MXPA99000374A - Method for preparing mixed amorphous vanadium oxides and their use as electrodes in reachargeable lithium cells - Google Patents

Abstract

A method for preparing an amorphous ternary lithiated vanadium metal oxide of the formula LixMyVzO(x+5z+ny)/2, where M is a metal, 0

Description

METHOD FOR THE PREPARATION OF MIXTOß AMORPHOS VANADIO OXIDES, AND THEIR USE AS ELECTRODES IN RECHARGEABLE LITHIUM CELLS BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to a novel method for the synthesis of a vanadium metal oxide, lithiated, ternary, amorphous, of the formula LixMyVzO (X + 5z + ny) / 2 where M is a metal, 0 <1. x < 3, 0 < and < 3, 1 < < 4, and n = 2 or 3; to a novel method for the preparation of a non-lithiated, binary, amorphous vanadium metal oxide of the formula yV2? (52 + ny) 2 / where M is a metal, 0 < and < 3, 1 < < 4, and n = 2 or 3; and a rechargeable, lithiated, intercalation battery cell comprising a positive electrode, a negative electrode, and an electrolyte, wherein the active material of the negative electrode is a lithiated, ternary, amorphous vanadium metal oxide (Li-MVO) of the formula LixMyV-0 (? + 5z + ny) 2 or a non-lithiated, binary, amorphous vanadium metal oxide (MV-0) of the formula REF: 29236 MyVzO (5- + ny) / 2, prepared according to the methods of the present invention. (2) Decription of the Previous Technique The secondary lithium ion cells represent an economically important sector of the battery market. A significant commercial mode of such secondary cells employs a lithiated metal intercalation oxide, such as the positive electrode, and a carbonaceous material such as the negative electrode. Such typical cells are described in U.S. Patent No. 5,460,904, which is incorporated by reference herein. The commonly used lithiated metal oxides include LiCo02, LiNi02 / and LiMn204 / of which LiCo02 is the most widely used material. A common feature of all these lithiated metallic oxides is that only about 0.5 lithium atoms per transition metal can be practically used at the cell loading / unloading sites. The investigations continue in the search for materials. of electrode more bar-at-os, better and -má-s efficient-} .

Attempts to increase the capacity of such cells are mainly focused on four areas: (1) the improvement of existing oxides based on cobalt, nickel or manganese; (2) the search for new lithiated metallic oxides, suitable for use in lithiated intercalation cells; (3) the improvement of the electrochemical characteristics of the carbonaceous negative electrode; and (4) the finding of alternative materials to replace the carbonaceous negative electrode in the lithiated intercalation cells. Several researchers have sought, with limited success, to improve the reversible capacity of the carbonaceous material in a lithiated intercalation cell. J. Dahn et al. Attempted to improve the electrochemical characteristics of the carbonaceous material by means of the pyrolytic processing of organic materials to obtain a carbonaceous electrode material. J. Dahn et al., Lithium batteries, (1994). F. Disma et al. Has explored the mechanical processing of negative electrode material to increase its electrochemical capacity. Unfortunately, these procedures have not proven to be significantly successful.

Recently, Yoshio et al. In the application of Japanese Patent JP 106642/92 and Guyomard et al., C.R. Acad. Sci. Paris, 320, 523 (1995), suggested a possible new procedure in negative electrode technology. These two research groups discovered that some electrodes based on lithiated vanadium oxide (initially sought as potential candidates for positive electrode materials), when discharged at lower voltages of approximately 0.2 V, could reversibly intercalate lithium ions in amounts up to approximately 7 lithium atoms per transition metal atom. However, these descriptions indicated that such lithiated vanadium oxide based electrodes were problematic when used as electrodes. Guyomard et al. Produced their lithiated vanadium oxides by means of an initial crystallization, a process which severely limits its suitability as an electrode material in commercial cells. Yoshio et al. Described the lithium metal oxide compounds that had been manufactured by means of a method which required calcination and annealing at temperatures above 500 ° C for a period of several days. In addition, Yoshio's coiapuesto-s; also suffered an initial crystallization, as well as containing also large numbers of diverse metallic elements that tend to become amorphous after the initial discharge. Thus, a need remains for an efficient and effective synthesis of non-lithiated, amorphous lithiated, vanadium oxide materials which are suitable for use as the active material in the negative electrodes of commercially significant lithiated secondary intercalation cells. .

BRIEF DESCRIPTION OF THE INVENTION Accordingly, an object of the present invention is to provide a novel method for synthesizing an amorphous, ternary, ternary vanadium metal oxide of the formula LixMyVzO (x + Sz + ny) /-./ where M is a metal, 0 <1. x < 3, 0 < y = 3, 1 = z < 4, and n = 2 or 3, which produces the metal oxide of vanadium lithiated, ternary in an amorphous form by means of an efficient and simple synthesis. Still another object of the present invention is to provide a novel method for preparing an amorphous, non-lithiated, non-lithiated vanadium metal oxide of the formula MyVz0 (bZ.ny) where M is a metal, 0 < and < 3, 1 < < 4, and n = 2 or 3, which produces the non-lithiated, binary vanadium metal oxide in an amorphous form by means of an efficient and simple synthesis. Still another objective of the present invention is to provide a rechargeable, lithiated, interleaving battery cell comprising a positive electrode, a negative electrode, and an electrolyte, wherein the active material of the negative electrode is a lithiated vanadium metal oxide, ternary , amorphous of the formula LixMyVzO (? + Sz + ny) / 2 or a non-lithiated, binary, amorphous vanadium metal oxide of the formula prepared according to the methods of the present invention. These objectives, among others, have been achieved by means of a method for the preparation of a metal oxide of vanadium lithiated, ternary, amorphous of the formula LixMyVzO (X + 5Z + ny) / 2, where M is a metal, 0 < x < 3, 0 < and < 3, 1 < < 4, and n = 2 or 3, comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03, and a nitrate salt of the formula 1A (N0Ó) O, which contains a large excess of a lithium salt; the heating of the solution; the addition of a sufficient amount of a base to obtain a pH greater than 8; and the precipitation of the amorphous lithiated vanadium metal oxide. In addition, these objectives, among others, have been achieved by means of a method for the preparation of a non-lithiated, binary, amorphous vanadium metal oxide of the formula MyVzO (5z + ny) / 2, where M is a metal, < and < 3, 1 = z - = 4, and n = 2 or 3, comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03, and a nitrate salt of the formula (M (N? 3) n) the heating of the solution, the addition of a sufficient amount of an acid to obtain a suitable pH for the solution, the addition of a sufficient amount of a base to obtain a pH suitable for precipitation Furthermore, these objectives, among others, have been achieved by means of a non-aqueous secondary cell comprising an active negative electrode material, an active positive electrode material and an electrolyte non-lithium. aqueous, wherein said active negative electrode material is a lithiated, ternary, amorphous vanadium metal oxide of the formula LixMyVz0 (X + Sz + ny) / 2 / where M is a metal 0 <x <3, 0 <; and < 3, l = z < 4, and n = 2 or 3, said or Litiated, ternary, amorphous vanadium metal oxide prepared by a process comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03 / and a nitrate salt of the formula M (N03) ) n. which contains a large excess of a lithium salt; the heating of the solution; the addition of a sufficient amount of a base to obtain a pH greater than 8; and the precipitation of the lithiated, amorphous vanadium metal oxide. In addition, these objectives, among others, have been achieved by means of a non-aqueous secondary cell comprising an active negative electrode material, an active positive electrode material and a non-aqueous electrolyte, wherein said active negative electrode material is a non-lithiated, binary, amorphous vanadium metal oxide of the formula MyVzO (az + - y)? z, where M is a metal, 0 <; and < 3, 1 < < 4, and n = 2 or 3, said non-lithiated, binary, amorphous vanadium metal oxide is prepared by a process comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NHV03 and NaV03, and a nitrate salt of the formula M (NO-) n, where n = 2 or 3; the heating of the solution; the addition of a sufficient amount of an acid to obtain a p-H suitable for the solution, * and the addition of a sufficient amount of a base to obtain a pH suitable for the precipitation of the vanadium metal oxide, non-lithiated, binary, amorphous.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the expected advantages thereof will readily be obtained as it is better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: Figure 1 describes the respective X-ray diffraction patterns of amorphous and crystalline LixNiV0, prepared according to the present invention; Figures 2 and 3 respectively describe the voltage / lithium content curve and the capacity / cycle number curve of a cell that employs Amorphous LixNiV04 as the active positive electrode material, namely Li; Figures 4 and 5 respectively describe the voltage / lithium content curve and the capacity / number of cycles curve of a cell employing crystalline LixNiV04 as the positive electrode material actiyo, namely Li; Figures 6 and 7 respectively describe the voltage / lithium content curve and the capacity / number of cycles curve of a cell employing LixNiV04, reanimated by mechanical grinding, as the active positive electrode material, namely Li; Figure 8 describes the respective X-ray diffraction patterns of the amorphous and crystalline InV04, prepared according to the present invention; Figures 9 and 10 describe the voltage versus lithium content curves for the cells employing InV04 as the active positive electrode material, namely Li and subjecting them to cycles, respectively, with varying relaxation times; Y Figure 11 depicts the curve of voltage versus lithium content for a Li-ion cell employing InV04 prepared according to the present invention, as the active negative electrode material, namely LixMn204.

DESCRIPTION OF THE INVENTION The replacement of the vanadium oxides by the graphite as the negative electrode in the rechargeable lithium ion cells results in a reduction of the output voltage of the cell. The average voltage at which these vanadium oxide-based materials intercalate the lithium ions is about 1.4 V, compared to an intercalation voltage of about 0.3 V for a conventional graphite negative electrode. However, the vanadium oxides can reversibly interlace up to about 7 lithium ions per unit formula, resulting in energy densities of approximately 800 to 900 Ah / g, which is approximately two to two and a half times higher than the density of power of conventional graphite electrodes. Due to this higher electrochemical capacity of the lithiated vanadium oxides, the energy density of a rechargeable lithium ion cell employing a vanadium oxide as the negative electrode is equivalent to that achieved with a negative graphite electrode, within ± 5%. A peculiar characteristic of materials based on vanadium oxide is a propensity to become. amorphous after intercalation / de-interleaving of lithium, as previously demonstrated by Delmas et al., J. Power Sources, 34, 103 (1991). Here, after discharging an electrochemical cell using V205 below a V, a substantial change in the electrochemical potential was observed in relation to the lithium content in LixV205, between the first and the second discharge. Specifically, a gradual variation of the voltage during the initial discharge was observed, while a smooth and continuous variation in the voltage with respect to the lithium content was found with the second discharge. It is believed that the observed propensity of the metal oxides of vanadium to become amorphous after the first discharge is a direct result of the vanadium characteristics. More specifically, it is suggested that this amorphization is a result of the tendency of vanadium ion to alter its sphere of coordination after reduction. For example, in the LiNiV04, vanadium is in an oxidation state +5 and has a tetrahedral geometry. After reduction to the V + 4 oxidation state, the V + 4 ion prefers an octahedral coordination sphere as a result of crystalline field stabilization. This change in coordination geometry results in local structural modification. It is believed that the amorphization observed during the electrochemical cycles results from such changes in coordination geometry, associated with the reduction in the oxidation state of vanadium. The identical problem with respect to the amorphization o-preserved with the V¿b, was also found with the new class of metal oxides of vanadium lithiates, as described by Guyomard et al. After the initial discharge of a cell that ejects a LiNiV0 electrode, the vanadium electrode became amorphous, resulting in a significantly different voltage / lithium content curve between the first and second discharges. In addition, it is noted that, after subjecting the cells to several cycles, the capacity of the electrodes based on LiMV04 (where M is a metal selected from the group of cadmium, cobalt, zinc, nickel, copper, and magnesium) increases significantly, in amounts of up to about 150 percent, making the balance of lithium ion cells very difficult. This increase in capacity after the cycle, which is also observed with other cell systems, results from a mechanical operation of the electrode material after cycling. Due to these problems regarding the balance of the metal oxide cells of lithiated vanadium, it is preferred to prepare the lithiated vanadium metal oxide compositions in an amorphous state. Conventionally, these materials have been prepared by reacting stoichiometric amounts of lithium carbonate (Li2C03), NH4V03 and M (N03) 2, (where M is a metal selected from the group consisting of cadmium, cobalt, zinc, nickel, copper , and magnesium) at 500 ° C for 48 hours. Alternatively, some synthetic methods provided the lithiated, crystalline vanadium metal oxide compositions, which had to be further processed by means of a amorphization step. Such syntheses are delayed, they are of inefficient energy and of intense labor. There remains a need for an effective and efficient method to prepare amorphous LiMV04. Because the lithiated vanadium metal oxides have generated such significant enthusiasm and widespread research interest regarding their use in lithiated intercalation cells, researchers have focused their research on the development of effective techniques for the manufacture of these compounds. Conventional fabrication of lithiated vanadium metal oxides requires calcination and annealing at temperatures greater than 500 ° C for a period of several days, a technique that is costly and inefficient. A new method was sought to produce lithiated vanadium metal oxides of controlled morphology and controlled grain size, to improve the electrochemical performance of the oxides. This has been achieved by a novel process, in which an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaVOj, and a nitrate salt of the formula M (? 03) n / which is prepared contains a large excess of a lithium salt that is built; the solution heats up; a sufficient amount of a base is added to obtain a pH greater than 8; and the amorphous lithiated vanadium metal oxide is precipitated spontaneously, providing fine particles of lithiated, mixed, amorphous vanadium metal oxides, the particles of which have a relatively large surface area. In their attempts to provide a simple and effective method for producing non-lithiated vanadium metal oxides of controlled morphology and controlled grain size, various methods in aqueous solution were explored by the present inventors. One procedure employed vanadium pentoxide and the iron nitrate salt as the starting materials. This method failed when attempts were made to extend it to other elements. A second procedure used ammonium metavanadate and the nitrate salt of a metal, which were dissolved in concentrated nitric acid. This method produced metallic oxides of vanadium whose degree of crystallinity was difficult to control, prompting an investigation for a new method of synthesis. In addition, attempts to prepare metal oxides of vanadium lithiated by these methods were completely unsuccessful. It is now believed that these methods failed to explain the importance of pH and the dissociation constant of the precursors. After discovering the present methods, however, the inventors were able to synthesize lithiated, amorphous, amorphous metal oxides of well-controlled morphology and non-lithiated vanadium metal oxides of well-controlled morphology. Initial attempts to synthesize LÍNÍVO4 through chemistry in solution were not successful. A solution of NH4VO3 was mixed with solutions of Ni (N03) 2 and LiN03. The stoichiometric quantities of the LixNiyVzO components (x + bi + r? Yj / z, where 0 <x <3, 0 <and <3, l = z <4, and n = 2 did not result in metallic oxide of mixed vanadium, expected but rather, two different nickel vanadium metal oxides, non-lithiated The present inventors now believe that, while the chemistry of the various transition metals is very similar, the chemistry of the transition metals and that of the alkali metals, such as lithium and sodium, are very dissimilar, perhaps as a result of the great difference in their respective electronegativities.To promote that the lithium ions combine with the ions of the transition metal, the reaction was carried out with a large excess of lithium, however, as this large excess of lithium was added in the form of LiOH, the resulting solution was basic, having a pH greater than 7. The precipitation of the amorphous LiNiV04 was then obtained by the further adjustment of the pH to a value in the range of about 8.0 'to about 9.0, preferably up to about 8.5, by the addition of an appropriate base such as NH OH or organic bases. Suitable bases include ammonia; amines; alkali hydroxides, including lithium hydroxide. These bases can be added directly or as aqueous solutions of the base. The present inventors have discovered that amorphous Li? IV04 can be prepared by a method which does not require calcination and annealing at temperatures greater than 500 ° C for a period of several days. They have found that lithiated, amorphous vanadium metal oxides can be prepared by means of a low temperature synthesis, comprising the creation of an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03, and a nitrate salt of the formula M (N03) n, which contains a large excess of a lithium salt; heating the solution; adding a sufficient amount of a base to obtain a pH greater than 8; precipitating the lithiated, amorphous vanadium metal oxide. Furthermore, this method is not limited to the amorphous, lithiated vanadium metal oxides, but rather, it can be used to prepare amorphous vanadium oxide-based compounds. Additionally, the present inventors discovered that a non-lithiated, binary, amorphous vanadium metal oxide of the formula MyVzO (bz + ny) / 2, where M is a metal, 0 <; and < 3, 1 < z = 4, and n = 2 or 3, can be prepared by means of a synthesis comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03, and a nitrate salt of the formula M (NOj) a, where n = 2 or 3; the heating of the solution; the addition of a sufficient amount of a base to obtain a suitable pH for the solution; and the precipitation of the lithiated, binary, amorphous vanadium metal oxide. Other features of the invention will become apparent in the course of the following descriptions of the exemplary embodiments, which are given for illustration of the invention and are not intended to be limiting thereof.

Example 1 The ammonium metavanadate (NH4V03) was initially dissolved in water by heating and stirring to produce a solution of approximately 2.5 x 10 t2M. A separate solution of Ni (N03) 2 / LiN03 was prepared in the ratio of about 1:15, such that the separated solution had a Ni (N03) 2 concentration of about 4.5 x 10"2 M, and a Li concentration. 030.0 of about 0.7 M. When all the ?H4V03 had dissolved, the cold solution of nitrate salts was added in. The pH of the resulting solution was 5 and did not occur.The precipitation.While the solution was heated (80 ° C at 90 ° C) and stirred, the pH was adjusted to 8.5 by means of a 3 N ammonia solution, a yellow precipitate appeared spontaneously, the mixture was continued stirring and heated for approximately 10 minutes. performed with a 0.1 μm filter In an alternative embodiment of the present invention, the precipitate can be separated from the filtrate by means of centrifugation.The solid precipitate, which was yellow-green in color, was then washed sequentially with water and ethanol to drag and eliminate the NíJ3. The precipitate was then dried in an oven at 50 ° C for about 12 hours. X-ray diffraction analysis of the solid indicated that the lithiated vanadium metal oxide was amorphous, as shown by trace 12 relatively without feature in Figure 1. The sample was then heated at 300 ° C for about 10 hours during the which crystallization was developed, as was conirmed in trace 16 of the subsequent X-ray analysis at room temperature. By carrying out a series of anneals in increments of 50 ° C in a temperature range of 300 ° C to 800 ° C, the continuous development of diffraction peaks was observed under X-ray analysis. The amorphous mixture was further confirmed by means of differential thermal analysis. After annealing at 800 ° C, to which it crystallized as a perfect crystal, the solid was identified as LiNiV04 by X-ray analysis (JCPDS 38-1395). To verify the stoichiometry of the compound, the determination of the Li /? I / V ratio was carried out by means of atomic absorption spectroscopy (AAS) analysis of the redissolved precipitate. The results confirmed the formula Li? IV04. The observed data is consistent with the phase diagram of the Li? IV04 provided in Chem. Bull. Soc. Jap., 11, 1483 (1979). The specific surface area of the lithiated, amorphous, amorphous nickel oxide and the lithiated, crystallized nickel and vanadium oxide was also measured, with the amorphous material having a specific surface area of about 30 to 36 m2 / g and the crystalline material ( annealed at 700 ° C) that had a specific surface area of about 3 to 4 m2 / g.

Example 2 A rechargeable lithium cell was constructed, using the lithiated, amorphous vanadium oxide, LiNiV04 of Example 1, as the active material of the positive electrode, and lithium metal as the active material of the negative electrode, in a Swagelock type assembly. The positive electrode was prepared from a 0.3 mm thin film of 6 parts by weight of carbon black and 56 parts of LiNiV04 intimately dispersed in a binder matrix of 16 parts of a copolymer of vinylidene fluoride: hexafluoropropylene (PVDF: HFP ) 88:12, and 16 parts of compatible dibutyl phthalate (DBP) as a plasticizer-. A 1 cm2 disc was cut from the film and immersed in diethyl ether to remove substantially all of the DBP plasticizer from the electrode composition. The DBP-free positive electrode disk, after vacuum drying for 1 hour, was placed in a dry box under a helium atmosphere. The negative electrode of the same size was prepared from a metallic sheet of lithium attached to a nickel disc. The positive and negative electrodes were electrically isolated by a separating disk cut from a fiber mesh, of silica, and soaked in an electrolytic solution of 1 M LiPF6 in a solvent mixture of 1/3 dimethyl carbonate and 2/3 ethylene carbonate. The cell assembly was then inserted into the Swagelock type physical apparatus where physical contact between cell components was assured by spring pressure while the cell was kept air-tight by stainless steel pistons. The cell was then removed from the dry box for the electrochemical test on a number of charge / discharge cycles between 0.05 V and 3 V by means of a MacPile system operating in a galvano-static mode. Figures 2 and 3 respectively describe the voltage / lithium content curve and the capacity / number of cycles curve for the amorphous LixNiV04 cell.

Example 3 It was prepared in a similar manner in a cell using the crystalline LixNiV04 material instead of the amorphous of Example 1, as the active positive electrode component. Figures 4 and 5 illustrate respectively the voltage / lithium content curve and the capacity / number of cycles of the cell. With both cells, approximately 7 lithium ions per unit formula can be reversibly intercalated. However, the initial capacity achieved with the Li ^ NiVO * is greater than that obtained with the crystalline LixNiV0, resulting in capacities for cells using amorphous LixNiV04 as large as 920 mAh / g, approximately 2.5 times higher than that obtained with a conventional graphite electrode. Furthermore, with the method of the present invention, it is not necessary to slowly transform the crystallized phase into a disordered amorphous phase. In this way, e-L lithium vanadium metal oxide, ternary, desired, is produced directly in an efficient and effective synthesis, in contrast to the conventional process that consumes time, which is energy inefficient and labor intensive. In addition, these graphs indicate that the amorphous phase can reversibly intercalate as many lithium ions as the crystallized phase, but at a faster rate. As noted, it is possible to transform the initial amorphous stage to the corresponding crystallized phase by annealing at 800 ° C. It is also possible to re-amorphize the crystallized phase by means of mechanical processing, for example, using a Spex 8000 impact ball mill, for use in a rechargeable cell, as shown in the following example.

Example 4 Two stainless steel balls with 1 gram of crystalline LixNiV04 material of Example 1 were placed in an air-tight sealed cell of 25 cm 3. The cell was mounted on a Spex 8000 device and ground with balls for 80 hours. The crystalline LixNiV0 was re-amorphized in this operation and the resulting material was replaced by the active positive electrode material of Example 2 in the preparation of a test cell. Figures 6 and 7 respectively describe the voltage / lithium content curve and the capacity / number of cycles curve for the resulting cell. The slight increase in the irreversible loss of capacity observed between the first discharge and the first charge of a cell containing the re-amorphized LixNiV04, is consistent with the small increase in the specific surface area, observed with the re- love i-zada (6 ?? 2 / g) in relation to the specific surface area of the crystallized sample (3 m2 / g). Furthermore, the irreversible loss of capacity between the first discharge and the first load supports the hypothesis that such loss of capacity occurs by means of a catalytic composition of the electrolyte on the surface of the metal oxide. It is also noted that the first discharge voltage is greater for the amorphous phase than for the crystallized phase. This observation e-? again consistent with the highest degree of amorphization. As the degree of disorder in the structure increases, the Fer i level rises in energy, resulting in an increase in the intercalation voltage. In addition, after subjecting the cycles, the observed capacity of the cell based on amorphous LixNiV04 remains more constant than the capacity of the cell based on crystalline LixNiV0. In addition, the capacity does not increase as previously observed with the lithiated, crystalline vanadium oxides. It is believed that this constant capacity is a direct result of the initial amorphous character of the lithiated vanadium metal oxide, produced by the process of the present invention, in contrast to the cycling which is required with the conventional syntheses of the lithiated, crystalline vanadium oxide. , to achieve the appropriate degree of amorphization.

Example 5 A process analogous to that of Example 1 was used in the synthesis of LiCoV04. The ammonium metavanadate (NH4V03) was initially dissolved in water with heating and stirring to produce a solution of approximately 2.5 x 10"2 M. A separate solution of Co (? 03) 2 / Li? 03 was prepared in a ratio of approximately 1:20, such that the separate solution had a Co (? 03) 2 concentration of approximately 4.5 x 10 ~ 2 M and a Li? 03 concentration of approximately 0.7 M. When the? H4V03 had completely dissolved, the cold solution of the nitrate salts was added. The pH of the resulting mixture was 5 and precipitation did not occur. While the solution was heated to a temperature of about 80 ° C to 90 ° C and stirred, the pH was adjusted to 8.5 by the addition of aliquots of a 3 ° ammonia solution. An orange precipitate appeared spontaneously. The mixture was continued to stir and heated for approximately 10 minutes. The amorphous LiCoV04 phase was recovered by centrifugation, and washed with water and ethanol to entrain and remove the NH3. The precipitate was then dried in an oven at 50 ° C for a few hours. X-ray diffraction analysis of the solid indicated that the lithiated vanadium metal oxide was amorphous. After heating, amorphous LiCoV04 powder appeared to be the predominant component. An analogous procedure can be employed in the synthesis of the other amorphous LixMyVz0 (x + b2 + ny) / 2, where M is a metal selected from the group consisting of manganese, cobalt, iron, nickel, copper, cadmium, chromium, magnesium, Aluminum and Indian, 0 <; x = 3, 0 < and < 3, 1 < < 4, and n = 2 or 3. Using molar proportions of Ni: V: Li :: 1: 1: 1, amorphous, lithiated vanadium oxides have been synthesized. These compounds were subsequently obtained in their stoichiometric conditions without using LiN03 as reagent. At a pH of 8.5, the analogous vanadium oxide? I3 (V04) 2 was obtained when the Li /? I ratio was zero or insufficient. Therefore, the structures are different for Li? IV04 and Ni 3 (V04) 2. When the pH was reduced below the preferred range, the? I2V207 was obtained. The pH of the solution containing Ni (N03) 2 and NH4V03 should be initially decreased to 2 by means of concentrated acid, for example HN03. After this, the pH is raised to a range of about 4 to about 5 to induce precipitation. During the initial pH adjustment from about 5 to about 2, the solution remained translucent. After washing and filtration, the X-ray diffraction analysis of the resulting solid indicated that the solid phase was amorphous. The successive annealing of the solid precipitate does not progress towards crystallization as clearly as with Ni3 (V04) 2 and LiNiV04. Under stoichiometric conditions, Ni: V :: 3: 2 for Ni3 (V04) 2 and Ni: V :: 1: 1 for Ni2V207, the corresponding vanadium oxides were obtained. The non-lithiated, binary vanadium oxides of the formula MyVz0 (5z.ny) / 2 / where M is a metal selected from the group consisting of manganese, cobalt, iron, nickel, copper, cadmium, chromium, magnesium, aluminum and indium , 0 < y = 3, 1 = z < 4, and n = 2 or 3; MV04, can be obtained by analogous aqueous synthesis.

Example 6 A solution of NH4V03 about 2.5 x 10"2 M was mixed with a solution of In (N03) 3 • 5H20 about 4.5 x 10" 2 M. The pH of the resulting solution was from about 2 to about 2.5. Instantaneously after mixing, a precipitate was observed. To ensure complete reaction, the precipitate was redissolved by lowering the pH of the solution to approximately 1 with the addition of 3N HN03 aliquots. The pH of the solution was then raised to approximately 4 by gently adding NH40H 3N, in which pH the amorphous InV04 was precipitated. At a pH greater than about 4, In (OH) 3 was observed, while at a pH of less than about 4, vanadium oxide (V205) or its ammoniacal salt (NH4-VQ3) appeared. The thermal analysis of the resulting amorphous phase at a rate of 10 ° C per minute indicated an approximate structural sequence in which, with the increasing temperature, an initial amorphous InV04-2.6H20 is transformed into amorphous InV04 which, In turn, at a temperature of approximately 550 ° C, it is transformed to the monoclinic InV04, which is then transformed to the orthorhombic InV04 at a temperature of approximately 730 ° C. As in Example 1, the X-ray diffraction analysis, described respectively in lines 82 and 86 of Figure 8, confirmed the structures of the amorphous and monoclinic phases. Swagelock test cells were prepared, as in Example 2, using the amorphous InV04 as the active positive electrode material. The resulting cells were likewise tested in the MacPile system in a C / 4 ratio with a variation in the relaxation time between the loading and unloading sites of 0.003 hours and 0.25 hours. The mounting / lithium content curves are shown for such cell tests in the first 10 cycles, respectively, in Figures 9 and 10. In both cases an irreversible component of the self-discharge corresponding to approximately 3 lithium atoms was observed. unit of formula and a reversible component - self-discharge of approximately 6 lithium atoms per unit of formula. These results correlate with an initial capacity of approximately 900 mAh / g and represent the first time that the intercalation of lithium in an amorphous non-lithiated vanadium oxide has been achieved.

Example 7 In the previous examples, the ability of amorphous vanadium oxides, prepared, to insert large amounts of lithium at low voltages, through the simplest and most expeditious electrolytic cells comprising negative electrodes of lithium metal and positive electrodes that incorporate vanadium oxide. These latter materials, however, are no less effective in the role of active negative electrode components, which are particularly useful in the more desirable lithium ion cells described, for example, in US Patent No. 5,460,904. The electrodes for such an exemplary cell were prepared in the manner described using as negative electrode a film of the LiNiV04 composition according to Example 2, above. A positive electrode was prepared as described in the annotated patent, in the form of a 0.2 mm thick film of 56 parts by weight of finely divided LiMn204, 6 parts of carbon black, 15 parts of the PVdF copolymer: HFP, and 23 parts of the DBP plasticizer. An electrolyte / separator film according to the patent was formed as a 85 μm thick film of the copolymer mixed with equal parts of DBP. The films were then assembled with the separator between the electrode components, and the assembly was laminated with heat and pressure. A 1 cm2 disc was cut from the laminate and immersed in diethyl ether to extract a substantial portion of the DBP plasticizer, and the disc was then immersed in the electrolytic solution of Example 2, which was absorbed into the copolymer matrix for activate the cell. The cell was then mounted on a Swagelock device and tested in cycles between 4.5 V and 2 V with a current density of 350 mA / cm2. The results of such a cycle are shown in Figure 11. It is expected that other embodiments and variations of the present invention will be apparent to the skilled practitioner, in light of the above teachings, and such modalities and variations are considered nonetheless to be within of the scope of the appended claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the. invention as above, property is claimed as contained in the following:

Claims (13)

1. A method for the preparation of an amorphous, ternary, ternary vanadium metal oxide of the formula LixMyVzO (X + 5z + ny) / 2, where M is a metal, < x < 3, 0 < and < 3, 1 < < 4, and n = 2 or 3, characterized in that: a) an aqueous solution of 1) is prepared. at least one metavanadate salt selected from the group consisting of NH4V03 and NaV0, 2) a nitrate salt of the formula M (N03) n / where M is said metal, and 3) an excess of a lithium salt; b) the resulting solution is heated; and c) a sufficient amount of a base is added to the heated solution, to have a suitable pH to precipitate the metal oxide of amorphous lithiated vanadium.

2. A method according to claim 1, characterized in that the aqueous solution is prepared by mixing: a) a first aqueous solution comprising the metavanadate salt; and b) a second aqueous solution comprising the nitrate and lithium salts.

3. A method according to claim 1, characterized in that the base is selected from the group consisting of ammonia, amines, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal salts of alcohols, and alkali metal salts of carboxylic acids.

4. A method according to claim 1, characterized in that the base is added in the form of an aqueous solution of said base.

5. A method according to claim 1, characterized in that the lithium salt is selected from the group consisting of LiN03, LiOH, LiOH »H20, and LÍ2C03.

6. A method according to claim 1, characterized in that the heating comprises heating the solution to a temperature in the range of about 80 ° C to 95 ° C.

7. A method according to claim 1, characterized in that the metal is at least one metal selected from the group consisting of manganese, cobalt, iron, copper, cadmium, nickel, chromium, indium, aluminum and magnesium.

8. A secondary, non-aqueous battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized the cell because the active positive electrode material is an amorphous metal-vanadium oxide, selected of the group consisting of: a) metal oxides of lithiated vanadium, ternary of the formula LixMyVzO (x + 5z.ny) / 2, where M is a metal, 0 < x < 3, 0 < and < 3, 1 < < 4, and n = 2 or 3; and b) non-lithiated, binary vanadium metal oxides of the formula MyVzO! 5z + ny) / 2 / where M is a metal, 0 < and < 3, l = z < 4, and n = 2 or 3.

9. A non-aqueous secondary battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized in that the active positive electrode material is an amorphous vanadium metal oxide consisting of a lithiated vanadium metal oxide, ternary of the formula LixMyVzO (x + 5z. ny> / z,, where M is a metal, 0 <x <3, 0 <and <3, l < z < 4, and n = 2 or 3 and prepared by a process according to claim 1.

10. A non-aqueous secondary battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized the cell because the active positive electrode material is a non-lithiated, binary vanadium metal oxide. the formula MyVzO (5z-ny) / 2 where M is a metal, 0 < and < 3, l < < 4, and n = 2 6 3 and prepared by a process according to claim 1.

11. A non-aqueous secondary battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized the cell because the active negative electrode material is an amorphous vanadium metal oxide selected from the group consists of: a) lithiated vanadium metal oxides, ternary of the formula LixMyVzO! x + 5z + ny) / 2, where M is a metal, 0 < x < 3, 0 < and < 3, 1 < < 4, and n = 2 or 3; and b) non-lithiated, binary vanadium metal oxides of the formula MyVz0 (5Z + - y) / 2f where M is a metal, 0 <1. and < 3, 1 < < 4, and n = 2 6 3.

12. A non-aqueous secondary battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized the cell because the active negative electrode material is a lithiated, binary vanadium metal oxide of the formula LixMyVzO (x + 5z .-. y) / 2 / where M is a metal, 0 < x < 3, 0 < and < 3, 1 < z = 4, and n = 2 or 3 and prepared by a process according to claim 1.

13. A non-aqueous secondary battery cell comprising an active negative electrode material, an active positive electrode material, and a non-aqueous electrolyte, characterized the cell because the active negative electrode material is a non-lithiated, binary vanadium metal oxide. the formula MyVzO (;, z-.--y./2/ where M is a metal, 0 <and <3, 1 <z <4, and n = 2 or 3 and prepared by a conformance process with claim 1. SUMMARY OF THE INVENTION A method is described for preparing an amorphous, ternary, ternary vanadium metal oxide of the formula LixMyVzO (X + 5z. Nyi 2 »where M is a metal, 0 <x <3, 0 <and <3, 1 <z <4, and n = 2 or 3, comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4V03 and NaV03, and a nitrate salt of the formula M ( N03) n, which contains a large excess of a lithium salt, the heating of the solution, the addition of a sufficient quantity of a base to obtain a suitable pH, and the precipitation of the lithiated, amorphous vanadium metal oxide. for preparing a non-lithiated, binary, amorphous vanadium metal oxide of the formula MyVz0 (.zz + nyj / 2 / where M is a metal, 0 <and <3, l <z <4, yn = 2 or 3, comprising the steps of creating an aqueous solution of at least one metavanadate salt selected from the group consisting of NH4VOj and NaV03, and a l of nitrate of the formula M (N03) -; the heating of the solution; the addition of a sufficient amount of an acid for the solution; and the addition of a sufficient amount of a base to obtain a suitable pH to precipitate the vanadium metal oxide, non-lithiated, amorphous. A rechargeable, lithiated, intercalation battery cell comprising a positive electrode, a negative electrode, and an electrolyte, wherein the active material of the negative electrode is a lithiated, ternary, amorphous vanadium metal oxide of the formula LixMyVzO (X + bz + ny) / - or a non-lithiated, binary, amorphous vanadium metal oxide of the formula MyVzO (5z + ny) / 2, prepared according to the methods of the present invention.