 FSI), trimethyl isobutyl phosphonium bis-fluorosulfonyl imide (P 111i4 FSI) and trimethyl isobutyl phosphonium bistrifluoromethylsulfonyl imide (P 111i4 TFSI) have been characterized and evaluated as electrolytes in lithium ion half-cells. It is found that ionic liquids with FSI − anion have superior properties over their TFSI − counterparts and those with the smaller cation, P 1113 , have better conductivity and viscosity. The two ionic liquids with FSI anion, P 1113 FSI and P 111i4 FSI, are liquid at room temperature and show high conductivities and low viscosities, reaching 10.0 mS/cm and 30 cP at room temperature for P 1113 FSI. They also exhibit electrochemical windows higher than 5 V and thermal stability exceeding 300 • C. Mixing the ionic liquids with 0.5 M LiPF 6 increases viscosities, lowers conductivities but improves electrochemical cathodic stability. The electrolyte mixtures have been evaluated in graphite/Li half cells, Li/LiFePO 4 and Li/LiMn 1.5 Ni 0.5 O 4 at C/12 for 100 cycles and at different rates: C/6, C/3, C and 2C for rate capabilities. Battery testing shows that unlike their TFSI − counterparts both ionic liquids with FSI − anion perform well with graphite anode and LiFePO 4 cathode but fail with the higher voltage LiMn Li-ion batteries have attracted a lot of attention since their successful application in portable consumer electronics mainly because of their unique properties such as high energy density and long cycle life. Since then, and due to increased market demand, interest has been drawn toward investigating Li-ion batteries as candidates for use in more energy-demanding applications such as electric vehicles (EV, HEV, PHEV) and large energy storage systems for the electrical grid.1-5 One important aspect of such investigation is to develop new and improved materials for Li-ion batteries to enhance their properties in terms of safety and performance, which is crucial to match the new demand. There have been a large number of studies on the anode, cathode and electrolyte components of Li-ion batteries for this purpose in recent years. Electrolyte solutions used in Li-ion batteries are usually composed of a lithium salt (LiPF 6 ) dissolved in a mixture of two or more carbonate solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC).6 These solvents are known to have safety concerns due to their flammability, volatility and reactivity to other battery components prompting an increased effort on finding safer alternatives. 7 In the last decade, a group of compounds called ionic liquids (ILs), has been of interest as an alternative to conventional battery electrolytes due to their excellent thermal and physiochemical properties such as non-flammability, negligible vapor pressure, good dissolution power, good electrochemical stability, wide liquid range and intrinsic ionic conductivity.7-13 Despite these aforementioned prope...

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Section: Resultsmentioning

confidence: 99%

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

Salem

Zavorine

Nucciarone

et al. 2017

J. Electrochem. Soc.

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“…Li-metal has higher energy density compared to other negative electrodes, but it suffers from dendrite formation, low cycling Coulombic efficiency, etc. 5 In this work, we study how the electrochemical performance of NMC cathodes is influenced by the choice of negative electrode, and how the surface layer formed on NMC positive electrode depend on the negative electrode material, by investigations of NMCLi-metal, NMC-LTO and NMC-graphite cells. This is motivated by the extensive use of Li-metal in literature to bench-mark cathode materials, which can neglect the influence of the negative elecz E-mail: reza.younesi@kemi.uu.se trode itself on the potential profile and cycling life of the positive electrode.…”

mentioning

confidence: 99%

How the Negative Electrode Influences Interfacial and Electrochemical Properties of LiNi_1/3Co_1/3Mn_1/3O₂Cathodes in Li-Ion Batteries

Björklund

Brandell

Hahlin

et al. 2017

J. Electrochem. Soc.

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The cycle life of LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NMC) based cells are significantly influenced by the choice of the negative electrode. Electrochemical testing and post mortem surface analysis are here used to investigate NMC electrodes cycled vs. either Li-metal, graphite or Li 4 Ti 5 O 12 (LTO) as negative electrodes. While NMC-LTO and NMC-graphite cells show small capacity fading over 200 cycles, NMC-Li-metal cell suffers from rapid capacity fading accompanied with an increased voltage hysteresis despite the almost unlimited access of lithium. X-ray absorption near edge structure (XANES) results show that no structural degradation occurs on the positive electrode even after >200 cycles, however, X-ray photoelectron spectroscopy (XPS) results shows that the composition of the surface layer formed on the NMC cathode in the NMC-Li-metal cell is largely different from that of the other NMC cathodes (cycled in the NMC-graphite or NMC-LTO cells). Furthermore, it is shown that the surface layer thickness on NMC increases with the number of cycles, caused by continuous electrolyte degradation products formed at the Li-metal negative electrode and then transferred to NMC positive electrode. Li-ion batteries (LiBs) are widely used in applications where rechargeability of high energy density storage units is required, such as portable devices including consumer electronics, vehicles and space applications. It is beneficial that the components are as light-weight as possible for portable devices, thereby decreasing the energy required to transport the device. One widely used positive electrode material contributing to high energy density is LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NMC), either operating at a higher potential or having a larger practical specific capacity than the classical LiMn 2 O 4 and LiFePO 4 materials.1,2 NMC is also less costly than the LiCoO 2 alternative due to the decreased cobalt content.In commercial cells, NMC electrodes are most often cycled vs. graphite negative electrodes which has a low working potential, enabling a large potential difference between the electrodes. However, the low working potential is outside of the electrochemical stability window of most common electrolytes, leading to formation of a solid electrolyte interphase (SEI) layer on the anode surface. A corresponding but thinner layer could also form on the side of the positive electrode depending on the working potential of the cathode. 3,4 Lithium is consumed during SEI formation, which results in a decrease in the cell capacity and an increase in the cell resistance. The problems caused by SEI layer formation can be resolved by changing the negative electrode to an electrode working at a higher potential -within the electrochemical stability window of the electrolytesuch as lithium titanate (Li 4 Ti 5 O 12 ; LTO). Although the increased working potential decreases the energy density of the cell, cycle life is generally increased. The Li-metal anode is another negative electrode that is commonly used as counter/reference electrode, at le...

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“…These results were obtained by measuring non-destructively a commercial lithium-ion battery. Recently, the use of lithium metal as a negative electrode material has been considered to result in high-performance batteries, as the lithium metal has the highest theoretical capacity, 3861 mAh/g, among general negative electrode materials [13][14][15]. However, there is a problem that lithium dendrite occurs at the surface of the negative electrode.…”

Section: Resultsmentioning

confidence: 97%

Dependency of the Charge–Discharge Rate on Lithium Reaction Distributions for a Commercial Lithium Coin Cell Visualized by Compton Scattering Imaging

et al. 2018

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Abstract:In this study, lithium reaction distributions, dependent on the charge-discharge rate, were non-destructively visualized for a commercial lithium-ion battery, using the Compton scattering imaging technique. By comparing lithium reaction distributions obtained at two different charge-discharge speeds, residual lithium ions were detected at the center of the negative electrode in a fully discharged state, at a relatively high-speed discharge rate. Moreover, we confirmed that inhomogeneous reactions were facilitated at a relatively high-speed charge-discharge rate, in both the negative and positive electrodes. A feature of our technique is that it can be applied to commercially used lithium-ion batteries, because it uses high-energy X-rays with high penetration power. Our technique thus opens a novel analyzing pathway for developing advanced batteries.

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Lithium salts for advanced lithium batteries: Li–metal, Li–O₂, and Li–S

Cited by 500 publications

References 186 publications

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

How the Negative Electrode Influences Interfacial and Electrochemical Properties of LiNi_1/3Co_1/3Mn_1/3O₂Cathodes in Li-Ion Batteries

Dependency of the Charge–Discharge Rate on Lithium Reaction Distributions for a Commercial Lithium Coin Cell Visualized by Compton Scattering Imaging

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Lithium salts for advanced lithium batteries: Li–metal, Li–O2, and Li–S

Cited by 500 publications

References 186 publications

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

Physical and Electrochemical Properties of Some Phosphonium-Based Ionic Liquids and the Performance of Their Electrolytes in Lithium-Ion Batteries

How the Negative Electrode Influences Interfacial and Electrochemical Properties of LiNi1/3Co1/3Mn1/3O2Cathodes in Li-Ion Batteries

Dependency of the Charge–Discharge Rate on Lithium Reaction Distributions for a Commercial Lithium Coin Cell Visualized by Compton Scattering Imaging

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Product

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About

Lithium salts for advanced lithium batteries: Li–metal, Li–O₂, and Li–S

How the Negative Electrode Influences Interfacial and Electrochemical Properties of LiNi_1/3Co_1/3Mn_1/3O₂Cathodes in Li-Ion Batteries