Preparation method of battery composite material and precursor thereof

Abstract

A preparation method of a battery composite material includes steps of providing phosphoric acid, manganese carbonate, water and a first reactant; processing a reaction of the phosphoric acid, the manganese carbonate and the water to produce a first product; calcining the first product to produce a precursor, which is written by Mn.sub.2P.sub.2O.sub.7; processing a reaction of the precursor and at least the first reactant to get a reaction mixture, and then calcining the reaction mixture to produce the battery composite material. As a result, the present invention achieves the advantages of reducing the times of the reduction-oxidation reaction, so that the stability of the processes is enhanced, and the difficulty of the processes is reduced.

Claims

1. A preparation method of a battery composite material, comprising steps of: (a) providing phosphoric acid, manganese carbonate, water and a first reactant, wherein the formula of the phosphoric acid is written by H.sub.3PO.sub.4, the first reactant is lithium carbonate, and the formula of the lithium carbonate is written by Li.sub.2CO.sub.3; (b) processing a reaction of the phosphoric acid, the manganese carbonate and the water to produce a first product; (c) calcining the first product to produce a precursor, wherein the formula of the precursor is written by Mn.sub.2P.sub.2O.sub.7; and (d) processing a reaction of the precursor and at least the first reactant to obtain a reaction mixture, and then calcining the reaction mixture to produce the battery composite material, wherein the step (d) further comprises steps of: (d1) mixing the precursor and at least the first reactant; (d2) adding water or solvent for grinding and drying to remove the water or the solvent; (d3) performing a high-temperature calcination; and (d4) producing the battery composite material.

2. The preparation method according to claim 1, wherein the battery composite material is lithium manganese phosphate or lithium manganese phosphate nano-co-crystalline olivine, and the formula of lithium manganese phosphate is written by LiMnPO.sub.4.

3. The preparation method according to claim 1, wherein the step (d) is implemented by processing a reaction of the precursor, the first reactant and a second reactant to obtain the reaction mixture and calcining the reaction mixture to produce the battery composite material.

4. The preparation method according to claim 3, wherein the second reactant is ferric phosphate dihydrate, the formula of the second reactant is written by FePO.sub.4.2H.sub.2O, and wherein the battery composite material is lithium ferric manganese phosphate or lithium ferric manganese phosphate nano-co-crystalline olivine, and the formula of lithium ferric manganese phosphate is written by LiMn.sub.xFe.sub.1-xPO.sub.4, x>0.

5. The preparation method according to claim 1, wherein the step (b) further comprises a step of (b1) allowing a first quantity of the water to dissolve a second quantity of the phosphoric acid and a third quantity of the manganese carbonate and stirring for a first time period for producing the first product.

6. The preparation method according to claim 5, wherein the weight ratio of the second quantity to the third quantity is 1:1.

7. The preparation method according to claim 5, wherein the first quantity is 3.2 liters, the second quantity is 462.7 grams, the third quantity is 460 grams, and the first time period is 24 hours.

8. The preparation method according to claim 1, wherein the step (c) further comprises steps of: (c1) adding a dispersant into the first product; (c2) grinding the first product at a first rotational speed for a second time period to obtain a precursor solution; and (c3) performing a spray drying action and a thermal treatment to the precursor solution.

9. The preparation method according to claim 8, wherein the first rotational speed is equal to or greater than 450 rpm and equal to or less than 650 rpm, and the second time period is 1 hour.

10. The preparation method according to claim 8, wherein the thermal treatment is performed at a temperature greater than 380 C. for at least 2 hours in nitrogen atmosphere.

11. The preparation method according to claim 8, wherein the dispersant is polyethylene glycol tert-octylphenyl ether.

12. The preparation method according to claim 1, wherein the high-temperature calcination is performed at a temperature between 550 C. and 750 C. for at least 8 to 12 hours in nitrogen atmosphere.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically illustrates the flow chart of a preparation method of a battery composite material according to an embodiment of the present invention;

(2) FIG. 2 schematically illustrates a detailed flow chart of the preparation method of a battery composite material according to an embodiment of the present invention;

(3) FIG. 3 schematically illustrates another detailed flow chart of the preparation method of a battery composite material according to an embodiment of the present invention;

(4) FIG. 4 schematically illustrates the X-ray diffraction analysis diagram of a precursor prepared by the preparation method of the battery composite material of the present invention;

(5) FIG. 5 schematically illustrates the SEM analysis diagram of a precursor prepared by the preparation method of the battery composite material of the present invention;

(6) FIG. 6 schematically illustrates the X-ray diffraction analysis diagram of a battery composite material prepared by the preparation method of the battery composite material of the present invention;

(7) FIG. 7 schematically illustrates the SEM analysis diagram of a battery composite material prepared by the preparation method of the battery composite material of the present invention;

(8) FIG. 8 schematically illustrates a charging and discharging characteristic diagram of a cell battery made of a battery composite material prepared by the preparation method of the battery composite material of the present invention;

(9) FIG. 9 schematically illustrates the X-ray diffraction analysis diagram of another battery composite material prepared by the preparation method of the battery composite material of the present invention;

(10) FIG. 10 schematically illustrates the SEM analysis diagram of another battery composite material prepared by the preparation method of the battery composite material of the present invention;

(11) FIG. 11 schematically illustrates a charging and discharging characteristic diagram of a cell battery made of another battery composite material prepared by the preparation method of the battery composite material of the present invention;

(12) FIG. 12A, FIG. 12B and FIG. 12C schematically illustrate the SEM analysis diagram of a lithium manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention; and

(13) FIG. 13A, FIG. 13B and FIG. 13C schematically illustrate the SEM analysis diagram of a lithium ferric manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(14) The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this disclosure are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.

(15) Please refer to FIG. 1. FIG. 1 schematically illustrates the flow chart of a preparation method of a battery composite material according to an embodiment of the present invention. A preparation method of a batter composite material of the present invention includes steps as follows. At first, providing phosphoric acid, manganese carbonate, water and a first reactant as shown in step S100, among which the formula of the phosphoric acid is written by H.sub.3PO.sub.4. In some embodiments, the first reactant is lithium carbonate (Li.sub.2CO.sub.3), a compound consisting of lithium, or a mixture of several compounds consisting of lithium, but not limited thereto.

(16) Next, processing a reaction of the phosphoric acid, the manganese carbonate and the water to produce a first product as shown in step S200. In some embodiments, the step S200 is preferred to include a step of allowing a first quantity of the water to dissolve a second quantity of the phosphoric acid and a third quantity of the manganese carbonate and stirring for a first time period for producing the first product. The first time period is not limited to 24 hours. The weight ratio of the second quantity to the third quantity is substantially 1:1. For example, the second quantity is 462.7 grams and the third quantity is 460 grams, such that the first quantity is preferably 3.2 liters. In other words, the step S200 may include a step of allowing 3.2 liters of the water to dissolve 462.7 grams of the phosphoric acid and 460 grams of the manganese carbonate and stirring for 24 hours for producing the first product. In addition, the first product may also be obtained through a step of processing a reaction of manganese and a compound releasing phosphate ions in a solution, but not limited thereto.

(17) Then, calcining the first product obtained in the step S200 to produce a precursor as shown in step S300, among which the formula of the precursor is written by Mn.sub.2P.sub.2O.sub.7.

(18) Finally, processing a reaction of the precursor and at least the first reactant to obtain a reaction mixture, and then calcining the reaction mixture to produce the battery composite material as shown in step S400, among which the battery composite material is for example LiMnPO.sub.4. It should be noted that the precursor is reacted with at least the first reactant in the step S400. Certainly, the precursor is not limited to be reacted with the first reactant, or be reacted with the first reactant and the second reactant. For example, the first reactant is lithium carbonate and the second reactant is ferric phosphate dihydrate, among which the formula of the second reactant is written by FePO.sub.4.2H.sub.2O. After calcining the reaction mixture, a battery composite material, which is for example lithium ferric manganese phosphate, is produced, among which the formula of lithium ferric manganese phosphate is written by LiMn.sub.xFe.sub.1-xPO.sub.4 (x>0).

(19) In the step S200 or the step S400, metal oxide, such as V.sub.2O.sub.5, TiO.sub.2 or MgO, can be added into the reaction, so that a LiMnPO.sub.4-like material consisting of the metal oxide, which can be called or named lithium manganese phosphate nano-co-crystalline olivine (LMP-NCO), or a LiMn.sub.xFe.sub.1-xPO.sub.4-like material consisting of the metal oxide, which can be called or named lithium ferric manganese phosphate nano-co-crystalline olivine (LFMP-NCO), is produced.

(20) Under this circumstance, the present invention provides a preparation method of a battery composite material for reducing the times of the reduction-oxidation reaction while adding lithium salts in manner of preparing the battery composite material through the reaction of lithium carbonate and the precursor produced via reactions. The stability of the processes is enhanced, and the difficulty of the processes is reduced. Meanwhile, the grinding time is significantly reduced, and further the costs per unit of time and money are reduced. The sensitivity of pH value of the process is reduced, the viscosity of the material and the blockage of processing pipes are avoided, and the processing temperature is stably controlled. Additionally, by utilizing lithium carbonate in replace of lithium hydroxide, the pH value of the process becomes more stable, such that the carbon-coating result and the product performance are both enhanced.

(21) Please refer to FIG. 1 and FIG. 2. FIG. 2 schematically illustrates a detailed flow chart of the preparation method of a battery composite material according to an embodiment of the present invention. As shown in FIG. 1 and FIG. 2, the detailed flow chart of the step S300 of the preparation method of the battery composite material of the present invention includes steps as follows. As shown in step S301, adding a dispersant into the first product. Next, grinding the first product at a first rotational speed for a second time period to obtain a precursor solution as shown in step S302. The first rotational speed is equal to or greater than 450 rpm and equal to or less than 650 rpm, and the second time period is 1 hour.

(22) In other words, the preferred embodiment of the step S302 is a step of grinding the first product at 450-650 rpm for 1 hour to obtain the precursor solution, but not limited thereto. Then, as shown in step S303, performing a spray drying action and a thermal treatment to the precursor solution in order to obtain a dry precursor (i.e. Mn.sub.2P.sub.2O.sub.7). In an embodiment, the thermal treatment is performed at a temperature greater than 380 C. for at least 2 hours in nitrogen atmosphere.

(23) The precursor of the preparation method of the battery composite material of the present invention is completely prepared. The detailed flow chart of the step S400 is described as follows. Please refer to FIG. 3. FIG. 3 schematically illustrates another detailed flow chart of the preparation method of a battery composite material according to an embodiment of the present invention. As shown in FIG. 3, the detailed flow chart of the step S400 includes steps of mixing the precursor (i.e. Mn.sub.2P.sub.2O.sub.7) and the first reactant, which is not limited to be lithium carbonate (Li.sub.2CO.sub.3), a compound consisting of lithium, or a mixture of several compounds consisting of lithium as shown in step S401, adding a dispersant, which is for example polyethylene glycol tert-octylphenyl ether (i.e. TritonX-100), and performing a spray granulation as shown in step S402, performing a high-temperature calcination, which is preferably performed at a temperature between 550 C. and 750 C. for at least 8 to 12 hours in nitrogen atmosphere, as shown in step S403, and producing the battery composite material, which is for example lithium manganese phosphate, lithium ferric manganese phosphate, lithium manganese phosphate nano-co-crystalline olivine, or lithium ferric manganese phosphate nano-co-crystalline olivine, as shown in step S404.

(24) The following embodiments are presented herein for purpose of illustration and description of the preparation method of the battery composite material of the present disclosure.

1st Embodiment

(25) At first, providing 460 grams of manganese carbonate (Purity >99%), 462.7 grams of phosphoric acid (Purity >85%), 3.2 liters of deionized water and 147.76 grams of lithium carbonate and mixing manganese carbonate, phosphoric acid and the deionized water to process a reaction and stirring for 24 hours. Next, adding a dispersant and grinding the mixture (450-650 rpm) for 1 hour to obtain a Mn.sub.2P.sub.2O.sub.7 precursor solution. Then, performing a spray drying action to the precursor solution, putting the product into a ceramic sagger, and performing a calcination to the product, among which the calcination is performed at a temperature greater than 380 C. for at least 2 hours in nitrogen atmosphere. The calcined compound is analyzed in manner of X-ray diffraction, and the analysis diagram is shown as FIG. 4. After comparing the diagram with JCPDS card, the compound is confirmed to be Mn.sub.2P.sub.2O.sub.7. The surface exterior is analyzed through SEM, and the SEM analysis diagram is shown as FIG. 5.

(26) Next, adding 283.84 grams of Mn.sub.2P.sub.2O.sub.7 obtained in the above-mentioned steps, 147.76 grams of lithium carbonate, 30 grams of fructose and 0.06 grams of TritonX-100 into pure water for grinding of the horizontal sander. After grinding, the LiMnPO.sub.4 precursor solution is obtained. Then, performing a spray drying action to this precursor solution, putting the product into a ceramic sagger, and performing a calcination to the product, among which the calcination is performed at 550 C.-750 C. for 8-12 hours in nitrogen atmosphere. The calcined compound is analyzed in manner of X-ray diffraction, and the analysis diagram is shown as FIG. 6. After comparing the diagram with JCPDS card, the compound is confirmed to be LiMnPO.sub.4. The surface exterior is analyzed through SEM, and the SEM analysis diagram is shown as FIG. 7.

(27) Next, mixing LiMnPO.sub.4 obtained in the above-mentioned steps, conductive carbon black (Super PC)) and 4 weight percent of binder (PVDF+NMP) in a ratio of 8:1:1. First, mixing 1 gram of conductive carbon black and 25 grams of binder (PVDF:NMP=40:960) for 10 minutes. The rotational speed is 1200 rpm. Then, adding 8 grams of LiMnPO.sub.4 and mixing for another 10 minutes. Next, coating the dispersed slurry on an aluminum substrate with a blade coater, among which the coating thickness is 0.3 millimeters. Then, putting the coated aluminum substrate into an oven and baking the coated aluminum substrate at 100 C. for 1 hour. Finally, forming the aluminum substrate as a circular plate, among which the diameter of the circular plate is 1.3 centimeters, and making a coin-cell battery with this circular plate, lithium metal (as the negative electrode), 1 molar concentration of LiPF.sub.6 and a mixed electrolyte of EC and DMC (volume ratio=1:1). The electric characteristics of charging and discharging of the coin-cell battery are tested and analyzed through a charging and discharging machine. The test and the analysis are performed at 0.1 coulombs for two cycles and 2 coulombs for two cycles. The charging and discharging characteristic diagram is shown as FIG. 8. The cutoff voltage of the coin-cell battery is 2 to 4.5 volts.

2nd Embodiment

(28) Adding metal oxide, such as V.sub.2O.sub.5, TiO.sub.2 or MgO, in the step S200 or the step S400 of the 1st embodiment, so that lithium manganese phosphate nano-co-crystalline olivine is produced. The rest portion of this embodiment is similar with the 1st embodiment, and is not redundantly described herein.

3rd Embodiment

(29) Utilizing 12 weight percent of lactose as a carbon source in replace of the 30 grams of fructose of the 1st embodiment. The rest portion of this embodiment is similar with the 1st embodiment, and is not redundantly described herein.

4th Embodiment

(30) At first, providing 460 grams of manganese carbonate (Purity >99%), 462.7 grams of phosphoric acid (Purity >85%), 3.2 liters of deionized water, 147.76 grams of lithium carbonate and 74.7 grams of ferric phosphate dihydrate (FePO.sub.4.2H.sub.2O) and mixing manganese carbonate, phosphoric acid and the deionized water to process a reaction and stirring for 24 hours. Next, adding a dispersant and grinding the mixture (450-650 rpm) for 1 hour to obtain a Mn.sub.2P.sub.2O.sub.7 precursor solution. Then, performing a spray drying action to the precursor solution, putting the product into a ceramic sagger, and performing a calcination to the product, among which the calcination is performed at a temperature greater than 380 C. for at least 2 hours in nitrogen atmosphere. The calcined compound is confirmed to be Mn.sub.2P.sub.2O.sub.7.

(31) Next, adding 227.1 grams of Mn.sub.2P.sub.2O.sub.7 obtained in the above-mentioned steps, 147.76 grams of lithium carbonate, 74.7 grams of FePO.sub.4.2H.sub.2O, 30 grams of fructose and 0.06 grams of TritonX-100 into pure water for grinding of the horizontal sander. After grinding, the LiMn.sub.0.8Fe.sub.0.2PO.sub.4 precursor solution is obtained. Then, performing a spray drying action to this precursor solution, putting the product into a ceramic sagger, and performing a calcination to the product, among which the calcination is performed at 550 C.-750 C. for 8-12 hours in nitrogen atmosphere. The calcined compound is analyzed in manner of X-ray diffraction, and the analysis diagram is shown as FIG. 9. After comparing the diagram with JCPDS card, the compound is confirmed to be LiMn.sub.0.8Fe.sub.0.2PO.sub.4. The surface exterior is analyzed through SEM, and the SEM analysis diagram is shown as FIG. 10.

(32) Next, mixing LiMn.sub.0.8Fe.sub.0.2PO.sub.4 obtained in the above-mentioned steps, conductive carbon black (Super PC)) and 4 weight percent of binder (PVDF+NMP) in a ratio of 8.5:0.5:1. First, mixing 0.5 grams of conductive carbon black and 25 grams of binder (PVDF:NMP=40:960) for 10 minutes. The rotational speed is 1200 rpm. Then, adding 8.5 grams of LiMn.sub.0.8Fe.sub.0.2PO.sub.4 and mixing for another 10 minutes. Next, coating the dispersed slurry on an aluminum substrate with a blade coater, among which the coating thickness is 0.3 millimeters. Then, putting the coated aluminum substrate into an oven and baking the coated aluminum substrate at 100 C. for 1 hour. Finally, forming the aluminum substrate as a circular plate, among which the diameter of the circular plate is 1.3 centimeters, and making a coin-cell battery with this circular plate, lithium metal (as the negative electrode), 1 molar concentration of LiPF.sub.6 and a mixed electrolyte of EC and DMC (volume ratio=3:7). The electric characteristics of charging and discharging of the coin-cell battery are tested and analyzed through a charging and discharging machine. The test and the analysis are performed at 0.1 coulombs for two cycles and 2 coulombs for two cycles. The charging and discharging characteristic diagram is shown as FIG. 11. The cutoff voltage of the coin-cell battery is 2.5 to 4.5 volts.

5th Embodiment

(33) Adding metal oxide, such as V.sub.2O.sub.5, TiO.sub.2 or MgO, in the step S200 or the step S400 of the 4th embodiment, so that lithium ferric manganese phosphate nano-co-crystalline olivine is produced. The rest portion of this embodiment is similar with the 4th embodiment, and is not redundantly described herein.

6th Embodiment

(34) Utilizing 12 weight percent of lactose as a carbon source in replace of the 30 grams of fructose of the 4th embodiment. The rest portion of this embodiment is similar with the 4th embodiment, and is not redundantly described herein.

7th Embodiment

(35) Adjusting the ratio of Mn to Fe of the 4th embodiment for achieving different features. In other words, the compound LiMn.sub.0.8Fe.sub.0.2PO.sub.4 is adjusted as LiMn.sub.xFe.sub.1-xPO.sub.4, among which x>0 and x is preferably 0.2-0.8. The rest portion of this embodiment is similar with the 4th embodiment, and is not redundantly described herein.

(36) Please refer to FIG. 12A, FIG. 12B and FIG. 12C. FIG. 12A, FIG. 12B and FIG. 12C schematically illustrate the SEM analysis diagram of a lithium manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention. The lithium manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention is analyzed through SEM, and the SEM diagrams captured under magnifications of 50000, 10000 and 1000 are respectively shown as FIG. 12A, FIG. 12B and FIG. 12C.

(37) Please refer to FIG. 13A, FIG. 13B and FIG. 13C. FIG. 13A, FIG. 13B and FIG. 13C schematically illustrate the SEM analysis diagram of a lithium ferric manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention. The lithium ferric manganese phosphate nano-co-crystalline olivine prepared by the preparation method of the battery composite material of the present invention is analyzed through SEM, and the SEM diagrams captured under magnifications of 50000, 10000 and 1000 are respectively shown as FIG. 13A, FIG. 13B and FIG. 13C.

(38) From the above description, the present invention provides a preparation method of a battery composite material and a precursor thereof for reducing the grinding time and the costs per unit of time and money in manner of preparing the battery composite material through the precursor produced via reactions. Meanwhile, the sensitivity of pH value of the process is reduced, the viscosity of the material and the blockage of processing pipes are avoided, the processing temperature is stably controlled, and the operation difficulty of the process is reduced. Furthermore, by utilizing lithium carbonate in replace of lithium hydroxide, the pH value of the process becomes more stable, such that the carbon-coating result and the product performance are both enhanced.

(39) While the disclosure has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.