The influence of electrolyte and graphite type on the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" display="inline" overflow="scroll"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>PF</mml:mtext></mml:mrow><mml:mrow><mml:mn>6</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math> intercalation behaviour at high potentials

Märkle, Wolfgang; Tran, Nicolas; Goers, Dietrich; Spahr, Michael E.; Novák, Petr

doi:10.1016/j.carbon.2009.05.029

Cited by 96 publications

(45 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 1 shows the current profile (a) and the gas evolution (b) of 12 + . While the current signal includes processes like capacitive currents related to the electrode surface or PF 6 − intercalation into the graphitic domains of the conductive carbon, which is reported to start around 4.6 V vs. Li/Li + , 25,26 we believe that the evolution of gaseous electrolyte oxidation products is a more meaningful indicator for the onset of electrolyte oxidation. As expected, Figure 1b shows that the oxidative CO 2 -release of VC starts at significantly lower potentials (∼4.3 V vs. Li/Li + ) compared to EC (∼4.8 V vs. Li/Li + ).…”

Section: Resultsmentioning

confidence: 89%

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Pritzl

Solchenbach

Wetjen

et al. 2017

J. Electrochem. Soc.

124

View full text Add to dashboard Cite

Vinylene Carbonate (VC) is an effective electrolyte additive to produce a stable solid electrolyte interphase (SEI) on graphite anodes, increasing the capacity retention of lithium-ion cells. However, in combination with LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes, VC drastically decreases cell performance. In this study we use on-line electrochemical mass spectrometry (OEMS) and electrochemical impedance spectroscopy (EIS) with a micro-reference electrode to understand the oxidative (in-)stability of VC and its effect on the interfacial resistances of both anode and cathode. We herein compare different VC concentrations corresponding to VC to graphite surface area ratios typically used in commercial-scale cells. At low VC concentrations (0.09 wt%, corresponding to 1 wt% in commercial-scale cells), an impedance increase exclusively on the anode and an improved capacity retention is observed, whereas higher VC concentrations (0.17 wt -2 wt%, corresponding to 2 wt -23 wt% in commercial-scale cells) show an increase in both cathode and anode impedance as well as worse cycling performance and overcharge capacity during the first cycle. By considering the onset potentials for VC reduction and oxidation in graphite/LNMO cells, we demonstrate that low amounts of VC can be reduced before VC oxidation occurs, which is sufficient to effectively passivate the graphite anode. During the first charge of a lithium ion battery (LiB), the so called solid electrolyte interphase (SEI) 1 is formed on the surface of the negative electrode. The standard electrolyte for LiBs consists of a mixture of cyclic and linear carbonates, e.g., ethylene carbonate (EC) and ethyl methyl carbonate (EMC), typically with lithium hexafluorophosphate (LiPF 6 ) as salt. Starting from a potential of ∼0.8 V vs. Li/Li + , EC is reduced electrochemically into ethylene gas and lithium ethylene dicarbonate (LEDC), which is a key component of the SEI.2,3 Vinylene carbonate (VC) is one of the most effective additives to modify the SEI on graphite anodes, as it is reduced at potentials more positive than 1.0 V vs. Li/Li + and hence suppresses the reduction of EC. 4,5Aurbach et al. have used VC as electrolyte additive in an EC/DMC (dimethyl carbonate) based electrolyte and that time reported a reduction of the irreversible capacity in the first cycles and an improved cycling stability at elevated temperatures for graphite anodes. The SEI resulting from the reduction of VC consists mainly of poly (vinylene carbonate) (poly(VC)). 4,6Important studies on the impact of different VC concentrations in graphite/NMC pouch cells have been carried out by the Dahn group. For example, Burns et al. 7 investigated the effect of different concentrations of VC (0, 1 and 2 wt%) on cycle life and impedance growth of full-cells with graphite anodes and either LCO (LiCoO 2 ) or NMC (Li(Ni 0.42 Mn 0.42 Co 0.16 )O 2 ) cathodes, employing galvanostatic cycling experiments coupled with high precision coulombic efficiency and electrochemical impedance spectroscopy (EIS) measurements. For cel...

show abstract

Section: Resultsmentioning

confidence: 89%

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Pritzl

Solchenbach

Wetjen

et al. 2017

J. Electrochem. Soc.

124

View full text Add to dashboard Cite

show abstract

“…The current for the first oxidation peak at 4.3 V versus Na + /Na was weak, whereas the second oxidation peak at 4.75 Vversus Na + /Na was strong. The calculated result also suggests an “activation” process during the charge/discharge cycles, in which the initial anions (

{PF}_{6}^{-}

) are required to widen the graphene interlayer gaps at the electrode/electrolyte interface to promote the subsequent anion intercalation . This process may also explain the gradual increase in the capacity during the early 30 cycles accompanying the increase in the electrochemical cycles (Figure b).…”

mentioning

confidence: 75%

“…Thus, the development of a Na‐based battery system with a high operating voltage comparable to that of a commercial Li ion battery should be essential for the practical application. Interestingly, to improve the working voltage, anion intercalation into graphite was demonstrated in dual ion batteries, which displayed high voltage up to 5 V . However, all the reported dual ion batteries were based on traditional rigid configuration, which failed to provide in‐plane thin film devices for practical application, especially for on‐chip microelectronics.…”

mentioning

confidence: 99%

Dual‐Graphene Rechargeable Sodium Battery

Wang

Liu

Zhang

et al. 2017

Small

View full text Add to dashboard Cite

Sodium (Na) ion batteries are attracting increasing attention for use in various electrical applications. However, the electrochemical behaviors, particularly the working voltages, of Na ion batteries are substantially lower than those of lithium (Li) ion batteries. Worse, the state-of-the-art Na ion battery cannot meet the demand of miniaturized in modern electronics. Here, we demonstrate that electrochemically exfoliated graphene (EG) nanosheets can reversibly store (PF ) anions, yielding high charging and discharging voltages of 4.7 and 4.3 V vs. Na /Na, respectively. The dual-graphene rechargeable Na battery fabricated using EG as both the positive and negative electrodes provided the highest operating voltage among all Na ion full cells reported to date, together with a maximum energy density of 250 Wh kg . Notably, the dual-graphene rechargeable Na microbattery exhibited an areal capacity of 35 μAh cm with stable cycling behavior. This study offers an efficient option for the development of novel rechargeable microbatteries with ultra-high operating voltage and high energy density.

show abstract

“…Consequently, single to a few layer thin sheets of high quality graphene°ake are dispersed in the electrolytic bath. [33][34][35][36][37][38] Cations such as lithium ions, 39,40 tetraalkylammonium ions (TBA þ , TMA þ , TEA þ ), 32,41,42 lithium-propylene carbonate ionic complexes 38 and N-butyl-methylpyrrolidium ions 43 52 have been explored generously. Anodic intercalation followed by exfoliation has been reported to be more e±cient (than the cathodic ones) in producing graphene°akes due to the nature and volume of evolution of gas at the graphite.…”

Section: Introductionmentioning

confidence: 99%

Simple, Fast and Cost-Effective Electrochemical Synthesis of Few Layer Graphene Nanosheets

Sahoo

Mallik

2015

NANO

View full text Add to dashboard Cite

We report an e±cient and green approach for mass production of few layered graphene nanosheets (FLGNSs) by intercalation and exfoliation of pyrolytic graphite sheet in a simple protic, H 2 SO 4 electrolyte. The as-prepared FLGNSs at the optimum intercalate concentration of 0.5 M H 2 SO 4 is able to produce large domain of lateral dimension of 11-26 m consisting of 4-6 stacked graphene layers, as con¯rmed by¯eld emission scanning electron microscopy and atomic force microscopy, respectively. Surface oxygenation and a characteristic absorbance peak at 228 nm are well observed for electrochemical exfoliated FLGNSs from Fourier transform infrared spectroscopy and UV-Vis spectra respectively. (002) planes of the obtained graphene sheets have been con¯rmed from X-ray di®raction pattern. The characteristic Raman bands have been observed at 1354 cm À1 and 1590 cm À1 in the exfoliated FLGNSs.

show abstract

The influence of electrolyte and graphite type on the PF6- intercalation behaviour at high potentials

Cited by 96 publications

References 20 publications

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Dual‐Graphene Rechargeable Sodium Battery

Simple, Fast and Cost-Effective Electrochemical Synthesis of Few Layer Graphene Nanosheets

Contact Info

Product

Resources

About

The influence of electrolyte and graphite type on the PF6- intercalation behaviour at high potentials

Cited by 96 publications

References 20 publications

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi0.5Mn1.5O4Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi0.5Mn1.5O4Cells

Dual‐Graphene Rechargeable Sodium Battery

Simple, Fast and Cost-Effective Electrochemical Synthesis of Few Layer Graphene Nanosheets

Contact Info

Product

Resources

About

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells