TERNARY LITHIUM NICKEL PHOSPHATE GLASSES, PROCESS FOR THEIR OBTAINMENT, AND THEIR USES

Abstract

The present invention relates to lithium nickel phosphate ternary glasses, as well as to a process for their production. The invention also relates to the preparation and use of said glasses as active materials for positive electrodes, in particular metal-ion accumulators, as well as said active materials and electrodes per se. (no figure)

Description

Title of the invention: TERNARY LITHIUM NICKEL PHOSPHATE GLASSES, METHOD FOR PRODUCING THEM, AND THEIR USES

[0001] The present invention relates to ternary lithium nickel phosphate glasses, as well as a process for their production. The invention also relates to the preparation and use of said glasses as active materials for positive electrodes, in particular metal-ion accumulators, as well as said active materials and electrodes per se.

[0002] LiCoO2 (LCO) is the technology used for the positive electrode of the first lithium-ion battery marketed by Sony in 1991. This technology has a very high energy density and is relatively easy to implement. However, the instability associated with the exploitation of cobalt dioxide (CoO2) makes this technology unsafe from an industrial point of view and speculation around cobalt prices increases its price.

[0003] Among the other well-established Li-ion battery positive electrode technologies, LiFePO4 (LFP) is a technology known for its very good power and cycling characteristics, while having the great advantage of having high intrinsic safety and having a very good lifespan, whether calendar or cycling.

[0004] However, the theoretical capacity of LiFePO4 (170 mAh / g) combined with an average operating voltage of 3.2V is an obstacle to its application in batteries requiring high energy densities. This constraint is illustrated by the limited autonomy of electric vehicles (less than 160 km) equipped with such technology, which limits their large-scale introduction.

[0005] To increase energy densities, it is generally necessary to develop new cathode materials beyond LFPs and LCOs that use more than one Li per 100 atomic mass units.

[0006] To increase energy densities, it is generally necessary to develop new cathode materials beyond LFP and LCO that are capable of exchanging more than one Li per transition metal.

[0007] The development of positive electrodes based on glass is an interesting approach, in particular because the process of synthesizing glasses remains easier to implement than for other synthesis routes (such as hydrothermal synthesis for example). Also, it is easily scalable for the synthesis of material on a large scale. In addition to this, the glass network forming the structure of the glasses is less rigid and consisting of a larger fraction of free volume (vacant space) than their crystallized counterparts. Theoretically, this would allow the glasses to incorporate and extract alkali ions easily and to more easily accept structural modifications that may occur during cycling. Due to the many accessible oxidation states of vanadium, vanadate-based glass electrodes have been considered as interesting alternatives. Currently in the literature, the best electrochemical performances for a vanadium-based glass are held by a material based on the Li2O - B2O3- V2O5 system, making it possible to reach 1000 Wh / kg on the scale of the active material over 10 cycles.

[0008] However, this material remains limited by a fairly low operating potential (2.4 V vs Li+ / Li) and especially by its extremely low first charge (20 mAh / g).

[0009] In addition, vanadium poses toxicity and cost problems limiting its long-term application in the electric mobility or stationary storage sector in particular.

[0010] An objective of the invention is thus to provide compounds which do not have the aforementioned drawbacks.

[0011] In particular, an objective of the invention is to provide compounds capable of being successfully used for the preparation of positive electrodes, in particular metal-ion accumulators (the metal being in particular an alkali or alkaline-earth metal, for example Li, Na, K, Mg or Ca), having high capacities and / or high energy densities, in particular higher than those relating to the devices of the prior art, while avoiding economically critical and / or toxic metals, such as cobalt or vanadium.

[0012] Also, the invention relates to a glass of the following formula (I):

[0013] x Li2O - y NiO - (100-xy) P2O5 (I),

[0014] with:

[0015] 0 < x <100

[0016] 10 < y < 100

[0017] 40 < x+y < 100.

[0018] By “glass” is meant in particular a metastable, amorphous or substantially amorphous solid compound.

[0019] By “amorphous” is meant in particular a solid compound having no atomic structure ordered at medium and long distance.

[0020] By "substantially amorphous" is meant in particular that the compound is more than 97%, in particular more than 98 or 99% amorphous by mass.

[0021] The amorphous character can be determined by any technique well known to those skilled in the art, in particular by X-ray diffraction (XRD).

[0022] According to a particular embodiment, 41 < x+y < 100, with in particular 42, 43, 44 or 45 < x+y < 100.

[0023] According to a particular embodiment, the invention relates to a glass such that 1 < x / y <4.

[0024] According to a particular embodiment, x <95, or even 90, 80, 70 or 60.

[0025] According to a particular embodiment, y <95, or even 90, 80, 70 or 60.

[0026] According to a particular embodiment, x <95, or even 90, 80, 70 or 60, and y <95, or even 90, 80, 70 or 60.

[0027] According to a particular embodiment, 0.5 < x / y < 2.5 or 3.0 or 4.0.

[0028] According to a particular embodiment, the invention relates to a glass as defined previously, whose formula is chosen from the following formulas: 31 Li2O - 15 NiO - 54 P2O5; 14 Li2O - 28 NiO - 58 P2O5 ; 21.5 Li2O - 21.5 NiO - 57 P2O5.

[0029] For any given particular formula (I) or (Io), each value of x and y is understood to be within ± 0.5%, or even + 1% or + 2%. Thus, for example, a value of x or y of 55 ± 1%, includes the values ​​from 54.45 to 55.55.

[0030] According to another aspect, the invention also relates to a method for preparing a glass as defined above, comprising a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2O5, to obtain said glass.

[0031] All the embodiments described previously relating to the glass of the invention also apply here, alone or in combination.

[0032] According to another aspect, the invention also relates to a process for preparing a glass of the following formula (Io):

[0033] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0034] with:

[0035] 0 < x <100

[0036] 10 < y < 100

[0037] x+y < 100.

[0038] Said method comprising a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2 O5, to obtain said glass.

[0039] All the embodiments described previously relating to the glass of the invention also apply here, alone or in combination.

[0040] According to a particular embodiment, x <95, or even 90, 80, 70 or 60.

[0041] According to a particular embodiment, y <95, or even 90, 80, 70 or 60.

[0042] According to a particular embodiment, x <95, or even 90, 80, 70 or 60, and y <95, or even 90, 80, 70 or 60.

[0043] According to a particular embodiment, the quenching can be carried out by casting onto a plate, for example a metal plate, or be accelerated by the application of mechanical stresses, for example by a drop hammer.

[0044] According to a particular embodiment, the method as defined previously comprises: - a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2O5, to obtain an intermediate glass; - a step (ii) of crushing the intermediate glass obtained at the end of step (i); - a step (iii) of tempering the crushed intermediate glass obtained at the end of step (ii), previously melted, to obtain the glass as defined above.

[0045] According to a particular embodiment, the molten mixture of step (i) as described above, and / or of step (iii) as described above, is, prior to quenching, at a temperature Tb of from 1000°C to 1400°C, for example approximately 1200°C.

[0046] By "quenching" is meant in particular a passage from the temperature Tb to a lower temperature, in particular ambient temperature, at a speed greater than or equal to approximately 1000°C / min for quenching cast on a plate and greater than or equal to approximately 10000°C / min for quenching of the drop hammer type.

[0047] According to a particular embodiment, step (i) as described above is preceded by a step of raising the temperature of the mixture of precursor powders to the temperature Ta and then by a second rise in temperature to the temperature Tb. The temperature Ta is 800°C with a temperature rise ranging from 10°C / h to 60°C / h. The rise in temperature to the temperature Tb is carried out at a heating rate of 60°C / h to 120°C / h.

[0048] According to a particular embodiment, the molten mixture of step (iii) as described above, is obtained by introducing the crushed intermediate glass of step (ii), as described above, directly at a temperature Tb of from 1000°C to 1400°C, for example approximately 1200°C.

[0049] According to a particular embodiment, the method according to the invention, as defined previously, comprises: - A step (i0) of increasing the temperature of a mixture of precursors (A) consisting of a source of NiO, a source of Li2O and a source of P2 05. This mixture is brought to temperature Ta followed by a second temperature increase to temperature Tb. The temperature Ta is 800°C with a temperature increase ranging from 10°C / h to 60°C / h. The temperature increase to temperature Tb is carried out at a heating rate of 60°C / h to 120°C / h. - a step (i) of quenching the molten mixture (A), to obtain said glass.

[0050] According to a particular embodiment, the method according to the invention, as defined previously, comprises: - A step (i0) of increasing the temperature of a mixture of precursors (A) consisting of a source of NiO, a source of Li2O and a source of P2 O5. This mixture is brought to the temperature Ta followed by a second increase in temperature up to the temperature Tb. The temperature Ta is 800°C with a temperature increase ranging from 10°C / h to 60°C / h. The increase in temperature up to the temperature Tb is carried out at a heating rate of 60°C / h to 120°C / h; - a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2O5, to obtain an intermediate glass; - a step (ii) of crushing the intermediate glass obtained at the end of step (i); - a step (iii0) of introducing the crushed intermediate glass at a temperature Tb, the temperature Tb being between 1000°C and 1400°C, for example approximately 1200°C; - a step (iii) of tempering the crushed intermediate glass in fusion obtained at the end of step (iii0), to obtain the glass as defined previously.

[0051] According to a particular embodiment, the method according to the invention, as defined previously, comprises: - A step (i0) of increasing the temperature, with stirring, of a mixture of precursors (A) consisting of a source of NiO, a source of Li2O and a source of P2O5. This mixture is brought to the temperature and then a second increase in temperature up to the temperature Tb. The temperature Ta is 800°C with a temperature increase ranging from 10°C / h to 60°C / h. The increase in temperature up to the temperature Tb is carried out at a heating rate of 60°C / h to 120°C / h. - a step (i) of quenching the molten mixture (A), to obtain said glass.

[0052] According to a particular embodiment, the stirring during step (i0) is mechanical stirring, in particular by a stirring blade.

[0053] According to a particular embodiment, the source of NiO comprises or consists of NiO, Ni2O3, and / or NiSO4.

[0054] According to a particular embodiment, the source of P2O5 comprises or consists of NH4H2PO4, P2O5, (NaPO3)6, H3PO4, and / or (NH4)2HPO4.

[0055] According to a particular embodiment, the source of Li2O comprises or consists of Li2CO3, Li2SO4, and / or LiOH.

[0056] According to another aspect, the invention also relates to a glass capable of being obtained according to one of the methods defined above.

[0057] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles as defined above.

[0058] According to a particular embodiment, the particles have a size of from 0.1 to 100 pm, in particular from 0.1 to 50 pm, notably from 1 to 50 pm.

[0059] According to a more particular embodiment, the particles have a size of 0.1 to 5 or even 2 μm.

[0060] All the embodiments described previously relating to the glass of the invention also apply here, alone or in combination.

[0061] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles of the following formula (Io):

[0062] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0063] with:

[0064] 0 < x <100

[0065] 10 < y < 100

[0066] x+y < 100.

[0067] All the embodiments described previously relating to the glass of the invention also apply here, alone or in combination.

[0068] According to a particular embodiment, the powder as defined previously is free of KBr.

[0069] According to a particular embodiment, the particles have a size of from 0.1 to 100 pm, in particular from 50 to 100 pm, or from 0.1 to 50 pm, in particular from 1 to 50 pm.

[0070] According to a more particular embodiment, the particles have a size of 0.1 to 5 or even 2 μm.

[0071] By "size" is meant in particular the largest dimension of a particle.

[0072] This size is in particular an average size determined by laser granulometry.

[0073] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles as defined above and an electronically conductive additive.

[0074] The electronically conductive additive, well known to those skilled in the art, may consist of or comprise hard carbon and / or graphite.

[0075] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles as defined above and carbon particles.

[0076] All embodiments described above relating to the glass and / or glass particles of the invention also apply here, alone or in combination.

[0077] According to a particular embodiment, the particles have a size of from 0.1 to 100 pm, in particular from 0.1 to 50 pm, notably from 1 to 50 pm.

[0078] According to a more particular embodiment, the particles have a size of from 0.1 to 5 μm.

[0079] By "carbon particles" is meant particles constituting carbon black.

[0080] By "carbon black" is meant in particular a powdery composition of carbon in amorphous form, which is in particular in the form of a powder consisting of or comprising spherical or spheroidal particles of 5 to 500 nm (largest dimension), in particular less than 100 nm.

[0081] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles and an electronically conductive additive, in particular carbon particles, the glass being of the following formula (Io):

[0082] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0083] with:

[0084] 0 < x <100

[0085] 10 < y < 100

[0086] x+y < 100.

[0087] All embodiments described above relating to the glass and / or glass particles of the invention also apply here, alone or in combination.

[0088] According to a particular embodiment, the glass particles are mixed with an electronically conductive additive, in particular carbon particles, thus constituting a composite material. In this composite, the additive particles, in particular carbon particles, are distributed in such a way that they envelop the glass particles.

[0089] According to a particular embodiment, the ratio of the mass of the glass particles to the mass of electronically conductive additive, in particular carbon particles, is from 90 / 5 or 80 / 10 to 50 / 40, this ratio being for example 70 / 25.

[0090] According to another particular embodiment, the ratio of the mass of the glass particles to the mass of electronically conductive additive, in particular carbon particles, is from 96 / 2 to 90 / 5.

[0091] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles as defined above, an electronically conductive additive, in particular carbon particles, and a binder.

[0092] All embodiments described above relating to the glass and / or glass particles of the invention also apply here, alone or in combination.

[0093] According to another aspect, the invention also relates to a powder consisting of or comprising glass particles, an electronically conductive additive, in particular carbon particles, and a binder, the glass being of the following formula (Io):

[0094] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0095] with:

[0096] 0 < x <100

[0097] 10 < y < 100

[0098] x+y < 100.

[0099] All embodiments described above relating to the glass and / or glass particles of the invention also apply here, alone or in combination.

[0100] According to a particular embodiment, the binder is a polymer, notably chosen from polyvinylidene fluoride (PVDF).

[0101] According to a particular embodiment, the powder as defined previously comprises, by mass:

[0102] -from 50 to 80% of glass particles as defined previously, in particular 70%;

[0103] -from 10 to 40% of carbon particles, in particular 25%; and

[0104] -from 5 to 10% of binder, in particular 5%.

[0105] According to a particular embodiment, the powder as defined previously comprises, by mass:

[0106] -from 90 to 96% of glass particles as defined previously;

[0107] -from 2 to 6% of carbon particles, in particular; and

[0108] -from 2 to 4% of binder.

[0109] According to another aspect, the invention also relates to a method for preparing a powder as defined above, comprising a step a) of grinding a glass as defined above.

[0110] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0111] According to a particular embodiment, the method of the invention as defined previously comprises: a. a first step of grinding, in particular using balls, of a glass as defined previously, to obtain a first glass powder; b. a second grinding step, in particular using balls, of a composition comprising the glass powder obtained from the previous grinding, as well as an electronically conductive additive powder, in particular carbon.

[0112] According to a more particular embodiment, the particles of the first glass powder have a size of 5 or even 10 to 20 μm.

[0113] The grinding according to a step a) as described above can in particular be carried out using a vibrating mill, in particular using a dry process, or an attritor (erosion grinding). In the case of a vibrating mill, the glass is typically placed in a grinding tank containing one or more grinding balls. By means of oscillations of the grinding tank horizontally, the material is ground by impacts between the grinding balls, the tank and the material to be ground.

[0114] The ball milling according to a step b) as described previously can in particular be carried out using a planetary mill, or a centrifugal mill.

[0115] According to another aspect, the invention also relates to the use of a glass as defined previously or of a powder as defined previously for the production of an electrode, in particular a positive one, in particular for a metal-ion accumulator.

[0116] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0117] According to another aspect, the invention also relates to the use of a glass or a glass powder for producing an electrode, in particular a positive one, in particular for a metal-ion battery or accumulator, the glass having the following formula (Io):

[0118] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0119] According to another aspect, the invention also relates to the use of a glass or a glass powder for producing an electrode, in particular a positive one, in particular for a metal-ion battery or accumulator, the glass having the following formula (Io):

[0120] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0121] with:

[0122] 0 < x <100

[0123] 10 < y < 100

[0124] x+y < 100.

[0125] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0126] According to another aspect, the invention also relates to an electrode, in particular a positive electrode, in particular for a metal-ion battery or accumulator, comprising a glass as defined previously or a powder as defined previously.

[0127] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0128] According to another aspect, the invention also relates to an electrode, in particular a positive electrode, in particular for a metal-ion battery or accumulator, comprising a glass or a glass powder, the glass of the following formula (Io):

[0129] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0130] with:

[0131] 0 <x<100

[0132] 10 < y < 100

[0133] x+y < 100.

[0134] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0135] According to another aspect, the invention also relates to a method for preparing an electrode, in particular a positive one, in particular for a metal-ion battery or accumulator, said method comprising a step A) of bringing into contact a powder consisting of or comprising glass particles, an electronically conductive additive, in particular carbon particles, and optionally a binder, as defined above, with a conductive support.

[0136] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0137] According to a particular embodiment, the conductive support is a metal support, the metal being aluminum (Al) and copper (Cu).

[0138] According to a particular embodiment, the method of the invention as defined previously comprises:

[0139] Ao) a step of preparing an ink by adding a solvent, in particular chosen from N-methyl-2-pyrrolidone (NMP), or aqueous-based polymers (such as, for example, carboxymethylcellulose), to a powder consisting of or comprising glass particles, an electronically conductive additive, in particular carbon particles and optionally a binder, the binder being, for example, dissolved beforehand in a solvent, in particular N-methyl-2-pyrrolidone (NMP), as defined above, and, optionally homogenization, in particular by mechanical stirring, to obtain a suspension;

[0140] A) a step A) of bringing a suspension as obtained at the end of step A) into contact with a conductive support, in particular by coating, for example of the “doctor blade” type to obtain a device;

[0141] B) optionally, a step of drying said device;

[0142] C) optionally a step of shaping, in particular by pelletizing, said device, optionally dried, in particular at a temperature of 50 to 100°C, in particular at approximately 60°C, and / or for 1 to 48 hours, for example for approximately 24 hours.

[0143] According to another aspect, the invention also relates to a battery or accumulator comprising an electrode, in particular a positive one, comprising a glass as defined previously or a powder as defined previously.

[0144] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0145] According to another aspect, the invention also relates to a battery or accumulator comprising an electrode, in particular a positive one, comprising a glass or a glass powder, the glass being of the following formula (Io):

[0146] x Li2O - y NiO - (100-xy) P2O5 (Io),

[0147] with:

[0148] 0 <x<100

[0149] 10 < y < 100

[0150] x+y < 100.

[0151] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention also apply here, alone or in combination.

[0152] According to a particular embodiment, the battery or accumulator as defined previously further comprises at least one electrolyte, a separator, in particular microporous, and a negative electrode, in particular consisting of or comprising a metal chosen from Li, Na and K.

[0153] These elements are well known to those skilled in the art, who will be able to select them, in particular from commercial elements, according to requirements.

[0154] The negative electrode may also be made of or comprising hard carbon or graphite.

[0155] According to a particular embodiment, the battery or accumulator as defined previously has a theoretical specific capacity greater than 80 mAh / g, in particular greater than 100 or even 120 mAh / g, and for example up to or exceeding 140 mAh / g.

[0156] The batteries and accumulators of the invention can, for example, be used in the field of electrical storage, in particular stationary, or in electric mobility, in particular for portable or wearable electronics, in integration into fibers and / or cables, in particular in the context of wired batteries, or for medical use.

[0157] In particular, the batteries and accumulators of the invention can be used in the field of electric mobility, in particular for electric vehicles, rechargeable hybrid electric vehicles, hybrid vehicles, or electric 2-wheelers.

[0158] In particular, the batteries and accumulators of the invention can be used in the field of portable electrical equipment, in particular telephony, portable computers, or portable tools.

[0159] According to another aspect, the invention also relates to a battery comprising a cell or an accumulator as defined previously.

[0160] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention, and / or an electrode, and / or a battery or accumulator also apply here, alone or in combination.

[0161] According to another aspect, the invention also relates to an electric portable system or one adapted to electric mobility, comprising a battery as defined above.

[0162] All the embodiments described above relating to the glass and / or glass particles, and / or a powder of the invention, and / or an electrode, and / or a battery or accumulator also apply here, alone or in combination. DEFINITIONS

[0163] As used herein, the value ranges in the form of "xy" or "from x to y" or "between x and y" include the bounds x and y, the integers between these bounds, as well as all other real numbers between these bounds. For example, "1-5", or "from 1 to 5" or "between 1 and 5" designates the integers 1, 2, 3, 4 and 5, as well as all other real numbers between 1 and 5. Preferred embodiments include each individual integer in the value range, as well as any subcombination of these integers and any set of real numbers between these integers. For example, preferred values ​​for "1-5" might include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, etc.

[0164] As used herein, the term "about" refers to a range of values ​​within ± 10% of a specific value. For example, the term "about 20" includes values ​​of 20 ± 10%, or values ​​from 18 to 22.

[0165] For the purposes of this description, percentages refer to percentages by mass relative to the total mass of the formulation, unless otherwise indicated. FIGURES

[0166] [Fig.l] shows a thermal cycle for producing glass 31 Li2O - 15 NiO - 54 P2O5, according to example 1.

[0167] [Fig.2] shows the galvanostatic cycling curves between 1.5 V vs Li / Li + and 4.5 V vs Li / Li + of the glass of composition 31Li2O - 15 NiO - 54 P2O5 with a charge start at C / 100. The first three cycles have been represented. The theoretical specific capacity based on the change of valence Ni2+ Ni4+ (i.e. the exchange of 2 electrons) is equivalent to 85 mAh / g.

[0168] [Fig.3] shows the galvanostatic cycling curves between 1.5 V vs Li / Li+ and 4.5 V vs Li / Li+ of the glass of composition 14Li2O - 28NiO - 58P2O5 with a charge start at C / 100. The first three cycles have been represented. The theoretical specific capacity based on the change of valence Ni2+ Ni4+ (i.e. the exchange of 2 electrons) is equivalent to 140 mAh / g.

[0169] [Fig.4] shows the galvanostatic cycling curves between 1.5 V vs Li / Li+ and 4.5 V vs Li / Li+ of the glass of composition 21.5Li2O - 21.5NiO - 57P2O5 with a charge start at C / 100. The first three cycles have been represented. The theoretical specific capacity based on the change of valence Ni2+ Ni4+ (i.e. the exchange of 2 electrons) is equivalent to 112 mAh / g. EXAMPLES

[0170] Example 1: Preparation of glass 31 Li 2 O - 15 NiO - 54 P 2 O 5

[0171] Glass in the system 31Li2O - 15NiO - 54P2O5 was produced by air quenching on stainless steel plate from a refined cast iron bath at 1200°C for 15 minutes as illustrated in [Fig.l]. This intermediate crushing is likely to allow, if necessary, to homogenize the molten liquid. The targeted molar proportion is obtained by weighing the different precursor powders ((NH4)2HPO4 for P2O5, Li2CO3 for Li2O, NiO for NiO) constituting the mixture. These precursors are then placed in Platinum Rhodium crucibles in order to avoid having parasitic diffusion of elements as in the case of alumina crucibles (diffusion of aluminum).

[0172] The cast iron bath is obtained by subjecting the mixture of precursor powders to a specific heat treatment ([Fig.l]) allowing the elimination of the chemical species from the precursors (CO2, H2O and NH3), in particular between 150°C and 220°C for the moles of NH3 and at 800°C for 2 hours for the moles of CO2.

[0173] The reaction equations being as follows:

[0174] (NH4)2HPO4(s) NH4H2PO4(s)+ NH3(g)

[0175] Li2CO3 + 2 (NH4H2PO4) + NiO [CO2(g)+ 2 NH3(g) + 3 H2O(g)] + Li2O + P2O5 + NiO

[0176] The raw material (without further heat treatment such as stabilization annealing) is then analyzed to determine its real chemical composition, its amorphous character as well as its microstructural and elemental homogeneity.

[0177] Initially, analyses by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) as well as measurements by Energy Dispersive X-ray Spectroscopy (EDX) made it possible to determine the actual composition of the sample.

[0178] The amorphous character of the material was verified and confirmed by X-ray powder diffraction.

[0179] Firstly, the microstructural homogeneity of the glass was confirmed by Scanning Electron Microscopy (SEM) by acquiring backscattered electron images from a polished section of the raw material. By coupling with an Energy Dispersive X-ray Spectroscopy (EDX) detector, it was possible to perform spotting to quantify the elements present in the sample, confirming the chemical composition.

[0180] Elemental distribution maps were then obtained, thus making it possible to verify and confirm the homogeneity of the distribution of the elements within the sample.

[0181] The glass is then ground for 3 min at 30 Hz using a vibrating mill (Retsch MM400) in order to be shaped into a button cell for electrochemical characterization.

[0182] Example 2: Electrochemical characterizations of the lithiated glasses of the invention • Preparation of the electrodes#

[0183] Firstly, an intimate mixture of active material / carbon black (Super Carbon C65) in the mass proportions 70 / 25 was prepared using an energetic mill (planetary mill PM 100) in the dry process. The grinding protocol lasts a total of 6 hours at 300 rpm, alternating 5 minutes of grinding and 5 minutes of rest (in order to avoid local heating which could lead to potential devitrification / crystallization), i.e. 3 hours of effective grinding. Then, the powder resulting from the grinding is characterized by X-ray diffraction to ensure that the amorphous character of the glass / carbon mixture is maintained.

[0184] The glass / carbon powder (i.e. composite material) obtained is then mixed with 5% by mass of polymer binder (solution of 10% by mass of Polyvinylidene Fluoride (PVDF) diluted in N-Methyl-2-Pyrrolidone (NMP)). An additional addition of solvent (NMP) is subsequently added in order to obtain an ink of acceptable viscosity for coating. This ink, consisting of a dispersion of composite particles in PVDF and NMP, is mechanically stirred (for 15 minutes at 1000 rotations per minute) using a mechanical disperser (Dispermat). The latter allows in particular to homogenize the dispersion and to disperse the composite aggregates formed during the grinding step. The ink is then coated by the “doctor blade” method (coating table with slit blade set at 100 pm) on an aluminum sheet, then dried for 24 hours at 60°C in air to remove the residual solvent (the NMP).

[0185] After drying, the electrode obtained is cut into 14 mm diameter discs, which are then pressed under a pressure of 10 tonnes. The mass of the pellets and their thicknesses were measured. The pellets are then dried under vacuum for 48 hours at 80°C in order to remove residual water. Finally, the electrodes are transferred to a glove box ([H2O] < 3 ppm, [O2] < Ippm), in order to be mounted in button cells. • Production of button batteries#

[0186] The electrodes are mounted in a so-called half-button cell configuration (CR2032 type format), in a glove box, in a Li-metal or Na-metal or K-metal configuration. The electrodes are arranged in a cover, inside which an insulating seal is affixed. Two separators are added to the electrode to be tested: a Viledon felt serving as an electrolyte reservoir, and a Celgard microporous separator preventing sodium dendritic growth. In the case of a K-ion battery, only one separator, the Whatmann, was used. A volume of 150 pL of electrolyte is added to the propipette. Then, the counter-electrode, a metal foil (Li, Na or K) deposited on a stainless steel shim, is affixed above the separators. A spring is added to the counter-electrode, then the half-button cell is closed with a small cover and crimped.

[0187] Depending on the configuration, the three electrolytes used are: Li-metal: IM of LiPF6 in EC:DMC:EMC (1:1:1 vol.) Na-metal: IM of NaPF6 in EC:DMC (50%voi.:50%voi.) + 2%mass. of FEC K-metal: 0.7M of KPF6 in EC:DEC (50%voL:50%voi.) + 2%mass. of VC • Galvanostatic cycling#

[0188] The performance of the battery thus obtained is evaluated with an ARBIN type test bench. The batteries are typically cycled at the C / 100 rate, at room temperature, with a potential window between 1.5V and 4.5V. The cycling tests are then initiated either in the charging configuration (extraction of lithium from the glass structure) or in discharge (insertion of lithium into the glass structure). • Examples of galvanosatic cycling curves#

[0189] Since the glass contains lithium, the battery is initially put into charging configuration in order to extract the lithium from the glass structure.

[0190] A galvanostatic cycling test with a charging start with a terminal at potential of 4.5 V vs Li7Li.

[0191] Figures 2 to 4 show examples of galvanosatic cycling curves.

Claims

Claims

1. Glass of the following formula (I): x Li2O - y NiO - (100-xy) P2O5 (Io), with: 0 < x < 100 10 < y < 100 40 <x+y < 100.

2. Glass according to claim 1, in which: - 41 < x+y < 100, with in particular 42, 43, 44 or 45 < x+y < 100, and / or - 0.5 < x / y < 2.5 or 3.0 or 4.0, the glass being for example among the following formulas: 31 Li2O - 15 NiO - 54 P2O5; 14 Li2O - 28 NiO - 58 P2O5; 21.5 Li2O - 21.5 NiO - 57 P2O5.

3. A method of preparing a glass according to claim 1 or 2, comprising a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2O5, to obtain said glass.

4. A method according to claim 3, comprising: - a step (i) of quenching a molten mixture (A), which consists of or comprises a source of NiO, the source of Li2O and a source of P2O5, to obtain an intermediate glass; - a step (ii) of crushing the intermediate glass obtained at the end of step (i); - a step (iii) of quenching the crushed intermediate glass obtained at the end of step (ii), previously melted, to obtain the glass according to claim 1 or 2; or wherein step (i) as described in claim 3 is preceded by a step of stirring the mixture (A).

5. A method according to any one of claims 3 to 4, wherein: - the source of NiO comprises or consists of NiO, Ni2O3, and / or NiSO4; - the source of Li2O comprises or consists of Li2CO3, Li2 SO4, and / or LiOH; and / or - the source of P2O5 comprises or consists of (NH4H2PO4, P2O5, (NaPO3)6,, H3PO4, and / or (NH4)2HPO4.

6. Powder consisting of or comprising glass particles as defined in any one of claims 1 to 2, wherein the particles have in particular a size of from 0.1 to 100 pm, in particular from 0.1 to 50 pm.

7. Powder according to claim 6, further comprising an electronically conductive additive, in particular carbon particles, and optionally, a binder.

8. Electrode, in particular positive, in particular for a metal-ion battery or accumulator, comprising a glass according to claim 1 or 2 or a powder according to claim 6 or 7.

9. Process for preparing an electrode, in particular a positive one, in particular for a metal-ion battery or accumulator, said process comprising a step A) of bringing into contact a powder consisting of or comprising glass particles, an electronically conductive additive, in particular carbon particles, and optionally a binder, according to one of claims 6 to 7, with a conductive support.

10. Battery or accumulator comprising an electrode, in particular positive, comprising a glass according to claim 1 or 2 or a powder according to claim 6 or 7, having in particular a theoretical capacity greater than 80 mAh / g.

11. A battery comprising a cell or accumulator according to claim 10.

12. Portable electric system or system adapted for electric mobility, comprising a battery according to claim 11.

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