The method of producing oxide of lithium and manganese li8mn2o4-5with the spinel structure (options) and secondary rechargeable battery

 

(57) Abstract:

The invention relates to a method for producing a compound oxide of lithium and manganese with a spinel structure and its use in secondary batteries. The method includes the stage of the preliminary injection of lithium manganese oxide by reaction with lithium hydroxide or lithium salt, or any mixture, mainly without the formation of oxide of lithium and manganese with spinel structure. And then the reaction of manganese oxide with a pre-entered in it lithium hydroxide lithium, or its salt, or any mixture at an elevated temperature with the formation of oxide of lithium and manganese LixMn2O4+co spinel structure, where the 0.9 <x <1.2 and 0 < < 0,4. In a specific embodiment of the invention the manganese dioxide in the reaction mixture with lithium hydroxide, or salt, or any mixture interacts with the formation of manganese dioxide with the included lithium, mostly without the formation of oxide of lithium and manganese with spinel structure. Manganese dioxide with the included lithium is separated from the editorial of the mixture and heated to form sesquioxide lithium manganese (LixMP2ABOUT3). Formed Sesqui the ve oxide of lithium and manganese. Product spinel used as a positive electrode in a secondary rechargeable batteries. The method according to the invention is simple to apply and control. Product spinel oxide of lithium and manganese, received one of the methods according to the invention, for use in secondary batteries as the positive electrode has superior characteristics, for example, lowering the irreversible loss of capacity when conducting cycle. 4 C. and 16 h.p. f-crystals, 1 table.

The invention relates to a method for producing a compound oxide of lithium and manganese with a spinel structure and its use in secondary batteries.

According to the prior art known methods for producing oxide of lithium and manganese (LiMn2O4) crystal structure of spinel for use in secondary batteries. In the method according to the prior art powders LiMn2O4receive by heating a mixture of powders of lithium carbonate and manganese oxide in air at temperatures of approximately 800oC to 900oC (D. G. Wickham & W. J. Croft, J. Phys. Chem. Solids, Vol.7, p.351 (1958)). In another method (U. S. Patent 5,135,732) hydroxides of lithium and ammonium in solution reacted with acetate of manganese in the Sol-gel colloidal smertnoi atmosphere with getting a jelly-like precipitate, which is dried and the result is granular spinel oxide of lithium and manganese for use in secondary cells. In another way lithium carbonate reacts with manganese acetate with the formation of the spinel oxide of lithium and manganese, which are dried (UK Patent Application GB 2276155). Product spinel oxide of lithium and manganese obtained by such methods according to the prior art, is characterized by a significant loss of power during a cycle of the secondary cell.

The method according to the invention contains the initial stage of formation of the reaction mixture containing manganese oxide and a lithium salt or lithium hydroxide, or a mixture of lithium salt and lithium hydroxide. Oxide of manganese, for example, can be MnO2, Mn2O3, Mn3O4or MnOOH or mixtures thereof. The lithium salt preferably include lithium nitrate, lithium carbonate, lithium acetate, lithium sulfate, or any of their mixtures. Can be used with lithium hydroxide or other lithium salts of weak acids. The mixture reacts with the formation of manganese oxide with a pre-entered in it lithium (Lix(Mn oxide)), namely, LixMnO2, LixMn2O3, LixMn3O

The method according to the invention is easier to apply and control in comparison with the methods known from the prior art. Product spinel oxide of lithium and manganese, obtained by the process according to the invention has improved characteristics for use in a loop and for storage when used as a positive electrode in a secondary (rechargeable) cells having a negative electrode containing lithium or lithium ions. Improved operating parameters are characterized, for example, low irreversible capacity loss during the holding cycle for use spinel positive electrode in a secondary cell. There is no reliable information on why this happens, but it is assumed that the pretreatment with lithium forms at least part of the frame of the lattice and crystal structure of spinel. Apparently, it is easier to obtain the final product spinel oxide of lithium and manganese with a minimum of defects in the crystal structure of spinel, which thus improves product performance is or chemically bound on the surface of manganese oxide with a pre-entered in it lithium Lix(Mn oxide) can have a strong influence on the morphology of the product spinel derived from it. Such surface features can improve the performance characteristics of spinel in the secondary cells.

The reaction of the preliminary injection of lithium is carried out within a temperature range, which provides the above-mentioned desired degree of pretreatment with lithium, but the temperature range which, however, is low enough to almost not formed oxide of lithium and manganese with the structure of a spinel having the formula LixMn2O4+(of 0.9 < x < 1.2 and 0 < < 0,4). "Lack of education" called spinel oxide of lithium and manganese should be understood so that, if during the reaction pretreatment with lithium and is formed of any number of named spinel oxide of lithium and manganese, it can be formed from less than 5 wt.% on the number of initial oxides of manganese, i.e., during the reaction of the preliminary injection of lithium between about 0 and 5 weight. percent of initial oxides of manganese may be in the limiting case turned in LixMn2O4+(of 0.9 < x < 1.2 and 0 < < 0,4). Rayapati from about 4 to 400oC, preferably from about 4 to 90oC, particularly preferably, from about 20 to 50oC, over a period of time preferably from about 0.5 to 15 hours, the Reaction pretreatment with lithium is carried out in aqueous solution, but may also be carried out in the solid phase, for example, if the reagents are lithium nitrate, or lithium hydroxide. Manganese oxide with a pre-entered in it lithium Lix(Mn oxide) can then react with lithium hydroxide or lithium salt, preferably lithium nitrate, lithium acetate, lithium sulfate or any mixture within the higher temperature range, preferably approximately from 650 to 900oC over a period of time preferably from about 24 to 48 hours with the formation of oxide of lithium and manganese with a spinel structure having a stoichiometric formula of LixMn2O4+(of 0.9 < x < 1.2 and 0 < < 0,4).

In a preferred implementation of the present invention, the powder of manganese dioxide (particularly preferably electrolytic manganese dioxide (EMD)) reacts with lithium hydroxide, resulting in a preliminary introduction lithium manganese dioxide with the image of the th preferably heated to convert it into sesquioxide lithium manganese (LixMn2O3), which, in turn, can react preferably with lithium carbonate (Li2CO3) with the formation of the spinel oxide of lithium and manganese. Alternatively, an intermediate stage of conversion of the manganese dioxide with a pre-entered in it lithium in LixMn2O3can be omitted, and may be carried out by direct reaction of manganese dioxide with a pre-entered in it lithium with lithium carbonate with the formation of the spinel oxide of lithium and manganese.

In accordance with the specific variant of realization of the present invention, the powder of manganese dioxide, it is advisable to first washed with acid, preferably sulfuric acid, which will be removed traces of sodium ions or other cations exchanged ions trapped in the particles of manganese dioxide. The washed acid MnO2first propulsives and then suspendered in fresh deionized water. To the suspension is added lithium hydroxide over a period of time between about 0.5 to 15 hours, while the suspension is added lithium hydroxide all this time is maintained at a temperature of from about 20 to 50oC. In the flax from 7 to 14, preferably from about 7 to 11, with the formation of manganese dioxide with a pre-entered in it lithium, having a stoichiometric formula of LixMnO2(0,015 < x < 0,070). Manganese dioxide with a pre-entered in it lithium is filtered and dried, after which it is heated at temperatures from about 550oC to 600oC to turn it into sesquioxide lithium and manganese LixMn2O3(0,015 < x < 0,070). Sesquioxide lithium and manganese LixMn2O3in turn reacts with lithium carbonate Li2CO3at temperatures of approximately 650oC to 800oC with the formation of the spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+where (range 0.9 < x < 1.2 and 0 < < 0,4). (It would be appreciated if the stoichiometric formula LixMnO2and LixMn2O3have been created to describe the same connection, respectively, with several more or less oxygen than is shown in the formula. Therefore, it should be understood that wherever there is a link on these connections, everywhere can be applied to more General formula LixMnO2+and Liwhat about -0,01 and +0,01).

In an alternative implementation of manganese dioxide with a pre-entered in it lithium (LixMnO2) receive, as described above, but may be omitted stage of turning it into sesquioxide lithium (LixMn2O3). Instead of manganese dioxide with a pre-entered in it lithium can be directly converted to spinel oxide of lithium and manganese by direct reaction with lithium carbonate at temperatures between about 650oC and 800oC. This implementation option when there are benefits in the absence of one stage has the disadvantage that the final spinel will contain more moisture in the lattice (OH in place of oxygen atoms in the locations of defects in the structure of spinel). Thus, the more pure the product spinel, namely, with a lower moisture content in the lattice is obtained by converting first manganese dioxide with a pre-entered in it lithium in sesquioxide lithium and manganese before final conversion to spinel, for example, by reaction of sesquioxide lithium and manganese with lithium carbonate as described above. This cleaner product - spinel has also improved the operation is other specific implementations of the present invention are reflected in the following examples.

Example 1

First, prepare a saturated solution of lithium hydroxide by adding an excess of lithium hydroxide, 100 g to 300 ml of deionized water and keeping the mixture overnight under stirring. The next day undissolved solids are filtered out to obtain a saturated solution of lithium hydroxide, which is still left to the side.

A sample of 100 g of electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 1000 ml of 1-molar H2SO4and stirring the mixture for 1 h At the end of the hour, the stirring stopped, and the acid solution is drained, leaving electrolytic manganese dioxide (EMD). EMD is subjected to a second washing 1-molar H2SO4this is same as first. After the second washing the acid solution is drained, and EMD propulsives deionised water and left overnight. The next day EMD propulsives 3 additional times with fresh deionized water. After the last propulsive water water is drained, leaving EMD.

After that EMD is poured a saturated solution of lithium hydroxide, and stirred acesa from hydroxide solution and dried. The analysis showed that the material has a stoichiometric formula of Liof 0.15, MnO2. The material is then heated to 600oC for 24 h to turn it in Liof 0.15Mn2O3. This material is then heated with lithium carbonate at a temperature of 750oC for 24 h with the formation of the product spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+(x = 1,05, = 0,2).

Example 2

The sample in 2000 electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 2500 ml of 1-molar H2SO4and stirring the mixture for 1 h At the end of the hour, the stirring stopped, and the acid solution is drained, leaving electrolytic manganese dioxide (EMD). EMD is subjected to a second washing 1-molar H2SO4this is same as first. After the second washing the acid solution is drained, and EMD propulsives deionised water and left overnight. The next day EMD propulsives an additional three times with fresh deionized water. After the last propulsive water EMD suspendered in fresh deionized water, and during the ohms mixture all the time is maintained at a temperature of 22oC. the Solution is stirred for 30 minutes at this temperature, and then the solid material is filtered and dried. The analysis showed that the material has a stoichiometric formula of Li0,067MnO2. The material is heated to 600oC for 24 h to turn it in Li0,067Mn2O3. This material is then heated with lithium carbonate at a temperature of 750oC for 24 h with the formation of the spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+(x = 1,05, = 0,2).

Example 3

A sample of 500 g of electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 2 l of 1-molar H2SO4and stirring for 1 h the acid solution is drained, and electrolytic manganese dioxide (EMD) is subjected to a second washing, the same that first, fresh acid solution. After that EMD propulsives by immersing it in fresh deionized water, where it is left overnight, after which it is filtered and dried.

EMD is divided into four equal parts (each 125 g), from which are prepared four sample spinel (within 15 minutes. Each portion of EMD is subjected to rinsing with water two more times, and then the material is filtered and dried. The first portion of EMD in 125 g is left aside for use as a reference product - spinel (sample 3A), which is obtained without processing EMD lithium hydroxide, and the remaining three portions EMD is used to derive product - spinel using stage pretreatment with lithium according to the invention.

Comparative spinel (sample 3A) without pretreatment with lithium obtained as follows:

Portion 125 g rinsed and dried EMD heated to 600oC for 24 h to turn it into Mn2O3. This material is heated to a temperature between approximately 700oC and 900oC with lithium carbonate to obtain a product spinel with the formula LixMn2O4+(x = 1,05, = 0,2).

Product - spinel (sample 3B) with a preliminary introduction lithium is obtained as follows:

Approximately 125 g rinsed and dried EMD suspendered in fresh deionized water, and within a time period of approximately 5 minutes, is added 1.2 g of lithium hydroxide until then, until the pH is perature stirred for 30 minutes, then filtered and dried. The analysis showed that the dried material has a stoichiometric formula of Li0,017MnO2. The material is then heated to 600oC for 24 h to turn it in Li0,017Mn2O3. This material is then heated with lithium carbonate at temperatures between 700oC and 900oC with the formation of the spinel product with the stoichiometric formula of LixMn2O4+(x=1,05, = 0,2).

Product - spinel (sample 3C) with a preliminary introduction lithium is obtained as follows:

Approximately 125 g rinsed and dried EMD suspendered in fresh deionized water, which is added 3.7 g of lithium hydroxide so that the pH value of the solution was equal to 11.0. The mixture all the time is maintained at a temperature of approximately 22oC. the Mixture at the given temperature, stirred for 30 minutes, then filtered and dried. The analysis showed that the dried material has a stoichiometric formula of Li0,052MnO2. The material is then heated to 600oC for 24 h to turn it in Li0,052Mn2O3. This material is then heated with lithium carbonate at temperatures between 700o= 0,2).

Example 4

The sample in 2000 electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 2500 ml of 1-molar H2SO4and stirring the mixture for 1 h At the end of the hour, the stirring stopped, and the acid solution is drained, leaving electrolytic manganese dioxide (EMD). EMD is subjected to a second washing 1-molar H2SO4this is same as first. After the second washing the acid solution is drained, and EMD propulsives deionised water and left overnight. The next day EMD propulsives an additional three times with fresh deionized water. After the last propulsive water EMD suspended in fresh deionized water, and within a time period of approximately 5 minutes, add 85 g of lithium hydroxide to bring the pH to 11.0 in. Solution all the time is maintained at a temperature of approximately 22oC. the Solution is stirred for 30 minutes at this temperature, and then the solid material is filtered and dried. The analysis showed that the material has a stoichiometric formula of Li0,067MnO2. The material is heated to 600olithium at temperatures between 700oC and 900oC for 24 h with the formation of product - spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+(x=1,05, = 0,2).

Example 5

The sample in 2000 electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 2500 ml of 1-molar H2SO4and stirring the mixture for 1 h At the end of the hour, the stirring stopped, and the acid solution is drained, leaving electrolytic manganese dioxide (EMD). EMD is subjected to a second washing 1-molar H2SO4this is same as first. After the second washing the acid solution is drained, and EMD propulsives deionised water and left overnight. The next day EMD propulsives an additional three times with fresh deionized water. After the last propulsive water EMD suspended in fresh deionized water, and within a time period of approximately 5 minutes, add 85 g of lithium hydroxide to bring the pH to 11.0 in. The solution is aged at a temperature of approximately 22oC. the Solution is stirred for 30 minutes at this temperature and then solid mate
MnO2. The material is heated to 600oC for 24 h to turn it in Li0,067Mn2O3. This material is then heated with lithium carbonate at temperatures between 700oC and 900oC for 24 h with the formation of product - spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+(x=1,05, = 0,2).

Example 6

The sample in 2000 electrolytic manganese dioxide in the form of particles (EMD brand for batteries from the company Kerr-McGee Corp. party room 9864) is washed in acid by adding 2500 ml of 1-molar H2SO4and stirring the mixture for 1 h At the end of the hour, the stirring stopped, and the acid solution is drained, leaving electrolytic manganese dioxide (EMD). EMD is subjected to a second washing 1-molar H2SO4this is same as first. After the second washing the acid solution is drained, and EMD propulsives deionised water and left overnight. The next day EMD propulsives an additional three times with fresh deionized water. After the last propulsive water EMD suspended in fresh deionized water, and within a time period of approximately 5 minutes, add 85 g Hydra is peremeshivaete for 30 minutes at this temperature, and then the solid material is filtered and dried. The analysis showed that the material has a stoichiometric formula of Li0,067MnO2. The material is heated to 600oC for 24 h to turn it in Li0,067Mn2O3. This material is then heated to temperatures between 850oC and 1000oC for 24 h to turn it in Li0,067Mn3O4. This material is then heated with lithium carbonate at temperatures between 700oC and 900oC for 24 h with the formation of product - spinel oxide of lithium and manganese with the stoichiometric formula of LixMn2O4+(x=1,05, = 0,2).

Tests of performance.

Operational characteristics of each of the products spinel oxide of lithium and manganese (samples 3A-3D) obtained in example 3 are tested using spinel as a cathode material (positive electrode) rechargeable (secondary) cell. The cathode is constructed from any of the products spinel by creating a mixture of spinel (60 wt.%), carbon (35 weight. %) and Teflon (tetrafluoroethylene) (5 weight%). The mixture is compressed, and 60 mg of the compressed mixture is used as a cathode material. The resulting cathode is inserted is oritel with equal parts of ethylene carbonate resulting and dimethylcarbonate.

Each cell in the form of coins were used in the tests cyclic operation (charging/discharging), while lithium cell used in a loop between a 4.3 and 3.0 V At a current density of 0.5 mA/cm3. Spinel between charged and discharged States of the test cells may have the stoichiometric formula of LixMn2O4+(or 0.1 < x < 1,2). The loss power density spinel (mAh/g per cycle, averaged over 50 cycles) is shown in the following table. Spinel obtained according to the invention, including the stage of the preliminary injection of lithium as described above in example 3 has better characteristics in the cycle, there is less capacity loss after 50 cycles compared with comparative spinel (sample 3A), which was not used stage pretreatment with lithium.

Although the present invention has been described with reference to specific embodiments, it should be understood that without deviating from the scope of the claims and concepts of the present invention there are various options for implementation. Accordingly, the invention does not imply restrictions in the form of specific options described here implement, as defined by the claims and their EC is spinel, incorporating the following stages: a) form a reaction mixture containing manganese oxide (oxide MP) and a reagent selected from the group consisting of lithium salts and lithium hydroxide and any mixture thereof; (b) the reaction of manganese oxide in the reaction mixture with the formation of manganese oxide with the included lithium Lix(oxide MT), where 0,015 < x < 0,2 mostly without the formation of oxide of lithium and manganese with a spinel structure having a stoichiometric formula of LixMn2O4+where to 0.9 < x < 1.2 and 0 < < 0,4; (C) the reaction of manganese oxide with the included lithium Lix(oxide MP) with a reagent selected from the group consisting of lithium salts and lithium hydroxide and any mixture with the formation of oxide of lithium and manganese LixMn2O4+with the spinel structure, where the 0.9 < x < 1.2 and 0 < < 0,4.

2. The method according to p. 1, in which the reagent manganese oxide (oxide MP) in the reaction mixture are selected from the group consisting of MnO2, MP2ABOUT3, MP3ABOUT4or Moon, or any mixtures thereof.

3. The method according to p. 1, in which the reactant lithium salt for stages (a) and (C) is selected from the group consisting of lithium nitrate, lithium acetate, lithium sulfate and lithium carbonate, and any mixtures thereof.

4. The method according to p. 1, in which chrome is the action on the stage (C) with the formation of oxide of lithium and manganese with spinel structure.

5. The method according to p. 1 wherein the reaction in stage (b) is conducted within a temperature range that is smaller than the temperature range at which the reaction is carried out at the stage (C).

6. The method according to p. 5, in which the reaction in stage (b) is conducted within a temperature range of approximately from 4 to 400oC.

7. The method according to p. 6, in which the reaction in stage (C) is conducted within a temperature range from about 650 to 900oC.

8. The method according to p. 1, in which the reagent manganese oxide on the stage (a) contains manganese dioxide.

9. The method of producing oxide of lithium and manganese LixMn2O4+with the spinel structure, which includes stages: (a) to form a reaction mixture containing manganese dioxide and a reagent selected from the group consisting of lithium salts and lithium hydroxide and any mixture thereof; (b) the reaction of manganese oxide in the reaction mixture with the formation of manganese dioxide with the included lithium LixMnO2where 0,015 < x < 0,2, mostly without the formation of oxide of lithium and manganese with a spinel structure having a stoichiometric formula of LixMn2O4+where to 0.9 < x < 1.2 and 0 < < 0.4, and c) the reaction of manganese dioxide with the introduction of negav> with the spinel structure, where the 0.9 < x < 1.2 and 0 < < 0,4.

10. The method according to p. 9, in which the reaction in stage (b) is conducted within a temperature range that is smaller than the temperature range at which carry out the reaction in stage (C).

11. The method according to p. 10, in which the reaction in stage (b) is conducted within a temperature range of approximately from 4 to 400oC.

12. The method according to p. 11, in which the reaction in stage (C) is conducted within a temperature range from approximately 650 to 800oC.

13. The method according to p. 9, which additionally includes the stage of separation of the oxide of lithium and manganese (Lix(oxide MP)) from the reaction mixture before the reaction in stage (C) with the formation of oxide of lithium and manganese with spinel structure.

14. The method according to p. 9, in which the reaction mixture of stage (a) contains electrolytic manganese dioxide (D) and lithium hydroxide, and the pH of the reaction mixture is between 7 and 14.

15. The method of producing oxide of lithium and manganese with spinel structure, which includes stages: (a) to form a reaction mixture containing manganese dioxide and a reagent selected from the group consisting of lithium salts and lithium hydroxide and any mixture thereof; xMnO2where 0,015 < x < 0,2, mostly without the formation of oxide of lithium and manganese with a spinel structure having a stoichiometric formula of LixMn2O4+where to 0.9 < x < 1.2 and 0 < < 0,4; (C) heating the manganese dioxide with the included lithium education sesquioxide lithium manganese (LixMn2O3), and (d) reaction of sesquioxide lithium and manganese with lithium carbonate to form lithium oxide and manganese LixMn2O4+with the spinel structure, where the 0.9 < x < 1.2 and 0 < < 0,4.

16. The method according to p. 15, in which the reaction in stage (b) is conducted within a temperature range of approximately from 4 to 400oC.

17. The method according to p. 16, in which the reaction in stage (d) is conducted within a temperature range from about 650 to 900oC.

18. The method according to p. 17, in which the reaction in stage (C) is conducted within a temperature range from approximately 550 to 600oC.

19. The method according to p. 15, in which the reaction mixture of stage (a) contains electrolytic manganese dioxide (D) and lithium hydroxide, and the pH of the mentioned reaction mixture is between 7 and 14.

20. Secondary rechargeable battery types, the ima is in them, characterized in that it contains a positive electrode containing lithium oxide and manganese with a spinel structure having a stoichiometric formula of LixMn2O4+where to 0.9 < x < 1,2, 0 < < 0,4, it called oxide of lithium and manganese obtained by the method according to p. 1.

 

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1 tbl

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3 cl, 1 tbl

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