METHOD OF PRODUCING THE PARTICULATE MATERIAL

Technical Field

[0001] The present invention relates to a method for producing a particulate material for a composite electrode. The present invention further relates to par ticulate materials for composite electrodes of a battery or battery cell, in partic ular to particulate materials obtained by the methods of the invention. The pre sent invention further relates to a composite electrode, in particular a composite cathode, comprising the particulate material, and to a battery cell comprising such a composite electrode, in particular a composite cathode.

Background Art

[0002] Nowadays, batteries comprising a solid state electrolyte (SSE), so- called solid state batteries (SSB) such as solid state lithium-ion (Li-ion) batter ies and solid state lithium-metal batteries, are considered as the next genera- tion battery. Where conventional batteries comprising a liquid electrolyte show limited safety upon use due to the flammability of most liquid electrolytes, solid state batteries are safer in use because the solid electrolyte used in these solid state batteries has a lower flammability.

[0003] Further, in terms of performance, commercially available solid elec- trolytes are close to matching conventionally used liquid electrolytes, especially for lithium sulphide comprising solid electrolytes, such as lithium phosphorus sulphide (U3PS4, in short LPS), which has a high ionic conductivity.

[0004] One drawback of solid state lithium sulphide electrolytes, such as LPS and LPSBr, is their relatively high density of between 1.5 g/cm ³ and 2.0 g/cm ³ , which is significantly higher than that of conventional liquid electrolytes, typically between 0.9 g/cm ³ and 1.1 g/cm ³ . Consequently, for a same energy density (unit: WTi/l), the solid state battery will be heavier than the conventional battery, when the anode and the cathode, in particular the active materials of the anode and the cathode, are identical for both batteries.

[0005] A further drawback of lithium sulphide electrolytes is that they pre sent a thermodynamic narrow electrochemical stability window, between 1.5 V and 2.5 V (vs. Li/Li ⁺ ). Consequently, these solid state electrolytes are sensitive to degradation when high voltage cathode active materials are used. Examples of high voltage cathode active materials are lithium nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO), lithium manganese oxide (LMO) or lithium iron phosphate (LFP).

[0006] A known solution to protect lithium sulphide solid state electrolytes from degradation from high voltage cathode active materials includes the use of a protective coating, such as a coating comprising LiNb03, UTi03, and/or AI2O3, as interface between the cathode active material and the solid state elec trolyte. One disadvantage of the use of a coating is an increase in the cost of the battery, and a more complex manufacturing process.

[0007] Another solution is an encapsulation of the cathode active material.

[0008] WO 97/44840 discloses a composite cathode comprising a sulphur- containing electroactive material, which, when in an oxidized state, comprises a polysulphide moiety -Sm-, wherein m is equal to or higher than 3, wherein the sulphur-containing electroactive material is encapsulated in an electroactive transition metal chalcogenide composition, such as vanadium oxide. The elec troactive transition metal chalcogenide composition retards the transport of an ionic reduction products of the Sulphur-containing electroactive material.

[0009] WO 2009/029746 discloses a solid state battery cathode which is a sintered mixture of an cathode active material, such as a lithium intercalation material, for example lithium tin oxide, an electronically conductive material and a solid ionically conductive material, such as a lithium-based solid state elec trolyte.

[0010] US 2015/0056520 discloses a solid state composite cathode com prising a sintered porous active material, wherein the pores thereof are impreg nated with an amorphous inorganic ionically conductive solid electrolyte. [0011] WO 2013/131005 discloses a composite cathode which is an active material dispersed in an amorphous inorganic ionically conductive metal oxide, which acts as a binder. The amorphous inorganic ion conductive metal oxide comprises lithium, lanthanum, zirconium and oxygen, for example lithium lan thanum zirconium oxide (lithium lanthanum zirconate, Li7La3Zr20i2, in short LLZO).

[0012] Drawbacks/disadvantages of the foregoing methods is that they are often rather complex, and/or may require high temperatures (e.g. for sintering), which may lead to damage of one or more of the components used to make the composite electrode. Further, the use of LLZO as ion conductive material is known to have a lower conductivity, and thus a reduced performance, com pared to sulphur-based ion conductive materials.

Summary of the Invention

[0013] It is an object of the present invention to overcome one or more of the above drawbacks. It is an aim of the invention to provide a method for pro ducing a particulate material for a composite electrode, wherein the method is less complex.

[0014] It is a further aim of the present invention to provide a particulate material for a composite electrode, in particular a composite cathode, wherein the particulate material, when used in an electrode in a battery cell, provides a higher cathode capacity, in particular a cathode capacity higher than the theo retically expected value, in combination with an excellent energy density, and wherein the capacity and energy density are stable over repeated plating/strip ping of the cathode and charging/discharging of the battery cell.

[0015] According to a first aspect of the invention, there is provided a method for producing a particulate material for a composite electrode as dis closed in the appended claims. The method comprises ball milling of an elec trode active component and a first lithium-comprising sulphide compound. [0016] The electrode active component comprises at least one transition metal M. The transition metal M has a pristine oxidation state of 5+ and option ally 4+ and/or 3+.

[0017] Advantageously, the transition metal M is vanadium (V). When the transition metal M is vanadium, it advantageously has a pristine oxidation state of 5+ and optionally 4+.

[0018] Alternatively, the transition metal can be titanium (Ti), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), aluminium (Al), ruthenium (Ru), magnesium (Mg), or cobalt (Co). When the transition metal M is iron, it advan- tageously has a pristine oxidation state of 5+, 4+ and optionally 3+.

[0019] Advantageously, when the transition metal M is vanadium, the elec trode active component comprises V2O5, V2O3, VO, H3V5O7, H2V3O8, or a mix ture of any two or more thereof.

[0020] The first lithium-comprising sulphide compound comprises an ele- ment X, wherein X is P, Ge, Si or Sn.

[0021] An electronically conductive component is added to the electrode active component and the first lithium-comprising sulphide compound, thereby obtaining the particulate material. Preferably, the electronically conductive component comprises a carbon-comprising component. [0022] According to a first embodiment of the first aspect of the invention, the first lithium-comprising sulphide compound advantageously comprises in the pristine state a Li-S-X bond. Advantageously, the first lithium-comprising sulphide compound comprises a LiPS-based component, a LiGePS-based component, a LiSiPS-based component, a LiSnPS-based component, a LiSiSnPS-based component, a LiGeSnPS-based component, or a mixture of any two or more thereof.

[0023] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is Li6PS5Clo.5Bro.5. [0024] According to a second embodiment of the first aspect of the inven tion, the first lithium-comprising sulphide compound comprises U2S and P2S5. Advantageously, the second embodiment of methods of the invention com prises a first ball milling step of the first lithium-comprising sulphide compound, thereby obtaining a second lithium-comprising sulphide compound. Advanta geously, the second lithium-comprising sulphide compound comprises a Li-S- X bond. Advantageously, the second lithium-comprising sulphide compound comprises a LiPS-based component, a LiGePS-based component, a LiSiPS- based component, a LiSnPS-based component, a LiSiSnPS-based compo nent, a LiGeSnPS-based component, or a mixture of any two or more thereof.

[0025] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s.

[0026] The second embodiment advantageously further comprises a sec ond ball milling step of the second lithium-comprising sulphide compound and the electrode active component, thereby obtaining particulate material.

[0027] Advantageously, a solvent, preferably an aromatic or an aliphatic solvent or a mixture thereof, is added during the ball milling step. Example of such an aliphatic solvent is heptane and that of an aromatic solvent is xylene, or mesitylene. A mixture of the latter solvents can also be contemplated.

[0028] According to a second aspect of the invention, there is provided a particulate material for a composite electrode as disclosed in the appended claims. The particulate material comprises an electrode active component, a lithium-comprising sulphide compound, and an electronically conductive com ponent, wherein the particulate material comprises one or more of the following bonds: X-Sx-X, M _y Sz, M _u Xv, wherein x is between 0 and 2, y is between 0 and 2, z is between 0 and 4 and u is between 0 and 2.

[0029] The electrode active component comprises at least one transition metal M. The transition metal M has an oxidation state in the composite of 3+, 4+, 5+, or a mixture of two or more thereof. The lithium-comprising sulphide compound comprises an element X, wherein X is P, Ge, Si or Sn. Preferably, the electronically conductive component comprises a carbon-comprising com ponent.

[0030] Advantageously, the transition metal M is vanadium (V). [0031] Advantageously, the electrode active component comprises V2O5,

V2O3, VO, H3V5O7, H2V3O8, or a mixture of any two or more thereof.

[0032] Advantageously, the lithium-comprising sulphide compound com prises a LiPS-based component, a LiGePS-based component, a LiSiPS-based component, a LiSnPS-based component, a LiSiSnPS-based component, a Li- GeSnPS-based component, or a mixture of any two or more thereof.

[0033] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s. [0034] Advantageously, the particulate material comprises the electrode active component and the lithium-comprising sulphide compound in a ratio of between 0.1 and 0.9, such as between 0.25 and 0.9, preferably between 0.5 and 0.85, more preferably between 0.6 and 0.75, wherein the ratio is expressed as the weight of the electrode active component divided by the sum of the weight of the electrode active component and the weight of the lithium-com prising sulphide compound.

[0035] The particulate material is advantageously obtained by methods of the invention.

[0036] The present invention further provides a composite electrode com- prising the particulate material of the invention. Preferably, the composite elec trode is a composite cathode.

[0037] The present invention further provides a battery cell comprising a composite electrode of the invention, preferably a composite cathode.

[0038] Advantages of the methods of the present invention are, without be- ing limited thereto, that a particulate material is obtained which, when used in a cathode in a battery cell, comprises a surprisingly high cathode capacity and an excellent energy density. Further, this high capacity and energy density val ues remain stable over repeated charging/discharging, and can thus contribute to a prolonged lifetime of the battery cell. Methods of the invention are further less complex than state-of-the-art methods, and exclude the need for any binder materials to be used.

Brief Description of Drawings

[0039] Aspects of the invention will now be described in more detail with reference to the appended drawings, wherein same reference numerals illus trate same features.

[0040] Figure 1 represents schematically the configuration of a typical coin cell.

[0041] Figure 2 represents XPS results for an inventive particulate material.

[0042] Figure 3 represents the energy density values for reference and in ventive battery cells.

Detailed description

[0043] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many dif ferent forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness.

[0044] Methods for producing a particulate material for a composite elec trode according to the first aspect of the invention comprise ball milling of an electrode active component and a first lithium-comprising sulphide compound.

[0045] Advantageously, the electrode active component comprises at least one transition metal M. The transition metal M advantageously has a pristine oxidation state of 5+ and optionally 4+ and/or 3+. The transition metal can be vanadium (V) titanium (Ti), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), aluminium (Al), magnesium (Mg), silver (Ag), gold (Au), cobalt (Co), cop per (Cu), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd) or platinum (Pt). Preferably, the transition metal is vanadium (V). When the transition metal M is vanadium, it advantageously has a pristine oxidation state of 5+ and op tionally 4+. When the transition metal M is iron, it advantageously has a pristine oxidation state of 5+, 4+ and optionally 3+.

[0046] Advantageously, when the transition metal M is vanadium, the elec trode active component comprises V2O5 (pristine oxidation state of 5+), V2O3, VO, H3V5O7, H2V3O8 (pristine oxidation state of 4+ and 5+), or a mixture of any two or more thereof.

[0047] Advantageously, the first lithium-comprising sulphide compound comprises an element X. Advantageously, X is P, Ge, Si or Sn.

[0048] Advantageously, an electronically conductive component is added to the electrode active component and the first lithium-comprising sulphide compound. The electronically conductive component can be added prior, dur ing and/or after the ball milling is carried out. For example, a first portion of the electronically conductive component, or a first electronically conductive com ponent is added prior to performing the ball milling, and a second portion of the electronically conductive component or a second electronically conductive component is added during the ball milling.

[0049] Preferably, the electronically conductive component comprises a carbon-comprising component, such as carbon fibres, carbon nanotubes, par ticulate carbon (e.g. a powder), or a combination of two or more thereof.

[0050] Optionally, an additional component can be added prior to and/or during ball milling. Preferred examples of such an additional component are dopant elements, such as Li, Al, Cu, Fe, Cr, Mn, Sn, Mo, Ni, Sn, Ag, Ru, for example oxides comprising one or more dopant elements.

[0051] Examples of such oxides comprising one or more dopant elements are U2O, L1O2, Mn02, MnCte, Mh2q7, T1O2, TiO, T12O3, Ru02, NiO, N12O3, Cr203, or Cr05. [0052] Optionally, a solvent is added to the electrode active component and the first lithium-comprising sulphide compound. Preferred examples of solvents are heptane, xylene, acetonitrile, mesitylene and mixtures of two or more thereof. When a solvent is added, the ball milling is considered a wet ball mill ing. Advantageously, the solvent is added prior to and/or during the ball milling.

[0053] Advantageously, the ball milling is carried out at a speed between 100 rpm and 1000 rpm, such as between 150 rpm and 750 rpm, preferably between 200 rpm and 600 rpm. The optimal speed for the ball milling depends on, without being limited thereto, the composition and the relative quantities of the components, whether a solvent and/or the electronically conductive com ponent are added, the type of solvent, and the equipment used.

[0054] Advantageously, the ball milling is carried out for a duration between 1 minute and 240 minutes, such as between 5 minutes and 180 minutes, be tween 10 minutes and 150 minutes, preferably between 15 minutes and 120 minutes, for example between 30 minutes and 90 minutes, more preferably between 45 minutes and 75 minutes. The optimal duration for the ball milling depends on, without being limited thereto, the composition and the relative quantities of the components, whether a solvent and/or the electronically con ductive component are added, the type of solvent, the ball milling speed, and the equipment used.

[0055] The inventors have surprisingly discovered that by using an optimal combination of parameters, such as speed and duration, for the mixture of com ponents that undergoes ball milling, a particulate material is obtained which has a surprisingly high energy capacity, in particular an energy capacity significantly higher than the theoretically expected value calculated from the mixture of in dividual components. The inventors have further noticed that the particulate material, when used in a cathode for a battery cell, can be charged and dis charged repeatedly.

[0056] The inventors have further noticed that the individual components, in particular the electrode active component and the lithium-comprising sul phide compound, i.e. the first lithium-comprising sulphide compound for the first embodiment and the second lithium-comprising sulphide compound for the second embodiment, are no longer distinguishable in the particulate material. In other words, and without wishing to be bound by any theory, the components react with each other during the ball milling according to the invention.

[0057] According to a first embodiment of the first aspect of the invention, the first lithium-comprising sulphide compound advantageously comprises in the pristine state a Li-S-X bond. Advantageously, the first lithium-comprising sulphide compound comprises a LiPS-based component, a LiGePS-based component, a LiSiPS-based component, a LiSnPS-based component, a LiSiSnPS-based component, a LiGeSnPS-based component, or a mixture of any two or more thereof.

[0058] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s. Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s.

[0059] Examples of a LiGePS-based component are Li4-aGei- _a PaS4 wherein x is between 0 and 1, and LiioGeP2Si2. Examples of a LiSnPS-based compo nent are LU-aSni- _a PaS4 wherein x is between 0 and 1. Examples of a LiSiPS- based component are LU-aSii-aPaS4 wherein x is between 0 and 1. Examples of a LiSiSnPS-based component are LU-a(Sii-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1. Examples of a LiGeSnPS-based component are LU-a(Gei-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1.

[0060] The electrode active component is advantageously as described above.

[0061] The electronically conductive component is advantageously as de scribed above, and is advantageously added to the electrode active component and the first lithium-comprising sulphide compound as described above. [0062] Optionally, a solvent as described above is added to the electrode active component and the first lithium-comprising sulphide compound as de scribed above.

[0063] Advantageously, the ratio of the electrode active component and the first lithium-comprising sulphide compound is between 0.1 and 0.9, preferably between 0.5 and 0.85, more preferably between 0.6 and 0.75, wherein the ratio is expressed as the weight of the electrode active component divided by the sum of the weight of the electrode active component and the weight of the lith ium-comprising sulphide compound.

[0064] Advantageously, the weight of the electronically conductive compo nent is between 0.5% by weight and 20% by weight based on the sum of the weight of the electrode active component, the first lithium-comprising sulphide compound and the electronically conductive component, such as between 1% by weight and 15% by weight, preferably between 2% by weight and 10% by weight, more preferably between 2.5% by weight and 7.5% by weight, for ex ample between 4% by weight and 6% by weight.

[0065] When a solvent is used, the ratio of the solvent and the electrode active component, the first lithium-comprising sulphide compound and the elec tronically conductive component is advantageously between 0.5 and 4, prefer ably between 0.75 and 3, more preferably between 1 and 2, wherein the ratio is expressed as the weight of the solvent divided by the sum of the weight of the electrode active component, the first lithium-comprising sulphide compound and the electronically conductive component when added prior to or during ball milling.

[0066] A second embodiment of the first aspect of the invention differs from the first embodiment in that the first lithium-comprising sulphide compound comprises U2S and P2S5 and in that a first ball milling step of the first lithium comprising sulphide compound comprising U2S and P2S5 is performed, thereby obtaining a second lithium-comprising sulphide compound. The first ball milling can be performed at a speed and for a duration as described in European pa tent EP 2988360. [0067] The second lithium-comprising sulphide compound advantageously has the same composition of the first lithium-comprising sulphide compound of the first embodiment. Advantageously, the second lithium-comprising sulphide compound comprises a Li-S-X bond. Advantageously, the second lithium-com prising sulphide compound comprises a LiPS-based component, a LiGePS- based component, a LiSiPS-based component, a LiSnPS-based component, a LiSiSnPS-based component, a LiGeSnPS-based component, or a mixture of any two or more thereof.

[0068] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s. Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s.

[0069] Examples of a LiGePS-based component are Li4-aGei- _a PaS4 wherein x is between 0 and 1, and LiioGeP2Si2. Examples of a LiSnPS-based compo nent are LU-aSni- _a PaS4 wherein x is between 0 and 1. Examples of a LiSiPS- based component are LU-aSii-aPaS4 wherein x is between 0 and 1. Examples of a LiSiSnPS-based component are LU-a(Sii-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1. Examples of a LiGeSnPS-based component are LU-a(Gei-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1.

[0070] The second embodiment further comprises a second ball milling step of the electrode active component and the second lithium-comprising sul phide compound. Advantageously, the second ball milling step is performed according to the ball milling of the first embodiment in terms of duration and speed.

[0071] The electrode active material is advantageously as described above. [0072] Advantageously, the electrode active component and the second lithium-comprising sulphide compound are present in the second ball milling step in a ratio of between 0.1 and 0.9, preferably between 0.5 and 0.85, more preferably between 0.6 and 0.75, wherein the ratio is expressed as the weight of the electrode active component divided by the sum of the weight of the elec trode active component and the weight of the lithium-comprising sulphide com pound.

[0073] The electronically conductive component is advantageously as de scribed above. The electronically conductive component can be added to the first lithium-comprising sulphide compound prior to and/or during the first ball milling step, and/or to the second lithium-comprising sulphide compound prior to, during and/or after the second ball milling step.

[0074] When the electronically conductive component is added to the first lithium-comprising sulphide compound, the weight of the electronically conduc tive component is between 0.5% by weight and 20% by weight based on the sum of the weight of the first lithium-comprising sulphide compound and the electronically conductive component, such as between 1% by weight and 15% by weight, preferably between 2% by weight and 10% by weight, more prefer ably between 2.5% by weight and 7.5% by weight, for example between 4% by weight and 6% by weight.

[0075] When the electronically conductive component is added to the sec ond lithium-comprising sulphide compound and thus also to the electrode ac tive compound, the weight of the electronically conductive component is be tween 0.5% by weight and 20% by weight based on the sum of the weight of the electrode active material, the second lithium-comprising sulphide com pound and the electronically conductive component, such as between 1% by weight and 15% by weight, preferably between 2% by weight and 10% by weight, more preferably between 2.5% by weight and 7.5% by weight, for ex ample between 4% by weight and 6% by weight. [0076] Optionally, a solvent as described above is added prior to and/or during the first ball milling. Optionally, a solvent as described above is added prior to and/or during the second ball milling.

[0077] When a solvent is added to the first lithium-comprising sulphide com- pound and to the second lithium-comprising sulphide compound, the solvents are advantageously the same. Alternatively, a first solvent can be added to the first lithium-comprising sulphide compound and a second solvent can be added to the second lithium-comprising sulphide compound.

[0078] When a solvent is added to the first lithium-comprising sulphide com- pound, the ratio of the solvent and the first lithium-comprising sulphide com pound and the electronically conductive component when added to the first lithium-comprising sulphide compound is advantageously between 0.5 and 1.5, preferably between 0.75 and 1.25, more preferably between 0.9 and 1.1, wherein the ratio is expressed as the weight of the solvent divided by the sum of the weight of the the first lithium-comprising sulphide compound and, when added to the first lithium-comprising sulphide compound, the electronically con ductive component.

[0079] When a solvent is added to the second lithium-comprising sulphide compound, the ratio of the solvent and the electrode active component, the second lithium-comprising sulphide compound and the electronically conduc tive component when added to the electrode active component and the second lithium-comprising sulphide compound is advantageously between 0.5 and 4, preferably between 0.75 and 3, more preferably between 1 and 2, wherein the ratio is expressed as the weight of the solvent divided by the sum of the weight of the electrode active material, the second lithium-comprising sulphide com pound and, when added, the electronically conductive component.

[0080] A third embodiment of the first aspect of the invention differs from the second embodiment in that the first ball milling step and the second ball milling step are combined in one ball milling step. In other words, the method comprises ball milling of an electrode active component as described above and a first lithium-comprising sulphide compound comprising U2S and P2S5. [0081] The ball milling is advantageously performed at a speed and/or for a duration as described above.

[0082] An electronically conductive component as described above is ad vantageously added as described in the first embodiment.

[0083] A solvent as described above can be added as described in the first embodiment.

[0084] A second aspect of the present invention discloses a particulate ma terial for a composite electrode. The particulate material comprises an elec trode active component, a lithium-comprising sulphide compound, and an elec tronically conductive component, wherein the particulate material comprises one or more of the following bonds: X-Sx-X, M _y Sz, M _u Xv, wherein x is between 0 and 2, y is between 0 and 2, z is between 0 and 4 and u is between 0 and 2.

[0085] The electrode active component comprises at least one transition metal M having an oxidation state in the particulate material of 3+, 4+, 5+, or a mixture of two or more thereof. Advantageously, the transition metal is as de scribed above, and is preferably vanadium (V). Advantageously, the electrode active component comprises V2O5, V2O3, VO, H3V5O7, H2V3O8, or a mixture of any two or more thereof.

[0086] The lithium-comprising sulphide compound comprises an element X, wherein X is P, Ge, Si or Sn. Advantageously, the lithium-comprising sul phide compound comprises a LiPS-based component, a LiGePS-based com ponent, a LiSiPS-based component, a LiSnPS-based component, a LiSiSnPS- based component, a LiGeSnPS-based component, or a mixture of any two or more thereof.

[0087] Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s. Examples of a LiPS-based component are L13PS4 (LPS), LiePSsY (LPSY) wherein Y is Cl, Br or I, LiePSsYo.sZo.s wherein Y and Z are different and wherein Y and Z are Cl, Br or I, and LiyPsSn. An example of LiePSsYo.sZo.s is LiePSsClo.sBro.s. [0088] Examples of a LiGePS-based component are Li4-aGei- _a PaS4 wherein x is between 0 and 1, and LiioGeP2Si2. Examples of a LiSnPS-based compo nent are LU-aSni-aPaS4 wherein x is between 0 and 1. Examples of a LiSiPS- based component are LU-aSii-aPaS4 wherein x is between 0 and 1. Examples of a LiSiSnPS-based component are Li4-a(Sii-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1. Examples of a LiGeSnPS-based component are LU-a(Gei-bSnb)i-aPaS4 wherein x is between 0 and 1 and b is between 0 and 1.

[0089] Advantageously, the electronically conductive component is as de scribed above. Preferably, the electronically conductive component comprises a carbon-comprising component, such as carbon fibres or carbon nanotubes.

[0090] Advantageously, the particulate material comprises the electrode active component and the lithium-comprising sulphide compound in a ratio of between 0.1 and 0.9, preferably between 0.5 and 0.85, more preferably be tween 0.6 and 0.75, wherein the ratio is expressed as the weight of the elec trode active component divided by the sum of the weight of the electrode active component and the weight of the lithium-comprising sulphide compound.

[0091] Preferably, the particulate material is obtained by methods of the present invention.

[0092] The inventors have noticed that in particulate materials of the inven tion, in particular particulate materials obtained by methods of the invention, two or more components of the particulate material are no longer individually distinguishable. In particular, the electrode active component and the lithium comprising sulphide compound are not distinguishable in the particulate mate rial, which indicates that reaction between these components takes place dur ing production of the particulate material, thereby forming bonds between the components.

[0093] In particular, when the transition metal is vanadium, the presence of oxidation states in the particulate material of 3+, 4+, 5+ indicates that a chem ical reaction took place between the electrode active component and another component. [0094] The inventors have surprisingly discovered that particulate materials obtained by methods of the present invention have a surprisingly high energy capacity, in particular an energy capacity significantly higher than the theoreti cally expected value calculated from the mixture of individual components. The inventors have further noticed that the particulate material, when used in a cath ode for a battery cell, can be charged and discharged repeatedly.

[0095] The present invention further discloses a composite electrode com prising the particulate material. Preferably, the electrode is a cathode, i.e. a composite cathode comprising the particulate material. Advantageously, the cathode consists of the particulate material.

[0096] The present invention further discloses a battery or battery cell com prising such a composite electrode, preferably such a composite cathode.

[0097] Fig. 1 represents an exemplary embodiment of a battery cell 10. The battery cell 10 has a coin-cell configuration known in the art as a CR2032 type configuration. The battery cell 10 comprises an anode 11 and a cathode 12. The cathode 12 is an electrode according to the present invention. The battery cell 10 further comprises a solid state electrolyte 13 between the anode 11 and the cathode 12. The anode can for example be a graphite-based anode. Ad vantageously, the battery cell 10 further comprises a coin cell lid 14, a coin cell base 15, a spacer 16 and a spring 17. The spacer 16 and the spring 17 provide good contact between the other components 11, 12, 13, 14, 15 of the battery cell 10.

[0098] The solid state electrolyte may be a solid polymer or a solid inorganic material, such as a solid inorganic glass or a ceramic material, for example a garnet material. For example, the solid state electrolyte may be a lithium sul phide solid state electrolyte, preferably U3PS4 or LiePSsBr, or may be polyeth ylene oxide) (PEO) with lithium salts dispersed in the polymer matrix of the PEO. Alternatively, the solid state electrolyte may be a garnet ceramic, such as a lithium-stuffed garnet material, for example lithium lanthanum zirconium ox ide (Li7La3Zr20i2, abbreviated as LLZO). [0099] The solid state electrolyte can be the same as the lithium-comprising sulphide compound of the particulate material comprised in the cathode.

Examples

Comparative example 1

[00100] A first reference cathode was made by ball milling of 6.9 g of lithium nickel manganese cobalt oxide (LiNiMnCo02), abbreviated as NMC, as the electrode active component, 2.6 g of lithium phosphorus sulphide (U3PS4), ab breviated as LPS, as the first lithium-comprising sulphide compound and 0.5g ofVGCF (vapour grown carbon fibres, manufactured by Showa Denko) as elec tronically conductive component in 20 g of heptane as solvent. The ball milling was performed using a ball mill equipment (Fritsch, P6) at 500 rpm for 1 hour, using 1058 g of 4 mm diameter zirconia balls. The obtained mixture was then pressed into a pellet at a pressure of 100 MPa to make a cp10 mm x 90 pm cathode. A battery cell according to Fig. 1 was made with the first reference cathode, LPS as solid state electrolyte and InLi (Indium-Lithium alloy) as an ode. The battery cells were sealed with a pneumatic press using a pressure of 80 MPa.

Comparative example 2

[00101] A second reference cathode was made by mixing 6.9 g of V2O5 as the electrode active component, 2.6 g of lithium phosphorus sulphide (L13PS4), abbreviated as LPS, as the first lithium-comprising sulphide compound and 0.5g of VGCF (Showa Denko) as electronically conductive component in 20 g of heptane as solvent. The mixing was performed by hand in a mortar for 15 minutes. The obtained mixture was then pressed into a pellet at a pressure of 500 MPa to make a cp10 mm x 90 pm cathode. A battery cell was made as described in comparative example 1 using the second reference cathode. Example 1

[00102] Four cathodes according to the invention were made using varying amounts of V2O5 as the electrode active component and LPS as the first lith ium-comprising sulphide compound. Table 1 shows the composition of the cathodes, wherein example 1-1 to example 1-4 refer to the four cathodes of this example. The total amount of V2O5 and LPS was kept constant at 9.5 g, as well as the amount and type of the electronically conductive component (0.5g of VGCF (Showa Denko)) and the solvent (20 g heptane). Examples 1-5 and 1-6 are the cathodes as obtained in example 1-1 wherein 20 g of heptane as solvent is replaced with 20 g of xylene and 20 g of mesitylene respectively.The ball milling was performed as described in comparative example 1. Four battery cells were made as described in comparative example 1 using the inventive cathodes.

Example T

[00103] Four cathodes according to the invention were made using varying amounts of V2O5 and NiO as the electrode active component and LPS as the first lithium-comprising sulphide compound. Table 1 shows the composition of the cathodes, wherein example T-1 to example T-4 refer to the four cathodes of this example. The total amount of V2O5, NiO and LPS was kept constant at 9.5 g, as well as the amount and type of the electronically conductive compo nent (0.5g of VGCF (Showa Denko)) and the solvent (20 g heptane). Example T-5 is the cathode as obtained in example T-1 wherein 20 g of heptane as solvent is replaced with 20 g of mesitylene or xylene. The ball milling was per formed as described in comparative example T. Four battery cells were made as described in comparative example 1 using the inventive cathodes.

Example 1”

[00104] Four cathodes according to the invention were made using varying amounts of V2O5 and Mn02 as the electrode active component and LPS as the first lithium-comprising sulphide compound. Table 1 shows the composition of the cathodes, wherein example 1”-1 to example 1”-4 refer to the four cathodes of this example. The total amount of V2O5, MnC and LPS was kept constant at 9.5 g, as well as the amount and type of the electronically conductive com ponent (0.5g of VGCF (Showa Denko)) and the solvent (20 g heptane). Exam ple 1”-5 is the cathode as obtained in example 1”-1 wherein 20 g of heptane as solvent is replaced with 20 g of mesitylene or xylene. The ball milling was performed as described in comparative example 1. Four battery cells were made as described in comparative example 1 using the inventive cathodes.

Example T”

[00105] Four cathodes according to the invention were made using varying amounts of V2O5 and Mh2q3 as the electrode active component and LPS as the first lithium-comprising sulphide compound. Table 1 shows the composition of the cathodes, wherein example 1”’-1 to example 1”’-4 refer to the four cath odes of this example. The total amount of V2O5, Mh2q3 and LPS was kept con stant at 9.5 g, as well as the amount and type of the electronically conductive component (0.5g of VGCF (Showa Denko)) and the solvent (20 g heptane). Example 1”’-5 is the cathode as obtained in example 1”’-1 wherein 20 g of heptane as solvent is replaced with 20 g of mesitylene or xylene. The ball mill ing was performed as described in comparative example 1. Four battery cells were made as described in comparative example 1 using the inventive cath odes.

Example 2

[00106] Four cathodes according to the invention were made using varying amounts of V2O5 as the electrode active component and LiePSsBr as the first lithium-comprising sulphide compound. Table 1 shows the composition of the cathodes, wherein example 2-1 to example 2-4 refer to the four cathodes of this example. The total amount of V2O5 and LiePSsBr was kept constant at 9.5 g, as well as the amount and type of the electronically conductive component (0.5g of VGCF (Showa Denko)) and the solvent (20 g heptane). The ball milling was performed as described in comparative example 1. Four battery cells were made as described in comparative example 1 using the inventive cathodes, and using LiePSsBr as solid state electrolyte.

Table 1

Example 3

[00107] The performance of the battery cells was measured by measuring the cathode capacity, the average voltage and the energy density by means of a biologic VMP-300 potentiostat, and by comparing the measured cathode ca- pacity with the theoretical cathode capacity.

[00108] Table 2 shows the values of the theoretical capacity, the cathode capacity, the average voltage and the energy density for each of the two refer ence battery cells (“Comparative 1” and “Comparative 2”) and for each of the battery cells according to the invention. [00109] The theoretical capacity, expressed in mAh per gram of electrode active component, is the cathode capacity value calculated based on the com ponents used to make the cathode, assuming a mixture of these components without any interaction or reacting taking place between two or more compo nents. [00110] The measured capacity is the cathode capacity as measured. Table 2 cathodes prepared using mesitylene and xylene.

[00111] From Table 1 it is clear that for the reference battery cell comprising NMC as electrode active component in the cathode (“Comparative 1”), the measured cathode capacity is the same as the theoretical cathode capacity. Also the reference battery cell comprising V2O5 as electrode active component in the cathode, the cathode being made form a particulate material obtained by hand mixing (“Comparative 2”) has a measured cathode capacity that equals the theoretical cathode capacity. [00112] However, all battery cells comprising a cathode comprising a partic ulate material obtained by ball milling according to the invention have a meas ured cathode capacity that is higher than the theoretical capacity. When com paring the second reference battery cell (“Comparative 2”) with the battery cell having a cathode obtained from the same starting composition (type and mass of each component) (“Example 1-4”) it is clear that the measured cathode ca pacity is significantly higher when the particulate material used to make the cathode is obtained by means of ball milling.

[00113] These higher values are obtained because during ball milling new bonds are formed between the electrode active component and the lithium- comprising sulphide compound, leading to a particulate material having im proved properties [00114] Fig. 2 shows the X-ray Photoelectron Spectroscopy (XPS) results for V2O5, LPS and the particulate material obtained by ball milling of the com ponents used for Example 1-2. It is clear the presence of Li-S-P bonds in LPS is confirmed. However, in the particulate material obtained by ball milling, not only the Li-S-P bond is identified, but also P-Sx-P bonds or V _x S _y bonds and VxPy bonds. The P-Sx-P (sulphur bridging) or V _x P _y bonds result from the chem ical reaction of the LPS with V2O5.

[00115] Further, the measured cathode capacity expressed per gram of electrode material increases with an increasing ratio of electrode active com- ponent in the electrode.

[00116] From Table 2 it follows also that the values for the battery cells com prising LiePSsBr as the lithium-comprising sulphide compound and as the solid state electrolyte are higher than for the battery cells comprising LPS as the lithium-comprising sulphide compound and as the solid state electrolyte (Ex- amples 2-1 to 2-4 vs. Examples 1-1 to 1-4, respectively).

[00117] Fig. 3 shows the measured energy density for the battery cells. It is clear that the cathode of the battery cell obtained from the same starting mix ture that is ball milled (Example 1-4) instead of hand mixed shows not only a higher energy density than the hand mixed sample (Comparative example 2), but also shows a higher energy density than the ball milled NMC reference sample (Comparative example 1).