Suppression of Toxic Compounds Produced in the Decomposition of Lithium-Ion Battery Electrolytes

Campion, Christopher L.; Li, Wentao; Euler, William B.; Lucht, Brett L.; Ravdel, Boris; DiCarlo, Jeffrey M.; Gitzendanner, R.; Abraham, K. M.

doi:10.1149/1.1738551

Cited by 151 publications

(156 citation statements)

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“…Similarly, POF 3 is an indicator of LiPF 6 decomposition, which is supposed to be mediated by ROH species (Equation 3) and/or other oxygen containing species such as Li 2 CO 3 and further, similar reactions. 13,36,37 Fragments m/z = 85 and 104 evolve in a strongly correlated manner (Figure 1a) and are not observed with LiClO 4 electrolyte salt (Figure 1b) proving that the corresponding signals originate from POF 3 38 and thus that LiPF 6 decomposition indeed is enhanced by galvanostatic cycling of HE-NCM. Substantial quantities of POF 3 evolve during the first discharge regardless of whether Li metal (Figure 1a) or delithiated LiFePO 4 ( Figure 1c) is used as counter electrode.…”

Section: Resultsmentioning

confidence: 95%

“…8 For example, Freunberger et al proposed a mechanism for reactions between oxygen radicals and the carbonate solvents resulting in formation of lithium dicarbonate, formate, acetate, Li 2 CO 3 , CO 2 and H 2 O. 9 Several electrochemically initiated side reactions implicating the solvents (notably oxidation of carbonates HRCO 3 ) and the LiPF 6 salt have been proposed: [10][11][12][13][14][15][16][17][18][19] HRCO 3 → RO · + CO 2 + H + + e − [1] LiPF 6 ↔ LiF + PF 5 [2] PF 5 + ROH → POF 3 + HF + RF [3] z E-mail: aurelie.gueguen@psi.ch POF 3 + ROH → POF 2 (OR) + HF [4] POF 3 + RCO 3 R → POF 2 OR + CO 2 + RF [5] For instance, when the cyclic ethylene carbonate (R = C 2 H 3 in Equation 1) is oxidized, 10 it may (via Equation 1) lead to the formation of RO . radicals, which subsequently may (via Equation 3) hydrolyze the salt and cause the formation of various organofluorine compounds, such as flouroethylene C 2 H 3 F. LiPF 6 is known to form an equilibrium (Equation 2) with LiF and PF 5 .…”

mentioning

confidence: 99%

“…[13][14][15][16][17][18][19] Thermally activated decomposition of carbonate and LiPF 6 based electrolytes has however been extensively studied (c.f. Nowak et al 20 and citations therein).…”

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confidence: 99%

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Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Guéguen

Streich

et al. 2016

J. Electrochem. Soc.

190

165

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The chemical and electrochemical instabilities of LiPF 6 in carbonate electrolytes for Li-ion batteries were studied with online electrochemical mass spectrometry (OEMS). Decomposition of carbonate electrolytes based on LiPF 6 eventually results in the formation of POF 3 , which is readily detected and followed in situ during operation of Li-rich HE-NCM-based Li-ion cells. Electrode potentials above ∼4.2 V leads to carbonate solvent oxidation and presumably the formation of ROH species, which subsequently hydrolyze the LiPF 6 salt and initiate a thermally activated autocatalytic electrolyte decomposition cycle involving POF 3 as a reactive intermediate. Activation of the Li 2 MnO 3 domains of the Li-rich cathode contributes along with electrolyte and separator impurities to further POF 3 generation. Electrode potentials below ∼2.5 V vs. Li + /Li impede POF 3 formation and presumably also further electrolyte decomposition by scavenging reactive intermediate species. As a result, much less POF 3 gas was detected upon the 2 nd charge when using Li metal counter electrode, contrary to delithiated LiFePO 4 . In situ OEMS confirm that the parasitic reactions involving LiPF 6 constitute an intricate reaction scheme, but more importantly, provide further evidence about what the components of this scheme are and how these may interact with each other. Rechargeable Li-ion batteries are nowadays extensively used to power electronics and are entering the transportation sector by powering electric vehicles (EV). A wide range of both negative (e.g. graphite) and positive electrode materials (e.g. layered cobalt oxides, spinel-type manganese oxides, and olivine-type iron phosphates) have been thoroughly investigated and are now in widespread use in commercial batteries. The specific energy of Li-ion batteries is limited mainly by the positive electrode materials, having typical practical specific charges of ∼150 mAh/g and average operating potentials of ∼3.8 V vs. Li + /Li, which significantly inhibits the introduction of Li-ion batteries as power source in new applications. In recent years, the layered Li-rich cobalt-nickel-manganese oxides xLi 2 MnO 3 (1−x)(LiMO 2 ) (x ∼ 0.5, M = Co, Ni, Mn), hereafter called HE-NCM, have been shown to exhibit a high and reversible specific charge (∼250 mAh/g) and a competitive average operating potential (∼3.75 V vs. Li + /Li). [1][2][3][4] The origin of such a high specific charge is not yet completely understood, as the exact structure of the HE-NCM materials is highly dependent on the synthesis conditions and models coming from structural characterization are still under debate. Several reports have shown the presence of so-called Li 2 MnO 3 domains in the compound 5,6 whereas other groups demonstrated the monophasic character of their materials.7 However, during the first charge, a long potential plateau at ∼4.5 V vs. Li + /Li, not observed for conventional layered oxides, results from the delithiation process of the Li 2 MnO 3 domains accompanied by oxygen extraction. The extracted oxy...

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Section: Resultsmentioning

confidence: 95%

mentioning

confidence: 99%

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Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Guéguen

Streich

et al. 2016

J. Electrochem. Soc.

190

165

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“…For example, as measured by DSC 2,3 the temperature for onset of thermal decomposition of the neat salt LiPF 6 was 573 o K in a heretically sealed sample pan and 450 o K at ambient pressure. In related ambient pressure experiments 1,2 , the onset temperature varied by as much as 130 o K between DSC and TGA measurements.…”

Section: Introductionmentioning

confidence: 99%

“…In related ambient pressure experiments 1,2 , the onset temperature varied by as much as 130 o K between DSC and TGA measurements. In addition, the identification of the decomposition products is also the subject of debate in the literature 5,6 . While both Armand and Abraham agreed that thermal dissociation of EC:LiPF 6 solvent alone does not produce fluoro-organics, they disagreed on the nature of catalysts which activate the formation of fluoro-organics during storage at elevated temperature ~ 85 o C. Armand attributed a catalytic effect to cathode active material (e.g.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of LiPF6 salt and Li-ion battery electrolytes containing LiPF6

Yang

Zhuang

Ross

2006

Journal of Power Sources

420

286

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The thermal stability of the neat LiPF 6 salt and of 1 molal solutions of LiPF 6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line FTIR. Pure LiPF 6 salt is thermally stable up to 380 o K in a dry inert atmosphere, and its decomposition path is a simple dissociation producing LiF as solid and PF 5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form POF 3 and HF. No new products were observed in 1 molal solutions of LiPF 6 in EC, DMC and EMC by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 358 o K for 300 -420 hrs. did not produce any significant quantity of new products as well. In particular, no alkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF 6 and the prototypical Liion battery solvents EC, PC, DMC or EMC.

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Lithium–Ion Batteries

Lucht

Markmaitree

Yang

2005

Encyclopedia of Inorganic Chemistry

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Suppression of Toxic Compounds Produced in the Decomposition of Lithium-Ion Battery Electrolytes

Cited by 151 publications

References 8 publications

Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Thermal stability of LiPF6 salt and Li-ion battery electrolytes containing LiPF6

Lithium–Ion Batteries

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Suppression of Toxic Compounds Produced in the Decomposition of Lithium-Ion Battery Electrolytes

Cited by 151 publications

References 8 publications

Decomposition of LiPF6in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Decomposition of LiPF6in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Thermal stability of LiPF6 salt and Li-ion battery electrolytes containing LiPF6

Lithium–Ion Batteries

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Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry

Decomposition of LiPF₆in High Energy Lithium-Ion Batteries Studied with Online Electrochemical Mass Spectrometry