HK1241560B

HK1241560B - Organic lithium battery

Info

Publication number: HK1241560B
Application number: HK18100632.4A
Authority: HK
Inventors: Margaud LECUYER; Marc Deschamps; Joël GAUBICHER; Philippe Poizot; Dominique Guyomard; Bernard Lestriez
Original assignee: Blue Solutions; Centre National De La Recherche Scientifique; Universite De Nantes
Priority date: 2014-12-01
Filing date: 2015-11-30
Publication date: 2019-10-04

Description

The present invention relates to the field of high energy and power density organic lithium batteries. In particular, the present invention concerns an organic lithium battery comprising a positive electrode based on redox organic compounds and an electrolyte comprising a high concentration of lithium salt, and its manufacturing process.

Lithium batteries have become indispensable components in many devices, including wearable devices, such as mobile phones, computers and lightweight tools, or heavier devices such as two-wheelers (bicycles, mopeds) or four-wheelers (electric or hybrid automobiles).

A lithium metal battery consists of at least one negative electrode and at least one positive electrode between which is placed a separator impregnated with a liquid electrolyte or a solid polymer electrolyte which itself provides both the physical separation of the electrodes and the transport of lithium ions. The negative electrode consists of a sheet of lithium metal or a lithium alloy, possibly supported by a current collector; and the positive electrode consists of a collector supporting an electrode material containing at least one positive electrode active material capable of inserting lithium ions in a reversible manner, possibly a polymer that acts as a current binding agent (e.g. polyvinyl fluoride or PVF) and possibly a liquid electrolyte (e.g. a liquid electrolyte) (e.g. a liquid electrolyte).₄, LiClO₄, LiPF₆Conventional electrolyte solvents (e.g. propylene carbonate, γ-butyrolactone, sulfolane, dimethoxyethane, tetrahydrofuran, 1,3-dioxolane, etc.) are saturated under normal conditions to about 1-1,5 mol/l lithium salt. The separator is usually made of a porous non-electronically conductive material, e.g. a polymer material based on polyphenes (e.g. polyethylene) or fibres (e.g. glass fibres or wood fibres).

During battery operation, lithium ions pass from one electrode to another through the electrolyte. When the battery is discharged, an amount of lithium reacts with the positive electrode active material from the electrolyte, and an equivalent amount is introduced into the electrolyte from the negative electrode active material, thus keeping the lithium concentration constant in the electrolyte. The insertion of lithium into the positive electrode is compensated by the supply of electrons from the negative electrode via an external circuit.

The various components of a lithium battery are chosen in such a way as to produce batteries with high energy density, good cycling stability and safe operation at the lowest possible cost.

For historical reasons as well as electrochemical performance, the technologies currently on the market rely almost exclusively on the use of inorganic electrode materials, mainly based on transition metals such as Co, Mn, Ni or Fe._{2 and}, LimnO₄, LiFePO₄, LiNi_OtherCo_OtherAl ,_OtherO_{2 and}, LiNi_{What Is the Kingdom? 3/15}Other_{What Is the Kingdom? 3/15}Co_{What Is the Kingdom? 3/15}O_{2 and}, LiNi_OtherOther_1.5O₄In addition, these inorganic materials are generally made from geological (i.e. non-renewable) resources and are energy intensive in their process. Given the announced battery production volumes (several billion units per year for Li-ion technology), these inorganic electrode materials may no longer be widely available in the long term. Furthermore, none of the existing technologies fully meet the needs while new environmental standards are emerging at European level (see http://ec.europa.eu/environment/batteries/waste directive, 2006/66/EC).

In this context, the development of organic lithium batteries comprising as active material of positive electrode a redox organic structure (e.g. nitroxide derivatives, polyaromatic compounds), i.e. an organic structure capable of implementing one or more reactions of reversible oxidation-reduction, in particular by exchanging electrons with an electrode and simultaneously associating with lithium ions, suggests certain potentials. Firstly, these redox organic structures have the advantage of including chemical elements (C, H, N, O, S, in particular) that can potentially be derived from renewable sources, thus attracting more specific resources.^{3 and}, they are therefore lighter than inorganic electrode materials, and therefore lead to lithium batteries with reduced weight.

Studies on organic lithium batteries since the early 1980s have focused exclusively on the search for new redox organic structures and have shown that the basic properties required for a redox organic structure to be implemented as a positive electrode active material are electroactivity, reversibility and near-insolubility in the electrolyte.

For example, π-conjugated conductive polymers such as polypyrrole, polythiophene, polyaniline, polyacetylene or polyacryloxy ((TEMPO) (with TEMPO: 2,2,6,6-tetramethyl piperidine-1-N-oxyl) have been used in lithium batteries as positive electrode material. However, these redox organic structures generally have low specific capacities of the order of 100 mAh/g, in particular because scales do not allow more than 0.5 electrons per monomer to be lost during oxidation reactions.

The use of quinone derivatives as positive electrode active material, a quinone generally characterized by two carbonylated functions present on an aromatic nucleus, has also attracted increasing interest. For example, 1,4-benzoquinone and 9,10-phenanthrenequinone (which have two carbonylated functions) have high theoretical specific capacities of the order of 500 mAh/g and 256 mAh/g respectively.₄The battery has good stability in terms of its discharge capacity. However, the reversibility of the oxidation-reduction reactions is insufficient and the average discharge voltage is relatively low (i.e. in the range of 2-2,5 volts). Similar results were obtained with anthraquinone.

For example, Yao et al. [Int. J. of Electrochem. Sci., 2011, 6, 2905] described an organic lithium battery comprising a negative electrode made of a sheet of lithium metal; a positive electrode made of an aluminum current collector supporting an electrode material including 5,7,12,14-pentacrylate (PT) active material, black acetylenes as an electron-generating agent and polytetrafluoroethylene as a constituent; a liquid electrolyte in liquid form; and a liquid electrolyte in the form of a liquid electrolyte (TF-B) in the form of a liquid electrolyte (TF-B) in the form of a liquid electrolyte.However, the cycling resistance of such a battery remains low as the initial specific capacity is in the range of 300 mAh/g and drops to 170 mAh/g after 10 cycles. This poor cycling stability is mainly due to the solubility of the positive electrode active material (PT) in the liquid electrolyte solvent (cf. γ-butyrolactone). Indeed, most low molar mass redox organic structures (i.e. molar mass less than 3000 g/mol) are soluble in the liquid electrolyte solvent.In addition, the concentration of active material that can be involved in an oxidation-reduction reaction is decreased, which leads to a drop in battery capacity.

Other indole-3-one-based redox organic structures, such as the dye Indigo, also called Indigotine or 2-(1,3-dihydro-3-oxo-2H-indole-2-ylidene)-1,2-dihydro-3H-indole-3-one, have also been proposed. In particular, Yao et al. [Chem. Letters, 2010, 39, 950] described an organic lithium battery comprising a negative electrode made of a sheet of lithium metal; a positive electrode made of an aluminum current collector supporting an electrode material including Indigotine as active material, acetylen black as an electronic conductor and polytrofluoroethylene; Lixafluorophosphate as a liquid electrolyte (PF).₆The specific capacity drops from 200 mAh/g to 20 mAh/g after about ten cycles, revealing poor cycling stability.

In order to prevent the active substance from dissolving in the electrolyte, patent application EP 2546907 A1 describes the manufacture of an organic lithium battery comprising a negative electrode made of a lithium metal sheet; a positive electrode made of an aluminium current collector supporting an electrode material comprising a redox organic structure of the pyrene-4,5,9,10-tetraone type meeting the following formula (1): - What? Acetylene black as an electronic conductor and polytetrafluoroethylene as a binder; a liquid electrolyte consisting of lithium hexafluorophosphate (LiPF)₆The organic lithium battery is improved in terms of cycling resistance and average discharge voltage. However, the preparation of the redox organic structure according to formula (1) is complex (i.e. involves a large number of steps) and time consuming.

Thus, the purpose of the present invention is to overcome the disadvantages of the above-mentioned prior art and to provide an economical organic lithium battery, which uses inexpensive, recyclable and non-toxic raw materials and has good electrochemical performance, particularly in terms of cycling resistance.

These aims are achieved by the invention described below.

The first object of the invention is therefore an organic lithium battery comprising: a negative electrode containing lithium metal or a lithium metal alloy,a positive electrode possibly supported by a current collector,the positive electrode containing at least one redox organic structure including at least two carbonyl functions C=0, two thione functions C=S or two imine functions C=N, at least one polymer binder P_{1 and 2}and at least one electronically conductive agent, the redox organic structure of which is different from the sulphuric agents selected from elemental sulphur S₈and organic sulphur compounds containing at least one SS bond, the organic lithium battery is characterised by the fact that it also contains an electrolyte containing at least one lithium L salt,_{1 and 2}and at least one liquid linear or cyclic polyether of a molar mass not exceeding 10 000 g·mol^{- One .}Approximately, it being understood that: * when the electrolyte is a liquid electrolyte, the lithium salt concentration L_{1 and 2}in the liquid electrolyte is approximately at least 1,6 mol/l, and the liquid electrolyte is permeable to a porous separator, and* where the electrolyte is a gelled polymer electrolyte, it also contains at least one polymer binder P_{2 and}soluble in linear or cyclic liquid polyethers of a molar mass of 10 000 g·mol or less^{- One .}The concentration of L-lithium salt in the solution is approximately_{1 and 2}in the said gelled polymer electrolyte, the O/Li ratio is not more than approximately 15, it being understood that in the O/Li ratio, O means the number of oxygen atoms supplied by the ether units of the liquid linear or cyclic polyether of molar mass equal to or less than 10 000 g·mol^{- One .}approximately, and possibly by the ether units of the polymer binder P_{2 and}if it contains lithium, and Li is the number of lithium ions provided by the lithium salt L_{1 and 2}- I 'm not .

The inventors of this application have thus found that the use of a high concentration of lithium salt in combination with the presence of a liquid linear or cyclic polyether of molecular mass less than or equal to 10 000 g·mol^{- One .}The fact that the concentration of lithium salt in the electrolyte of the organic lithium battery is approximately 0,05 g/cm3 makes it possible to significantly improve the electrochemical performance of the battery, in particular in terms of specific capacity stability during discharge over a large number of cycles. This is quite surprising since an increase in the lithium salt concentration in a conventional electrolyte is usually accompanied by a decrease in ionic conductivity, an increase in viscosity and a decrease in the mobility of lithium ions, leading to a decrease in specific capacity and a limitation in the current regime that can be used.

The use of such an electrolyte greatly limits the dissolution and diffusion of the redox organic structure of the positive electrode into the battery.

In addition, the organic lithium battery of the invention has the advantage of being able to be implemented with various redox organic structures without having to modify their structures, including by adding new functional groups.

Liquid linear or cyclic polyether is preferably a liquid linear or cyclic polyether with a molar mass of 2000 g·mol or less^{- One .}approximately, and preferably still less than or equal to 600 g·mol^{- One .}I guess.

Liquid polyether is preferably linear.

The linear or cyclic liquid polyether of the battery electrolyte of the invention may be chosen from: * polyethylene glycols with formula H-[O-CH]_{2 and}- What?_{2 and}[ Man ]_{m and m}-OH in which m is between 1 and 13,* glycol ethers of formula R-[O-CH]_{2 and}- What?_{2 and}[ Man ]_p-O-R', wherein the pests are between 1 and 13 and R and R', identical or different, are linear, branched or cyclic alkyl groups, which may comprise 1 to 20 carbon atoms*, ethers of formula R^{1 and 2}- [ CH ]_{2 and}- Oh]_{Q is}-R^{1 and}wherein q is between 1 and 13, R^{1 and 2}and R^{1 and}, identical or different, are linear, branched or cyclic alkyl groups, which may contain 1 to 20 carbon atoms and possibly heteroatoms; cyclic ethers may contain 2 to 20 carbon atoms; cyclic polyethers may contain 3 to 40 carbon atoms; and one of their mixtures.

The polyethers used in the electrolyte of the invention are particularly stable with respect to lithium and redox organic structures, thus limiting parasitic reactions to the maximum.

In a preferred embodiment, the linear or cyclic liquid polyether is tetraethylene glycol dimethyl ether (TEGDME) of formula CH_{3 and}O-(CH_{2 and}- What?_{2 and}(b)₄- Oh, my God._{3 and}(i.e. R, R' = CH)_{3 and}and p = 4) or ethylene glycol tetra (TEG) with formula H-(O-CH_{2 and}- What?_{2 and}(b)₄-OH (i.e. m is equal to 4).

Lithium salt L_{1 and 2}may be chosen from lithium fluorate (LiFO)_{3 and}The following substances are used: - lithium hexafluorophosphate (LiPF), - lithium bis (trifluoromethane sulphonyl) imide (LiTFSI), - lithium hexafluorophosphate (LiPF)₆The use of lithium fluoroborate (LiBF) in the manufacture of₄The use of lithium methaborate (LiBO) in the manufacture of_{2 and}The use of lithium perchlorate (LiClO) in the manufacture of₄The main components of the product are:_{3 and}The following substances are to be classified in the same heading as the product:_{2 and}O₄(b)_{2 and}or LiBOB) and mixtures thereof.

LiTFSI is the lithium salt L_{1 and 2}I like it.

It is obvious that the electrolyte in the battery of the invention is non-aqueous, i.e. it does not contain water or aqueous solvents, because an aqueous electrolyte is not compatible with a negative lithium metal electrode.

The electrolyte preferably does not contain organic solvents of the carbonate type, which are unstable in the presence of a lithium electrode in the long term and lead to the consumption of the latter by the formation of a lithium foam.

The first is that the electrolyte is a liquid electrolyte, so it completely soaks the porous separator to permeate the porosity.

The choice of porous separator is not limited and is well known to the professional.

The porous separator may be made of a porous non-electronically conductive material, usually a polymer material based on polyolefin (e.g. polyethylene) or fibres (e.g. glass fibres or wood fibres).

According to this first variant, the concentration of lithium salt L_{1 and 2}The concentration of the substance in the liquid electrolyte is approximately 1.6 to 8 mol/l, preferably about 1.8 to 6 mol/l, and preferably again about 2.1 to 5 mol/l.

The liquid electrolyte may be a lithium salt L_{1 and 2}in solution in a solvent containing at least one liquid linear or cyclic polyether.

The liquid electrolyte may only consist of a lithium salt L_{1 and 2}and a liquid linear or cyclic polyether.

The liquid electrolyte is preferably a solution containing 4.5 mol/l LiTFSI in TEGDME.

A second variant is that the electrolyte is a gelled polymer electrolyte.

The O/Li ratio of the gelled polymer electrolyte may be approximately 2 to 15, preferably 3 to 10 and preferably 4 to 8.

The polymer binder P_{2 and}The gelled polymer electrolyte must be soluble in liquid polyether.

The polymer binder P_{2 and}may allow the solubilization of L-lithium salt_{1 and 2}The gelled polymer electrolyte can then be used alone, i.e. without a porous separator, and thus form a self-supporting dry electrolyte film.

The polymer binder P_{2 and}The gelled polymer electrolyte can be selected from: * polyolefins such as homopolymers or copolymers of ethylene, homopolymers or copolymers of propylene (e.g. copolymer of ethylene and propylene);* polymers containing several ether units such as polyethers, polyoetherimides or polyvinyl ethers;* halogenated polymers such as homopolymers or copolymers of vinyl chloride, vinyl fluoride (PVdF), vinyl dehydrate, polyethylene or polyethylene tetrafluoride or polyethylene or polyethylene fluoride and polyethylene hexafluoride (PFPdP);;;((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((

For the purposes of this Regulation, a copolymer is a polymer compound obtained from at least two different monomers.

The polymer binder P_{2 and}may have a molar mass of more than 10 000 g·mol^{- One .}approximately, preferably strictly above 50 000 g·mol^{- One .}approximately, and preferably still strictly above 100 000 g·mol^{- One .}I guess.

Polyethers may have a linear, comb or block structure.

Examples of polyethers include homopolymers or copolymers of ethylene oxide (e.g. POE, copolymer of POE), methylene oxide, propylene oxide, epichlorohydrin or allyl glycidyl ether.

The gelled polymer electrolyte may contain approximately 40 to 80% by mass of polymer binder P_{2 and}, and preferably about 50 to 70% by mass of polymer binder P_{2 and}, relative to the total mass of the gelled polymer electrolyte.

According to a particularly preferred embodiment of the invention, the polymer binder P_{2 and}is a mixture of a polymer P_2Aand a polymer P_Other, said polymer P_2Aa thickness of not more than 0,05 mm_{1 and 2}present in high concentration in the polymer electrolyte gelled and said polymer P_Otherallowing the mechanical holding of the polymer gelled electrolyte.

It is enough that any one of the polymers P_2Aor P_Otherwhether or not soluble in linear or cyclic liquid polyethers of a molar mass of 10 000 g·mol or less^{- One .}I guess.

Preferably, the two polymers P_2Aand P_Otherare soluble in linear or cyclic liquid polyethers of a molar mass not exceeding 10 000 g·mol^{- One .}I guess.

The polymer P_2Acan be a polymer comprising several ether units as defined above.

The polymer P_Othermay be a halogenated polymer as defined above.

The gelled polymer electrolyte may contain approximately 5 to 30% by mass of polymer P_2A, and preferably 10 to 25% by mass of polymer P_2A, relative to the total mass of the gelled polymer electrolyte.

Polymers P_2AThe preferred copolymer is ethylene oxide and propylene oxide and the copolymer is ethylene oxide and butylene oxide.

The gelled polymer electrolyte may contain approximately 20 to 50% by mass of polymer P_Other, and preferably approximately 30 to 45% by mass of polymer P_Other, relative to the total mass of the gelled polymer electrolyte.

Polymers P_OtherThe preferred products are vinylidene polyfluoride (PVdF) and vinylidene and hexafluoropropylene fluoride copolymer (PVdF-co-HFP).

The gelled polymer electrolyte may contain approximately 18 to 50% by mass of L-lithium salt_{1 and 2}, preferably still approximately 25 to 50% by mass of L-lithium salt_{1 and 2}, and preferably still about 30 to 45% by mass of L-lithium salt_{1 and 2}in relation to the total mass of the gelled polymer electrolyte.

The gelled polymer electrolyte may comprise approximately 1 to 35% by mass of liquid linear or cyclic polyether, preferably approximately 2 to 30% by mass of liquid linear or cyclic polyether, and preferably approximately 2 to 15% by mass of liquid linear or cyclic polyether, relative to the total mass of the gelled polymer electrolyte.

The battery conforming to the invention can operate between 0 and 110 °C approx. and preferably between 20 and 100 °C approx.

In a particular embodiment of the invention, the positive electrode of the battery of the invention comprises at least 50% by mass of redox organic structure, and preferably at least 65% by mass of redox organic structure, relative to the total mass of the positive electrode.

In the present invention, the expression redox organic structure means an electroactive organic structure capable of reacting reversibly with lithium, i.e. an organic structure capable of one or more reversible oxidation-reduction reactions by exchanging electrons with an electrode and simultaneously combining with lithium ions.

The redox organic structure represents the active material of the positive electrode (i.e. positive electrode material) of the organic lithium battery of the invention.

In the present invention, the redox organic structure being different from the sulphur agents selected from elemental sulphur S, the₈and organic sulphur compounds containing at least one S-S bond, this is not a positive electrode active material such as those generally used as positive electrode active material in a lithium sulphur battery.^{2 and}- Sh-sh-sh_n-R^{3 and}in which R^{2 and}and R^{3 and}, identical or different, represent a linear, branched or cyclic alkyl chain, which may comprise 1 to 20 carbon atoms, and n being between 1 and 50; or disulfide polymers having a chain of S-S bonds which may be broken during the discharge cycle of a lithium sulphur battery, and reformed during the charge cycle._{2 and}S_wwhere w > 1 or the carbon-sulphur polymers of formula (C_{2 and}S_X1(b)_andwherein x_{1 and 2}= 2.5 to 50 and y_{1 and 2}≥ 2

The redox organic structure may be different from Li_{2 and}S which corresponds to the discharged state of compounds of formula Li_{2 and}S_was defined above.

The redox organic structure includes at least two C=O carbonyl functions, two C=S thione functions or two C=N imine functions, possibly present on at least one aromatic nucleus.

According to a particularly preferred form of the invention, the redox organic structure belongs to any of the following families: quinones, anthraquinones, benzoquinones, naphthoquinones, oxo-indolilidenes, skeleton C derived compounds₆O₆(i.e. rhodizonate derivatives), compounds containing at least one tetracyclic pyracen, and compounds derived from the skeleton calix[4]arena.

The redox organic structure comprising at least two thione functions C=S can be chosen from the sulphur equivalents of these compounds, e.g. cyclohexadieneedithiones, compounds derived from the skeleton C_{2 and}S_{2 and}(C)₆H₄(b)_{2 and}, thio-indolylidenes and skeleton C derivatives₆O_nS_6n- I 'm not .

The positive electrode may comprise approximately 1 to 30% by mass, and preferably approximately 2 to 20% by mass, of an electronic conductor, relative to the total mass of the positive electrode.

The electronic conductivity generating agent suitable for the present invention is preferably chosen from carbon black, SP carbon, acetylene black, carbon fibres and nanofibres, carbon nanotubes, graphene, graphite, metal particles and fibres and any of their mixtures.

The agent generating electronic conductivity is preferably carbon black.

The agent generating an electronic conductivity is preferably in the form of spherical particles (i.e. in the form of balls) in order to promote conduction particularly in the direction perpendicular to the positive electrode (i.e. in the direction of its thickness) and thus to promote electrochemical processes within the electrode.

Examples of carbon black include carbon black marketed under the names: Ketjenblack 600JD®, Ketjenblack 700JD® and Timcal Ensaco 350G®.

Depending on the particular embodiment, the positive electrode contains approximately 2 to 30% by mass of polymer binder P._{1 and 2}, and preferably about 5 to 20% by mass of polymer binder P_{1 and 2}, relative to the total mass of the positive electrode.

The polymer binder P_{1 and 2}may be chosen from ethylene copolymers and homopolymers; propylene copolymers and homopolymers; homopolymers and copolymers of ethylene oxide (e.g. POE, copolymer of POE), methylene oxide, propylene oxide, epichlorohydrin, allyl glycidyl ether and mixtures thereof; halogenated polymers such as homopolymers and copolymers of ethylene chloride, vinyl fluoride (PVdF), polyvinyl chloride, polyvinyl polyvinyl tetrafluoride (PE), polyvinyl chloride, polyvinyl chloride, polyvinyl chloride, polyvinyl chloride, polyvinyl chloride and their mixtures; polymers such as polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methacrylate (PVN), polyvinyl methalic acid, polyvinyl methalic acid, polyvinyl methalic acid, polyvinyl methalic acid, polyvinyl methalic acid, polyvinyl methalic acid, polyvinyl methalic acid, poly (PVPA), polyvinyl methalic acid, poly (PVA), poly (PVA), poly (PVA), polyvinyl) or their mixtures;

The polymer binder P_{1 and 2}is preferably a copolymer of POE or a copolymer of vinylidene fluoride and hexafluoropropylene.

The positive electrode may also contain at least one liquid linear or cyclic polyether as defined in the present invention, the presence of which improves the ionic conductivity of the positive electrode.

The positive electrode may then comprise approximately 2 to 30% by mass of linear or liquid cyclic polyether, and preferably approximately 8 to 20% by mass of linear or liquid cyclic polyether, relative to the total mass of the positive electrode.

The positive electrode may also contain at least one L-lithium salt_{2 and}- I 'm not .

The positive electrode can then contain approximately 1 to 25% by mass of L-lithium salt._{2 and}, preferably 1 to 15% by mass of L-lithium salt_{2 and}, and preferably still about 1 to 10% by mass of L-lithium salt_{2 and}, relative to the total mass of the positive electrode.

Lithium salt L_{2 and}may be chosen from lithium fluorate (LiFO)_{3 and}The following substances are used: - lithium hexafluorophosphate (LiPF), - lithium bis (trifluoromethane sulphonyl) imide (LiTFSI), - lithium hexafluorophosphate (LiPF)₆The use of lithium fluoroborate (LiBF) in the manufacture of₄The use of lithium methaborate (LiBO) in the manufacture of_{2 and}The use of lithium perchlorate (LiClO) in the manufacture of₄The main components of the product are:_{3 and}The following substances are to be classified in the same heading as the product:_{2 and}O₄(b)_{2 and}or LIBOB) and their mixtures.

LiTFSI is the lithium salt L_{2 and}I like it.

The positive electrode of the invention may have a porosity of less than or equal to about 40% by volume, and preferably less than or equal to about 30% by volume, in relation to the total volume of the positive electrode, thus improving the energy density of the battery.

It should be noted that the total mass of the positive electrode includes the mass of the redox organic structure, the mass of the polymer binder P_{1 and 2}, the mass of the electronic conductor, possibly the mass of the liquid linear or cyclic polyether if present and possibly the mass of the lithium salt L_{2 and}If he's here.

The positive electrode can be prepared: (a) by mixing at least one redox organic structure with at least one electronically conductive agent, at least one polymer binder P_{1 and 2}, possibly at least one L-lithium salt_{2 and}, possibly at least one liquid linear or cyclic polyether, and possibly at least one solvent thereof binding polymer P_{1 and 2}(b) by applying the electrode paste to at least one support, (c) by drying the electrode paste to obtain a positive electrode in the form of a supported film.

The polymer binder P_{1 and 2}, lithium salt L_{2 and}and liquid linear or cyclic polyether are as defined in the present invention.

Step (a) may be carried out by extrusion or by grinding.

Extrusion is very advantageous as it allows easy production of low-porous electrodes with low solvent use. It also avoids a calendering step on the dry electrode which can lead to changes in the electrode structure and affect the quality of the electronic permeate network. Finally, the calendering step has the disadvantage of increasing the number of steps to obtain the electrode and thus its production cost.

The solvent of the polymer binder P_{1 and 2}of step (a) allows the polymer binder P to be solubilized_{1 and 2}- I 'm not .

When present, the solvent preferably represents less than or equal to 30% by mass of the total mixture of redox organic structure, electronic conductivity agent, polymer binder P_{1 and 2}, possibly L-lithium salt_{2 and}and possibly of liquid linear or cyclic polyether.

The use of a small amount of solvent from the polymer binding agent P in the positive electrode manufacture_{1 and 2}This low porosity allows the amount of redox organic structure present in the positive electrode to be controlled and optimized, and thus optimum energy volume densities to be achieved.

The solvent for step (a) may be chosen from water, N-methylpyrrolidone, carbonate-type solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or methyl and ethyl carbonate, acetone, alcohols such as methanol, ethanol or propanol and mixtures thereof.

The solvent is preferably chosen from water, acetone, alcohols and their mixtures.

Step (b) may be carried out by rolling or by induction.

The support may be a current collector and/or a support film.

An example of a current collector is an aluminium current collector coated with a carbon-based layer (anti-corrosion layer).

An example of a film carrier is siliconised polyethylene terephthalate (PET) plastic film.

The positive electrode film obtained from step (c) may be approximately 2 to 100 μm thick, preferably approximately 10 to 60 μm.

Step (c) may be carried out at a temperature sufficient to remove the solvent from step (a).

The second subject-matter of the invention is a process for the manufacture of an organic lithium battery as defined in the first subject-matter of the invention, characterized by the following steps: (a) a step for the preparation of a liquid electrolyte or a gelled polymer electrolyte as defined in the present invention, including mixing of at least one liquid linear or cyclic polyether d with at least one lithium salt L_{1 and 2}, The process shall also include either of the following B1 or B2 sequences: B1) a step of assembly of a positive electrode, a negative electrode, as defined in the present invention, and a polymer gel electrolyte prepared in step A, orB2-i) a step of assembly of a positive electrode, a negative electrode and a porous separator, as defined in the present invention, andB2-ii) a step of impregnation of the assembly as obtained in step B2-i) by the liquid electrolyte prepared in step A).

Liquid linear or cyclic polyether, lithium salt L_{1 and 2}and polymer binder P_{2 and}are as defined in the first subject matter of the invention.

The liquid electrolyte in step A) is preferably prepared by dissolving at least one lithium salt L under agitation._{1 and 2}in a liquid linear or cyclic polyether, possibly at a temperature of approximately 20 to 120 °C.

The polymer electrolyte gelled in step A) can be obtained by extrusion of at least one polymer binder P_{2 and}with a solution containing at least one liquid linear or cyclic polyether and at least one L-lithium salt_{1 and 2}to obtain an electrolyte paste, then by rolling the electrolyte paste, in particular between two support films, to obtain a gelled polymer electrolyte film.

Extrusion can be carried out at a temperature of approximately 60 to 170°C.

The two support films may be siliconised PET plastic films.

The present invention is illustrated by the following examples, but is not limited to them.

Examples

The raw materials used in the examples are listed below: It consists of a mixture of hydrocarbons having carbon numbers predominantly in the range of C1 through C5 and boiling in the range of approximately -15oC to -15oC (-10oF to -15oF).⁵G.mol^{- One .}, ZSN 8100 , Zeospan,copolymer of vinylidene fluoride and hexafluoropropylene (PVdF-co-HFP), Mw = 6.10⁵G.mol^{- One .}, Solex , Solvay,LiTFSI, 3M,Siliconated PET film, Mitsubishi,Tetraethylene glycol dimethyl ether (TEGDME) with a purity of 99%, Sigma Aldrich,Polypropylene single layer separator, Celgard 2500,N-methylpyrrolidone (NMP), with a purity of 99.5%, Sigma Aldrich.

Unless otherwise stated, all materials used are those specified by the manufacturer.

The Commission shall adopt implementing acts. Manufacture of batteries B-1, B-2 and B-3 1.1 Preparation of the positive electrode

3 g Ketjenblack carbon black, 21 g Indigotein, 4.8 g co-POE copolymer, 1.2 g lithium salt (LiTFSI) and 5 g water were mixed at 80°C for 20 minutes in a blender sold under the trade name Plastograph® EC by Brabender®. The amount of water used was approximately 16.6% by mass of the total weight of the carbon black, Indigotein, co-POE copolymer and LiTFSI lithium salt.

The resulting paste was then rolled at 95°C on an aluminum current collector covered with a carbon-based coating.

The resulting film was dried at 110°C for 20 minutes in a furnace to obtain an E-1 positive electrode in the form of a film conforming to the invention.

Table 1 below shows the mass composition of the positive electrode E-1 obtained: - What?

TABLEAU 1


	10	4	16	70

1.2 Preparation of gelled polymer electrolytes

Lithium salt (LiTFSI) was dissolved in TEGDME under magnetic agitation at 50°C. Then a copolymer of POE Zeospan® and a copolymer of vinylidene and hexafluoropropylene fluoride (PVdF-co-HFP) was added to the resulting mixture. The resulting mixture was mixed in the Plastograph® EC blender as described in example 1.1 at 130°C for 40 minutes. The resulting electrolyte paste was rolled at 125°C between two silicon PET plastic films.

Table 2 below shows the mass composition of two polymer gelled electrolytes obtained: - What?

TABLEAU 2


6	39	20	35	4
24,7	13,3	22	40	22

1.3 Preparation of a solid polymer electrolyte

The solid polymer electrolyte was prepared by extrusion of a mixture of lithium salt (LiTFSI), Zeospan® POE copolymer and PVDF-co-HFP, and then by rolling the electrolyte paste obtained at 125°C between two siliconised PET plastic films.

Table 3 below shows the mass composition of the solid polymer electrolyte obtained: - What?

TABLEAU 3


	0	12	48	40

The solid polymer electrolyte not conforming to the invention and as prepared above, includes a lithium salt concentration such that the O/Li ratio of the number of oxygen atoms supplied by the ether units of the co-POE to the number of lithium ions supplied by the lithium salt is 22.

1.4 Manufacture of organic lithium batteries

Three batteries B-1, B-2 and B-3 were prepared by assembling under an anhydrous atmosphere (air with a dew point < -40°C) by manual rolling at room temperature: The positive electrode E-1 obtained in example 1.1 above,a negative electrode containing lithium metal as a lithium metal film of approximately 100 μm thickness, and the gelled polymer electrolyte PG-1 obtained in example 1.2 above, or the gelled polymer electrolyte PG-2 obtained in example 1.2 above, or the solid polymer electrolyte PS-1 obtained in example 1.3 above.

The B-1 battery conforms to the invention as it comprises a positive electrode, a negative electrode and a gelled polymer electrolyte as defined in the present invention.

In contrast, B-2 and B-3 batteries are not in conformity with the invention as they do not include a liquid electrolyte or gelled polymer as defined in the present invention.

The specific capacity (in mAh/g) of the B-1 battery (full round curve), the B-2 battery (full triangle curve), and the B-3 battery (full square curve) as a function of the number of cycles at a current of C/10 and a temperature of 100°C is shown in Figure 1.

These results show that the use of a gelled polymer electrolyte as defined in the present invention allows the initial specific capacity to be maintained to the same order of magnitude as that obtained with a solid polymer electrolyte (B-3 battery) in organic lithium batteries.

The relative capacity corresponding to the ratio of the discharge capacity of cycle n to the discharge capacity of cycle one, of batteries B-1 (full round curve), B-2 (full triangle curve) and B-3 (full square curve) as a function of the number of cycles at a current of C/10 and a temperature of 100 °C is shown in Figure 2.

In particular, Figure 2 shows for the B-3 battery (solid polymer electrolyte) a very rapid drop in discharge capacity in the first cycles and no stabilization in subsequent cycles, probably related to a dissolution of Indigotein in the solid polymer electrolyte and thus its diffusion.

The use of a solid polymer electrolyte with a lithium salt concentration such that the O/Li ratio of the number of oxygen atoms supplied by the ether units of the co-POE to the number of lithium ions supplied by the lithium salt is greater than 15 is also not appropriate as it would result in a significant increase in the viscosity of the electrolyte and thus a significant reduction in the capacity returned and thus in the energy density.

The Commission shall adopt implementing acts. Manufacture of batteries B-4 and B-5 2.1 Preparation of the positive electrode

1.75 g Ketjenblack carbon black, 24.5 g Indigotein, 4.53 g TEGDME, 1.42 g LiTFSI lithium salt, 2.8 g PVDF-co-HFP polymer and 5 g N-methylpyrrolidone (NMP) were mixed at 120°C for 20 minutes in a blender sold under the trade name Plastograph® EC by Brabender®. The amount of NMP used was approximately 14% by mass of the total weight of the indigotein, indigotein, TEGDME, LiTFSI lithium salt and PVDF-co-HFP.

The resulting paste was then rolled at 80°C on an aluminum current collector covered with a carbon-based coating.

The resulting film was dried at 110°C for 20 minutes in a furnace to obtain an E-2 positive electrode in the form of a film conforming to the invention.

Table 4 below shows the mass composition of the positive electrode E-2 obtained:

TABLEAU 4


	5	4,06	12,94	8	70

2.2 Preparation of two liquid electrolytes

Two liquid electrolytes L-1 and L-2 were prepared by dissolving a lithium salt LiTFSI in TEGDME under magnetic agitation for 10 min at 50°C. The liquid electrolyte L-1, as described in the invention, had a lithium salt concentration of 2.27 mol/l. The liquid electrolyte L-2, as not described in the invention, had a concentration of 0.9 mol/l.

2.3 Manufacture of organic lithium batteries

Two batteries B-4 and B-5 were prepared by assembling under an anhydrous atmosphere (air with a dew point < -40°C) by manual rolling at room temperature: the positive electrode E-2 obtained in example 2.1 above,a negative electrode containing lithium metal in the form of a lithium metal film approximately 100 μm thick, and a Celgard 2500 separator impregnated with liquid electrolyte L-1 obtained in example 2.2 above, or a Celgard 2500 separator impregnated with liquid electrolyte L-2 obtained in example 2.2 above.

The specific capacity (in mAh/g) of the B-4 battery (curve with full black lozenges) and the B-5 battery (curve with empty lozenges) according to the number of cycles at a current of C/20-D/20 (charge or discharge in 20 hours) and a temperature of 40°C is shown in Figure 3.

This figure 3 shows a slower decrease in discharge capacity for the B-4 battery of the invention (curve with full black lozenges), which shows the effectiveness of a high lithium salt content in slowing the diffusion of the active substance in the liquid electrolyte.

Claims

Organic lithium battery comprising:
- a negative electrode comprising lithium metal or an alloy of lithium metal,

- a positive electrode optionally supported by a current collector, said positive electrode comprising at least one redox organic structure comprising at least two carbonyl C=O functional groups, two thione C=S functional groups or two imine C=N functional groups, at least one polymer binder P₁ and at least one agent generating electron conductivity, said redox organic structure being different from the sulphur-comprising agents chosen from elemental sulphur S₈ and sulphur-comprising organic compounds comprising at least one S-S bond,
said organic lithium battery being characterized in that it additionally comprises an electrolyte comprising at least one lithium salt L₁ and at least one liquid linear or cyclic polyether with a molar mass of less than or equal to 10 000 g·mol^-1, it being understood that:
* when the electrolyte is a liquid electrolyte, the concentration of lithium salt L₁ in said liquid electrolyte is at least 1.6 mol/l, and the liquid electrolyte impregnates a porous separator, and

* when the electrolyte is a gelled polymer electrolyte, it additionally comprises at least one polymer binder P₂ which is soluble in the liquid linear or cyclic polyether with a molar mass of less than or equal to 10 000 g·mol^-1, and the concentration of lithium salt L₁ in said gelled polymer electrolyte is such that the O/Li ratio is at most 15, it being understood that, in the O/Li ratio, "O" denotes the number of oxygen atoms provided by the ether units of the liquid linear or cyclic polyether with a molar mass of less than or equal to 10 000 g·mol^-1, and optionally by the ether units of the polymer binder P₂, if it contains them, and "Li" denotes the number of lithium ions provided by the lithium salt L₁.
Battery according to Claim 1, characterized in that the lithium salt L₁ is chosen from lithium fluorate (LiFO₃), lithium bis(trifluoromethanesulphonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF₆), lithium fluoroborate (LiBF₄), lithium metaborate (LiBO₂), lithium perchlorate (LiClO₄), lithium nitrate (LiNO₃), lithium bis(fluorosulphonyl)imide (LiFSI), lithium bis(oxalato)borate (LiB(C₂O₄)₂ or LiBOB) and their mixtures.
Battery according to either one of the preceding claims, characterized in that the positive electrode comprises at least 50% by weight of redox organic structure, with respect to the total weight of said positive electrode.
Battery according to any one of the preceding claims, characterized in that the positive electrode comprises from 1 to 30% by weight of agent generating an electron conductivity, with respect to the total weight of the positive electrode.
Battery according to any one of the preceding claims, characterized in that the agent generating an electron conductivity is chosen from carbon black, sp carbon, acetylene black, carbon fibres and nanofibres, carbon nanotubes, graphene, graphite, metal particles and fibres, and one of their mixtures.
Battery according to any one of the preceding claims, characterized in that the positive electrode comprises from 2 to 30% by weight of polymer binder P₁, with respect to the total weight of the positive electrode.
Battery according to any one of the preceding claims, characterized in that the polymer binder P₁ is chosen from copolymers and homopolymers of ethylene; copolymers and homopolymers of propylene; homopolymers and copolymers of ethylene oxide, of methylene oxide, of propylene oxide, of epichlorohydrin or of allyl glycidyl ether, and their mixtures; halogenated polymers; polyacrylates; polyalcohols; electron-conducting polymers; polymers of cationic type; and one of their mixtures.
Battery according to any one of the preceding claims, characterized in that the polymer binder P₂ is chosen from polyolefins, polymers comprising several ether units, halogenated polymers, non-electron-conducting polymers of anionic type, polyacrylates, elastomers and one of their mixtures.
Battery according to any one of the preceding claims, characterized in that the gelled polymer electrolyte comprises from 40 to 80% by weight of polymer binder P₂, with respect to the total weight of the gelled polymer electrolyte.
Battery according to any one of the preceding claims, characterized in that the polymer binder P₂ is a mixture of a polymer P_2-A and of a polymer P_2-B, said polymer P_2-A making it possible to dissolve the lithium salt L₁ present in a high concentration in the gelled polymer electrolyte and said polymer P_2-B making it possible to provide the mechanical strength of said gelled polymer electrolyte.
Battery according to Claim 10, characterized in that the polymer P_2-A is a polymer comprising several ether units and the polymer P_2-B is a halogenated polym er.
Battery according to any one of the preceding claims, characterized in that the O/Li ratio of the gelled polymer electrolyte ranges from 3 to 10.
Battery according to any one of the preceding claims, characterized in that the gelled polymer electrolyte comprises from 1 to 35% by weight of liquid linear or cyclic polyether, with respect to the total weight of the gelled polymer electrolyte.
Battery according to any one of Claims 1 to 7, characterized in that the concentration of the lithium salt L₁ in the liquid electrolyte ranges from 1.8 to 6 mol/l.
Process for the manufacture of an organic lithium battery as defined in any one of Claims 1 to 14, characterized in that it comprises the following stages:
A) a stage of preparation of a liquid electrolyte or of a gelled polymer electrolyte as defined in any one of Claims 1 to 14,
said process additionally comprising one or other of the following sequences B1 or B2:
B1) a stage of assembling a positive electrode, a negative electrode, as are defined in any one of Claims 1 to 14, and a gelled polymer electrolyte prepared in stage A), or

B2-i) a stage of assembling a positive electrode, a negative electrode and a porous separator, as are defined in any one of Claims 1 to 14, and

B2-ii) a stage of impregnation of the assembly as obtained in stage B2-i) by the liquid electrolyte prepared in stage A).