WO2013142994A1 - Liquides ioniques à activité redox - Google Patents

Liquides ioniques à activité redox Download PDF

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Publication number
WO2013142994A1
WO2013142994A1 PCT/CA2013/050247 CA2013050247W WO2013142994A1 WO 2013142994 A1 WO2013142994 A1 WO 2013142994A1 CA 2013050247 W CA2013050247 W CA 2013050247W WO 2013142994 A1 WO2013142994 A1 WO 2013142994A1
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redox
electrolyte
ionic liquid
active ionic
active
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Dominic Rochefort
John FORGIE
Dean Macneil
Bruno GELINAS
Soumia EL KHAKANI
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Valorisation-Recherche LP
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Valorisation-Recherche LP
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/02—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof using combined reduction-oxidation reactions, e.g. redox arrangement or solion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/54—Electrolytes
    • H01G11/58—Liquid electrolytes
    • H01G11/62—Liquid electrolytes characterised by the solute, e.g. salts, anions or cations therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0045—Room temperature molten salts comprising at least one organic ion
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention relates to redox-active ionic liquids. More specifically, the present invention is concerned with redox-active ionic liquids for use as electrolyte additives in secondary batteries and supercapacitors.
  • lithium-ion batteries are the power supply of choice for portable electronic devices because they store more energy per volume than any other portable rechargeable battery available. LIB are considered the best battery option for the next generation of hybrid and electric vehicles (HEV and EV) and are currently used in EV developed by major car manufacturers (such as the GM Volt and Nissan Leaf). Current lithium-ion cells contain, simplistically, two active electrodes separated by a polymeric separator, surrounded by a liquid organic electrolyte solution.
  • Li-ion batteries One major problem of Li-ion batteries is the difficulty of internally preventing the battery from going into an abuse situation. Ideally, EV manufacturers would prefer to ensure that their batteries are completely prevented from entering an abuse situation.
  • An example of an abuse situation is overcharge where the electrodes and electrolyte may be degraded leading to excessive heat generation and temperature increase as well as a decrease in battery performance.
  • the probability of overcharge situations increases when individual cells are placed in a battery pack as one needs to ensure that every cell has an identical capacity.
  • the battery pack of the Tesla roadster contains over 6000 individual lithium-ion cells in 11 modules. The manufacturer must ensure that every one of the about 600 cells per module is exactly the same capacity (balanced).
  • redox shuttles redox-active chemical moieties
  • Redox shuttles provide an oxidizable and reducible charge-transporting species that can repeatedly transport charge between the negative and positive electrodes once the potential reaches a desired value. They are typically dissolved in the electrolyte of the cell and operate by oxidizing (reducing) at a potential about 0.4 volts above (or below) the maximum (minimum) voltage of the cell. The dissolved oxidized (reduced) species then migrate to the other electrode and get reduced (oxidized) to regenerate the shuttle and repeat the cycle. The shuttle essentially provides an internal shunt for the cell. A major stumbling block towards the successful deployment of redox shuttles is the fact that their solubility within liquid organic electrolytes is limited to about 0.1 mol/L.
  • This concentration limits the maximum current that can be passed via the shuttle since one molecule can only transfer one electron at a time and the maximum rate at which the shuttle can be used to prevent overcharge (overdischarge) depends on its concentration. Also, when a shuttle is in operation, as no electrical work is being performed, the cell generates heat. This heat must be dissipated, especially in EV applications where the current could be large giving rise to larger temperature increases and possible decay of the electrodes and electrolyte at these temperatures. Finally, the shuttle must be stable at the potential of each operating electrode.
  • a redox-active ionic liquid as an additive in an electrolyte of a secondary battery or of a supercapacitor, the redox-active ionic liquid comprising a redox shuttle linked to an ionic liquid.
  • redox-active ionic liquid is of formula RS-LK-IL, wherein RS is the redox shuttle, LK is a bond or a linker, and IL is the ionic liquid.
  • LK is -alkylene-, -COO-alkylene-, -CO-alkylene-, -O-alkylene-, -N-alkylene-, or -S-alkylene-.
  • any one of items 1 to 6, wherein the redox shuttle is ferrocene, or a ferrocene derivative, a dihydrophenazine, a metallocene, a dimethoxybenzene derivative, a thiantlurene derivative, 2,5-di-ferf- butyl-1 ,4-dimethoxybenzene (DDB), a phenothiazine derivative, 2,2,6,6-tetramethylpiperinyloxide (TEMPO), 2-(pentafluorophenyl)-tetrafluoro-1 ,3,2-benzodioxaborole (PFPTFBB), or an organometallic complex between a metal center and a ligand.
  • the redox shuttle is:
  • R is H, N0 2 , S0 3 H, F or CI
  • R a is H or F
  • R b is H or tert-butyl
  • L is SCN, CN or CO
  • Mi is Fe, Ru, Os, Co, Rh or lr
  • M 2 is Fe.
  • R a is H and M2 is Fe.
  • Rb is H or tert-butyl
  • the ionic liquid comprises a imidazolium, pyridinium, pyrazolium, triazolium, thiazolium, oxazolium, pyridazinium, pyrimidinium, pyrazinium, pyrrolidinium, piperidinium, phosphonium, or quaternary ammonium cation with an accompanying anion.
  • R' is an alkyl, such as CH3, C4H9, CsHi 7 or C12H25
  • A- is an anion, such as TFSI, BF4, P0F6 CF3SO3
  • Cat + is an imidazolium cation, such as 1 -butyl-3-methylimidazolium, a pyridinium cation, quaternary ammonium cation, a pyrrolidinium cation or a piperidinium cation.
  • R' is CH3, C4H9, CsHi 7 or C12H25, and A- is bistriflimide or PF6 " .
  • a redox-active ionic liquid as defined in any one of items 1 to 21 the redox-active ionic liquid being for use as an additive in an electrolyte of a secondary battery or of a supercapacitor.
  • An electrolyte additive comprising a redox-active ionic liquid as defined in any one of items 1 to 21.
  • the electrolyte of item 25 comprising more than about 0.1 mmol/L of the redox-active ionic liquid.
  • the electrolyte of item 26 comprising up to about 50% by volume of the redox-active ionic liquid based on the total volume of the electrolyte and redox-active ionic liquid.
  • the electrolyte of item 27 comprising between about 1 and about 5% of the redox-active ionic liquid.
  • the electrolyte of item 29, being a lithium-ion battery electrolyte.
  • a secondary battery or supercapacitor comprising an electrolyte comprising a redox-active ionic liquid electrolyte additive as defined in any one of items 1 to 21.
  • 33. A method of manufacturing a redox-active ionic liquid electrolyte additive as defined in any one of items 1 to 21 , the method comprising linking a redox shuttle to an ionic liquid.
  • a method of increasing the solubility of a redox shuttle in an electrolyte comprising linking the redox shuttle to an ionic liquid, thereby producing a redox-active ionic liquid as defined in any one of items 1 to 21.
  • a method of manufacturing an electrolyte comprising adding a redox-active ionic liquid as defined in any one of items 1 to 21 to a conventional electrolyte.
  • a method of manufacturing a battery or supercapacitor comprising an electrolyte comprising adding a redox-active ionic liquid as defined in any one of items 1 to 21 to the electrolyte.
  • a method of increasing the stability of an electrolyte comprising add adding a redox-active ionic liquid as defined in any one of items 1 to 21 to the electrolyte.
  • a method of improving the safety of a battery or supercapacitor comprising an electrolyte comprising add adding a redox-active ionic liquid as defined in any one of items 1 to 21 to the electrolyte.
  • a method of reducing the risks of overcharge or overdischarge of a battery or supercapacitor comprising an electrolyte comprising add adding a redox-active ionic liquid as defined in any one of items 1 to 21 to the electrolyte.
  • a method of increasing the amount of a redox shuttle that can be added to an electrolyte without precipitation comprising linking the redox shuttle to an ionic liquid, thereby producing a redox-active ionic liquid as defined above.
  • Figure 1 shows the overcharge protection mechanism of a redox shuttle
  • Figure 2 shows the synthesis of the compounds of Example 1 ;
  • Figure 3 shows the cyclic voltammogram of a 50% solution of compound 1 in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 4 shows cyclic voltammograms of 1 x 10 2 mol L 1 of compound 1 in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 5 is a plot of peak current versus square root of scan rate for the anodic (diamonds) and cathodic (squares) currents;
  • Figure 6 is an Arrhenius plot for the solutions of compound 1 in varying amounts of EC/DEC (1 :2) with and without LiTFSI (measurements were done at an interval of 5 °C from 25 to 75 °C.
  • the R 2 obtained from the fittings range from 0.9878 to 0.9988);
  • Figure 7 is a charging curve for a Li/Li4Ti 5 0 2 cell in EC/DEC, pure and modified with 10% Fc-MlmTFSI at C/10 (contains 1.5 M LiTFSI);
  • Figure 8 shows successive charge/discharge curves (C/10) for Li/Li 4 Ti 5 0i2 cells using EC/DEC (1.5 M LiTFSI) electrolyte, (a) pure and (b) modified with 10% Fc-MlmTFSI;
  • Figure 9 shows the capacity curves (C/10) for Li/Li 4 Ti 5 0i2 cells using EC/DEC (1.5 M LiTFSI) electrolyte either pure (solid line) or modified with 10% Fc-MlmTFSI (broken lines) (The parameters were set to a full charge followed by a 100% overcharge and a cut-off at 4V.);
  • Figure 10 is a charging curve for Li/V 2 0 5 cell in EC/DEC, pure and modified with 10% Fc-MlmTFSI at C/10 (contains 1.5 M LiTFSI);
  • Figure 11 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 50% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 12 is a cyclic voltammogram of 50% ionic liquid in EC/DEC (1 :2 v/v) (no LiTFSI);
  • Figure 13 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 50% ionic liquid in EC/DEC (1 :2 v/v) (no LiTFSI);
  • Figure 14 is a cyclic voltammogram of 10% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 15 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 10% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 16 is a cyclic voltammogram of 1 % solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 17 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 1 % solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 18 is a cyclic voltammogram of 0.34% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • Figure 19 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 0.34% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v);
  • Figure 20 shows the TGA curve for the ferrocenyl(methyl)imidazolium-TFSI redox ionic liquid in pure form
  • Figure 21 is an Arrhenius plots for the FcEBIm TFSI in EC/DEC 1 :2 with presence or not of LiTFSI (measurements were done at an interval of 5 °C from 25 to 75 °C);
  • Figure 22 shows A) cyclic voltammograms obtained using different concentration of FcEBIm TFSI (1 , 10 and 50%) in EC/DEC 1 :2 with presence or not of LiTFSI (the scan rate was 100 mV s-1 ) and B) cyclic voltammograms obtained using a 10% solution of FcEBIm TFSI in EC/DEC 1 :2 with 1.5 M LiTFSI (the scan rates were 25, 50, 100, 150, 200, 500, 1000, 2000, 5000 and 10000 mV s 1 );
  • Figure 23 shows the synthesis of compound 1 of Example 3.
  • Figure 24 shows the synthesis of compounds 2 and 3 of Example 3;
  • Figure 26 shows the DSC of compound 2 of Example 3.
  • Figure 27 shows the DSC of compound 3 of Example 3.
  • Figure 28 shows the TGA of compound 1 of Example 3.
  • Figure 39 shows the TGA of compound 2 of Example 3.
  • Figure 30 shows the TGA of compound 3 of Example 3.
  • Figure 31 shows the TGA of compound 4 of Example 3.
  • Figure 32 shows the cyclic voltammogram of compounds 1 -3 of Example 3 (1 mM in EC:DEC + 1.5 M LiTFSI, 100 mV/s);
  • Figure 33 shows the cyclic voltammogram of compound 1 of Example 3 showing the formation of a new compound upon cycling (Inset shows the stable behaviour of compound 2. Conditions: 10 mM in EC:DEC + 1.5 M LiTFSI, 100 mV/s));
  • Figure 34 shows the cyclic voltammogram of compound 1 of Example 3 (1 mM) in EC:DEC + 1.5 M LiTFSI at different scan rates;
  • Figure 35 shows the cyclic voltammogram of compound 2 of Example 3 (1 mM) in EC:DEC + 1.5 M LiTFSI at different scan rates;
  • Figure 36 shows the cyclic voltammogram of compound 3 of Example 3 (1 mM) in EC:DEC + 1.5 M LiTFSI at different scan rates;
  • Figure 37 shows the cyclic voltammogram of compound 4 of Example 3 (1 mM) in EC:DEC + 1.5 M LiTFSI at different scan rates;
  • Figure 38 is a plot of current maximum against square root of scan rate for compounds 1 -4 of Example
  • Figure 39 shows the cyclic voltammogram of compound 1 of Example 3 (1 M in 1.5 M LiTFSI in EC:DEC);
  • Figure 40 shows the cyclic voltammogram of compound 2 of Example 3 (0.7 M in 0.7M LiTFSI EC:DEC);
  • Figure 41 shows the cyclic voltammogram of compound 2 of Example 3 (1 M in 0.7 M LiTFSI EC:DEC);
  • Figure 42 shows the cyclic voltammogram of compound 3 of Example 3 (0.1 M in 0.5 MLiPF 6 EC:DEC);
  • Figure 43 shows the cycling profile of 0.7 M of compound 2 of Example 3 in 0.7 M LiTFSI
  • Figure 44 shows the cycling profile of 1 M of compound 2 of Example 3 in 0.7 M LiTFSI
  • Figure 45 shows the cycling profile of 0.1 M of compound 3 of Example 3 in 0.5 M LiPF6 (10 first cycles in A and 34 cycles in B);
  • Figure 46 shows the cycling profile of 0.1 M compound 4 of Example 3 (in 0.5 M LiPF6 in EC:DEC:PC:DMC).
  • Redox-Active Ionic Liquid for use as an Additive in an Electrolyte of a Secondary Battery or of a Supercapacitor
  • a redox-active ionic liquid for use as an additive in an electrolyte of a secondary battery or of a supercapacitor.
  • a battery is a device that converts chemical energy directly to electrical energy.
  • a secondary battery is a battery that can be recharged; that is, it can have its chemical reactions reversed by supplying electrical energy to the cell, restoring its original composition.
  • Many types of secondary batteries are known including: Lead-acid, Nickel-cadmium, Zinc-manganese, Nickel-hydrogen, Nickel-metal hydride, Nickel-zinc, Lithium air, Lithium-ion, Lithium-ion polymer, Lithium sulfur, Sodium-ion, Zinc bromide, Vanadium redox, Sodium-sulfur, and Silver-oxide batteries.
  • a battery (rechargeable or not) consists of a number of cells; each cell consisting of two electrodes (anode and cathode) separated by a conductive electrolyte containing anions and cations.
  • the electrolyte is a substance containing free ions and that is electrically conductive.
  • the most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible.
  • Examples of electrolytes in various types of secondary batteries include KOH dissolved in water, LiPF6 dissolved in an organic solvent, LiTFSI dissolved in PEO (polyethylene oxide), and (among many others) V2O5 in H2SO4.
  • the redox-active ionic liquid of the invention can be used in any electrolyte of any secondary battery.
  • Lithium-ion batteries are a type of secondary battery. They contain, simplistically, two active electrodes separated by a polymeric separator, surrounded by a liquid organic electrolyte solution.
  • the electrolytes currently in use in commercial Li-ion batteries are based on mixtures of propylene (PC), ethylene (EC), diethyl (DEC), ethylmethyl (EMC), and dimethyl (DMC) carbonates (or a combination thereof) as solvent, with a soluble lithium salt (such as LiPF6, L1BF4, LIBOB or a combination thereof), and various additives to improve the lifetime of the battery and its safety. While these solvents possess the dielectric constants and viscosities required to dissolve appreciable amounts of Li salts and to transport them rapidly, they generally are flammable, volatile and subject to oxidation at high potentials.
  • a supercapacitor is a device that stores energy as a charge in an electric double layer, at the interface between an electrolyte and a high surface area conductor.
  • a supercapacitor is composed of two electrodes (typically made of porous activated carbon) deposited on current collectors, most of the times identical. These electrodes are immersed in an electrolyte and are separated by a porous insulating membrane.
  • the electrolyte can be aqueous-based: for instance a water solution of potassium hydroxide (KOH) or sulphuric acid (H2SO4), or organic-based: acetonitrile, propylene carbonate, ethylene carbonate, diethyl carbonate.
  • the redox-active ionic liquid of the invention can be used in any electrolyte of any supercapacitor.
  • the redox-active ionic liquid of the invention comprises a redox shuttle linked to an ionic liquid.
  • the inventors have indeed found that modifying a redox shuttle to attach thereto an ionic liquid allowed producing redox-active ionic liquids.
  • redox-active ionic liquids have further been found to be useful as additives in the electrolytes of batteries and supercapacitors.
  • the presence of the redox-active ionic liquids does not negatively impact the properties of the electrolyte to which the redox-active ionic liquids are added and once in it, the redox- active ionic liquids act both as an ionic liquid and a redox shuttle.
  • the incorporation of the redox shuttle moiety onto the ionic liquid structure has no negative impact of the transport properties. In some cases, it may even increase the oxidation potential of the redox shuttle.
  • these redox-active ionic liquids present several other advantages.
  • the redox-active ionic liquids can have low vapor pressure and be non-flammable. They can therefore reduce the volatility, increase the flash point, and/or reduce the flammability of the electrolyte (i.e. increase the thermal stability of the electrolyte).
  • the incorporation of the redox shuttle moiety onto the ionic liquid structure generally increases the decomposition temperature of the redox shuttle. This may reduce safety risks, in particular the risk of explosion. It could thus reduce the costs associated with expensive electronics and other mechanical safety devices used to prevent such occurrences.
  • Another advantage is that the attachment of the ionic liquid allows, in embodiments, to increase, often greatly increase, the solubility of the redox shuttle in the electrolyte.
  • the overcharge protection afforded by any redox shuttle depends on the number of redox molecules dissolved in the electrolyte. There must be enough of these molecules to transport all of the excess electrons during charging conditions (rapid or slow charging). Therefore, the redox-active ionic liquids of the invention should have increased usefulness at high charge (discharge) rates, since they can transfer more charge.
  • the redox shuttle and the ionic liquid may be linked directly or indirectly.
  • the link is achieved through covalent bonds, where the redox shuttle and the ionic liquid are covalently attached directly to one another or are attached through a linker.
  • the redox-active ionic liquid is of formula RS-LK-IL, wherein RS is the redox shuttle, LK is either a bond or a linker, and IL is the ionic liquid.
  • the linker may be -alkylene-, -COO-alkylene-, -CO-alkylene-, -O-alkylene-, -N- alkylene-, or -S-alkylene-, wherein the alkylene group may comprise between 1 and 12 carbon atoms, preferably between 1 and 6 carbons atoms, more preferably between 1 and 3 carbon atoms.
  • LK is -CH2- or -CH 2 CH 2 - .
  • a redox shuttle is a molecule added to an electrolyte to prevent overcharge and/or over-discharge.
  • overcharge and/or over-discharge can lead to chemical and electrochemical reactions within the battery, causing rapid temperature rise, self-accelerating reactions, and even explosion. In supercapacitors, this can lead to electrode material deterioration and losses in charge storage ability.
  • the redox shuttle molecule In a battery or a supercapacitor, the redox shuttle molecule is to be reversibly oxidized and reduced at a defined potential slightly higher (or lower) than the charge (or discharge) potential of the cell. Therefore, under normal conditions the shuttle has no function, but if the cell is over-oxidized (or over-reduced), the redox shuttle becomes oxidized (or reduced) receiving the excess charge; this new oxidized (or reduced) species then migrates to the opposite electrode and regenerates the redox shuttle to its initial state. This prevents the overcharging (or over discharging) of the battery or supercapacitor since the excess charge is used to drive the redox shuttle and not to overcharge (overdischarge) of the material.
  • an ideal redox shuttle should have an oxidation or reduction potential slightly (for instance about 0.3 or 0.4 V) above or below the charge or discharge potential (respectively) of the cell. This allows the cell to be normally charged before the shuttle molecule begins to function. Given the above, the skilled person will easily be able to choose which of the redox-active ionic liquid of the invention can be used in a given battery or supercapacitor.
  • the potential of the redox shuttle should ideally not exceed the electrochemical window of the electrolyte. Otherwise, the electrolyte could be oxidized when used.
  • the redox shuttle that is part of the redox-active ionic liquid of the invention can be any redox shuttle known in the art. It may also be any derivative of these redox shuttles.
  • the redox-shuttle may include those described in:
  • Non-limiting examples of redox shuttles include ferrocene and ferrocene derivatives, dihydrophenazine systems, metallocenes, dimethoxybenzene derivatives, thiantlurene derivatives, 2 ,5 -d i -ie/t-b uty I - 1 ,4- dimethoxybenzene (DDB), phenothiazine derivatives, 2,2,6,6-tetramethylpiperinyloxide (TEMPO), 2- (pentafluorophenyl)-tetrafluoro-l ,3,2-benzodioxaborole (PFPTFBB), and organometallic complexes between a metal center and a ligand (non-limiting examples of which including acetylacetone, ortho-phenantrolines, and bipyridines.
  • DDB dimethoxybenzene
  • phenothiazine derivatives 2,2,6,6-tetramethylpiperinyl
  • Non-limiting examples of derivatives of the above includes molecules where substituents or side chains, non-limiting examples of which are alkyi chains, alkyi ethers, carboxylic groups, alkyi esters, alkyi sulfonyls, have been added.
  • the redox shuttle is:
  • R is H, N0 2 , SO3H, F or CI
  • R a is H or F
  • R b is H or tert-butyl
  • L is SCN, CN or CO
  • Mi is Fe, Ru, Os, Co, Rh or Ir
  • M 2 is Fe.
  • the redox shuttle is:
  • the redox shuttle is :
  • Rb is H or tert-butyl
  • ionic liquid per se refers to a salt (comprising anion(s) and cation(s)) that is molten at low temperature, for example below about 100°C, below about 50°C, preferably at room temperature.
  • redox-active ionic liquids comprising the redox shuttle linked to the ionic liquid will have melting points different from that of their corresponding ionic liquids.
  • the redox- active ionic liquids may be molten at relatively low temperature, for example below about 200°C, below about 150°C, below about 100°C, below about 50°C, preferably at room temperature.
  • the redox-shuttle can be linked to the cation or to the anion of the ionic liquid. In embodiments, the redox-shuttle is linked to the cation.
  • ionic liquids There are many classes of ionic liquids. Among them, substituted imidazolium-based salts have multiple applications. Depending on their anion, aprotic ionic liquids can have high conductivity, low vapor pressure, high thermal stability and/or a large window electrochemical.
  • the ionic liquid that is part of the redox-active ionic liquid of the invention can be any ionic liquid. It may also be any derivative of these ionic liquids.
  • the ionic liquid that is part of the redox- active ionic liquid of the invention can be any ionic liquid known in the art to be useful as an electrolyte for batteries or supercapacitors. It may also be any derivative of these ionic liquids.
  • the ionic liquid may those described in: • Ionic liquids as electrolytes for Li-ion batteries— An overview of electrochemical studies, Andrzej Lewandowski and Agnieszka Swiderska-Mocek, Journal of Power Sources, Volume 194, Issue 2, 1 December 2009, Pages 601-609, and
  • the ionic liquid comprises cation with an accompanying anion, the cation comprising a nitrogen-containing ring with one or more optional side chains.
  • the ionic liquid comprises an imidazolium, pyridinium, pyrazolium, triazolium, thiazolium, oxazolium, pyridazinium, pyrimidinium, pyrazinium, pyrrolidinium, piperidinium, phosphonium, or quaternary ammonium cation (including derivatives thereof) with an accompanying anion.
  • Non-limiting examples of derivatives of ionic liquids includes cations where substituents or side chains have been added and/or one or more heteroatoms, such as O, have been inserted in the ring.
  • Side chains can include alkyl, alkoxy, and alkoxylakyl chains.
  • the cation is N-methyl-N-alkyl-pyrrolidinium, N-methyl-N-alkyl-pyridinium, N- methyl-N-alkylpiperidinium, N-methyl-N-alkyl-imidazolium, N-methyl-N-alkyl-phosphonium, N-methyl-N-alkyl- ammonium, N-methyl-N-alkyl-guanidinium, or N-methyl-N-alkyl-isouronium.
  • anions can be employed with the above cations, from simple halides to inorganic anions such as tetrafluoroborate and hexafluorophosphate and to large organic anions like bistriflimide (bis(trifluoromethane)sulfonimide, TFSI), triflate (trifluoromethanesulfonate, CF3SO3 ) or tosylate.
  • bistriflimide bis(trifluoromethane)sulfonimide, TFSI
  • triflate trifluoromethanesulfonate
  • CF3SO3 bistriflimide
  • Non- halogenated organic anions such as formate, alkylsulfate, alkylphosphate or glycolate, can also be used.
  • the anions of the ion liquid are thus inorganic. In other embodiments they are organic.
  • the anion is an imide.
  • the anion is bis(trifluoro methane sulfonyl)imide or bis(perfluoro ethyl sulfonyl) imide.
  • the anion is an amide, which includes, but is not limited to, bis(trifluoro methane sulfonyl) amide.
  • the anion is trifluoromethanesulfonate, hexafluorophosphate (PF 6 ), tetrafluoroborate (BF 4 ), or tetraperchlorate (CIO4 ).
  • R' is an alkyl, for example Ch , C4H9, CeHi? or C12H25
  • A- is an anion, for example bistriflimide, BF4-, PF6 " or CF3SO3 "
  • Cat + is an imidazolium cation, for example 1-butyl-3-methylimidazolium, a pyridinium cation, a quaternary ammonium cation, a pyrrolidinium cation or a piperidinium cation.
  • the ionic liquid is N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N
  • R' is -CH3, -C4H9, -CsH or -C12H25, preferably -CH3, and A- is bistriflimide or PF6 " .
  • the redox-active ionic liquid of the invention is
  • n 0, 3, 7 or 1 1 ,
  • the redox-active ionic liquid is to be used as an additive in an electrolyte of a secondary battery or of a supercapacitor.
  • the redox-active ionic liquid will be mixed with the electrolyte, in which it should be miscible.
  • the redox-active ionic liquids of the invention are miscible (if liquid at room temperature) or soluble (if solid) with organic solvents over a wide range of concentration.
  • the maximum amount of redox-active ionic liquid added to the electrolyte will depend on the desired properties of the battery or supercapacitor.
  • an excess of redox-active ionic liquid may be defined as the concentration at which the conductivity and/or viscosity of the electrolyte is decreased below a desired minimum level.
  • the minimum amount of redox-active ionic liquid added to the electrolyte will depend on the magnitude of protection desired. This will in turn depend on the end use of the battery or capacitor and the nature of its electrolyte and electrodes.
  • the electrolyte may comprise more than about 0.1 mmol/L of the redox-active ionic liquid, for example, more than about 1 , 10, or 100 mmol/L, an up to about 1 mol/L.
  • the electrolyte comprises between about 1 and about 5% of the redox-active ionic liquid.
  • the present invention also relates to a redox-active ionic liquid as defined above per se.
  • the invention relates to such redox-active ionic liquids for use as additives in electrolytes of secondary batteries, such as lithium-ion batteries, or supercapacitors as described above.
  • the present invention also relates to an electrolyte additive, this additive comprising a redox-active ionic liquid as defined above.
  • the present invention also relates to an electrolyte comprising a redox-active ionic liquid as defined above.
  • the present invention also relates to a method of manufacturing a redox-active ionic liquid electrolyte additive as defined above, the method comprising linking a redox shuttle to an ionic liquid.
  • the present invention also relates to a method of increasing the solubility of a redox shuttle in an electrolyte, the method comprising linking the redox shuttle to an ionic liquid, thereby producing a redox-active ionic liquid as defined above. More specifically, the present invention relates to a method of increasing the amount of a redox shuttle that can be added to an electrolyte without precipitation, the method comprising linking the redox shuttle to an ionic liquid, thereby producing a redox-active ionic liquid as defined above. In cases where the redox-active ionic liquid produced is solid at room temperature, the increase amount is due to the increased solubility of the redox-active ionic liquid in the electrolyte. In cases where the redox-active ionic liquid produced is liquid at room temperature, the increase amount is due to the miscibility of the redox-active ionic liquid in the electrolyte.
  • the present invention also relates to:
  • the method comprising adding a redox-active ionic liquid as defined above to the electrolyte.
  • the electrolyte is an electrolyte as described above in respect of the use of the redox-active ionic liquid.
  • the electrolyte can be a secondary battery electrolyte, such as a lithium-ion battery electrolyte, or a supercapacitor electrolyte.
  • the quantity of redox-active ionic liquid in the electrolyte is as described above in respect of the use of the redox-active ionic liquid.
  • the electrolyte may comprises more than about 0.1 mmol/L of the redox-active ionic liquid, for example, more than about 1 , 10, or 100 mmol/L or more than about 1 mol/L, for example between about 1 and about 5% of the redox-active ionic liquid.
  • the term "about” has its ordinary meaning. For example, it may means plus or minus 10% of the numerical value thus qualified.
  • alkyl refers to branched or linear radicals of formula -C n H2n+i .
  • alkylene refers to branched or linear radicals of formula -C n H2n-. In embodiments, n may range from 1 to 12.
  • An electroactive ionic liquid (IL), 1 -ferrocenylmethyl)-3-methylimidazolium- b ' ⁇ s(trifluoromethanesulfonyl)arr ⁇ 0e (TFSI) was synthesised and its electrochemical properties investigated when diluted with ethylene carbonate/diethyl carbonate (EC/DEC) solvent at various ratios. Cyclic voltammetry data were gathered to determine the redox potential, diffusion coefficient and heterogeneous rate constants of the electroactive imidazolium TFSI ionic liquid in solutions.
  • Cyclic voltammetry measurements were performed in a heart-shaped electrochemical cell using a potentiostat from Princeton Applied Research (model PARSTAT 2273).
  • the electrodes were platinum, platinum wire and silver wire as the working, counter and reference electrodes, respectively.
  • the solutions were degassed with nitrogen for 15 minutes prior to measurements. All measurements are referenced against the E of the Fc/Fc + redox couple.
  • Viscosity was measured with a Cambridge Applied System VL-4100 apparatus using pistons with range 0.5 to 10 cP and 10 to 200 cP. All measurements were performed at 25 °C.
  • Figure 3 shows the cyclic voltammogram of a 50% solution of 1 dissolved in an electrolyte of 1.5 M LiTFSI in ethylene carbonate / diethyl carbonate (EC/DEC) at both 100 and 10 mV s 1 scan rates.
  • Ratio corresponds to 1 x 10 2 mol L 1 .
  • n is the number of electrons, in this case one, F is the Faraday constant, A is the electrode area, C is the concentration, R is the gas constant, T is the temperature, v ⁇ s the scan rate and D is the diffusion coefficient.
  • the diffusion coefficients calculated were 6.57 x 10 7 and 6.16 x 10 7 cm 2 s 1 , for the reduced and the oxidised forms, respectively. Although the diffusion coefficient is not as high as other redox shuttles used for Li-ion battery safety, the greater concentration of our redox shuttle that can be dissolved in solution compensates for this.
  • the ratio of DO/DR is 0.93; this value is close to 1 and shows that the diffusion expectedly follows Arrhenius-type behaviour.
  • the solution had a viscosity of 4.69 x 10 3 Pa-s.
  • the heterogeneous rate transfer constant (k s ) was determined using peak-to-peak separation ( ⁇ ) using Nicholson's method, 31 which relates ⁇ with a kinetic parameter ⁇ , which in turn allows the heterogeneous rate transfer to be calculated from the following equation (Nicholson, R. S. Analytical Chemistry 1965, 37, 1351 ):
  • the blank an EC/DEC (1 :2) + 1.5 M LITFSI solution, has a conductivity of 6.02 and 13.18 mS cnr 1 at 25 and 75 °C, respectively.
  • a 50% solution in EC/DEC (1 :2) has a conductivity at 25°C of 4.03 mS cnr 1 , at 75°C the conductivity measured (12.17 mS cnr 1 ) is almost as high as the blank solution.
  • the addition of the lithium salt to the 50% solution produces a much more viscous solution resulting in a diminished conductivity, over 60% loss at 25°C and 45% loss at 75°C compared to the solution without the salt.
  • the conductivity of EC/DEC + LiTFSI solution can be kept as high as the blank up to 10% of ionic liquid in the solution. It is this solution that we particularly propose be used as the electrolyte in Li-ion batteries. Although the conductivity of the solution is lower than the blank, it is still in the same order of magnitude. Further, more concentrated solutions could also be beneficial for over-charge protection. After 10%, the interaction between the lithium salt and the ionic liquid occurs to a greater extent; increasing the viscosity (see below) and hence lowering the measured conductivity of the solution.
  • the blank solution expectedly produces the lowest value with an activation energy of 13.6 kJ mol "1 .
  • the anomaly in this series of measurements is the 0.34% solution which produces an E sa for conductivity from the Arrhenius plot of 19.1 kJ mol "1 .
  • This discrepancy is unusual as generally there is a strong correlation between ionic conductivity and activation energy: typically, it is found that higher conductivity is associated with lower activation energies, 35 and the 0.34% solution has the highest recorded conductivities at 25°C and 75°C.
  • a Percentage corresponds to 1 x 10 2 mol L 1 .
  • Figure 7 shows a typical charging curve for Li/Li4Ti 5 0i2.
  • 163 mAh/g normal charging is observed with a stable cell voltage of 1.6 V.
  • the charger is programmed to apply constant current for twice the required amount of time to fully charge the battery.
  • the sudden increase in cell voltage above 163 mAh/g shows that the cell is undergoing overcharging.
  • the overcharge cut-off voltage is 4V vs Li/Li+.
  • the potential stabilizes at a plateau at 3.35 V.
  • Figure 8 shows the charge/discharge cycles, starting with a full charge, followed by a 100% overcharge for a Li/Li4Ti 5 0i2 coin cell at a C/10 rate, using the unmodified electrolyte in (a) and the electrolyte containing 10% of Fc-Mlm TFSI in (b).
  • the overcharging situation appears very clearly for the cell without redox shuttle added (Fig. 4b) where the voltage increases sharply up to the 4 V cut-off after the charging plateau at 1.6 V of the Li4TisOi2 material. Adding the redox ionic liquid in the electrolyte prevents reaching the cut-off voltage of 4V.
  • Figure 9 shows the specific capacity curves for the same experiments to further detail the effect of the addition of Fc-Mlm on the charge storage.
  • the curves obtained with the unmodified electrolyte shows reversibility and a maximum specific capacity of 163 mAh/g, before reaching the overcharging point.
  • Fc-Mlm is added, a 6% loss in capacity is observed after the first cycle, but tends to stabilize as the third cycle coincides with the second. While these results show the possibility of using an electroactive ionic liquid to prevent Li-ion battery cathode from overcharging, improving the stability and modifying the ionic liquid with redox moieties with higher oxidation potential will be required to apply these electrolytes in current or future commercial battery systems.
  • FIG. 10 shows a charging curve for Li/V 2 0 5 cell in EC/DEC, pure and modified with 10% Fc-MlmTFSI at C/10 (contains 1.5 M LiTFSI).
  • Figure 9 shows that after being fully charged, the cell without the redox shuttle charges to 4V, while the addition of the redox shuttle shows a plateau in charge voltage again at 3.35V, as aboved with Li4Ti5012.
  • FIG 1 1 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 50% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 12 is a cyclic voltammogram of 50% ionic liquid in EC/DEC (1 :2 v/v) (no LiTFSI).
  • FIG 13 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 50% ionic liquid in EC/DEC (1 :2 v/v) (no LiTFSI).
  • FIG 14 is a cyclic voltammogram of 10% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 15 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 10% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 16 is a cyclic voltammogram of 1 % solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 17 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 1% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 18 is a cyclic voltammogram of 0.34% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • FIG 19 shows cyclic voltammograms of (a) oxidation and (b) reduction limits of 0.34% solution in 1.5 M LiTFSI in EC/DEC (1 :2 v/v).
  • the redox ionic liquid (1) presents a melting point of 47 °C, but remained in the liquid phase at room temperature in a supercooled state which is commonly found in ionic liquids.
  • RILs redox ionic liquids
  • FcEBIm TFSI 1 -(ferrocenyl)3-butylimidazolium TFSI
  • FcEOlm TFSI 1 -(ferrocenyl)3-octylimidazolium TFSI
  • FcEDIm TFSI 1 -(ferrocenyl)3- dodecenylimidazolium TFSI
  • the solutions used had different concentration of RIL (100, 50, 10, 1 %) in EC/DEC 1 :2 (Ethylene cabonate/Diethylene carbonate) solution with presence of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).
  • n 3: FcEBIm TFSI;
  • Figure 21 is an Arrhenius plots for the FcEBIm TFSI in EC/DEC 1:2 with presence or not of LiTFSI (measurements were done at an interval of 5 °C from 25 to 75 °C).
  • Figure 22 shows A) Cyclic voltammograms obtained using different concentration of FcEBIm TFSI (1, 10 and 50%) in EC/DEC 1:2 with presence or not of LiTFSI (the scan rate was 100 mV s-1) and B) Cyclic voltammograms obtained using a 10% solution of FcEBIm TFSI in EC/DEC 1:2 with 1,5 M LiTFSI (the scan rates were 25, 50, 100, 150, 200, 500, 1000, 2000, 5000 and 10000 mV s-1).
  • Compound 1 is an ionic liquid in which an ethyl-methyl-imidazolium (EMI) cation is directly connected to a methoxyphenoxy group.
  • EMI ethyl-methyl-imidazolium
  • TMSI Bis(trifluoromethanesulfonyl)amide
  • Compounds 2 and 3 are both imidazolium salts with the only difference between being the anion, TFSI, and hexafluorophosphate (PF6), respectively.
  • the cation in both examples is propyl-methyl-imidazolium, this time linked to a 2,5-di-tert-butyl-dimethoxyphenoxy group.
  • Ionic Liquid 1 was synthesised in four steps, as depicted in the scheme shown in Figure 23.
  • Compound 6 was synthesised from the etherification of 4-methoxyphenol (5) with 2-chloroethanol in 80% yield. The corresponding alcohol was brominated to give compound 7 in 78% yield. Reaction of 7 with 1 -methylimidazole affords the imidazolium bromide salt, 8 in 82% yield. Conversion of the bromide counter ion to TFSI was achieved from a metathesis reaction of 8 with lithium bis(trifluromethanesulfonyl)amide in an aqueous solution to give the desired product 1.
  • Redox-active imidazolium salts 2 and 3 were synthesised in a similar fashion, as shown in Scheme 2 in Figure 24, using 3-bromo-propanol in the etherification step to provide 10 in 56% yield.
  • bromination to 11 was performed with carbon tetrabromide (82% yield) which was then reacted with 1 -methylimidazole to give imidazolium bromide salt, 12 in 73% yield.
  • the TFSI salt (2) was synthesised from a metathesis reaction of 12 with lithium bis(trifluoromethanesulfonyl)amide in methanol in 67% yield. Methanol was used as the solvent rather than water as compound 11 is insoluble in aqueous media.
  • the PF6 salt (3) was obtained from the reaction of 12 with silver hexaflurorophosphate in acetonitrile, the resulting silver bromide precipitate was filtered and the desired salt 3 was collected under reduced pressure in 75% yield. Compounds 1-3 were vacuum-dried at 80°C for 24 h.
  • 2,5-di-tert-butyl-4-methoxyphenol was purchased from Frontier Scientific. 2,5-di-tert-1 ,4- dimethoxybenzene was purchased from 3M. Dichloromethane, hexanes, methanol, and ether were purchased from Fisher. All other chemicals and solvents were purchased from Sigma-Aldrich. All were used without further purification.
  • Electrospray ionisation mass spectrometry were performed by the Centre regional de spectroscopie de masse de I'Universtite de Montreal.
  • Thermogravimetric analysis was performed on a TGA 2950 TA Instruments, measurements were performed under nitrogen from room temperature to 600 °C.
  • Diffusion coefficients were calculated from the gradient of peak current (i p ) against the square root of the scan rate through the Randles-Sevcik equation: (1) where n is the number of electrons, in this case one, F is the Faraday constant, A is the electrode area, C is the concentration, R is the gas constant, T is the temperature, v is the scan rate and D is the diffusion coefficient.
  • the heterogeneous rate transfer constant (k s ) was determined using peak-to-peak separation ( ⁇ ⁇ ) using Nicholson's method, which relates ⁇ ⁇ with a kinetic parameter ⁇ , which in turn allows the heterogeneous rate transfer to be calculated from the following equation:
  • the addition of the bulky tert-butyl groups has clearly a large effect on the melting point, the aliphatic groups possibly providing additional symmetry or helping facilitate ⁇ - ⁇ stacking of the aromatic cores.
  • the TFSI derivative has a lower melting point than the PF6 version, as the anion in this case is unable to hydrogen-bond and has a more delocalised charge.
  • TGA Thermogravimetric analysis
  • Compound 1 shows a quasi-reversible wave at +1.00 V, full reduction of the oxidised species in this case to the neutral compound is not possible as the radical cation formed from the oxidation reacts with another radical cation to give a dimer. At this concentration, dimerisation is not seen when multiple CV cycles are performed but at higher concentrations (10 mM) this phenomena can be observed upon the first ten cycles (see Fig 33). Indeed, Fig. 33 shows a decrease of the peaks at 0.98 and 1.13 V (compound 1), with new peaks appearing at 0.56 and 0.69 V (dimers of 1).
  • the difference in potential can be attributed to the imidazolium cation on the chain pulling electron density away from the core thus requiring more energy to remove an electron.
  • the diffusion coefficients (reduced, DR and oxidised, Do forms) of compounds 1-4 and the heterogeneous rate transfer (k s ) of compounds 2-4 were measured. Compound 1 does not show a reversible oxidation and therefore Do and k s could not be calculated.
  • the diffusion coefficient was calculated from a series of oxidations at different scan rates (Fig. 34 to 38).
  • the diffusion coefficients of the reduced forms are all in the same order of magnitude (x 10 7 cm 2 s 1 ), for the four compounds with the only difference being the PF6 salt (3) which has a higher diffusion coefficient in both the reduced and oxidised forms.
  • the reason for the small increase can be explained by the PF6 salt experiencing less interaction with the electrolyte than the other imidazolium salts, which will encounter an association of multiple TFSI anions with a lithium cation.
  • compound 3 with less interaction to the electrolyte than 2 has predictably a higher k s value (0.0090 and 0.0049 cm s 1 , respectively).
  • k s value 0.0090 and 0.0049 cm s 1 , respectively.
  • An interesting comparison is between compounds 2 and 4, the diffusion coefficient is marginally higher for 2 and the k s are identical. This indicates that the incorporation of the redox shuttle into an imidazolium salt has no negative effect to the transport properties.
  • CV of compound 1 (Fig. 39) was performed outside the glovebox using platinum working electrode, platinum wire counter electrode and silver pseudo reference.
  • 1 M solution was prepared in a 1.5 M lithium bis(trifluromethanesulfonyl)amide (LiTFSI) solution.
  • CV of 1 (Fig. 39) is referenced to ferrocene (Fc/Fc + ), an additional x-axis versus lithium (Li/Li + ) is provided for comparison.
  • This ionic liquid has no protective tert-butyl arms and therefore polymerising when oxidised as seen with an irreversible wave in the CV.
  • Coin cell cycling was carried out with lithium cells containing compounds 2 and 3 as electrolyte additives.
  • CR-2032 coin cells were assembled in an Argon-filled glove box using a LiFePC t (LFP) cathode and lithium foil as anode.
  • LFP cathodes were prepared by mixing 80% of pure active material LFP (Phostech Lithium), 10% conductive carbon (Super S, Timcal) and 10% polyvinylidene fluoride (PVDF) binder.
  • Two standard electrolytes for Lithium-ion batteries were used; LiTFSI and LiPF6 both in EC:DEC (1 :2 v/v) solvent at different concentrations.
  • Figure 43 shows cycling profile of a cell containing 0.7 M compound 2 in 0.7 M LiTFSI electrolyte.
  • the potential increases from the open circuit voltage to 3.5 V where the charge process takes place for 10 hours enabling a full charge of LiFePC t at a constant voltage. Then, the potential rises to reach the set cut off voltage (4.2 V).
  • the potential should drop until the discharge potential is reached and the cell starts discharging. Whereas, a cell protected by a redox shuttle will show a plateau indicating the redox shuttle's oxidation at its determined potential.
  • the redox shuttle's (compound 2) activity is shown at 4 V for the 1 st cycle and stabilises at 3.9 V over cycling as suggested by cyclic voltammograms shown above.
  • the potential of the redox shuttle shows a trend to higher potential before demonstrating a flat potential plateau, which may be due to an activation process of the redox shuttle on the cathode surface.
  • the 6 th cycle shows a potential drop that was resumed quickly after a return in power. Twenty cycles were completed and the cell continues cycling demonstrating the same performances offering a good protection of LFP during overcharge.
  • Figure 44 shows the cycling profile of 1 M of 2. At high concentration, compound 2 still provides a good overcharge protection for LFP. Interestingly, the redox-shuttle plateau is stabilised from the 2nd cycle indicating that more redox-shuttle was available to be oxidized. Also, the higher concentration of redox shuttle is expected to ensure protection of cells operating at higher rates of charge. The cell is not limited to the number of cycles shown.
  • FIG. 45 shows cycling profile of a cell containing ionic salt 3 for which a redox shuttle plateau is stabilised after 3 cyles (Fig. 45A) suggesting that during first few cycles, on the cathode surface the redox shuttle molecules were progressively activated. Indeed, a different carbonates mixture is expected to increase the solubility of our ionic salt 2 and consequently improved operation ensuring a full overcharge protection from the 1 st charge cycle.
  • Over 34 cycles have been performed (Fig. 45B) and the cell was still provides the same performance. For the same reason mentioned above, the 18 th cycle shows a potential drop due to an abrupt power cut in the testing facility.
  • Redox shuttles 1-3 provide a comparable overcharge protection as that provided by compound 4.

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Abstract

L'invention concerne l'utilisation d'un liquide ionique à activité redox en tant qu'additif dans un électrolyte d'une batterie secondaire ou d'un supercondensateur, le liquide ionique à activité redox comprenant une navette redox liée à un liquide ionique. En outre, l'invention concerne également de tels liquides ioniques à activité redox et des électrolytes comprenant de tels liquides ioniques à activité redox. L'invention concerne également un procédé de fabrication de tels additifs d'électrolyte liquides ioniques à activité redox de même que des procédés d'augmentation de la solubilité d'une navette redox dans un électrolyte, de fabrication d'un électrolyte, de fabrication d'une batterie ou d'un supercondensateur, d'augmentation de la stabilité d'un électrolyte, d'amélioration de la sécurité d'une batterie ou d'un supercondensateur, et de réduction des risques de surcharge ou de surdécharge d'une batterie ou d'un supercondensateur.
PCT/CA2013/050247 2012-03-30 2013-03-27 Liquides ioniques à activité redox Ceased WO2013142994A1 (fr)

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CN105161757A (zh) * 2015-07-24 2015-12-16 张家港市国泰华荣化工新材料有限公司 一种含有氧化还原型防过充添加剂的锂离子电池电解液
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WO2020120922A1 (fr) * 2018-12-14 2020-06-18 Université De Rennes 1 Matériau poreux fonctionnalisé et utilisation comme électrode de pseudo-supercondensateur
CN112630283A (zh) * 2020-12-18 2021-04-09 河南城建学院 (e, e)-1,1′-双(2-吡啶乙烯基)二茂铁作为电化学传感器的应用
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WO2025175356A1 (fr) * 2024-02-23 2025-08-28 The University Of Adelaide Batteries zinc-iode sans effet navette

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020009635A1 (en) * 1997-12-01 2002-01-24 Christophe Michot Novel materials for use as electrolytic solutes
US20040021928A1 (en) * 2002-06-21 2004-02-05 Warner Benjamin P. Electrolytes for electrooptic devices comprising ionic liquids
US20050123831A1 (en) * 1996-12-30 2005-06-09 Christophe Michot Pentacyclic anion salts or tetrazapentalene derivatives and their uses as ionic conducting materials
JP2009215182A (ja) * 2008-03-07 2009-09-24 Toray Fine Chemicals Co Ltd 新規有機常磁性イオン液体化合物及びそれを含む支持電解質

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050123831A1 (en) * 1996-12-30 2005-06-09 Christophe Michot Pentacyclic anion salts or tetrazapentalene derivatives and their uses as ionic conducting materials
US20020009635A1 (en) * 1997-12-01 2002-01-24 Christophe Michot Novel materials for use as electrolytic solutes
US20040021928A1 (en) * 2002-06-21 2004-02-05 Warner Benjamin P. Electrolytes for electrooptic devices comprising ionic liquids
JP2009215182A (ja) * 2008-03-07 2009-09-24 Toray Fine Chemicals Co Ltd 新規有機常磁性イオン液体化合物及びそれを含む支持電解質

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
BALASUBRAMANIAN ET AL.: "Redox Ionic Liquid Phases: Ferrocenated Imidazoliums", J. AM. CHEM. SOC., vol. 128, no. 31, 2006, pages 9994 - 9995 *
FONTAINE ET AL.: "Mass transport and heterogeneous electron transfer of a ferrocene derivative in a room-temperature ionic liquid", JOURNAL OF ELECTROANALYTICAL CHEMISTRY, vol. 632, no. 1-2, 1 July 2009 (2009-07-01), pages 88 - 96, XP026146348, DOI: doi:10.1016/j.jelechem.2009.04.001 *
FORGIE ET AL.: "Application of Electroactive Ionic Liquids to Improve the Safety of Lithium-Ion Batteries", ABSTRACT # 1214, HONOLULU PRIME 2012, 7 October 2012 (2012-10-07), Retrieved from the Internet <URL:http://ma.ecsdl.org/content/MA2012-02/12/1214.full.pdf+html> [retrieved on 20130529] *
LEWANDOWSKI ET AL.: "Ionic liquids as electrolytes for Li-ion batteries-An overview of electrochemical studies", JOURNAL OF POWER SOURCES, vol. 194, no. 2, 1 December 2009 (2009-12-01), pages 601 - 609, XP026499638, DOI: doi:10.1016/j.jpowsour.2009.06.089 *
PRATT III ET AL.: "Synthesis and characterization of ionic liquids containing copper, manganese, or zinc coordination cations", DALTON TRANS., vol. 40, 2011, pages 11396 - 11401 *
TANABE ET AL.: "Viologen-Based Redox-Active Ionic Liquid Crystals Forming Columnar Phases", ORGANIC LETTERS, vol. 21, no. 9, 2007, pages 4271 - 4274 *
ZHANG ET AL.: "Redox Shuttle Additives for Lithium-Ion Battery", LITHIUM ION BATTERY - NEW DEVELOPMENTS, February 2012 (2012-02-01), pages 173 - 188 *

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