Ionic liquids containing tricyanomethanide anions: physicochemical characterisation and performance as electrochemical double-layer capacitor electrolytes

Martins, Vitor L.; Rennie, Anthony J. R.; Torresi, Roberto M.; Hall, Peter

doi:10.1039/c7cp03377j

Cited by 29 publications

(21 citation statements)

References 43 publications

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“…The method used to determine maximum operating voltage is based on the method proposed by Weingarth et al . and is described in detail elsewhere ,. Basically, the difference in coulombic charge between the discharge and charge processes (Δ q = q charge − q discharge ) of cyclic voltammograms (CVs) recorded at 5 mV s −1 over different voltage windows were determined.…”

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 65%

“…Figure b shows the maximum operating voltage determination for both ILs, [Pip 1,4 ][B(CN) 4 ] and [Pyr 1,4 ][B(CN) 4 ], from 0.5 V up to 3.0 V for positive determinations, and from −1.0 V down to −3.0 V for the negative determinations. A maximum operating voltage of 3.7 V was determined for both ILs which is much higher than the values found for other ILs containing anions based on the cyano group, such as [N(CN) 2 ] (2.5 V) and [C(CN) 3 ] (3.0 V), and similar to that shown by the IL [Pyr 1,4 ][Tf 2 N] . It is worth noting that other approaches to enhance the maximum operating voltage of EDLCs were also described in literature.…”

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 65%

“…The ideal IL will maximize electrochemical stability, thermal stability, ionic conductivity and possess a liquid range to satisfy the engineering application requirements. N ‐butyl‐ N ‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Pyr 1,4 ][Tf 2 N]) is one of the most commonly researched ILs because it possesses a good balance between these desirable properties and acts as an informal reference against which other ILs can be compared.…”

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

“…However, the determined operating voltage is only 2.5 V which is much lower than the 3.7 V used for [Pyr 1,4 ][Tf 2 N] . In an earlier work, we have studied the tricyanomethanide ([C(CN) 3 ]) anion and found similar results, obtaining higher power but reduced energy densities in comparison with [Pyr 1,4 ][Tf 2 N] …”

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

“…This is a likely consequence of its higher ionic conductivity (6.9 vs 3.7 mS cm −1 , see Table ) and smaller cation size; these features combined facilitate mass transport into the smaller pores, resulting in an increased specific capacitance. It is worth noting that this feature was also observed when the [C(CN) 3 ] anion was used with the same cations . Figure b shows that higher capacitance is retained over a broad range of scan rates when the [Pyr 1,4 ][B(CN) 4 ] IL is used.…”

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

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Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

et al. 2018

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Supercapacitors are energy storage devices designed to operate at higher power densities than conventional batteries, but their energy density is still too low for many applications. Efforts are made to design new electrolytes with wider electrochemical windows than aqueous or conventional organic electrolytes in order to increase energy density. Ionic liquids (ILs) with wide electrochemical stability windows are excellent candidates to be employed as supercapacitor electrolytes. ILs containing tetracyanoborate anions [B(CN)4] offer wider electrochemical stability than conventional electrolytes and maintain a high ionic conductivity (6.9 mS cm−1). Herein, we report the use of ILs containing the [B(CN)4] anion for such an application. They presented a high maximum operating voltage of 3.7 V, and two‐electrode devices demonstrate high specific capacitances even when operating at relatively high rates (ca. 20 F g−1 @ 15 A g−1). This supercapacitor stored more energy and operated at a higher power at all rates studied when compared with cells using a commonly studied ILs.

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Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 65%

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 65%

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

Section: Physicochemical Properties Of Pc‐based Electrolyte [Pyr14]mentioning

confidence: 99%

See 3 more Smart Citations

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

et al. 2018

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Ionic Liquids for Supercapacitors

Tian

2023

Sustainable Materials for Electrochemical Capacitors

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Nonfluorinated Ionic Liquid Electrolytes for Lithium Metal Batteries: Ionic Conduction, Electrochemistry, and Interphase Formation

Karimi

Zarrabeitia

Mariani

et al. 2020

Advanced Energy Materials

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The increasing demand for electric vehicles is a strong driving force for the development of batteries beyond the state-of-the-art lithium-ion batteries (LIBs) in terms of cost, energy performance and safety. [1] Moving to cell chemistries based on Li metal anodes, such as Li-S (2567 Wh kg −1) and Li-O 2 (3505 Wh kg −1) batteries, appears to be vital considering energy performance and cost. Lithium exhibits a high theoretical capacity (3861 mAh g −1) and has the most negative redox potential (−3.04 V vs SHE). Nonetheless, this promising anode displays high reactivity toward most electrolytes leading to the formation of an interphase layer at the electrode/electrolyte interface known as the solid electrolyte interphase (SEI). Because the Li metal surface is regenerated upon charging of the cell, the reductive decomposition of the electrolyte may occur in every cycle, leading to the irreversible consumption of both Li and the electrolyte, capacity loss, and inhomogeneous lithium deposition. This latter results in dendrite formation, which may induce internal short circuit and cell failure. In this scenario, the choice of the electrolyte is crucial to ensure the formation of a uniform, flexible and yet highly ionic conductive SEI layer, which can withstand the extreme conditions occurring at the Li metal interface. Among the several proposed solutions, ionic liquids (ILs)-based electrolytes are capable of forming an interphase with such properties. [2] Additionally, they feature low flammability, low volatility, and relatively high ionic conductivity. [3] Recent studies of bis(trifluoromethanesulfonyl)imide (TFSI)based and bis(fluorosulfonyl)imide (FSI)-based ILs showed efficient Li stripping/plating behavior. [2,4] Nevertheless, fluorinated ILs are still relatively expensive and pose concerns about their environmental impact. Therefore, we focused our attention on fluorinefree ILs, combining cyano-based anions (dicyanamide, DCA − and tricyanomethanide, TCM −) with the pyrrolidinium cation (shown in Figure 1), due to their reduced costs (F-free) and potentially enhanced safety and environmental friendliness. [4] In this work mixtures of LiDCA:Pyr 14 DCA and LiTCM:Pyr 14 TCM as well as LiDCA:Pyr 14 TCM electrolytes are Cyano-based ionic liquids (ILs) are prime candidates for the manufacturing of cheaper and safer batteries due to their inherently low-volatility and absence of expensive fluorinated species. In this work, N-methyl-N-butylpyrrolidinium (Pyr 14)-based ILs featuring two different cyano-based anions, i.e., dicyanamide (DCA) and tricyanomethanide (TCM), and their mixture with the respective Li salts (1:9 salt:IL mole ratio), alongside their combination (DCA-TCM), are evaluated as potential electrolytes for lithium metal batteries (LMBs). The electrolytes display significant ionic conductivity at room temperature (5 mS cm −1) alongside an electrochemical stability window up to 4 V, suitable for low-voltage LMBs such as Li-sulfur, as well as promising cycling stability. In addition to the detailed physicochem...

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Ionic liquids containing tricyanomethanide anions: physicochemical characterisation and performance as electrochemical double-layer capacitor electrolytes

Cited by 29 publications

References 43 publications

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

Ionic Liquids for Supercapacitors

Nonfluorinated Ionic Liquid Electrolytes for Lithium Metal Batteries: Ionic Conduction, Electrochemistry, and Interphase Formation

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