Method for synthesis of carbon-coated redox materials with controlled size

• US 20040033360A1
• Filed: 06/19/2003
• Published: 02/19/2004
• Est. Priority Date: 09/26/2000
• Status: Active Grant

• Current Assignee: Centre National De La Recherche Scientifique, Hydro-Quebec (Province of Québec), Universite De Montreal, L'
• Original Assignee: Centre National De La Recherche Scientifique, Hydro-Quebec (Province of Québec), Universite De Montreal, L'
• Inventors: Ravet, Nathalie, Armand, Michel, Magnan, Jean-Francois, Gauthier, Michel
• Granted Patent: US 7,601,318 B2
• Time in Patent Office: Days
• US Class Current: 428/408
• CPC Class Codes: C01B 17/96 Methods for the preparation of sulfates in general particular individual sulfates, see the relevant groups of subclasses C01B - C01G, according to the cation
• CPC Class Codes: C01B 25/37 Phosphates of heavy metals
• CPC Class Codes: C01B 25/45 containing plural metal, or metal and ammonium
• CPC Class Codes: C01B 33/20 Silicates persilicates C01B15/14 ; containing aluminium C01B33/26
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: H01G 11/02 using combined reduction-oxidation reactions, e.g. redox arrangement or solion
• CPC Class Codes: H01G 11/46 Metal oxides
• CPC Class Codes: H01G 11/50 specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
• CPC Class Codes: H01G 11/86 specially adapted for electrodes carbonisation or activation of carbon for the manufacture of electrodes H01G11/34
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2991 : Coated
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A method for the synthesis of compounds of the formula C—Li_xM_1−yM′_y(XO₄)_n, where C represents carbon cross-linked with the compound Li_xM_1−yM′_y(XO₄)_n, in which x, y and n are numbers such as 0≦x≦2, 0≦y≦0.6, and 1≦n≦1.5, M is a transition metal or a mixture of transition metals from the first period of the periodic table, M′ is an element with fixed valency selected among Mg²⁺, Ca²⁺, Al³⁺, Zn²⁺ or a combination of these same elements and X is chosen among S, P and Si, by bringing into equilibrium, in the required proportions, the mixture of precursors, with a gaseous atmosphere, the synthesis taking place by reaction and bringing into equilibrium, in the required proportions, the mixture of the precursors, the procedure comprising at least one pyrolysis step of the carbon source compound in such a way as to obtain a compound in which the electronic conductivity measured on a sample of powder compressed at a pressure of 3750 Kg.cm⁻² is greater than 10⁻⁸ S.cm⁻¹. The materials obtained have excellent electrical conductivity, as well a very improved chemical activity.

Claims

1. A method for the synthesis of compounds of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, wherein C represents carbon cross-linked with the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n in which x, y and n are numbers such as 0≦

x≦

2.0≦

y ≦

0.6, and 1≦

n≦

1.5, M is a transition metal or a mixture of transition metals from the first line of the periodic table, M′

is an element with fixed valency selected among Mg²⁺, Ca²⁺, Al³⁺, Zn²⁺ or a combination of these same elements and X is chosen from among S, P and Si,

by bringing into equilibrium, in the required proportions, a mixture (preferably intimate and/or homogeneous) comprising at least;

a) a source of M, at least one part of the said transition metal or metals that constitutes M being in an oxidation state greater or less than that of the metal in the final compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n;

b) a source of an element M′

;

c) a compound that is a source of lithium; and

d) possibly a compound that is a source of X,

e) a source of carbon, called carbon conductor

the sources of the elements M, M′

, Li and X may be introduced or not, in whole or in part, in at least one step, in the form of compounds having more than one source element, and

the synthesis being carried out by thermodynamic or kinetic reaction and bringing into equilibrium, in the required proportions, the mixture of the source compounds (also called precursors) a) to d), with a gaseous atmosphere, in such a way as to cause an oxidation state of the transition metal to the desired valency (preferably, this valency is equal to two for iron, manganese, cobalt and nickel, and three or four for titanium and vanadium) for the forming of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, by controlling the composition of the said gaseous atmosphere, the temperature of the synthesis reaction step. and the amount of the source compound c) relative to the other source compounds a), b) and d);

a method comprising at least one pyrolysis step of the source compound e) such as to obtain a compound whose electronic conductivity, measured on a sample of powder compressed at a pressure greater than or equal to 3000, preferably 3750 Kg.cm<sup>−

2</sup>, is greater than 10<sup>−

8</sup> S.cm<sup>−

1</sup>.

2. A method according to claim 1, in which the synthesis reaction between the source compounds a) to d) is carried out simultaneously with the pyrolysis reaction of the source compound e).

3. A method according to claim 1, in which the pyrolysis reaction is carried out in a second step, consecutive to the synthesis reaction between the source compounds a) to d) and preferably in reducing or neutral gas atmosphere.

4. A method according to any one of claims 1 to 3, in which compounds of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n are obtained in the form of particles in which the size and/or the shape of the particles of compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is essentially determined by the size and the shape of the intimate and/or homogeneous mixture of the precursors used for the synthesis reaction, and more specifically by the size and/or the shape of the initial precursors M and M′

.

5. A method according to claim 4. in which the size of the particles of compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n obtained is between 0.1 and 10 micrometers.

6. A method according to claim 5. in which the size and the shape of the particles of the compound C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n do not differ by more than 80% from that of the size of precursors a) to d), preferably in which the size and the shape of the particles of compound C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n do not differ by more than 80% from that of precursor a) and if necessary. from that of precursor b).

7. A method according to any one of claims 1 to 6, in which the amount of carbon-source compound (called carbon conductor) is chosen in such a way as to coat at least a part of the surface of the particles of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n with carbon.

8. A method according to claim 7. in which the amount of bound carbon is less than 5%, preferably less than 3%, of the mass of the compounds of formula Li_xM₁₋

yM′

_y(XO₄)_n.

9. A method according to claim 7 or 8, in which at least 30% of the surface of the particles of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n is covered with carbon.

10. A method according to any one of claims 1 to 4, in which the amount of carbon conductor source compound in the reaction medium is chosen in such a way as to bond the particles of compound Li_xM₁₋

yM′

_y(XO₄)_n with each other and to constitute agglomerates with sizes comprised between 1 and 20 microns.

11. A method according to claim 10, in which the amount of bound carbon is less than 7%, preferably less than 3%, of formula Li_xM₁₋

yM′

_y(XO₄)_n.

12. A method according to any one of claims 1 to 4, in which the final form of the compound C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n is determined by the form given to the mixture of precursors a) to d) before synthesis.

13. A method according to claim 12, in which the technique used to give a specific form to the mixture of precursors is chosen from among the techniques of spray-drying, precipitation, coprecipitation, agglomeration and/or pelletization.

14. A method according to claim 13, in which the technique used to give a specific form to the mixture of precursors is spray-drying, and the final form of the compound C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n that is obtained is spherical agglomerates with sizes comprised between 1 and 30 micrometers, said agglomerates being made up of smaller particles of the compound of C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n.

15. A method according to any one of claims 1 to 14, in which the organic substance that is the source of the carbon conductor is selected from the group constituted by polymers and oligomers containing a carbon skeleton, simple carbohydrates or polymers and the aromatic hydrocarbons.

16. A method of synthesis according to any one of claims 1 to 14, in which the carbon conductor source contains, in the same compound or in the mixture that constitutes this source, oxygen and hydrogen that are bound chemically and from which pyrolysis locally releases carbon monoxide and/or carbon dioxide and/or hydrogen and water vapor that contributes, in addition to depositing carbon, to creating locally the reducing atmosphere required for synthesis of the material Li_xM₁₋

yM′

_y(XO₄)_n.

17. A method according to any one of claims 1 to 16, in which the carbon conductor source compound is mainly constituted by a block copolymer comprising at least one carbon source segment that can be pyrolyzed and a segment that is soluble in water and organic solvents in such a way as to allow its distribution, preferably homogeneously, throughout the compound Li_xM₁₋

yM′

_y(XO₄)_n or its precursors.

18. A method of synthesis according to any one of claims 15 to 17, in which the organic carbon conductor source substance is at least one of the compounds of the group made up of polyethylene, polypropylene, glucose, fructose, sucrose, xylose, sorbose, starch, cellulose and its esters, block polymers of ethylene and ethylene oxide and polymers of furfuryl alcohol.

19. A method according to claims 1 to 18, in which the source compounds a) to d) are in the form of powder or at least partially compressed in the form of pastilles, prior to the synthesis (preferably carried out in continuous mode), in such a way as to increase the points of contact between the reagents and to increase the density of the final product while allowing the reaction with the gaseous phase.

20. A method of synthesis according to any one of claims 1 to 19, in which the carbon conductor source compound is present at the time of the compacting step for the compounds a) to d).

21. A method according to any one of claims 1 to 20, in which the method is carried out continuously, preferably in a reactor that promotes the equilibrium of solid powders, agglomerated or not, with the gaseous phase, e.g. from among those reactors, rotary kilns, fluidized beds, belt-driven kilns, that allow control of the composition and the circulation of the gaseous atmosphere.

22. A method according to claim 21. in which the solid feed is greater than 1 kg/h, the temperatures are preferably between 650 and 800 degrees Celsius, the dwell time is preferably less than 5 hours. and even more preferably less than ½

hour.

23. Method of synthesis according to any one of claims 1 to 22, in which the reduction is obtained by the action of a reducing atmosphere chosen in such a way as to be able to reduce the oxidation state of the metallic ion M to the level required for the composition of the compound without reducing it to the neutral metallic state.

24. Method of synthesis according to claim 23, in which the reducing atmosphere contains hydrogen or a gas that is capable of generating hydrogen under the synthesis conditions, ammonia or a substance capable of generating ammonia under the synthesis conditions or carbon monoxide, these gases being used in their pure state or in mixtures and it also being possible to use them in the presence of water vapor and/or in the presence of carbon dioxide and/or in the presence of a neutral gas (such as nitrogen or argon).

25. Method of synthesis according to claim 23, in which the reducing atmosphere is made of a mixture of CO/CO₂ or H₂/H₂O, NH₃/H₂O or a mixture of them, generating an oxygen equilibrium pressure less than or equal to that determined by the transition metal at the state of oxidation corresponding to the precursors introduced to form the compound Li_xM₁₋

yM′

_y(XO₄)_n, but greater than that corresponding to the reduction of any one of the transition elements present in the metallic state, ensuring the thermodynamic stability of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n in the reaction mixture, independently of the synthesis reaction time.

26. Method of synthesis according to claim 23, in which the gaseous atmosphere is made of a mixture of CO/CO₂ or H₂/H₂O, NH₃/H₂O or a mixture of them, generating an oxygen equilibrium pressure greater than or equal to that determined by at least the transition elements, when the precursor is introduced in the metallic form. to form the compound Li_xM₁₋

yM′

_y(XO₄)_n, but greater than that corresponding to a superoxidation of the transition elements beyond their assigned valence in Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, insuring the thermodynamic stability of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n in the reaction mixture, independently of the synthesis reaction time.

27. Method of synthesis according to claim 23, in which the reducing atmosphere is made up of a mixture of CO/CO₂, H₂/H₂O, NH₃/H₂O or a mixture of them, generating an oxygen equilibrium pressure less than or equal to that determined by one of the transition metals present in Li_xM₁₋

yM′

_y(XO₄)_n, possibly being able to lead to the reduction of at least this transition element to the metallic state, the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, being obtained by controlling the temperature and the contact time with the gaseous phase or the proportion of the precursor c) in the reaction mixture;

the synthesis temperature preferably being comprised between 200 and 1200°

C., still more preferably between 500 and 800°

C. and the time of contact between the reaction mixture and the gaseous phase preferably being comprised between 2 minutes and 5 hours and still more preferably between 10 and 60 minutes.

28. Method according to any one of claims 23 to 27, in which the gaseous reducing atmosphere is obtained by decomposition, in a vacuum or in an inert atmosphere, of an organic compound or of a mixture of organic compounds containing at least hydrogen and oxygen, bound chemically, and of which the pyrolysis generates carbon monoxide and/or a mixture of carbon dioxide and monoxide, of hydrogen and/or a mixture of hydrogen and water vapor that is able to carry out the reduction that leads to the formation of the compound Li_xM₁₋

yM′

_y(XO₄)_n.

29. A method of synthesis according to claims 23 to 28, in which the gaseous reducing atmosphere is obtained by partial oxidation by oxygen or by air, of a hydrocarbon and/or of carbon, possibly in the presence of water vapor (preferably water vapor and in an amount between 0.1 and 10 molecules, inclusively, of H₂O per atom of carbon in the hydrocarbon) at an elevated temperature (preferably comprised between 400 and 1200°

C.), making possible the formation of carbon monoxide or hydrogen or of a mixture of carbon monoxide and hydrogen.

30. A method according to any one of claims 1 to 29, in which the gaseous phase is made up of a gas that is reformed in-situ or ex-situ.

31. A method according to claim 30, in which the reformed gas atmosphere is obtained from methane or from propane or from a natural gas or from a mixture of these, with the addition of air and possibly the addition of water vapor or from a mixture of these, at a predetermined partial pressure, by condensation or injection into the reformed mixture.

32. A method according to any one of claims 1 to 31, in which the thermal processing (which includes the formation reaction of Li_xM₁₋

yM′

_y(XO₄)_n and the reduction and pyrolysis and possibly dehydration of one or several of sources a) to d)) is carried out by heating from normal temperature to a temperature between 500 and 1100°

C.

33. A method of synthesis according to claim 32, in which the maximum temperature reached is comprised between 500 and 800°

C.

34. A method of synthesis according to any one of claims 1 to 33, in which the dwell time of the reagents in the thermal processing step is less than 5 hours, preferably less than 1 hour.

35. A method according to any one of claims 1 to 34. in which the electrochemical capacity of the compound Li_xM₁₋

yM′

_y(XO₄)_n, in which n=1, is greater than 150 mAh/g<sup>−

1</sup>, measured for specific intensities greater than 10 mA.g<sup>−

1</sup>.

36. A method of synthesis according to any one of claims 1 to 35. in which the source of M is also the source of X and/or the source of M′

is also the source of X and/or the source of lithium is also the source of X and/or the source of X is also the source of lithium.

37. A method of synthesis according to any one of claims 1 to 36, in which bringing the mixture of precursors a) to d) into equilibrium is carried out in the form of an intimate and/or homogeneous mixture of the solid phase and the gaseous phase.

38. A method of synthesis according to any one of claims 1 to 37, in which the transition metal or metals is (are) chosen at least partially from the group constituted by iron, manganese, cobalt and nickel, the complement for the transition metals preferably being chosen from the group constituted by vanadium, titanium, chromium and copper.

39. A method of synthesis according to any one of claims 1 to 38, in which the compound that is the source of M is in an oxidation state that can vary from 3 to 7.

40. A method of synthesis according to claim 39, in which the compound that is the source of M is iron (III) oxide or magnetite. manganese dioxide. di-vanadium pentoxide. trivalent ferric phosphate, ferric hydroxyphosphate and lithium or trivalent ferric nitrate or a mixture of the latter.

41. A method of synthesis according to any one of claims 1 to 40. in which the compound that is the source of lithium is chosen from the group constituted by lithium oxide or lithium hydroxide, lithium carbonate, the neutral phosphate Li₃PO₄ the acid phosphate LiH₂PO₄, the orthosilicates, the metasilicates or the polysilicates of lithium, lithium sulfate, lithium oxalate and lithium acetate or a mixture of the latter.

42. A method of synthesis according to claim 41, in which the lithium source compound is lithium carbonate of the formula Li₂CO₃.

43. A method of synthesis according to any one of claims 1 to 42, in which the source of X is chosen from the group constituted by sulfuric acid, lithium sulfate, phosphoric acid and its esters, the neutral phosphate Li₃PO₄ or the acid phosphate LiH₂PO₄, the monoammonium or diammonium phosphates, trivalent ferric phosphate, manganese and ammonium phosphate (NH₄MnPO₄), silica, lithium silicates, alkoxysilanes and their partial hydrolysis products and mixtures of the latter.

44. A method of synthesis according to claim 42, in which the X precursor compound is ferric phosphate, anhydrous or hydrated.

45. A method according to any one of claims 1 to 44, in which at least one of the lithium derivatives obtained is of the formula LiFePO₄, LiFe₁₋

sMn_sPO₄ wherein 0≦

s≦

0.9, LiFe<sub>1−

y</sub>Mg_yPO₄ and LiFe<sub>1−

y</sub>Ca_yPO₄ wherein 0≦

y≦

0.3, LiFe<sub>1−

s−

y</sub>Mn_sMg_yPO₄ wherein 0≦

s≦

1 and 0≦

y≦

0.2, Li_1+xFeP<sub>1−

x</sub>Si_xO₄ wherein 0≦

x≦

0.9. Li_1+xFe<sub>1−

s</sub>Mn_sP<sub>1−

x</sub>Si_xO wherein 0≦

s≦

1, Li_1+zFe<sub>1−

s−

z</sub> Mn_sP<sub>1−

z</sub>S_zO₄ wherein 0≦

s≦

1, 0≦

z≦

0.2. Li_1+2qFe<sub>1−

s−

q</sub>Mn_sPO₄ wherein 0≦

s≦

1, and 0≦

q≦

0.3, Li_1+sFe<sub>1−

s</sub>Mn_s(S<sub>1−

r</sub>P_rO₄)_1,5 wherein 0≦

r≦

1, 0≦

s,t≦

1 or Li_0,5+uFe<sub>1−

t</sub>Ti_t(PO₄)_1,5 wherein 0≦

t≦

1 and wherein 0≦

u≦

1.5.

46. A method of synthesis according to any one of claims 1 to 13. in which the compounds of formula Li_xM₁₋

yM′

_y(XO₄)_n have an olivine or Nasicon structure, including the monoclinic form.

47. A method of synthesis according to any one of claims 1 to 46, in which the reaction parameters, and in particular the kinetics of the reduction by gaseous phase, are chosen in such a way that the carbon conductor is not consumed in the course of the reduction process.

48. A method of synthesis according to claim 47, in which the amount of substance that is the carbon conductor source, present in the reaction medium subjected to reduction, is chosen such that the amount of carbon conductor in the reaction medium will preferably be between 0.1 and 15%, and still more preferably that it will be between 0.3 and 1.5% of the total mass of the reaction mixture.

49. A method of synthesis according to any one of claims 1 to 48, in which the temperature and duration of the synthesis are chosen as a function of the nature of the transition metal, i.e. above a minimum temperature at which the reactive atmosphere is capable of reducing the transition element or elements to their oxidation state required in the compound Li_xM₁₋

yM′

_y(XO₄)_n and below a temperature or a time leading to a reduction of the transition element or elements to the metallic state or an oxidation of the carbon resulting from pyrolysis of the organic substance.

50. A method of synthesis according to any one of claims 1 to 49, in which the thermal processing is carried out by heating from the normal temperature to a temperature comprised between 500 and 1100°

C., in the presence of a reducing atmosphere.

51. A method of synthesis according to claim 50, in which the maximum temperature reached is comprised between 500 and 800°

C.

52. A method of synthesis according to any one of claims 1 to 51, in which the compound Li_xM₁₋

yM∝

0_y(XO₄)_n is LiMPO₄ and in which the amount of carbon conductor after pyrolysis is comprised between 0.1 and 10% by mass in comparison to the mass of the compound LiMPO₄.

53. A method of synthesis according to any one of claims 1 to 52, in which the compound that is the source of carbon is chosen in such a way that it is easily dispersible at the time of the processing used to insure an intimate mixture with precursors a) to d) by solubilization, by agitation and/or by mechanical grinding and/or by ultrasound homogenization in the presence, or not, of a liquid or by spray-drying of a solution of one or several precursors and/or of a suspension and/or of an emulsion.

54. A method of synthesis according to any one of claims 1 to 53, in which the compound obtained has the formula LiFePO₄.

55. A method of synthesis according to any one of claims 1 to 54, in which the core of the particles obtained is essentially (preferably at least 95%) constituted by a compound of the formula LiFePO₄, and in which the material obtained preferably has an amount of carbon conductor comprised between 0.2 and 5% in comparison to the mass of the particles obtained.

57. Material that can be obtained by a method according to any one of claims 1 to 56, comprising a core and a coating and/or a cross-linking, the said material having

a conductivity, measured on a sample of powder compacted at 3750 Kg.cm⁻

2 that is greater than 10<sup>−

8</sup> S.cm<sup>−

1</sup>;

an amount of carbon conductor between 0.2 and 5%;

preferably between 0.3 and 2%; and

a granulometry that is preferably between 0.05 and 15 micrometers, and preferably between 0.1 to 10 micrometers.

63. Cell according to any one of claims 58 to 61, characterized in that at least one of the positive electrodes contains one of the products obtainable by a method according to any one of claims 1 to 55, used alone or in mixture with a double oxide of cobalt and lithium or with a complex oxide of the formula Li_xNi₁₋

y−

z−

q−

rCo_yMg_zAl_rO₂ where 0.1≦

x≦

1, 0≦

y, z and r≦

0.3, or with a complex oxide of the formula Li_xMn<sub>1−

y−

z−

q−

r</sub>Co_yMg_zAlrO₂-qF_q where 0.05≦

x≦

1 and 0≦

y, z, r, q≦

0.3.

67. Electrochemical cell according to any one of claims 58 to 66, characterized in that it functions as a super-capacity, characterized in that the positive electrode material is a material according to claims 54 to 56, and the negative electrode is a carbon with a specific surface area greater than 1 m².g⁻

1 (preferably greater than 5 m².g<sup>−

1</sup>), in the form of powder, fiber or mesoporous composite of a carbon-carbon composite type.

68. Electrochemical cell according to any one of claims 58 to 67, characterized in that it functions as a light modulation system and in this case, the optically inactive counter-electrode is a material according to claim 55 or 56, spread in a thin layer on a transparent conductor support of a glass or polymer type covered with doped tin oxide (SnO₂:

Sb or SnO₂;

F) or doped indium oxide (In₂O₃;

Sn). element with fixed valency selected from the group consisting of mg²⁺, ca²⁺, Al³⁺, zn²⁺and combinations thereof and X is S, P or Si, comprising;

bringing into equilibrium in a reaction medium, in the required proportions, a mixture comprising the following precursors

a) a source of M, wherein at least one part of the said transition metal or metals that constitute M is in an oxidation state greater or less than that of the metal in the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n;

b) a source of an element M′

;

c) a compound that is a source of lithium;

d) optionally, a compound that is a source of X; and

e) an organic substance that is a source of carbon conductor

wherein the source of the elements M, M′

, Li and X are introduced, in whole or in part, in at least one step, in the form of compounds having more than one source element, wherein a synthesis reaction is carried out by thermodynamic or kinetic reaction and bringing into equilibrium, in the required proportions, the mixture of precursors a) to d), with a gaseous atmosphere, so to result in an oxidation state of the transition metal of the desired valency for the formation of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, by controlling the composition of the gaseous atmosphere, the temperature of the synthesis reaction, and the amount of precursor c) relative to the precursors a), b) and d); and

performing at least one pyrolysis reaction with precursor compound e) so as to obtain a compound with an electronic conductivity, when measured on a sample of powder compressed at a pressure greater than or equal to 3000, greater than 10<sup>−

8</sup>.cm<sup>−

1</sup>.

56. Material made of particles having a core and/or a coating and/or a cross-linking, the said core comprising at least one compound of the formula C—

Li_xM<sub>1−

y</sub>M′

_yXO₄)_n, in which C represents carbon cross-linked to the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, x, y and n are numbers such as 0≦

x≦

2, 0≦

y≦

0.6, and 1≦

n≦

1.5, M is a transition metal or a mixture of transition metals from the first line of the periodic table, M′

is an element with fixed valence chosen from among Mg²⁺, Ca²⁺, Al³⁺, Zn²⁺ and X is chosen from among S, P and Si, the said materials having a conductivity greater than 10<sup>−

8</sup> Scm<sup>−

1</sup>, on a sample of powder compacted at 3750 Kg.cm<sup>−

2</sup> and of which the granulometry of the said constituent particles of the material is preferably comprised between 0.05 and 15 micrometers, preferably between 0.1 and 10 micrometers.

58. Electrochemical cell comprising at least two electrodes and at least one electrolyte, characterized in that at least one of its electrodes contains at least one of the materials according to claim 56 or 57.

59. Cell according to claim 58, characterized in that the electrolyte is a polymer, solvating or not, optionally plasticized or gelled by a polar liquid containing one or more metallic salts in solution.

60. Cell according to claim 59, characterized in that the electrolyte is a polar liquid immobilized in a microporous separator and containing one or several metallic salts in solution.

61. Cell according to claim 60, in which at least one of the metallic salts is a lithium salt.

62. Cell according to any one of claims 58 to 61, characterized in that at least one of the negative electrodes is made of metallic lithium, a lithium alloy, especially with aluminum, antimony, zinc, tin, possibly in nanomolecular mixture with lithium oxide or a carbon insertion compound, especially graphite, a double nitride of lithium and iron, cobalt or manganese, a lithium titanate of the formula Li_xTi_(5+3y)/4O₄, where 1≦

x<

(11−

3y)/4 (or) where 0≦

y≦

1.

64. Cell according to any one of claims 58 to 62, characterized in that the polymer used to bind the electrodes or as electrolytes is a polyether, a polyester, a polymer based on methyl methacrylate units, an acrylonitrile-based polymer and/or a vinylidene fluoride or a mixture of these.

65. Cell according to any one of claims 58 to 64. characterized in that the cell comprises a non-protogenic solvent that contains ethylene or propylene carbonate, an alkyl carbonate having 1 to 4 carbon atoms, γ

-butyrolactone, a tetraalkylsulfamide, an α

-ω

dialkyl ether of a mono-, di-, tri-. tetra- or oligo-ethylene glycol with molecular weight less than or equal to 5000, as well as mixtures of the solvents named here.

66. Cell according to any one of claims 58 to 65, characterized in that it functions as a primary or secondary generator, as a super-capacity or as a light modulation system.

70. The method according to claim 69, wherein the synthesis reaction between the precursors a) to d) is carried out simultaneously with the pyrolysis reaction of precursor e).

71. The method according to claim 69, wherein the pyrolysis reaction is carried out in a second step, consecutive to the synthesis reaction between precursors a) to d) in a reducing or neutral gaseous atmosphere.

72. The method according to claim 69, wherein a compound of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is obtained in the form of a particle wherein the size and shape of the particle of compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is essentially determined by the size and the shape of a intimate or homogeneous mixture of precursors a) to d) used for the synthesis reaction.

73. The method according to claim 72, in which the size of the particle of compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is between 0.1 and 10 micrometers.

74. The method according to claim 73, wherein the size and the shape of the particle of the compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n does not differ by more than 80% from that of the size of precursors a) to d).

75. The method according to claim 69, wherein the amount carbon conductor is sufficient to coat at least a part of the surface of the particle of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n with carbon.

76. The method according to claim 75, wherein the amount of carbon bound to the particle is less than 5% of the mass of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n.

77. The method according to claim 75, wherein at least 30% of the surface of the particle of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n is covered with carbon.

78. The method according to claim 69, wherein the amount of carbon conductor in the reaction medium is sufficient to bond particles of compound Li_xM₁₋

yM′

_y(XO₄)_n to each other and to constitute agglomerates with sizes between 1 and 20 microns.

79. The method according to claim 78, in which the amount of carbon bound to the particles is less than 7% of the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n.

80. The method according to claim 69, wherein a final form of the compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is determined by a form given to the mixture of precursors a) to d) before synthesis.

81. The method according to claim 80, wherein the form given to the mixture of precursors a) to d) is via a technique selected from the group consisting of spray-drying, precipitation, coprecipitation, agglomeration and pelletization.

82. The method according to claim 81, wherein the technique used to give a specific form to the mixture of precursors a) to d) is spray-drying, and wherein the final form of the compound C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is a spherical agglomerate with a size between 1 and 30 micrometers, wherein the agglomerate comprises smaller particles of the compound of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n.

83. The method according to claim 69, wherein the organic substance that is the source of the carbon conductor is selected from the group consisting of polymers and oligomers containing a carbon skeleton, simple carbohydrates and polymers, and aromatic hydrocarbons.

86. The method according to claim 83, wherein the organic substance comprises at least one compound of the group consisting of polyethylene, polypropylene, glucose, fructose, sucrose, xylose, sorbose, starch, cellulose, cellulose esters, block polymers of ethylene and ethylene oxide, and polymers of furfuryl alcohol.

84. A method according to claim 69, wherein the source of carbon conductor source comprises, in the same compound or in a mixture that constitutes the source of carbon conductor, oxygen and hydrogen that are bound chemically and from which pyrolysis locally releases carbon monoxide, carbon dioxide, or hydrogen and water vapor to create locally a reducing atmosphere required for synthesis of a compound of formula Li_xM₁₋

yM′

_y(XO₄)_n.

85. The method according to claim 69, wherein the source of carbon conductor comprises a block copolymer comprising at least one carbon source segment that can be pyrolyzed and a segment that is soluble in water and organic solvents to allow distribution, through the compound Li_xM₁₋

yM′

_y(XO₄)_n or precursors a) to d).

87. The method according to claim 69, wherein precursors a) to d) are in the form of powder or at least partially compressed in the form of pastilles, prior to the synthesis so as to increase points of contact between reagents and to increase the density of the compound of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n while allowing the reaction with the gaseous atmosphere.

88. The method according to claim 69, wherein precursors a) to d) are compacted in the presence of carbon conductor.

89. The method according to claim 69, wherein the method is carried out continuously in a reactor that promotes the equilibrium of solid powders, agglomerated or not, with the gaseous atmosphere via control of the composition and the circulation of the gaseous atmosphere.

90. The method according to claim 89, wherein the synthesis reaction comprises a solid feed of precursors a) to d) greater than 1 kg/h, and wherein the temperature of the synthesis is between 650°

C. and 800°

C., and the dwell time of the synthesis reaction is less than 5 hours.

91. The method according to claim 69, wherein a reduction is obtained by the action of a reducing gaseous atmosphere able to reduce an oxidation state of a metallic ion of M to the level required for the composition of the compound without reducing the oxidation state of a metallic ion of M to a neutral metallic state.

92. The method according to claim 91, wherein the reducing gaseous atmosphere comprises hydrogen or a gas capable of generating hydrogen under synthesis conditions, ammonia or a substance capable of generating ammonia under synthesis conditions, or carbon monoxide, wherein the hydrogen, ammonia, or carbon monoxide gas is used in a pure state or in a mixture, and, optionally, in the presence of water vapor, carbon dioxide, or a neutral gas.

93. A method according to claim 91, wherein the reducing atmosphere comprises a mixture of CO/CO₂, H₂/H₂O, NH₃/H₂O, or a mixture thereof, generating an oxygen equilibrium pressure less than or equal to that determined by the transition metal at the state of oxidation corresponding to precursors a) to d) introduced to form the compound Li_xM₁₋

yM′

_y(XO₄)_n, but greater than that corresponding to the reduction of any one of the transition elements present in a metallic state, insuring the thermodynamic stability of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n in the reaction mixture, independent of reaction time of the synthesis.

94. The method according to claim 91, wherein the reducing gaseous atmosphere comprises a mixture of CO/CO₂, H₂/H₂O, NH₃/H₂O, or a mixture thereof, generating an oxygen equilibrium pressure greater than or equal to that determined by at least the transition metal, when a precursor is introduced in a metallic form, to form the compound Li_xM₁₋

yM′

_y(XO₄)_n, but greater than that corresponding to a superoxidation of the transition metals beyond an assigned valence in Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, insuring the thermodynamic stability of Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n in the reaction mixture, independent of reaction time of the synthesis.

95. The method according to claim 91, wherein the reducing gaseous atmosphere is made up of a mixture of CO/CO₂, H₂/H₂O, NH₃/H₂O, or a mixture thereof, generating an oxygen equilibrium pressure less than or equal to that determined by one of the transition metals present in Li_xM₁₋

yM′

_y(XO₄)_n, wherein the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n is obtained by controlling the temperature and contact time with the reducing gaseous atmosphere or the proportion of the precursor c) in the reaction mixture;

wherein the temperature of the synthesis is between 200°

C. and 1200°

C., and wherein contact time between the reaction mixture and the reducing gaseous atmosphere is between 2 minutes and 5 hours.

96. The method according to claim 91, wherein the reducing gaseous atmosphere is obtained by decomposition, in a vacuum or in an inert atmosphere, of an organic compound or of a mixture of organic compounds comprising at least hydrogen and oxygen, bound chemically, and wherein pyrolysis of the organic compound or mixture of organic compounds generates carbon monoxide, a mixture of carbon dioxide and monoxide, hydrogen, or a mixture of hydrogen and water vapor able to carry out the reduction leading to the formation of the compound Li_xM₁₋

yM′

_y(XO₄)_n.

97. The method according to claim 91, wherein the gaseous reducing atmosphere is obtained by partial oxidation by oxygen or air, of a hydrocarbon or carbon, optionally in the presence of water vapor, at an a temperature between 400°

C. and 1200°

C. to facilitate formation of carbon monoxide, hydrogen, or of a mixture of carbon monoxide and hydrogen.

98. The method according to claim 69, wherein the gaseous atmosphere comprises a gas reformed in situ or ex situ.

99. The method according to claim 98, wherein the reformed gas is obtained from methane, propane, a natural gas, or a mixture thereof, wherein air and optionally water vapor or a mixture of air and water vapor are added by condensation or injection into the reformed gas.

100. The method according to claim 69, wherein thermal processing comprising formation of Li_xM₁₋

yM′

_y(XO₄)_n, reduction, pyrolysis, and, optionally, dehydration of one or more of precursors a) to d)) is carried out by heating to a temperature between 500°

C. and 1100°

C.

101. The method according to claim 100, wherein the maximum temperature of thermal processing is between 500°

C. and 800°

C.

102. The method according to claim 69, wherein dwell time of precursors a) to e) in thermal processing is less than 5 hours.

103. The method according to claim 69, wherein the compound Li_xM₁₋

yM′

_y(XO₄)_n, wherein n=1, has an electrochemical capacity greater than 150 mAh/g<sup>−

1</sup>, measured for specific intensities greater than 10 mA.g<sup>−

1</sup>.

104. The method according to claim 69, wherein the source of M is also the source of X, the source of M′

is also the source of X, the source of lithium is also the source of X, or the source of X is also the source of lithium.

105. The method according to claim 69, wherein bringing the mixture of precursors a) to d) into equilibrium is carried out in the form of an intimate or homogeneous mixture of precursors a) to d) and the gaseous atmosphere.

106. The method according to claim 69, wherein the transition metal or metals is selected from the group consisting of iron, manganese, cobalt, nickel, vanadium, titanium, chromium, and copper.

107. The method according to claim 69, wherein the source of M is in an oxidation state from 3 to 7.

108. The method according to claim 107, wherein the source of M is a compound selected from the group consisting of iron (III) oxide, magnetite, manganese dioxide, di-vanadium pentoxide, trivalent ferric phosphate, ferric hydroxyphosphate, lithium, trivalent ferric nitrate, and mixtures thereof.

109. The method according to claim 69, wherein the compound that is the source of lithium is selected from the group consisting of lithium oxide, lithium hydroxide, lithium carbonate, neutral phosphate Li₃PO₄, acid phosphate LiH₂PO₄, lithium orthosilicates, lithium metasilicates, lithium polysilicates, lithium sulfate, lithium oxalate, lithium acetate and mixtures thereof.

110. The method according to claim 109, wherein the source of lithium is lithium carbonate of the formula Li₂CO₃.

112. The method according to claim 110, wherein the source of X is anhydrous or hydrated ferric phosphate.

111. The method according to claim 69, wherein the source of X is selected from the group consisting of sulfuric acid, lithium sulfate, phosphoric acid, phosphoric acid esters, neutral phosphate Li₃PO₄, acid phosphate LiH₂PO₄, monoammonium phosphate, diammonium phosphate, trivalent ferric phosphate, manganese and ammonium phosphate (NH₄M_nPO₄), silica, lithium silicates, alkoxysilanes and partial hydrolysis products thereof, and mixtures thereof.

113. The method according to claim 69, wherein at least one compound of formula Li_xM₁₋

yM′

_y(XO₄)_n is of the formula LiFePO₄;

LiFe<sub>1−

s</sub>Mn_sPO₄, wherein 0≦

s≦

0.9;

LiFe<sub>1−

y</sub>Mg_yPO₄ or LiFe<sub>1−

y</sub>Ca_yPO₄, wherein 0≦

y≦

0.3;

LiFe<sub>1−

s−

y</sub>Mn_sMg_yPO₄, wherein 0≦

s≦

1 and 0≦

y≦

0.2;

Li<sub>1−

x</sub>FeP<sub>1−

x</sub>Si_xO₄, wherein 0≦

x≦

0.9;

Li_1+xFe<sub>1−

s</sub>Mn_sP<sub>1−

x</sub>Si_xO, wherein 0≦

s≦

1;

Li_1+zFe<sub>1−

s−

z</sub>Mn_sP<sub>1−

z</sub>S_zO₄, wherein 0≦

s≦

1, 0≦

z≦

0.2;

Li_1+2qFe<sub>1−

s−

q</sub>Mn_sPO₄, where 0≦

s≦

1, and 0≦

q≦

0.3;

Li_1+rFe<sub>1−

8</sub>Mn_s(S<sub>1−

r</sub>P_rO₄)_1,5, wherein 0≦

r≦

1, 0≦

s,t≦

1;

or Li_0,5+uFe<sub>1−

t</sub>Ti_t(PO₄)_1,5 wherein 0≦

t≦

1 and 0≦

u≦

1.5.

114. The method according to claim 69, wherein the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n has an olivine or Nasicon structure.

115. The method according to claim 69, wherein reaction parameters of the kinetics of reduction by the gaseous atmosphere, are chosen such that the carbon conductor is not consumed during reduction.

116. The method according to claim 115, wherein the amount of carbon conductor in the reaction medium is between 0.1% and 15% of the total mass of the reaction mixture.

117. The method according to claim 69, wherein the temperature and duration of the synthesis are chosen as a function of the nature of the transition metal, wherein the temperature is above a minimum temperature at which the gaseous atmosphere is capable of reducing the transition metal or metals to an oxidation state required in the compound Li_xM₁₋

yM′

_y(XO₄)_n and below a temperature leading to a reduction of the transition metal or metals to a metallic state or an oxidation of the carbon resulting from pyrolysis of the organic substance, and wherein the duration is less than a time leading to a reduction of the transition metal or metals to a metallic state or an oxidation of the carbon resulting from pyrolysis of the organic substance.

118. The method according to claim 69, wherein thermal processing is carried out by heating to a temperature between 500°

C. and 1100°

C., in the presence of a reducing atmosphere.

119. The method according to claim 118, wherein the maximum temperature of thermal processing is between 500 and 800°

C.

120. The method according to claim 69, wherein the compound Li_xM₁₋

yM′

_y(XO₄)_n is LiMPO₄ and wherein the amount of carbon conductor after pyrolysis is between 0.1% and 10% by mass in comparison to the mass of the compound LiMPO₄.

121. The method according to claim 69, wherein the organic substance that is the source of carbon conductor is dispersed in processing an intimate mixture with precursors a) to d) by solubilization, agitation, mechanical grinding, ultrasound homogenization, optionally in the presence of a liquid, or by spray-drying of a solution, suspension or emulsion of one or more of precursors a) to d).

122. The method according to claim 69, wherein the compound of formula Li_xM₁₋

yM′

_y(XO₄)_n is LiFePO₄.

123. The method according to claim 69, wherein a particle is obtained, wherein said particle has a core essentially comprising a compound of the formula LiFePO₄, and wherein the particle has an amount of carbon conductor comprised between 0.2 and 5% in comparison to the mass of the particle.

124. A material made of particles comprising a core and/or a coating and/or a cross-linking, wherein the core comprises at least one compound of the formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n wherein C represents carbon cross-linked with the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, x, y and n are numbers such that 0≦

x≦

2, 0≦

y≦

0.6 and 1≦

n≦

1.5, M is a transition metal or a mixture of transition metals from the first line of the periodic table, M′

is an element with fixed valence selected from the group consisting of Mg²⁺, Ca²⁺, Al³⁺, and Zn²⁺, and X is S, P or Si, wherein the conductivity of the material is greater than 10<sup>−

8</sup> Scm<sup>−

1</sup>, measured on a sample of powder compacted at 3750 Kg.cm<sup>−

2</sup>, and wherein the granulometry of the particles of the material is between 0.05 and 15 micrometers.

126. An electrochemical cell comprising at least two electrodes and at least one electrolyte, wherein at least one of its electrodes comprises at least one material according to claim 124.

127. The electrochemical cell according to claim 126, wherein the electrolyte is a solvating or non-solvating polymer, optionally plasticized or gelled by a polar liquid containing one or more metallic salts in solution.

128. The electrochemical cell according to claim 126, wherein the at least one electrolyte is a polar liquid immobilized in a microporous separator and containing one or several metallic salts in solution.

129. The electrochemical cell according to claim 128, wherein at least one of the metallic salts is a lithium salt.

130. The electrochemical cell according to claim 126, wherein at least one of the electrodes is negative and comprises metallic lithium;

a lithium alloy, optionally in nanomolecular mixture with lithium oxide or a carbon insertion compound;

a double nitride of lithium and iron, cobalt or manganese;

or a lithium titanate of the formula Li_xTi_(5+3y)/4O₄, wherein 1≦

x≦

(11−

3y)/4 and 0≦

y≦

1.

132. The electrochemical cell according to claim 126, wherein the at least two electrodes are bonded with a polymer wherein the polymer is a polyether, a polyester, a polymer based on methyl methacrylate units, an acrylonitrile-based polymer, vinylidene fluoride, or a mixture thereof, or wherein the electrolyte is a polymer wherein the polymer is a polyether, a polyester, a polymer based on methyl methacrylate units, an acrylonitrile-based polymer, vinylidene fluoride, or a mixture thereof.

133. The electrochemical cell according to claim 126, further comprising a non-protogenic solvent comprising ethylene carbonate, propylene carbonate, an alkyl carbonate having 1 to 4 carbon atoms, γ

-butyrolactone, a tetraalkylsulfamide, an α

-ω

dialkyl ether of a mono-, di-, tri-, tetra- or oligo-ethylene glycol with molecular weight less than or equal to 5000, or a mixture thereof.

134. A primary generator comprising an electrochemical cell according to claim 126.

135. A secondary generator comprising an electrochemical cell according to claim 126.

136. An supercapacitor comprising an electrochemical cell according to claim 126.

137. The supercapacitor of claim 136, wherein at least one electrode is a positive electrode and the negative electrode comprises carbon with a specific surface area greater than 1 m².g¹ in the form of powder, fiber, or mesoporous composite of a carbon-carbon composite type.

138. A light modulation system comprising an electrochemical cell according to claim 126.

139. The light modulation system of claim 138, wherein the at least one electrode is a optically inactive counter-electrode comprising the material spread in a thin layer on a transparent conductor support of a glass or polymer type covered with doped tin oxide (SnO₂:

Sb or SnO₂;

F) or doped indium oxide (In₂O₃;

Sn).

125. A material comprising a compound of formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n obtained by a method according to claim 69, comprising a core and a coating and/or a cross-linking, wherein the conductivity of the material, measured on a sample of powder compacted at 3750 Kg.cm<sup>−

2</sup>, is greater than 10<sup>−

8</sup> S.cm<sup>−

1</sup>, wherein the amount of carbon conductor of the material is between 0.2 and 5%, and wherein the granulometry of the material is between 0.05 and 15 micrometers.

131. An electrochemical cell comprising at least two electrodes and at least one electrolyte, wherein at least one electrode comprises at least one material made of particles comprising a core and/or a coating and/or a cross-linking, wherein the core comprises at least one compound of the formula C—

Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n wherein C represents carbon cross-linked with the compound Li_xM<sub>1−

y</sub>M′

_y(XO₄)_n, x, y and n are numbers such that 0≦

x≦

2, 0≦

y≦

0.6 and 1≦

n≦

1.5, M is a transition metal or a mixture of transition metals from the first line of the periodic table, M′

is an element with fixed valence selected from the group consisting of Mg²⁺, Ca²⁺, Al³⁺, and Zn²⁺, and X is S, P or Si, wherein the conductivity of the material is greater than 10<sup>−

8</sup> Scm<sup>−

1</sup>, measured on a sample of powder compacted at 3750 Kg.cm ², wherein the granulometry of the particles of the material is between 0.05 and 15 micrometers, and wherein at least one of the positive electrodes contains one compound obtained by a method according to claim 69, wherein said compound is alone or in a mixture with a double oxide of cobalt and lithium;

or with a complex oxide of the formula Li_xNi<sub>1−

y−

z−

q−

r</sub>Co_yMg_zAl_rO₂, wherein 0.1≦

x≦

1, 0≦

y, z and r≦

0.3;

or with a complex oxide of the formula Li_xMn<sub>1−

y−

z−

q−

r</sub>Co_yMg_zAlrO₂-qF_q, wherein 0.05≦

x≦

1 and 0≦

y, z, r, q≦

0.3.