MXPA97008175A - Electroquimica de li secondary cell - Google Patents

Abstract

The present invention relates to active materials for the oxygen deficient splints Li + xMn2-xO4-Ð, where less equal x less equal 0.33 and 0.01 less equal to less equal 0.5, for a secondary electrochemical element of lithium. Its range of occurrence in the phase diagram for the manganese and lithium oxide compounds delimited at their corners by MnO, MnO2 and Li2MnO3 is defined by the corner compounds of LiMn2O4, Li2Mn4O7, Li8Mn10O21, Li4 / 3Mn5 / 3o4, with the exception of of all the compounds located along the lines Limn2o4-Li4 / 3Mn5 / 3O4 and LiMn2o4-Li2Mn2O4. Spinels are produced by a modified ceramic process from a mixture of starting materials containing Li and Mn whose reaction product is reduced calcined in an Ar / H2 atmosphere. The x fraction of Li can be partially or completely replaced by foreign monovalent or polyvalent cations from the series consisting of Co, Mg, Zn, Ni, Ca, Bi, Ti, V, Rh and

Description

LITHIUM ELECTROCHEMICAL SECONDARY CELL DESCRIPTION OF THE INVENTION The invention relates to a secondary electrochemical cell having a negative electrode containing lithium as the active material, having a positive electrode containing a spinel of manganese oxide and lithium as the active material and having a non-aqueous electrolyte. The field of application of the invention therefore encompasses all secondary cells whose negative electrodes are composed of lithium metal, a lithium alloy or a carbon material that allows intercalation with Li. The importance of lithium oxide and manganese spinels for the development of novel rechargeable battery systems already emerges from a series of patent publications, for example US publications 4707371, US-PS 4828834, US-PS 4904552, US-PS 5240794. Representatives of this group of compounds which are particularly suitable as active material of the electrode crystallize in a spinel lattice having a closed cubic packing arrangement of the oxygen atoms, for example LiMn2Δ4 and L2. MnsO - ^ - The extraction of Li from LiMn2? 4 with a dilute mineral acid (H2SO4, H3PO4, HNO3, HCIO4 or HCl) or even by electrochemical means results in the formation of a? -Mn? 2- The latter has a defective spinel structure with a reduced grid constant. Other compounds such as LiMn? 2 have an octahedrally crosslinked salt crosslinker. In the L2Mn3, the oxygen atoms form a cubic closed package in which the Li + and Mn ^ + ions are distributed by themselves over the octahedral holes in sequence of alternating layers. The compounds LiMn2? 4 and LÍ4Mn5? - | 2 mentioned are stoichiometric spinels (Germán Offenlegungsschrift 4119944). LiMn2? 4, which is frequently used as a cathode in cells and rechargeable batteries, is produced by causing a lithium salt or lithium hydroxide to react with a manganese oxide at temperatures above 750 ° C. In the cubic oxygen reticle of the spinel of LiMn2? 4, the Li + ions are located in tetrahedral holes and the Mn3 + / M4 + ions in octahedral holes. The grid constant is 8.25 Á. Most spinels of Li4M 5? P2 rich in lithium can also be described by the formula Li [L? / 3Mn5 / 3]? 4 both stoichiometrically and with respect to the atomic distribution. How? -n? 2 contains only 4-valent manganese. The symmetry of the crystal is also cubic, but, due to the substitution of the large ions of Mn3 + (r = 0.645 Á), which forms half of the manganese in the LiMn2? 4 for the smaller ions Mn4 + (r = 0.530 A) the constant of the crosslinked is substantially reduced to 8.17 A). Although the replacement of Mn3 + by Li + according to 3 Mn3 +? Li + + 2 Mn4 + results in a higher Li content in the L4Mn5? I2 in total, when compared to that of the LiMn2? 4, the concentration of the electrochemically active Li does not increase since only the lithium located in the gaps Tetrahedral is accessible under normal potential conditions for an electrochemical intercalation and deintercation. This is because the lithium intercalated additionally shares the octahedral spaces with the manganese and is immobilized in those points. It is also known that lithium batteries can be operated at 4V and at 3V with manganese oxide and lithium compounds as the cathode material. If the LiMn2? 4 spinel is the discharge product, it can be recharged by Li de-interleaving, as a result of which the average oxidation level of Mn increases from 3.5 to 4 (in the? -Mn? 2). Such cathode material, which corresponds to the general composition of Li1.xMn2? 4 where 0 < x < 1, can be used for a 4V system. The structure of the spinel is retained over the range of the total composition and the ratio of Mn / O is constant. In the case of a 3V system, the LiMn2? 4 spinel is the cathode material of the general composition of Lil +? Mn2? 4, where 0 < x < 1, in the loaded state. This discharge (intercalation of Li) results finally in the L2M 2? 4 with tetragonal crystal symmetry. The material of the electrode consequently becomes the material of phase 2, with the disadvantageous consequences that the reversibility of the electrode reaction decreases (reduced resistance to forming a cycle) and that the Mn ions present in the phase of L2Mn2 ? 4, exclusively in the 3-valent state tends to disproportionate according to 2 Mn ^ + - »Mn4 + + Mn2 +, Mn2 +, in which process they dissolve in the electrolyte, like Mn2 +. In order to stop, at least partially, the tetragonal distortion of the spinel structure, Germán Offenlegungsschrift 4328755 has already proposed a stoichiometry Li1 + xMn2 - ?? 4 + d, where 0 < X < 0.33 and 0 < § < 0.5, for the material of the cathode, in which the connection of the variable parameters x and g can be chosen in such a way that, in the unloaded state in which it is used, the material must still have a cubic symmetry (reticulated spinel ) and the average degree of oxidation of Mn is not below 3.5. In contrast to the "oxygen-rich" spinels mentioned in the above is a spinel of Li (Li- | / 3Mn5 / 3)? 4_d, deficient in oxygen, which was characterized by M. N. Richard et al. (Solid State lonics 73 (1994), 81-91). Here an increased § (deficient in oxygen) is responsible for an average degree of oxidation of Mn which decreases from 4 to 3.5. As a result, Li can be deinterleaved, with simultaneous oxidation of the Mn3 +, with the result that such a spinel can also be used as a reversible functioning cathode material. Common in all known Li-rich spinels of the type Li1 + xMn2 - ?? 4 and all the oxygen-rich spinels of the type Li1.xMn2 - ?? 4 + d is at a true density and a relatively low bulk density with globulitic crystallites large and the relatively large BET surface (> 3 m ^ / g). Capacities achievable with cathode materials can vary between 1 20 mAh / g and 10 mAh / g, depending on the value of x. Compounds of the type Li1 + xMn2? 4 have, as soon as the stoichiometry of L2 n2? 4 approaches, their tetragonal crystal structures (two-phase region) and are therefore no larger in the region of existence of cubic spinels from the point of view of crystal chemistry. In addition these 3V materials rich in Li, particularly LÍ2Mn2? 4, are currently unstable in the air and are sensitive to moisture. In most cases, improved storage capacities at high temperatures and satisfactory cyclization stability are obtained only at the expense of low capacities. The object of the invention is therefore to provide a cathode material at the base of an oxide spinel. manganese and lithium, which is free as much as possible of the deficiencies mentioned above and can be used in lithium batteries to be operated at 3V or 4V. The object is carried out, according to the invention, by a secondary electrochemical cell having a positive electrode, as defined in claim 1 of the patent. It has been found that the manganese oxide and lithium spinels of the composition Li1 + xMn2-x? 4_§, wherein 0 < x < 0.33 and 0.01 < § < 0.5, completely fill the expectations. However, all compounds for which x = 1 / 2§ ± 0.01 are excluded, where x is dependent on § in the aforementioned relationship. Preferred values are 0.02 < d = ° -5 > in particular 0.05 < d = 0.5 The values of x and 5 in the manganese oxide spinels according to the invention are at the same time such that the oxidation level of the central manganese cation is between 3.0 and 4.0. Under these circumstances, the compounds are O-deficient spinels, which are preferably composed of individual phases and can be classified as cubic. Particularly advantageous spinels according to the invention satisfy the composition L1? + x n2 - ?? 4_d, where 0 < x < 0.33 and 0.05 < = 0.5, excluding all compositions where x = 1? § ± 0.05.

The spinels according to the invention are suitable as an electrode material in secondary lithium batteries, where they impart to the secondary batteries an improved initial capacity, cyclization stability and insensibility for storage at high temperatures. In addition, novel lithium manganese oxide spinels have, compared to known spinels, almost twice the bulk density, resulting in a duplication of the volumetric energy density expressed in watts per liter. In these spinels, the oxidation level of the central manganese cation must be within limits 3.4 and 3.8. In a variant of the spinels according to the invention, the excess Li of x extending beyond the Li-j n can be replaced partially or totally by monovalent or multivalent cations. Preferably, elements Co, Mg, Zn, Ni, Ca, Bi, Ti, V, Rh and Cu are suitable for such partial substitution of Li. The quantitative proportion of the mixture of foreign adulterated products depends on the valence of the related cation. If D is the adulterated element and b is the valence, the general formula for such a spinel is Li1 Dx / kMn2-xb, 4- if the x component of total Li is replaced with D. For better understanding, the invention is explained below with reference to a few diagrammatic figures.

Figure 1 shows a phase diagram for manganese oxide and lithium compounds. Figure 2 shows an elongation of a portion of the phase diagram of Figure 1. Figure 3 shows the diffractogram of X-ray energy of an oxygen-deficient spinel according to the invention. Figure 4 shows the oxidation rates of the manganese central cation of the oxygen deficient spinels as a function of the Li content. Figure 5 shows the discharge capacities of the O-deficient spinels as a function of the Li content. Figure 6 shows the influence of a storage at high temperature on the behavior of the capacity of the O-deficient spinels. According to Figure 1, an isosceles triangle drawn between its corner points with MnO, Mn? 2 and L2Mn? 3 to represent the phase relationships between the defined manganese oxide and lithium spinels. In this phase diagram, spinels are derived from the general formula Li1 + xMn2-? 4 + d, where 0 < x < 0.33 and 0 < d < 0.5 and already described in the patent literature (see Germán Offenlegungsschrift 4328755) are located in the triangle defined by the corner points LiMn2? 4, L¡4 / 3Mn5 / 3? 4 and L¡2Mn4? G. The region of The existence of the known spinels also includes the connecting lines between the corner points. The connection line between LiMn2Ü4 and L¡4 / 3Mn5 / 3? 4, for example, also characterizes an individual phase transition between two "ideal" spinel phases. For the purpose of a better summary of the phase relationship, the lines extending parallel to the side of the L2Mn? 3 ~ Mn? 2 in the diagram show the respective degree of oxidation of the manganese at the intersection with the MnO- side. Mn? 2- On the other hand, the lines (a) that extend obliquely through the triangle indicate the direction in which the de-interleaving and re-interleaving of the lithium occurs. In this way, the de-interleaving of the lithium, for example of the LiMn2? 4 ends theoretically - to -Mn? 2- The lines that extend obliquely are therefore characteristic lines of the load / discharge. The region of existence of spinels according to the invention has oxygen deficiency, therefore they extend within the area defined by the four corner points of LiMn2? 4, L¡2Mn4? 7, LigMn1 or? 2i and LÍ4 / 3Mn5 / 3? 4, except for all those compounds which are in the connection line of LiMn2? 4-L¡2Mn2? 4 (described in the publication of the United States 5196279) and except for the known compounds located in the line of Connection LiMn2? 4 > L4 / 3Mn5 / 3? 4. including corner compounds (see US-PS 5316877). As is evident, the degree of oxidation of the central manganese cation can assume values between 3.0 (in L2Mn4? 7) and 4.0 (in L4 / 3Mn5 / 3? 4) within this region. The outer corner points of L¡2Mn4? 7 and LigMn < ? or? 21 result from the general formula according to claim 1 as a result of substituting x = 0 and d = 0.5 or x = 0.33 and d = 0.5 and normalization to atomic parameters of integer. As is further evident from the diagram, the novel cathode material comprises oxidation grades of manganese from 3.0 to 4.0. Therefore, in the case of more Li-rich compositions this can be used for 3V systems and in the case of more Li-poor compositions for 4V systems. Further details about the region of existence of O-deficient spinels according to the invention can be obtained from the elongated portion of the phase diagram according to Figure 2. The range defined by patent claim 1 is limited by the connecting lines < 1.0Mn2.??3.99 - Li1.0Mn2.0O3.5 (= Li2Mn 07), »1.0M 2.??3.5-L¡? .33Mn- | .67? 3.5? («4 / 3Mn5 / 3 ° 3.50 = LÍ8Mn- | o? 2l).

L¡? .33Mn1.67 ° 3.50 - l1.33Mn1.67 ° 3.99 (i4 / 3Mn5 / 3 ° 3.99). '1.33Mn1.67 ° 3.99 - H .03Mn2.0 ° 3.99. of all those compositions that are made for which they are in the connection line of Li-j Q n2.o? 4 -L¡? .25Mn? .7503.50 »- which are distinguished by the constant ratio of Mn / O of 1: 2 and which are already described in US-PS 5196279. Also excepted is a range around the connecting line which extends between the equine compounds of L¡- | , 0Mn2.0 ° 3.99. i1.24Mnl .76 ° 3.50.

Li1.26Mn1.74 ° 3.50 and i1.01Mn1.99 ° 3.99 and is generally defined by Li < j + xMn2 - ?? 4_d, where 0.1 < d < 0.5 and x = 1/2 d ± 0.01. However, preferably the region exempted from the region of existence of spinels according to the invention is located between the corner compounds of Li1.0Mn2.0O3.99, L?? .2? Mi.80 ° 3.50 > L "1.3? Mn? 70O3.50 and Li1.07M1.93O3.95. This results from the general formula if 0. 05 < d < 0.5 and x = 1/2 d ± 0.05. The spinels located in the connection line of L? QMn2.o? 4 - L¡43Mn5 / 3? 4 are not oxygen deficient and form a simple phase transition. The oxygen-deficient spinels according to the invention are produced by a ceramic process which It is per se, usually standard for spinels. The process includes the following stages: a. reaction of a constituent containing lithium selected from the group consisting of lithium salts LiOH x H2O, LÍ2CO3 with a manganese oxide at temperatures between 350 ° C and 900 ° C, b. subsequent calcination of the material from 500 ° C to 850 ° C and optionally gradual cooling. In an advantageous modification of the process, the indication is made, according to the invention, that, after the reaction of the constituent containing lithium with manganese oxide, the reaction product is treated in an atmosphere of Ar / H2 of 600 °. C at 850 ° C, that the cooling of the material obtained at room temperature takes place under Ar / H2, and that this is followed by subsequent calcination of the material from 500 ° C to 850 ° C and optionally gradual cooling under Ar /? 2- Cooling under Ar / H2 can take place with slow annealing; however, rapid cooling may also be advantageous. Not only electrolytic manganese dioxide (EMD) can be used as the starting material, but also chemically produced manganese dioxide (CMD), P-CMD, NMD (pyrolusite) or ß- n? 2 in addition to the salts of Li, LiOH x H2O or LÍ2CO3. The P-CMD is particularly suitable for the synthesis of ceramics named as the first one involving stages a, b. The P-CM D is a fine pore -Mn? 2 which is prepared according to US-PS 5277890 by means of wet chemistry from MnSO4 and Na2S2? G. The water content of LiOH can vary between x = 0 and x = 2. The calcination temperature of the mixture prepared stoichiometrically during phase a, is in the range of 350 ° C to 900 ° C and the annealing time is 4 to 80 hours (in air). The spinels obtained under these conditions are remarkable for the true density and the high bulk density. The preparation takes place, for example, as follows: Synthesis 1: To prepare a spinel of the stoichiometric composition L? 04 ^ n? .96O3.94, 15,000 g of P-CMD and 3.6295 g of LiOH • I H2O are intimately crushed in an agate mortar, the mixture obtained is calcined in a corundum crucible in air for 4 hours at 750 ° C, removed from the oven at that temperature, cooled to room temperature in air, finally crushed again, calcined for an additional 16 hours at 750 ° C and finally cooled in air after having been removed again from the oven at the preparation temperature.

The individual phase nature of the material obtained can be demonstrated by means of an X-ray energy diffractogram. In this process, a cross-linking constant of a-8.237 A is determined. The average oxidation level of the manganese is determined (degree of oxidation) by potentiometric titration (Fe (ll) / Ce (IV)) and found to be 3.49. The Li content and the Mn content of the specimen can be determined by ICP analysis. In the modified ceramic synthesis, both preparations freshly prepared from step a and the substances obtained from synthesis 1 can serve as precursors. These are now subjected to a calcination treatment in the presence of a mixture of gases of Ar / 8% H2, wherein this treatment decomposes the spinels to form a product containing low valence manganese, preferably Mn? *. A direct reduction of the initial spinel to a defined oxygen content deficient in principle is possible, but requires analytical monitoring from case to case. According to the invention, the reductive decomposition is therefore followed by a repeated treatment of calcination in an atmosphere of Ar /? 2 in order to oxidize to a certain oxygen content, the cooling at the end is carried out in the same protective atmosphere that contains little oxygen. The final product obtained has a defined oxygen deficiency and is also a single phase compound. After the treatments, temperatures are used which have served to prepare the precursor: 350 ° C to 900 ° C. The preparation of an O-deficient spinel without interruption is possible, for example, in the following way: Synthesis 2: To prepare a spinel of composition Li. Mni 9O3.90, 12.7663 g of CM D and 3.3534 g of LiOH x H2O are intimately crushed in an agate mortar, the obtained mixture is calcined in a corundum crucible for 4 hours in air at 700 ° C, removed from the oven this temperature, cooled to room temperature in air, finely ground, again calcined for an additional 16 hours at 700 ° C and finally cooled in air after having been removed again from the oven at the preparation temperature. The material obtained is now decomposed during 3 hours at 700 ° C in Ar / H2 and stopped at room temperature under Ar / H2- The desired final product is obtained by additional treatment for 3.5 hours at 700 ° C, then for 2 hours at 650 ° C with Ar / 8% of O2 and cool in this gas mixture.

From the X-ray energy diffractogram, Figure 3 is shown, which can be classified as cubic and confirms the individual phase nature of the material, a reticulated constant of a - 8.236 for this spinel. The average oxidation level of manganese is determined by potentiometric titration (Fe (ll) / Ce (IV)) and found to be 3.53 (theoretical 3.53). The Li content and the Mn content of the specimen is determined as in the case of synthesis 1 by ICP analysis. Spinel Li1 .1 Mn1 .gO3.go prepared by synthesis 2 is shown in Figure 2 (elongation of a portion of the phase diagram) as an asterisk. The O-deficient spinels according to the invention, which are obtained by syntheses 2, are in the same upper segment of the individual phase region, but are not represented graphically. For the preparations which are completely identical in each case with respect to the weight of the initial material, the analysis results in small differences in the content of O, depending on whether ß-Mn? 2 or CMD has been used as starting material. These preparations have the following compositions: Li 1 .2Mn1 .9O3.93 (ß-Mn02) Li? . : Mn? .803.96 (CMD) li? .3Mn? . 03. B4 (ß-Mn02) Their positions in the phase diagram are denoted by Z and Z2, respectively. The establishment of some high oxygen deficiency seems to be promoted by the use of ß-Mn? 2- In a modification of the invention metal compounds containing multivalent metal cations instead of some lithium compounds as starting substances can be Also included in the synthesis described, with the result that the lithium manganese spinels are produced, which contain a strange adulteration and have an oxygen deficiency. The oxides, carbonates or salts of metals from the series consisting of Co, Mg, Zn, Ni, Ca, Bi, Ti, V, Rh and Cu, and possibly also the pure elements are, for example, suitable for the reaction . The crosslinking constants of the O-deficient spinels according to the invention are virtually identical to those of the known spinels which are described by the general formula Li + xMn2-x? 4 + d, where 0 < x < 0.33 and 0 < < 0.5 (see 5316877). With the increased values of x they exhibit a linear drop of a - 8.25 A at x = 0 to about 8.16 A at x = 0.33. The contraction of the lattice in this direction is in accordance with the expectations since, in Li1.33Mn1 .57O4, all the manganese is present in the tetravalent state and the Mn ^ + ions have a smaller radius than the Mn3 + ions. The crosslinked constants therefore do not in their own proportion indicate any presence of an O-deficient spinel. On the other hand, the non-linear dependence of the oxidation level of the manganese (degree of oxidation) on the x content of lithium it is remarkable for the O-deficient spinels. In this connection, the ratio of Mn4 + / Mn3 + plays a decisive role for the spinel capacity of manganese dioxide and lithium for the Li extraction and the Li intercalation, which can take place either chemically or electrochemically. Figure 4 shows how the degree of oxidation (ratio Mn4 + / Mn3 +) is altered within the phase of the spinel Li? + xMn2 - ?? 4 + d when x increases. For = 0, the degree of oxidation increases linearly (calculated straight line) until the intercalation of Li ends at x = 1/3 in the spinel L4 / 3Mn5 / 3? 4. Despite its high Li content, Li de-interleaving is not possible (theoretically, a specific capacity of 216 mAh must be achievable if all Lix are reversibly cyclized) since all manganese is present as Mn4 + and its further oxidation is not possible under normal conditions. However, if the spinel has an oxygen deficiency -§ > 0, according to the invention, Figure 4 shows that this substance, whose increases in the contents x of Li and correspond here to increased oxygen deficiencies, - = 0.2, have a regularly strong deviation from the ratio Mn4 + / Mn3 + from of the straight line calculated in favor of a residual content of Mn3 +. The degree of oxidation is preferable between 3.5 and 3.8. This means that, since its residual content of Mn3 +, even the spinel L4 / 3Mn5 3? 4"d can still be cycled with a corresponding low capacity of about 20 to 50 mAh / g. Only the nonlinear dependence of the oxidation degree of Mn on x, the non-linear dependence - which inevitably follows after it - of the discharge capacity on x is a reliable criterion for the presence of an O-deficient spinel. The last relationship will become clear from Figure 5. In the latter, the discharge capacities C [mAh / g] - each measurement after 5 cycles - are plotted for a plurality of O-deficient spinels against the content x of Li. While all Mn must be tetravalent in the case of known spinels without oxygen deficiency for x = 0.33 and no discharge is possible, the actually observed capacity of approximately 40 mAh / g provides evidence for the fact that an O-deficient spinel is present. It is further found that, from the various grades of manganese oxide used to produce the spinels, the ß- Mn? 2 apparently has a particularly favorable effect on capacity characteristics. This is in accordance with the observation, already mentioned that ß-Mn? 2 has a tendency to produce some oxygen deficiency greater than CMD. The preferred form of ß-Mn? 2 for the ceramic synthesis of O-deficient spinels also finds confirmation in the fact that, in the case of these preparations, the loss of capacity which has to be accepted as a result of storage at high temperatures (HT) it is comparatively low. In this way, it can be observed from Figure 6, that the spinels according to the invention, produced with ß-Mn? 2 have capacity losses? C [%] of only between 0% and 15% after the discharge of the fifth cycle, which is preceded by a storage of 7 days at HT at 60 ° C, compared with specimens which are not stored at HT, while the capacity losses due to storage at HT appreciably they vary in the case of spinels produced with CMD and up to 35% higher. However, after all, the O-deficient spinels according to the invention are also notable for the good cycling stability and average discharge voltage slightly higher than the known spinels of the type L 1? + xMn2 - ?? 4 + d. As a result of the special production process involving temporary exposure to an Ar / H2 atmosphere (synthesis 2), a true density and higher apparent density is reached than in the case for synthesis 1. Consequently, O-deficient spinels are particularly suitable for improving the energy density per unit volume of blow cells and prismatic cells.

Claims (6)

1 . An electrochemical secondary cell having a negative electrode containing lithium as the active material, having a positive electrode containing a spinel of manganese oxide and lithium as the active material and having a non-aqueous electrolyte, characterized in that the material of the positive electrode is an oxygen deficient lithium manganese oxide spinel of the general composition Li? + xMn2? 4"d, where 0 < x < 0.33 and 0.01 < d = 0.5, excluding all compositions where x = V2 § ± 0.01.

2. The electrochemical secondary cell according to claim 1, characterized in that the material of the positive electrode is a spinel of manganese oxide and lithium deficient in oxygen of the general composition Li? + xMn2-x? 4_d, where 0 < x < 0.33 and 0.05 < d = 0.5, excluding all compositions where x = 1 / 2delta ± 0.05.

3. The electrochemical secondary cell according to any of claims 1 or 2, characterized in that some of the x component of Li is replaced by an additional multivalent or monovalent metallic cation selected from the series consisting of Co, Mg, Zn, Ni, Ca, Bi, Ti, V, Rh and Cu.

4. A method for producing an oxygen deficient spinel as an active material for the positive electrode of a secondary electrochemical cell according to any of claims 1 or 2, the method is characterized in that it comprises the following steps. to. reaction of a constituent containing lithium selected from the group consisting of lithium salts LiOH x H2O, LÍ2CO3 with a manganese oxide at temperatures between 350 ° C and 900 ° C, b. subsequent calcination of the material from 500 ° C to 850 ° C and cooling.

5. The method according to claim 4, characterized in that after the lithium-containing constituent has reacted with the manganese oxide, the reaction product is treated in an Ar / H2 atmosphere of 600 ° C to 850 ° C and the material obtained is cooled to room temperature Ar / H2 and where it is followed by calcination Rear of the material from 500 ° C to 850 ° C and cooling under Ar / O2.

6. The method according to any of claims 4 or 5, characterized in that in addition to the constituent containing lithium, an oxide, a carbonate or a compound similar to a salt of one of the metals of Co, Mg, Zn, Ni, is used, Ca, Bi, Ti, V, Rh and Cu, and optionally also the pure metal as an additional co-reactant.