Abstract: A method is disclosed for suppressing propagation of a metal in a solid state electrolyte during cycling of an electrochemical device including the solid state electrolyte and an electrode comprising the metal. One method comprises forming the solid state electrolyte such that the solid state electrolyte has a structure comprising a plurality of grains of a metal-ion conductive material and a grain boundary phase located at some or all of grain boundaries between the grains, wherein the grain boundary phase suppresses propagation of the metal in the solid state electrolyte during cycling. Another method comprises forming the solid state electrolyte such that the solid state electrolyte is a single crystal.

Abstract: A solid electrolyte contains aluminum in an amount of 100 to 1000 ppm, inclusive, on a mass basis, and has lithium ion conductivity. It is preferable that aluminum is derived from an oxide of aluminum. It is also preferable that the solid electrolyte is a sulfide solid electrolyte containing a lithium element, a phosphorus element, and a sulfur element. It is also preferable that the solid electrolyte has an argyrodite-type crystal structure. It is also preferable that the solid electrolyte has a lithium ion conductivity of 4.0 mS/cm or greater.

Abstract: There is disclosed an electrolyte composition comprising one or two or more polymers, oxide particles having a hydrophobic surface, at least one electrolyte salt selected from the group consisting of a lithium salt, a sodium salt, a calcium salt, and a magnesium salt, and an ionic liquid.

Abstract: Provided are a porous inorganic insulator-sulfur composite and a lithium-sulfur battery including the same. More particularly, provided are a composite having sulfur supported in pores of a porous inorganic insulator, a cathode for lithium-sulfur batteries or an interlayer, which includes the composite, and a lithium-sulfur battery including the cathode or the interlayer.

Abstract: Disclosed is an all-solid-state lithium ion secondary battery being excellent in cycle characteristics. The all-solid-state lithium ion secondary battery may be an all-solid-state lithium ion secondary battery, wherein an anode comprises an anode active material, an electroconductive material and a solid electrolyte; wherein the anode active material comprises at least one active material selected from the group consisting of a metal that is able to form an alloy with Li, an oxide of the metal, and an alloy of the metal and Li; and wherein a bulk density of the solid electrolyte is 0.3 g/cm3 or more and 0.6 g/cm3 or less.

Abstract: A solid electrolyte material comprises Li, T, X and A wherein T is at least one of P, As, Si, Ge, Al, and B; X is one or more halogens or N; A is one or more of S and Se. The solid electrolyte material has peaks at 17.8°±0.75° and 19.2°±0.75° in X-ray diffraction measurement with Cu-K?(1,2)=1.5418 ? and may include glass ceramic and/or mixed crystalline phases.

Abstract: Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes Al2O3 (alumina), WC (tungsten carbide) and ZrO2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al2O3; and (2) a grain boundary of crystal grains of the Al2O and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO2, and the balance being the Al2O3, and wherein the ZrO2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

Abstract: The present invention provides a positive electrode active material for an all-solid-state lithium-ion battery, an electrode, and an all-solid-state lithium-ion battery capable of smoothly exchanging lithium ions with a solid electrolyte at a positive electrode and improving battery performance. A positive electrode active material for an all-solid-state lithium-ion battery formed of particles includes crystals of a lithium metal composite oxide, in which the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and the particles have an average crush strength of more than 50 MPa and satisfy Expression (1). 1.

Abstract: A method for producing an electrode comprising a porous garnet-type ion-conducting oxide sintered body with high ion conductivity, the electrode, and an electrode-electrolyte layer assembly comprising the electrode and an electrolyte layer comprising a dense garnet-type ion-conducting oxide sintered body with high ion conductivity. Disclosed is a method for producing an electrode, the method comprising: preparing crystal particles of a garnet-type ion-conducting oxide; preparing a lithium-containing flux; preparing the electrode active material; preparing an electrolyte material by mixing the crystal particles of the garnet-type ion-conducting oxide and the flux; and sintering the electrolyte material and the electrode active material by heating at a temperature of 650° C. or less, wherein a number average particle diameter of the flux is larger than a number average particle diameter of the crystal particles of the garnet-type ion-conducting oxide.

Abstract: An electrolyte precursor solution includes a metallic compound containing elements constituting an electrolyte, a solvent capable of dissolving the metallic compound, and an anionic surfactant having a sulfate group (SO42?) bonded to a hydrophobic group R. By reacting such an electrolyte precursor solution with active material particles containing lithium, lithium sulfate derived from the anionic surfactant is interposed at the interface between the surface of the active material particle and the electrolyte so as to enhance the dissociation of lithium ions at the interface, and thus, an excellent ion conductivity can be realized.

Abstract: Set forth herein are garnet material compositions, e.g., lithium-stuffed garnets and lithium-stuffed garnets doped with alumina, which are suitable for use as electrolytes and catholytes in solid state battery applications. Also set forth herein are lithium-stuffed garnet thin films having fine grains therein. Disclosed herein are novel and inventive methods of making and using lithium-stuffed garnets as catholytes, electrolytes and/or anolytes for all solid state lithium rechargeable batteries. Also disclosed herein are novel electrochemical devices which incorporate these garnet catholytes, electrolytes and/or anolytes. Also set forth herein are methods for preparing novel structures, including dense thin (<50 um) free standing membranes of an ionically conducting material for use as a catholyte, electrolyte, and, or, anolyte, in an electrochemical device, a battery component (positive or negative electrode materials), or a complete solid state electrochemical energy storage device.

Abstract: A solid electrolyte which reduces grain boundary resistance and exhibits a high total ion conductivity is provided. The solid electrolyte includes a first area which has a cubic garnet type crystalline and a second area which is amorphous, around the first area, in which each of the first area and the second area contains a composite oxide represented by formula (1) or (2) as a forming material, and an abundance ratio of metal atoms each having an ionic radius of 78 pm or more gradually increases from the first area to the second area. Li7+xLa3?xZr2AxO12??(1) [In formula (1), A is at least one selected from the group consisting of Mg, Ca, Sr, and Ba. In addition, x is 0.1 or more and 0.6 or less.] Li7La3?xZr2BxO12??(2) [In formula (2), B is at least one selected from the group consisting of Sc and Y. In addition, x is 0.1 or more and 0.6 or less.

Abstract: A positive electrode active material for a secondary battery and a secondary battery including the same are provided. The positive electrode active material for a secondary battery includes on the surface of a core, a surface treatment layer composed of a B and Si-containing amorphous oxide, and thus may exhibit reduced moisture reactivity, improved thermal and chemical stability, and high-voltage stability.

Abstract: A main object of the present disclosure is to provide a sulfide solid electrolyte material with favorable Li ion conductivity. To achieve the above object, the present disclosure provides a sulfide solid electrolyte material comprising a composition of Li(4+x)AlxSi(1?x)S4 (0<x<1), and having a peak at a position of 2?=25.19°±1.00°, 29.62°±1.00°, 30.97°±1.00° in X-ray diffraction measurement using a CuK? ray.

Abstract: The invention relates to an electrode unit for an electrochemical device, comprising a solid electrolyte (3) and a porous electrode (7), the solid electrolyte (3) dividing a compartment for cathode material and a compartment for anode material and the porous electrode (7) being extensively connected to the solid electrolyte (3), with a displacer (23) being accommodated in the anode material compartment, where the displacer (23) is manufactured from a stainless steel or from graphite foil and bears resiliently against the internal geometry of the solid electrolyte (3) in such a way that the displacer (23) does not contact the solid electrolyte over its full area, or with the displacer comprising an outer shell (62) of stainless steel or graphite, and a core (64) of a nonferrous metal, the nonferrous metal being thermoplastically deformable at a temperature which is lower than the temperature at which the stainless steel is thermoplastically deformable, and where for production the shell (62) of stainless steel

Abstract: An exemplary lithium secondary battery includes: a positive electrode including a positive-electrode active substance layer 103; a negative electrode; and a solid electrolyte layer 104. The positive-electrode active substance layer 103 comprises lithium cobaltate, and has an ?-NaFeO2 type crystal structure. The positive-electrode active substance layer 103 includes a lower layer 103a, and an upper layer 103b interposed between the lower layer and the solid electrolyte layer. The lower layer 103a is oriented in the (110) plane. The upper layer 103b is composed only of first regions 103b1 oriented in the (110) plane and second regions 103b2 oriented in the (018) plane, the first and second regions being mixedly present in the xy plane of the positive-electrode active substance layer. The solid electrolyte layer 104 comprises lithium lanthanum titanate, and has a tetragonal perovskite-type crystal structure. The solid electrolyte layer 104 is oriented in the (110) or (102) plane.

Abstract: An exemplary all-solid lithium secondary battery includes a positive electrode including a positive-electrode active substance layer, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode. The positive-electrode active substance layer is composed of lithium cobaltate, and has an ?-NaFeO2 type crystal structure. The positive-electrode active substance layer has a (018) plane oriented in a normal direction of a principal face of the positive-electrode active substance layer. The solid electrolyte layer is composed of lithium lanthanum titanate and has a tetragonal perovskite-type crystal structure. The solid electrolyte layer has a (110) plane or a (102) plane oriented in a normal direction of a principal face of the solid electrolyte layer.

Abstract: Provided is a sodium secondary battery including: a sodium ion conductive solid electrolyte separating an anode space and a cathode space from each other; an anode positioned in the anode space and containing sodium; a cathode solution positioned in the cathode space; and a cathode immersed in the cathode solution and including graphite felt formed with open pore channel of which an opening part is formed on a surface of the graphite felt facing the solid electrolyte.

Abstract: A separator for an alkali metal ion rechargeable battery includes a porous ceramic alkali ion conductive membrane which is inert to liquid alkali ion solution as well as anode and cathode materials. The porous ceramic separator is structurally self-supporting and maintains its structural integrity at high temperature. The ceramic separator may have a thickness of at least 200 ?m and a porosity in the range from 20% to 70%. The separator may be in the form of a clad composite separator structure in which one or more layers of porous and inert ceramic or polymer membrane materials are clad to the alkali ion conductive membrane. The porous and inert alkali ion conductive ceramic membrane may comprise a NaSICON-type, LiSICON-type, or beta alumina material.

Abstract: Disclosed are an open internal electrode AMTEC unit cell, a method for manufacturing the same and a method for connecting circuits. In order to overcome the difficulty in collecting electricity within a conventional AMTEC unit cell, an internal electrode of which a portion is open to the outside, so that the internal electrode and an external electrode can be electrically connected to each other at the outside of the unit cell, and a metal support is used as the internal electrode, so that the internal electrode has durability and stability, and a solid electrolyte is formed in the form of a thin film, and as a result, the AMTEC unit cell has an improved efficiency and a simpler manufacturing process.

Abstract: A solid electrolyte suitable for use in all solid type lithium ion secondary battery is made by sintering a form, particularly a greensheet, comprising at least lithium ion conductive inorganic substance powder. The solid electrolyte has porosity of 20 vol % or over.

Abstract: A solid electrolyte battery using a solid electrolyte capable of realizing high conductivity, and a process for producing a solid electrolyte battery are provided. The solid electrolyte battery is structured as a laminate of a positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode collector layer formed in order on a substrate. The solid electrolyte layer is a thin film formed of a compound of the formula Li3 M04 (M =V, Nb, Ta, or Db).

Abstract: Disclosed is to a method of manufacturing an anode active material, including mixing a first solution having a metal oxide precursor dissolved therein, a second solution having a polymer as a carbon fiber precursor dissolved therein, and an ionic liquid solution for nitrogen doping and formation of a porous structure, thus preparing an electrospinning solution, electrospinning the electrospinning solution, thus preparing a metal oxide-nitrogen-porous carbon nanofiber composite, and thermally treating the composite, and to an anode and a lithium battery using the anode active material.

Abstract: A vehicle power supply system comprises a battery module that includes a plurality of battery cells, battery cell control devices and a signal transmission path through which signals are transmitted. The battery cell control devices comprises a voltage measurement circuit that measures terminal voltages at the battery cells, an abnormality diagnosis circuit that diagnoses an abnormality in the battery cell control device, a timing control circuit that outputs a signal for instructing measurement phase and a signal for instructing diagnosis phase, and a communication circuit that outputs a signal indicating the terminal voltage and a signal based upon a diagnosis result by the abnormality diagnosis circuit.

Abstract: An inorganic solid electrolyte glass phase composite is provided comprising a substance of the general formula La2/3-xLi3xTiO3 wherein x ranges from about 0.04 to about 0.17, and a glass material. The glass material is one or more compounds selected from Li2O, Li2S, Li2SO4, Li3PO4, P2O5, P2O3, Al2O3, SiO2, CaO, MgO, BaO, TiO2, GeO2, SiS2, Sb2O3, SnS, TaS2, P2S5, B253, and a combination of two or more thereof. A lithium-ion conducting solid electrolyte composite is disclosed comprising a lithium-ion conductive substance of the general formula La2/3-xLi3xTiO3—Z wherein x ranges form about 0.04 to 0.17, and wherein “Z” is the glass material identified above. A battery is disclosed having at least one cathode and anode and an inorganic solid electrolyte glass phase composite as described above disposed on or between at least one of the cathode and the anode.

Abstract: A lithium-lanthanum-titanium oxide sintered material has a lithium ion conductivity 3.0×10?4 Scm?1 or more at a measuring temperature of 27° C., the material is described by one of general formulas (1?a)LaxLi2-3xTiO3-aSrTiO3, (1?a)LaxLi2-3xTiO3-aLa0.5K0.5TiO3, LaxLi2-3xTi1-aMaO3-a, Srx-1.5aLaaLi1.5-2xTi0.5Ta0.5O3 (0.55?x?0.59, 0?a?0.2, M=at least one of Fe or Ga), amount of Al contained is 0.35 mass % or less as Al2O3, amount of Si contained is 0.1 mass % or less as SiO2, and average particle diameter is 18 ?m or more.

Abstract: An all-solid lithium secondary battery 20 includes a solid electrolyte layer 10 composed of a garnet-type oxide, a positive electrode 12 formed on one surface of the solid electrolyte layer 10 and a negative electrode 14 formed on the other surface of the solid electrolyte layer 10. This all-solid lithium secondary battery 20 includes an integrally sintered complex of the solid electrolyte layer 10 and the positive electrode active material layer 12a. This complex is obtained by integrally sintering a stacked structure of an active material layer and a solid electrolyte layer. The solid electrolyte layer includes: abase material mainly including a fundamental composition of Li7+X?Y(La3?x,Ax) (Zr2?Y,TY)O12, wherein A is one or more of Sr and Ca, T is one or more of Nb and Ta, and 0?X?1.0 and 0?Y<0.75 are satisfied, as a main component; and an additive component including lithium borate and aluminum oxide.

Abstract: A solid electrolyte is disclosed. The solid electrolyte includes a main portion that includes ?-alumina or ??-alumina, and an edge portion integrally provided with the main portion. The edge portion has a mixed portion that includes ?-alumina and includes ? alumina or ??-alumina. A concentration gradient of the ?-alumina in the edge portion decreases in a first direction from the edge portion to the main portion.

Abstract: In a Li ion conductivity oxide solid electrolyte containing lithium, lanthanum, and zirconium, a part of oxygen is substituted by an element M (M=N, Cl, S, Se, or Te) having smaller electronegativity than oxygen.

Abstract: A beta alumina solid electrolyte (BASE) and a method of preparing the same are provided. When the method is used, evaporation of sodium is suppressed and thus a beta alumina solid electrolyte having a high density, a low porosity, and a composition that is near a desired (target) composition is produced.

Abstract: To provide a dense beta-alumina-based sintered compact having a high ionic conductivity as a solid electrolyte by firing at a low temperature to suppress the volatilization of Na2O and its production method. By adding RNbO3 which is a material having a low melting point to a beta-alumina powder, followed by firing, it is possible to obtain a beta-alumina-based sintered compact having a low firing temperature and containing, as the main component, dense ?? alumina crystals which are free from anomalous grain growth during the firing process.

Abstract: A solid-state battery cell includes an anode, a cathode, and a solid electrolyte matrix. At least the anode or the cathode may include an active electrode material having pores. Further, an inner surface of the pores may be coated with a first surface-ion diffusion enhancement coating. The solid electrolyte matrix may further include an electrically insulating matrix for a solid electrolyte. The electrically insulating matrix may have pores or passages and an inner surface of the pores or the passages may be coated with a second surface-ion diffusion enhancement coating.

Abstract: The invention relates to solid-state electrolytes for use in lithium-air batteries or in lithium-water batteries. It is the object of the invention to provide solid electrolyte for use in lithium-air batteries or lithium-water batteries, with the solid electrolyte having sufficient strength, good conductivity for lithium ions, imperviousness for gas and water resistance and being inexpensive in manufacture. The solid-state electrolyte in accordance with the invention has an open-pore ceramic carrier substrate. In this respect, at least one layer which is conductive for lithium ions, which has an electrical conductivity of at least 10?5 Scm?1 and which is gas-impervious is formed on the surface facing the cathode. In this respect, the carrier substrate has greater mechanical strength and a larger layer thickness than the at least one layer.

Abstract: A solid electrolyte material of conducting a lithium ion comprises a sulfide-based lithium-ion conductor and ?-alumina. Such a solid electrolyte material exhibits superior lithium-ion conductivity. Further, a battery device provided with such a solid electrolyte material is also provided. Furthermore, an all-solid lithium-ion secondary battery provided with such a battery device is also provided.

Abstract: A ceramic material that can exhibit sufficient compactness and lithium (Li) conductivity to enable the use thereof as a solid electrolyte material for a lithium secondary battery and the like is provided. The ceramic material contains aluminum (Al) and has a garnet-type crystal structure or a garnet-like crystal structure containing lithium (Li), lanthanum (La), zirconium (Zr) and oxygen (O).

Abstract: A lithium ion conductive glass ceramics which solves a problem of low thermal stability of the related-art lithium ion conductive glass ceramics and which is high in lithium ion conductivity, high in thermal stability of a raw glass and easy for molding is provided. The amount of a specified component in a glass ceramics (raw glass) is limited to a specified range, and specifically, a ZrO2 component is incorporated in the range of from 0.5% to 2.5% in terms of % by mass on the oxide basis.

Abstract: A process for making a solid electrolyte for an electrochemical cell. The process includes providing a multilayer material having a porous layer and a nonporous layer, the nonporous layer containing a first oxide selected from alpha-alumina, gamma-alumina, alpha-gallium oxide, and/or combinations thereof. In addition, an alkali-metal oxide vapor is provided and the nonporous layer is exposed to the alkali-metal oxide vapor at an elevated temperature such that the nonporous layer is converted to a solid second oxide electrolyte layer that is conductive to alkali metal ions. The second oxide is an alkali-metal-beta-alumina, alkali-metal-beta?-alumina, alkali-metal-beta-gallate, and/or alkali-metal-beta?-gallate.

Abstract: Provided is a solid electrolyte including an epitaxial thin film crystal made of an electrolyte containing at least lithium.

Abstract: A new battery configuration and process are detailed. The battery cell includes a solid electrolyte configured with an engineered metallization layer that distributes sodium across the surface of the electrolyte extending the active area of the cathode in contact with the anode during operation. The metallization layer enhances performance, efficiency, and capacity of sodium batteries at intermediate temperatures at or below about 200° C.

Abstract: A main object of the present invention is to provide a solid electrolyte material having excellent Li ion conductivity. To attain the object, the present invention provides a solid electrolyte material represented by a general formula: Lix(La1-aM1a)y(Ti1-bM2b)zO?, wherein “x”, “y”, and “z” satisfy relations of x+y+z=1, 0.850?x/(x+y+z)?0.930, and 0.087?y/(y+z)?0.115; “a” is 0?a?1; “b” is 0?b?1; “?” is 0.8???1.2; “M1” is at least one selected from the group consisting of Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, and Ba; and “M2” is at least one selected from the group consisting of Mg, W, Mn, Al, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr, and Ga.

Abstract: A sulfide-based lithium-ion-conducting solid electrolyte glass is formed from sulfide-based lithium-ion-conducting solid electrolyte, and ?-alumina.

Abstract: Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

Abstract: Provided is a positive electrode active material for a lithium secondary battery including a positive electrode active material particle and an electrolyte-containing metal oxide coating layer having a porous structure and a method of manufacturing the same. A lithium secondary battery to which the positive electrode active material including the electrolyte-containing metal oxide coating layer is applied can have improved charge/discharge efficiency and lifespan characteristics at the same time.

Abstract: A nonaqueous electrolyte composition includes: a nonaqueous solvent; an electrolyte salt; a matrix resin; a filler; and a surfactant.

Abstract: A sodium-chalcogen cell is described which is operable at room temperature, in particular a sodium-sulfur or sodium-oxygen cell, the anode and cathode of which are separated by a solid electrolyte which is conductive for sodium ions and nonconductive for electrons. The cathode of the sodium-chalcogen cell includes a solid electrolyte which is conductive for sodium ions and electrons. Moreover, a manufacturing method for this type of sodium-chalcogen cell is described.

Abstract: The invention relates to an electrode unit for an electrochemical device for storing electrical energy, comprising a solid electrolyte (3) and a porous electrode (7), the solid electrolyte (3) dividing a compartment for cathode material and a compartment for anode material and the porous electrode (7) being extensively connected to the solid electrolyte (3) and the cathode material flowing along the porous electrode (7) during discharging. On the side remote from the solid electrolyte (3), the porous electrode (7) is covered towards the compartment for the cathode material with a segment wall (9), the segment wall (9) comprising inlet openings (15) in the direction of flow of the cathode material, through which the cathode material penetrates into the porous electrode (7), reacts chemically with the anode material in the porous electrode (7) and emerges back out of the porous electrode (7) through outlet openings (17) downstream in the direction of flow.

Abstract: The present invention provides a lithium-sulfur battery using a solid high-ionic conductor in a three-dimensional (3D) porous structure. In particular, at a higher temperature (120° C. or higher) than a melting temperature, the lithium-sulfur battery does not have fluid sulfur leaking outside of a battery cell electrode. The lithium-sulfur battery can be operated at both a high temperature and room temperature. The battery of the invention can be used without performance degradation and with increased ion conductivity at a high temperature, thus improving the battery's power performance.

Abstract: The invention relates to a unique battery having a physicochemically active membrane separator/electrolyte-electrode monolith and method of making the same. The Applicant's invented battery employs a physicochemically active membrane separator/electrolyte-electrode that acts as a separator, electrolyte, and electrode, within the same monolithic structure. The chemical composition, physical arrangement of molecules, and physical geometry of the pores play a role in the sequestration and conduction of ions. In one preferred embodiment, ions are transported via the ion-hoping mechanism where the oxygens of the Al2O3 wall are available for positive ion coordination (i.e. Li+). This active membrane-electrode composite can be adjusted to a desired level of ion conductivity by manipulating the chemical composition and structure of the pore wall to either increase or decrease ion conduction.

Abstract: A non-aqueous electrochemical cell is disclosed having a heat-resistant coating on at least one of a negative electrode, a positive electrode, and a separator, if provided. The heat-resistant coating may consume heat in the cell to stabilize the cell, act as an electrical insulator to prevent the cell from short circuiting, and increase the mechanical strength and compression resistance of the coated component. In certain embodiments, the heat-resistant coating serves as a solid state electrolyte to produce a solid state electrochemical cell.

Abstract: The invention relates to a lithium vanadium oxide which corresponds to the formula Li1+?V3O8 (0.1???0.25). It is composed of agglomerates of small needles having a length l from 400 to 1000 nm, a width w such that 10<l/w<100 and a thickness t such that 10<l/t<100. It is obtained by a process consisting in preparing a precursor gel by bringing ?-V2O5 and a Li precursor into contact in amounts such that the ratio of the concentrations [V2O5]/[Li] is between 1.15 and 1.5 and in subjecting the gel to a heat treatment comprising a first stage at 80° C.-150° C. for 3 h to 15 days and a second stage between 250° C. and 350° C. for 4 min to 1 hour, under a nitrogen or argon atmosphere. It is useful as an active material of a positive electrode.