WO2010095082A1

WO2010095082A1 - High safety lithium-ion battery

Info

Publication number: WO2010095082A1
Application number: PCT/IB2010/050655
Authority: WO
Inventors: Bruno Scrosati; Priscilla Reale; Alessandra Fernicola; Werner Tillmetz; Margret Wohlfahrt-Mehrens; Pierre Kubiak
Original assignee: Universita' Degli Studi Di Roma La Sapienza; Zentrum Fur Sonnenenergie-Und Wasserstoff-Forschung Baden Wurttemberg
Priority date: 2009-02-18
Filing date: 2010-02-12
Publication date: 2010-08-26
Also published as: EP2399263A1; ITRM20090072A1; IT1393271B1

Abstract

A Lithium-Ion battery characterised in that it comprises: a. an ionic liquid consisting of a cationic portion of quaternary ammonium of formula R₁N+R₂R₃ R₄ where: R₁ is a linear or branched alkyl with from 2 to 5 carbon atoms, optionally substituted with an ethyl alkoxy group with from 1 to 3 carbon atoms; R₂, R₃ e R₄, being the same or different, are a linear or branched alkyl with from 2 to 5 carbon atoms, or R₃ and R₄, together with the nitrous atom to which they are bound form a pyrrolidinium or piperidinium; b. an anionic part, wherein the anion is selected form the group consisting of: bis(methantrifluoridesulphonyl)imide, tetrafluorideborate, esafluoridephosphate; c. a lithium salt selected form the group consisting of lithium N,N- (bis(methantrifluoridesulphonyl)imide, lithium tetrafluorideborate, lithium esafluoridephosphate and lithium bisoxalateborate; is disclosed. The battery is safe thanks to the high thermal stability of the ionic liquid as used in the present invention, without additives, as flame retardant or other additives, being suitable for the use in the field of mobile electronic, sustainable transportation and Renewable energy.

Description

High safety Lithium-Ion Battery

Description

The present invention refers to the technical field of Lithium-Ion batteries and more in particular to safety and to ameliorate efficiency of this type of batteries. Thanks to their high energy content, Lithium-Ion batteries prevail in the consumer electronics area and promote spreading of cellular phones, lap-top computers, digital audio players and so on. However, Lithium-Ion batteries need improved efficiency to be applied in the expanding markets of power stations fed by discontinuous sources or power systems for electric or hybrid vehicles.

Safety is one of the unsolved problems affecting said batteries, due to the instability of the battery's components. More in particular, the use of electrolyte solutions of lithium salts in volatile organic solvents is dangerous. Vaporization of solvents, which is triggered by local overheating and/or by electrochemical decomposition of the same solvents, may produce gaseous side products which increase the internal pressure. This event may cause not only cell breaking, but also to violent side-reactions or fires and explosions. These risks are related to battery abuse, such as high working temperatures or mechanical shock. Regarding the problems related to the use of non-aqueous electrolytes, also from the point of view of battery safety and of battery efficiency, especially in case of anodes of carbonaceous materials see patents US 5,340,670 e US 5,612,155 which suggest to improve battery's features by using innovative carbonaceous materials.

Patent US 6,413,678 suggests solving safety problems of said type of batteries by using a gas evolving system. In the battery, a carbonyl compound, subject to temperature increasing, decomposes and produces gaseous products, which are insoluble, or poorly soluble in the electrolyte. A suitable breaking valve stably and safely increases the pressure within the battery.

Consequently, one important goal in this field is to design and develop battery configurations performing better than present systems in terms of safety, energy, power and costs. One way to solve safety problems of Lithium-Ion batteries with organic solvents, as non-aqueous electrolytes, is the use of ionic liquids, namely salts in the liquid state at room or sub-room or at least at the battery's working temperature.

This choice is justified by the features of the above materials which induce high ionic conductivity (thus a low internal battery resistance), low volatility (preventing pressure variation in the battery) and high thermal stability (ensuring reliable operability in a wide range of temperature) and non-flammability (ensuring operational safety).

The ionic liquids are composed by several combinations of different anions and cations.

Patent application US 2007/026318 discloses some of said ionic liquids and their drawbacks due to their reactivity with the electrodes (see for example patent applications JP 4-349365, JP 11 -86905). Said document disclose the technical solution of inserting allyl phosphate in the ionic liquid. Among the compounds bearing the quaternary ammonium cation pyrrolidinium derivatives are mentioned, all characterised by a methyl on the quaternary nitrogen residue, which are useful to counteract side reactions on the electrodes. However, imidazole derivatives are preferred since they lower the viscosity of the ionic liquid and enhance battery performances, as suggested in patent application US 2008/0076030. Allyl phosphate is preferred as essential component to enhance safety and avoid explosions by acting as a flame retardant. Examples of Lithium-Ion batteries using non-aqueous electrolytes, like ionic liquids, are disclosed in EP 1 906 841 , US 2007/023801 , WO 2005/104288.

It is well known in the art that, although the ionic liquid ensures safety of the battery, performance is due to the solvent capable of maintaining satisfactory viscosity levels in the system in term of battery's efficiency.

The stability of the electrodes in consideration of the electrolyte used cannot be presumed and requires investigation of the system.

The technical problem of safety of Lithium-Ion batteries, including those using organic solvents, is not yet solved in the state of the art, in particular relating to the stability of the ionic liquid and the performance required by the devices using said the batteries and considering their use in more challenging fields such as the storage in stations powered by discontinuous sources or power systems for electric or hybrid vehicles.

The compound N-n-butyl-N-ethylpyrrolidinium N,N-bis(methyltrifluoridesulphonyl)imide, herein indicated as Py₂₄TFSI, its preparation, and its possible use as a ionic liquid has been disclosed in A. Fernicola, F. Croce, B. Scrosati, T. Watanabe, H. Ohno; Journal of Power Sources 174 (2007) 342-348.

In this paper the ionic liquid was disclosed for uses different from those being object of the present patent and precisely for a Lithium-metal battery. In the case of a Lithium-metal battery the organic electrolyte becomes unstable for cyclation and reacts giving a solid product, which, in a small extent, protects the electrode (passivation), then the solid deposition proceeds and a non-uniform layer forms stacked structures (dendrites) which can cause short-circuits. On the other hand, in the Lithium-Ion batteries safety problem is mainly linked to accidental overheating of the battery above a threshold temperature. If the device is unable to efficiently dissipate heat in excess, overheating causes side reactions of the organic solvent in the electrolyte and produces inflammable gases which increase internal pressure and heighten the risk of fire and explosions. The solution proposed by the present invention consists of ionic liquids as electrolytic components being non-volatile, non-flammable and stable compared with the material for electrodes proposed in the cells combinations herein disclosed.

Summary of the invention

It has now been found that the use of a particular salt as an ionic liquid solves the above problems. In particular, a Lithium-Ion battery with a particular configuration of electrodes and the ionic liquid of the invention shows particularly advantageous features.

Therefore, one object of the present invention is a Lithium-Ion battery characterised in that the ionic liquid comprises a) an ionic liquid consisting of a cationic portion of quaternary ammonium of formula

R1 N+R2 R3 R4 where:

R1 is a linear or branched alkyl with from 2 to 5 carbon atoms, optionally substituted with an alkoxyethyl group with from 1 to 3 carbon atoms;

R2, R3 e R4, being the same or different, are a linear or branched alkyl with from 2 to 5 carbon atoms, or R3 and R4, together with the nitrrogen atom to which they are bound form a pyrrolidinium or piperidinium group; b) an anionic part, wherein the anion is selected form the group consisting of: N, N- bis(trifluoromethanesulphonyl)imide tetrafluoborate, and N,N-bis(trifluoromethanesulphonyl)imide esafluophosphate;

c) a lithium salt selected form the group consisting of lithium N, N-

(bis(methantrifluoridesulphonyl)imide, lithium tetrafluorideborate, lithium esafluoridephosphate and lithium bisoxalateborate.

The Lithium-Ion battery according to the present invention has the advantage of maintaining satisfactory performance, despite the absence of a solvent and of maintaining the increase of viscosity due to the ionic liquid and in particular of ensuring compatibility with electrodes.

The battery is safe thanks to the high thermal stability of the ionic liquid as used in the present invention. Furthermore, opposite to the batteries known in the art which use ionic liquids-based electrolytes, the combination of said ionic liquid with the proposed electrolytes ensure the stability of each component without using additives, as flame retardant or other additives. The invention is herein disclosed in detail also referring to the figures and examples.

Figure 1 shows TGA (Thermo Gravimetric Analysis) curves of pure ionic liquid Py₂₄-TFSI and of its solutions with LiTFSI.

Figure 2 shows conductivity of pure ionic liquid Py₂₄-TFSI and of its solutions with LiTFSI.

Figure 3 shows a charge-discharge cycle of the Li₄Ti₅O₁₂/ Py₂₄TFSI - LiTFSI /LiFePO₄ Lithium-Ion battery.

Figure 4 shows charge-discharge cycles of SnC/ Py₂₄TFSI-LiTFSI / LiFePO₄ battery. Figure 5 shows charge-discharge cycles Of TiO₂ / Py₂₄TFSI-LiTFSI / LiFePO₄ battery.

Figure 6 show conductivity at room temperature of a hybrid gel-like membrane assembled by the Py₂₄TFSI-LiTFSI solution on the PVdF-HFP matrix, compared with a similar membrane containing LiPF₆- PC-EC.

Detailed description of the invention

According to the present invention, the ionic liquid is made of a cationic portion as disclosed in the above formula (I).

A first group of preferred compounds consists of: N-n-butyl-N-ethylpirrolidinium, N-ethyl-N-propylpirrolidinium, N-ethyl-N-pethylpirrolidinium, N-ethyl-N- propoxyethylpirrolidinium, N-ethyl-N-propylpiperidinium, N-ethyl-N-isopropylpiperidinium, N-butyl-N- ethylpiperidinium, N-isobutyl-N-ethylpiperidinium, N-secbutyl-N-ethylpiperidinium, N-methoxyethyl-N- piperidinium, N-ethyl-N-etoxyethylpiperidinium, N-butyl-N,N,N-triethylammonium, N,N,N-triethyl-N- propylammonium, N-butyl-N,N-diethyl-N-methylammonium and N-butyl-N,N-diethyl-N-propylammonium. In a second preferred embodiment, the compound of formula (I) is N-n-butyl-N-ethylpirrolidinium.

In a third preferred embodiment, the anionic portion of the ionic liquid is N,N-(bis(methantrifluoridesul- phonyl)imide.

In a more preferred embodiment, the ionic liquid is N-n-butyl-N-ethylpirrolidinium, N,N-(bis(methantri- fluoridesulphonyl)imide. The compound N-n-butyl-N-ethylpirrolidinium, N,N-(bis(methantrifluoridesulphonyl)imide being the ionic liquid of the best embodiment for the Lithium-Ion battery, its preparation and investigation on its possible use as a ionic liquid and herein indicated as Py₂₄TFSI have been disclosed in the above mentioned A. Fernicola, F. Croce, B. Scrosati, T. Watanabe, H. Ohno; Journal of Power Sources 174 (2007) 342-348,.

The ionic liquid of the invention is prepared as disclosed in the paper of Fernicola et al, as summarised in the following scheme:

Said method of preparation can be used for anyone of the compounds of the above formula (I) wherein R₃ and R₄ with the nitrogen atom to which they are bound form a pirrolidinic or piperidinic ring. The heterocyclic compound with an alkyl chain on the nitrogen atom is available on the market or can be prepared following known methods. The alkyl halide of the required length, according to the above definition of R_2, is also available on the market or can be prepared with the known methods. The reaction between nitrogen heterocycle and the alkyl halide is well-known to the organic chemist with ordinary skills in the art, said reaction is carried out in an organic solvent under time and temperature conditions which can easily set also looking at similar reactions known in the art. Equally, the isolation of the reaction product is made conventionally for example by solvent crystallization or by chromatography or by equivalent methods. Then, the intermediate product reacts with a salt of the anion which forms the final ionic liquid. Helpful reference, disclosing the synthesis of ionic liquids similar to these herein disclosed are: D. R. MacFarlane, P. Meakin, J. Sun, N. Amini, M. Forsyth J. Phys. Chem. B 103 (1999) 4164-4170; e G. B. Appetecchi, S. Scaccia, C. Tizzani, F. Alessandrini, S. Passerini, J. Electrochem. Soc. 153 (2006) A1685-A1691.

Py₂₄TFSI ionic liquid is added to a lithium salt, LiTFSI, to ensure an appropriate carriage of the lithium ion in the battery. It has been experimentally proved that, being the anion of the salt the same used in ionic liquid, the components are compatible. In a further preferred embodiment, said ionic liquid is engulfed in a membrane as herein disclosed in details.

Obviously, the battery according to the present invention comprises an anode-cathode system. Anode- cathode systems known in the art may be used.

In a preferred reaction the cathode in selected in the group consisting of: lithium phosphates and metals, metal oxides intercalated by lithium ions, lithium oxides and manganese.

In a further preferred embodiment, said cathode is selected in the group consisting of: LiFePO₄, LiCoPO₄, LiMnPO₄, LiCO-MnPO₄; LiCoO₂, LiNiO₂, LiCo-NiO₂; LiMn₂O₄, LiNio_,5Mni_,504, LiCo_1Z3Mn_1Z3Ni_1Z3O₂.

In a further preferred embodiment, the anode is selected in the group consisting of: graphite, titanium oxides containing lithium or MC alloys, wherein M is selected in the group consisting of silicon, antimony, aluminium or a combination thereof.

In particular, the anode is selected in the group consisting of Li₄Ti₅O₁₂, SnC, TiO₂.

The material of the anode SnC is prepared starting form a tin-based organometallic, which is engulfed in a resorcinol-formaldehyde gel. The product is calcinated in argon flux to reduce the tin content in the tin metallic precursor and carbonization of the gel. Said procedure allows obtaining a final material with a nominal composition Sn / C 1 :1. The synthesis has been disclosed in G. Derrien, J. Hassoun, S. Panero, B. Scrosati, Adv. Mater. 19 (2007) 2336.

TiO₂ is an electrod ic material in P . Ku biak, J . Gesereick, N. Hϋsing, M. Wohlfahrt-Mehrens Electrochemical performance of mesoporous TiO2 anatase Journal of Power Sources, 175 (1 ) pp. 510- 516 (2008). Li₄Ti₅O₁₂ is a material known in the field of Lithium-Ion batteries.

However, the specific combination of Li₄Ti₅O₁₂ with the cathode and the electrolyte on which the ionic liquid is based in the cell disclosed in example 1 have the unexpected advantage of not requiring any additional stabilizing agent, since said combination is enough stable.

Particularly preferred forms of the battery according to the present invention are: a) anode (negative electrode): Li₄Ti₅O₁₂, cathode (positive electrode): LiFePO₄, electrolyte:

Py₂₄TFSI-LiTFSI; b) anode (negative electrode): SnC, cathode (positive electrode): LiFePO₄, electrolyte: Py₂₄TFSI- LiTFSI; c) anode (negative electrode): TiO₂, cathode (positive electrode): LiFePO₄, electrolyte: Py₂₄TFSI- LiTFSI.

Figure 1 shows the thermal stability in a thermogravimetric analysis of the ionic liquid and of the two solutions with LiTFSI, the results are shown in figure 1. It has to be underlined that the high thermal stability of the pure ionic liquid rises up to 368 ⁰C, similar values can be obtained with its solution with the lithium salt. Said feature is responsible for the better safety grade of the battery using said system. Figure 2 shows the conductivity of the tested systems. The conductivity of the solution decreases when the salt concentration increases (for the corresponding increase of the viscosity) the values are in the range of mS/cm, thus high enough to allow their use in the Lithium-Ion batteries and in the Lithium batteries, being comparable with those of the electrolytic solutions currently used in said devices.

The above features demonstrate that the Py₂₄TFSI-LiTFSI system according to the present invention can be optimally used as electrolyte in Lithium-Ion batteries giving the advantages of thermal stability, low volatility and, in particular, safety.

To develop the technology of Lithium-Ion batteries it is important to use polymeric patterns which ensure operational reliability (absence of liquids) and design flexibility (modular development geometry). The general concept requires flexible, self-sustaining and lithium transporting membranes to be used for the electrolytic separation in polymeric batteries. In this sense, in the present work membranes, obtained engulfing the Py₂₄TFSI-LiTFSI solution in a co-polymeric polyvinylidene-exafluoropropylene PVdF-HFP, matrix the have been developed, they are indicated as Py₂₄TFSI-LiTFSI, PVdF-HFP.

Said membranes are stable up to 325 ⁰C, and maintain the high thermal stability of the solution making the ionic liquid. The conductivity is a 6,4 x 10^'4 Scnrf¹, said value is similar in the electrolytic solutions used in the Lithium-Ion batteries available on the market. The Py₂₄TFSI-LiTFSI, PVdF-HFP membranes can be thus applied in new designed lithium batteries having high thermal stability, safety, reliability and modular development geometry. Like the Py₂₄TFSI-LiTFSI solution of which they are made, said membranes can be used as electrolytic walls in batteries using the electrolytic materials of the present invention. Polymeric matrix based on several polymers including polyvinylydene fluoride (PVdF), a co-polymeric polyvinylidene fluoride exafluoropropylene (PVdF-HFP), polyacrylonitrile (PAN), Poly(methyl methacrylate) (PMMA), Polyvinyl alcohol (PVA) and combinations thereof can be used in the preparation of the ionic liquid engulfed in a membrane.

In addition to the above mentioned membranes, it is meant that said membranes can include several liquid solutions comprising a lithium salt which can be selected in the families of lithium tetrafluoroborate, lithium esafluorophosphate and lithium bis(trifluoromethansulphonyl)imide dissolved in mixtures of aprotic organic solvents which be selected in the families of carbonates, as ethylene carbonate, EC, propylene carbonate, PC, dimethylcarbonate, DMC e diethylcarbonate, DEC.

The battery according to the present invention can be manufactured according to the common general knowledge in the field and any specific description is required. As an example, see Gold Peak Industries Ltd. Lithium Ion Technical Handbook and the references cited thereof.

The battery according to the present invention can have different manufacturing configurations as, for example, disclosed in US 2008/0076030, US 2007/0026318, US 2003/0054254.

The following examples further explain the invention. Example 1

A battery with the following configuration has been prepared: anode (negative electrode): Li₄Ti₅Oi₂ cathode (positive electrode): LiFePO₄ electrolyte: Py₂₄TFSI-LiTFSI The operative process is the lithium ion exchange from one electrode to the other, where the electrolyte acts as a lithium ions transporter. Figure 3 shows a charge cycle:

Li₄Ti₅O₁₂ + LiFePO₄ → Li₍₁._x)FePO₄ + Li_(4+x)Ti₅0i₂

And a discharge cycle:

Li₍₁._x)FePO₄ + Li_(4+x)Ti₅0₁₂ → Li₄Ti₅O₁₂ + LiFePO₄ of said battery.

Figure 3 shows a charge-discharge cycle of the above disclosed battery.

Example 2

A battery with the following configuration has been prepared: anode (negative electrode): SnC cathode (positive electrode): LiFePO₄ electrolyte: Py₂₄TFSI-LiTFSI

Also in this case, the operative process is the reversible lithium ion exchange from the cathode to the anode.

Figure 4 shows charge-discharge cycles of SnC/ Py₂₄TFSI-LiTFSI / LiFePO₄ battery. Example 3

A battery with the following configuration has been prepared: anode (negative electrode): TiO₂ cathode (positive electrode): LiFePO₄ electrolyte: Py₂₄TFSI-LiTFSI The cell reaction is the following: LiFePO₄ + TiO₂ <→ Li-^_xFePO₄ + Li_xTiO₂.

Figure 5 shows charge-discharge cycles of said battery.

Example 4 Lithium-Ion batteries with hybrid gel-like membranes

Said membranes have been prepared by casting the liquid solutions commonly used in the Lithium-Ion batteries (as control example a exafluorophosphate solution has been LiPF₆ used) in a mixture of aprotic organic solvents (for example a solution of ethylene carbonate and EC-PC) in a polymeric matrix (for example the same PVdF-HFP matrix above disclosed). For the preparation of the hybrid gel-like membranes see Handbook of Batteries - Second Edition, D. Linden, McGraw-Hill Inc. New York (2005).

In the same manner, a membrane engulfed with the ionic liquid of the invention Py₂₄TFSI-LiTFSI has been prepared.

The comparison between the two membranes is shown for a measurement interval of 20 days. Conductivity of the membrane including ionic liquid is slightly lower than the membrane including the conventional electrolytes due to the higher viscosity of the ionic liquid in comparison with the conventional liquid electrolyte. The conductivity of our system is anyhow satisfactory for the purpose of the battery. Furthermore, some experiments show that conductivity strictly depends on the amount of ionic solution in the membrane. It is therefore possible to adjust the conductivity properties of the membrane by appropriately modifying the composition thereof (LiTFSI-Py₂₄TFSI / PVdF-HFP ratio).

Figure 6 shows conductivity at room temperature of a hybrid gel-like membrane prepared by assembling the LiPF₆-PC-EC (• - upper line) and the LiTFSI-Py₂₄TFSI (• - lower line) solution in the PVdF-HFP matrix. Figure 6 shows that conductivity at room temperature of the hybrid gel-like membrane prepared by assembling the LiPF₆-PC-EC solution in the PVdF-HFP matrix is ,7 x 10³ Scnrf¹, at room temperature, similar to the conductivity of the liquid solution of which it is made. Furthermore, the conductivity of the membrane stays in a range of interesting values for the use in batteries in a wide range of temperature, which is around 10^'4 Scm^'1 at 0 ⁰C to around 10^'3 Scm^'1 at 60 ⁰C. The advantage of said membrane is that they maintain the same operational features of the liquid solution even in a polymeric configuration. The hybrid membranes can be applied in Lithium-Ion batteries with a new polymeric configuration and with high safety, reliability and modular development geometry. Similarly with the configurations previously disclosed, said membranes can be used as electrolytic walls in batteries using the electrodic materials disclosed in the present invention. Industrial applicability of the present invention is clear. As an example mobile electronic, last generation mobile phones, sustainable transportation and Renewable energy.

Claims

1. Lithium-Ion batteries characterised in that the electrolytes comprising: a) an ionic liquid consisting of a cationic portion of quaternary ammonium of formula

R1 N+R2 R3 R4 where:

R1 is a linear or branched alkyl with from 2 to 5 carbon atoms, optionally substituted with an ethyl alkoxy group with from 1 to 3 carbon atoms;

R2, R3 e R4, being the same or different, are a linear or branched alkyl with from 2 to 5 carbon atoms, or R3 and R4, together with the nitrous atom to which they are bound form a pyrrolidinium or piperidinium; b) an anionic part, wherein the anion is selected form the group consisting of: bis(methantrifluoridesulphonyl)imide, tetrafluorideborate, esafluoridephosphate; c) a lithium salt selected form the group consisting of lithium N, N- (bis(methantrifluoridesulphonyl)imide, lithium tetrafluorideborate, lithium esafluoridephosphate and lithium bisoxalateborate.

2. Battery according to claim 1 , wherein said cationic portion is selected from the group consisting of N-n-butyl-N-ethylpirrolidinium, N-ethyl-N-propylpirrolidinium, N-ethyl-N-pethylpirrolidinium, N- ethyl-N-propoxyethylpirrolidinium, N-ethyl-N-propylpiperidinium, N-ethyl-N-isopropylpiperidinium, N-butyl-N-ethylpiperidinium, N-isobutyl-N-ethylpiperidinium, N-secbutyl-N-ethylpiperidinium, N- methoxyethyl-N-piperidinium, N-ethyl-N-etoxyethylpiperidinium, N-butyl-N,N,N-triethylammonium,

N,N,N-triethyl-N-propylammonium, N-butyl-N,N-diethyl-N-methylammonium and N-butyl-N,N- diethyl-N-propylammonium.

3. Battery according to anyone of claims 1-2, wherein said ionic liquid is engulfed in a membrane.

4. Battery according to anyone of claims 1-3, wherein the cathode is selected form the group consisting of lithium phosphates and metals, metal oxides intercalated by lithium ions, lithium oxides and manganese.

5. Battery according to claim 4, wherein said cathode is selected form the group consisting of: LiFePO₄, LiCoPO₄, LiMnPO₄, LiCO-MnPO₄; LiCoO₂, LiNiO_2, LiCo-NiO_2, LiMn₂O₄, LiNi_{0 5}Mn_{1 5}O₄, LiCθi_/3Mni_/3Nii_/3θ₂.

6. Battery according to anyone of claims, wherein the anode is selected form the group consisting of: graphite, titanium oxides containing lithium or MC alloys wherein dove M is selected in the group consisting of silicon, antimony, aluminium or a combination thereof.

7. Battery according to claim 6, wherein said anode is selected form the group consisting of: Li₄Ti₅O₁₂, SnC, TiO₂ 8. Battery with the following configuration: anode Li₄Ti₅O₁₂, cathode LiFePO₄, electrolyte Py₂₄TFSI-

LiTFSI.

9. Battery with the following configuration: anode SnC, cathode LiFePO₄, electrolyte Py₂₄TFSI- LiTFSI.

0. Battery with the following configuration: anode TiO₂, cathode LiFePO₄, electrolyte Py₂₄TFSI- LiTFSI.