Deciphering the multi-step degradation mechanisms of carbonate-based electrolyte in Li batteries

Gachot, Grégory; Grugeon, Sylvie; Armand, Michel; Pilard, Serge; Guénot, Pierre; Tarascon, Jean‐Marie; Laruelle, Stéphane

doi:10.1016/j.jpowsour.2007.11.110

Cited by 359 publications

(382 citation statements)

References 25 publications

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“…When Gr/Gr cells are cycled in the electrolyte without SA, three new peaks located at 11.8 minutes, 12.9 minutes and 13.9 minutes arise which are assigned respectively to ethylene glycol bis-(methyl carbonate), ethylene glycol ethylmethyl bis-(carbonate), ethylene glycol bis-(ethyl carbonate). 28 These bis-(alkyl carbonates) are depicted (molar masses and chemical structure) in Table IV. These compounds have been earlier identified as electrolyte degradation byproducts, 29 and form on the graphite electrode according to the reduction mechanism 30,31 reported in Fig. 13.…”

Section: Xps Analysis Of Lithiated Graphite Interfaces-symmetricmentioning

confidence: 92%

Reactivity of Succinic Anhydride at Lithium and Graphite Electrodes

Charton

Santos-Peña

Biller

et al. 2017

J. Electrochem. Soc.

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Succinic anhydride (SA) is an useful electrolyte additive for high voltage cathodes but has also a negative impact on graphite (Gr) or Li anodes. For this reason, the Li/electrolyte and Gr/electrolyte interfaces were investigated at 20 • C and 45 • C using half or symmetrical cells. When SA is added at 1% by weight to the electrolyte (alkylcarbonate mixture + LiPF 6 ), an increase in the Li/Li cell impedance at 20 • C occurs owing to the formation of a resistive solid electrolyte interphase (SEI), composed of an inorganic inner layer and an organic outer layer, whereas at 45 • C or in absence of SA, the interphase is more inorganic in nature. The reversible capacity of graphite, cycled in Gr/Li half-cells in the presence of SA, is very low at 20 • C but almost ten times larger at 45 • C. Cycling symmetrical Gr/Gr cells at 45 • C indicates that Gr capacity is lower in the presence of SA in connection with the presence of an organic and polymer rich SEI. GC-MS analysis of the electrolyte after cycling shows that ethylene glycol bis-(alkylcarbonate) derivatives disappear when SA is present, owing to the ability of SA to react with lithium alkoxides to yield oligopolyester. Lithium ion batteries (LIBs) are a reliable way to store electric energy, with high gravimetric and volumetric energy density, which allows their application in nomad systems including electric and/or hybrid vehicles. However, electric vehicles range is unsuitable for most of the consumers and, therefore, energy density should be improved. In the past twenty years, many researches have been performed on electrode materials and electrolytes with the aim to enhance battery performance. Use of 5V class positive electrodes (cathodes) is a convenient way to increase LIBs energy density. It explains the development of promising "high voltage" materials like Li 3 V 2 (PO 4 ) 3 , 1 Li 2 CoPO 4 F 2 or the LiNi 0.5 Mn 1.5 O 4 (LNMO) 3 spinel. Nevertheless, the use of new cathodes operating at high voltage leads to the degradation of the battery electrolyte, usually based on a mixture of cyclic and linear alkylcarbonates containing LiPF 6 as salt and functional additives. Unfortunately, standard electrolytes are oxidized on 5 V cathodes and this significantly limits the battery cycling life. From the first cycles, electrolyte components degrade forming by-products, which in turn, can interact with electrodes surface. As an example, a passive layer is formed on graphite (Gr)/electrolyte interface at the first charge. This layer, known as the Solid Electrolyte Interphase (SEI), has a strong impact on the LIBs performances. Electrolyte formulation influences the chemical nature and structure of the SEI. With the aim to improve SEI quality and stability, SEI-forming additives like vinylene carbonate (VC) are generally added to the electrolyte in low amount (less than 5% by weight). These additives are designed to generate a protective passive layer on the active material surface preventing continuous electrolyte decomposition reactions.Whereas additives can be ...

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Section: Xps Analysis Of Lithiated Graphite Interfaces-symmetricmentioning

confidence: 92%

Reactivity of Succinic Anhydride at Lithium and Graphite Electrodes

Charton

Santos-Peña

Biller

et al. 2017

J. Electrochem. Soc.

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“…A transesterification was proposed, a start from alkoxides has been described and a PF 5 (Lewis acid) supported mechanism has also been published on [30][31][32][33].…”

Section: Resultsmentioning

confidence: 99%

“…10 Progress of the 1,3-dioxolane concentration versus the CV's potential from an experiment with a bare LNMO cathode Fig. 11 General formula of the polyethylene-based oligomers found in an SEI [30] second reaction on a very small scale. The concentration and its profile were the same for both cathode materials.…”

Section: Resultsmentioning

confidence: 99%

Electrolyte-cathode interactions in 5-V lithium-ion cells

Kohs

Kahr

Ahniyaz³

et al. 2017

J Solid State Electrochem

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The electrolyte/electrode interactions on the anode side of a lithium-ion cell and the formation of the solid electrolyte interphase (SEI) have been investigated intensively in the past and are fairly well understood. Present knowledge about the reactions on the cathode side and the resulting cathode electrolyte interphase (CEI) is less detailed. In this study, the electrolyte/electrode interactions on the surface of the high-voltage cathode material LiNi 0.5 Mn 1.5 O 4 (LNMO), both bare and FePO 4 -coated, were investigated. The gases evolving upon first time charging of the system were investigated using a GC/MS combination. The degradation products included THF, dimethyl peroxide, phosphor trifluoride, 1,3-dioxolane and dimethyl difluor silane, formed in the GC's column as its coating reacts with HF from the experiments. Although these substances and their formation are in themselves interesting, the absence of many degradation products which have been mentioned in the existing literature is of equal interest. Our results clearly indicate that coating a cathode material can have a major influence on the amount and composition of the gaseous decomposition products in the formation phase.

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“…These products are 1) typical of irradiated EC;2 )typical of irradiated DEC;a nd 3) due to the presence of the two compounds in the mixture, such as dicarbonate, carbonate with two ether functions, and carbonate with ether functions, as already reported in the field of LIBs. [8,34,40] …”

Section: Composition Of the Gas Phase After Irradiationmentioning

confidence: 99%

“…The degradation of the electrolyte often cannot be investigated by using the usual thermally activated aging methods, whiche xplainsw hy these studies may be costly,lengthy,and usuallyq ualitative. [8] Recently,w ed emonstrated that radiolysis (i.e. the chemical reactivity induced by the interaction between matter and ionizing radiation)provides an elegant solution to these issues because it is ap owerful tool for quick identification( minutest o days as it strongly accelerates aging processes)o ft he species produced by the degradation of aL IB electrolyte after several weekst om onths of cycling.…”

Section: Introductionmentioning

confidence: 99%

Degradation of an Ethylene Carbonate/Diethyl Carbonate Mixture by Using Ionizing Radiation

et al. 2017

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The reactivity of ethylene carbonate (EC) and of a EC/diethyl carbonate (DEC) mixture was studied under ionizing radiation to mimic the aging phenomena that occur in lithium‐ion batteries. Picosecond‐pulse radiolysis experiments showed that the attachment of the electron to the EC molecule is ultrafast (k(e−EC+EC)=1.3×109 L mol−1 s−1 at 46 °C). This reaction rate is accelerated by a factor of 5.7 compared with the electron attachment to propylene carbonate, which implies that the presence of the methyl group significantly slows the reaction. In a 50:50 EC/DEC mixture, just after the electron pulse the electron is solvated by a mixture of EC and DEC molecules, but its fast decay is attributed exclusively to electron attachment to the EC molecule. Stable products detected after steady‐state irradiation were mainly H2, CH4, CO, and CO2. The evolution of the radiolytic yields with the EC fraction shows that H2 and CH4 did not exhibit linear behavior, whereas CO and CO2 did. Indeed, H2 and CH4 mainly arise from the excited state of DEC, the formation of which is significantly affected by the evolution of the dielectric constant of the mixture and by the electron attachment to EC. CO formation is mainly due to the reactivity of the EC molecule, which is not affected in the mixture, as proven by pulse‐radiolysis experiments.

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Deciphering the multi-step degradation mechanisms of carbonate-based electrolyte in Li batteries

Cited by 359 publications

References 25 publications

Reactivity of Succinic Anhydride at Lithium and Graphite Electrodes

Reactivity of Succinic Anhydride at Lithium and Graphite Electrodes

Electrolyte-cathode interactions in 5-V lithium-ion cells

Degradation of an Ethylene Carbonate/Diethyl Carbonate Mixture by Using Ionizing Radiation

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