Improved synthesis of olivine-type lithium metal phosphate cathode materials

Abstract

An improved method of forming a lithium metal phosphate positive electrode material, a precursor of the positive electrode material, and a battery including the positive electrode material is described. The method comprises: forming a first aqueous solution comprising Li + in a first molar concentration and PO4 3-in a second molar concentration; forming a second aqueous solution comprising an organic acid or a salt of an organic acid and a metal selected from the group consisting of Fe, Ni, Mn and Co wherein the metal is present at a third molar concentration; forming a precipitate; drying the precipitate; and calcining the precipitate, thereby forming a lithium metal phosphate positive electrode material having a chemical formula represented by LiMPO4 / C, in which the lithium metal phosphate positive electrode material contains up to 3% by weight of carbon.

Description

[0001] This patent application is a divisional application of the patent application with application number 2018800474502, application date July 18, 2018, and invention name “Improved Synthesis of Olivine-Type Lithium Metal Phosphate Positive Electrode Materials”. Technical Field

[0002] The present invention relates to olivine-type lithium metal phosphate LiMPO4 (LMP) cathode materials, where M represents Fe, Mn, Ni, or Co, and combinations thereof. The present invention also relates to improved methods for synthesizing LMP. More specifically, the present invention relates to the synthesis of a particularly preferred LMP cathode material, LiFePO4 (LFP), which is made from low-cost materials and requires less processing than conventional solid-phase or hydrothermal methods. Even more preferably, the present invention relates to the improved synthesis of LMP, particularly LFP, preferably including carbon as a coating. Background Art

[0003] LMP (and more specifically LFP) is a cathode material widely used in lithium-ion batteries. LFP is commercially synthesized by either solid phase or hydrothermal methods, both of which require multiple time-consuming steps or expensive precursors. Both solid phase and hydrothermal methods are known to form undesirable impurities. The final cathode material is typically coated with a carbon source to improve conductivity, thereby forming a material known in the art as LiFePO4 / C, which stands for carbon-coated lithium iron phosphate, it being understood that the stoichiometry of carbon is not represented in the simplified notation LiFePO4 / C or LFP / C. For the purposes of this disclosure, the notation LMP / C refers to the analogous notation for carbon-coated lithium metal phosphate LiMPO4 / C.

[0004] Solid-phase methods require a homogenous mixture with uniform particle distribution. Uniform particle distribution is difficult to achieve on a production scale. In an industrial setting, mechanical mixing and grinding of large amounts of solids at high temperatures is a difficult process to control, leading to the formation of undesirable impurities.

[0005] The hydrothermal method requires an excess of LiOH and produces Li2SO4 as a waste byproduct. Lithium hydroxide is a relatively expensive lithium source, and Li2SO4 is an undesirable byproduct that needs to be recovered. The need to recover Li2SO4 complicates the overall manufacturing process and increases costs. The hydrothermal method also requires the use of an autoclave reactor at high temperatures and high pressures, which is an expensive process for large-scale production.

[0006] Despite the difficulties associated with synthesis, LFP is gaining widespread acceptance worldwide as a preferred cathode material for batteries. The field of lithium-ion batteries, particularly those using LFP cathodes, is expected to grow. Given growing awareness of the environmental impact of manufacturing processes and the costs and difficulties associated with LFP synthesis, those skilled in the art have long sought a synthesis method that uses lower-cost raw materials and requires less processing. This article provides an improved synthesis method. Summary of the Invention

[0007] The present invention relates to a positive electrode material comprising a lithium metal phosphate, preferably comprising carbon as a coating, and in particular to a positive electrode material comprising lithium iron phosphate, preferably comprising carbon as a coating. The present invention also relates to an improved method for producing a positive electrode material comprising a lithium metal phosphate, preferably comprising carbon as a coating, and in particular to a positive electrode material comprising lithium iron phosphate, preferably comprising carbon as a coating.

[0008] More particularly, the present invention relates to methods for synthesizing lithium iron phosphate / carbon (LFP / C) materials using lower cost raw materials or starting materials and simplified processes with minimal processing.

[0009] A particular feature of the present invention is the ability to produce LiFePO4 / C in aqueous solution at relatively low temperatures and ambient pressures.

[0010] It will be appreciated that these and other embodiments are provided in terms of a method of forming a lithium metal phosphate positive electrode material, comprising:

[0011] A first aqueous solution is formed, comprising a first molar concentration of Li + and the second molar concentration of PO4 3- ;

[0012] forming a second aqueous solution comprising an organic acid or a salt of an organic acid and a metal selected from the group consisting of Fe, Ni, Mn, and Co, wherein the metal is present at a third molar concentration;

[0013] causing a precipitate to form;

[0014] drying the precipitate; and

[0015] The precipitate is calcined to form a lithium metal phosphate cathode material having a chemical formula represented by LiMPO 4 / C, wherein the lithium metal phosphate cathode material includes up to 3 wt % of carbon.

[0016] Yet another embodiment is provided in terms of a method of forming a lithium metal phosphate cathode precursor material, comprising:

[0017] A first aqueous solution is formed, comprising a first molar concentration of Li + and the second molar concentration of PO4 3- ;

[0018] forming a second aqueous solution comprising an organic acid or a salt of an organic acid and a metal, wherein the metal is selected from the group consisting of Fe, Ni, Mn, and Co, and the metal is present at a third molar concentration;

[0019] causing a precipitate to form; and

[0020] The precipitate was dried.

[0021] Yet another embodiment is provided in terms of a method of forming a battery, comprising:

[0022] A lithium metal phosphate cathode material is formed, comprising:

[0023] A first aqueous solution is formed, comprising a first molar concentration of Li + and the second molar concentration of PO4 3- ;

[0024] forming a second aqueous solution comprising an organic acid or a salt of an organic acid and a metal, wherein the metal is selected from the group consisting of Fe, Ni, Mn, and Co, and the metal is present at a third molar concentration;

[0025] causing a precipitate to form;

[0026] drying the precipitate; and

[0027] calcining the precipitate to form a lithium metal phosphate cathode material having a chemical formula represented by LiMPO4 / C, wherein the lithium metal phosphate cathode material comprises up to 3 wt% carbon;

[0028] as well as

[0029] The lithium metal phosphate cathode material is combined with the anode, separator, and dielectric in the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the powder XRD pattern of the dried precursor material.

[0031] Figure 2 The figure is the powder XRD pattern of the calcined LiFePO4 / C positive electrode material of the present invention.

[0032] Figure 3 is a graphical illustration of the charge / discharge curves of the LiFePO4 / C versus Li half-cell of the present invention at 0.1C and 1C rates.

[0033] Figure 4Graph showing the cycling of the LiFePO4 / C of the present invention relative to a Li half-cell at a 1C rate.

[0034] Figure 5 FIG4 is a graph showing the rate performance of the LiFePO4 / C of the present invention relative to the commercial half-cell at different current rates. DETAILED DESCRIPTION

[0035] The present invention relates to an improved synthesis of LMP / C, and more specifically, LiFePO4 / C, using relatively low-cost raw materials and minimal processing. More specifically, the present invention relates to a method for forming LiFePO4 / C using Li2CO3 as a lithium source and iron oxide (Fe2O3) as an iron source, both of which are commercially available at lower costs than LiOH and iron sulfate. Furthermore, the generated byproducts, which require recovery or disposal, are not difficult to handle.

[0036] This method for synthesizing LiFePO4 utilizes nominal stoichiometric amounts of Li2CO3 and Fe2O3 and can be performed in aqueous solution at low temperatures, such as 40°C. These advantages are important because it does not require waste disposal of Li2SO4. Since this method can be used under conditions close to ambient temperature and pressure and does not require specialized equipment, it has significant advantages over hydrothermal methods. In addition, since the reaction is carried out in aqueous solution, the particle size of LFP can be controlled and the uniformity of the particle size can be improved. Due to the low electrical conductivity of the LFP material, a carbon source can also be added in situ, further simplifying the entire process to directly form LiFePO4 / C.

[0037] The synthesis method comprises the following steps. A stoichiometric amount of Li2CO3 is added to water to produce a carbonate suspension, wherein Li2CO3 is preferably in excess of up to about 5 mol%, and water is preferably deionized water. In addition, a phosphate is added to the deionized water independently of the Li2CO3 suspension. The phosphate is preferably selected from the group consisting of (NH4)3PO4, (NH4)2HPO4, NH4H2PO4 and H3PO4, wherein NH4H2PO4 is preferred in some embodiments, however, if it is desired to minimize ammonia as a calcined product, H3PO4 is preferred. An iron source in the form of Fe2O3 is added to the solution containing the phosphate while mixing. With continuous mixing, preferably for at least 2 hours, a carbon source such as a mixture of citric acid and oxalic acid is added to the H3PO4 / Fe2O3 suspension. The Li2CO3 suspension is added dropwise and preferably mixed at about 40°C for 1 to 24 hours. The carbon source (preferably in the form of a carbohydrate) acts as a reducing agent to prevent oxidation of Fe(II) to Fe(III) and acts as a carbon source to improve the conductivity of the final LiFePO4 material. Organic acids are preferred, with citric acid monohydrate (C6H8O7-H2O) and oxalic acid dihydrate (H2C2O4-2H2O) being particularly preferred. If desired, anhydrous acids may be used instead of hydrated acids.

[0038] FeC2O4 can be used instead of Fe2O3, but this is not preferred. When FeC2O4 is used as the iron source, if the reaction time is less than about 5 hours, a Li3PO4 impurity phase may be observed after calcination. Reaction times up to 48 hours can be used; however, there is no advantage in running the reaction for more than about 24 hours. If Fe2O3 is used, shorter times can be used.

[0039] During the reaction, the pH of the solution is low and does not need to be controlled. The pH is usually about 1.0 to about 1.7.

[0040] After the reaction of the iron salt, phosphate and organic acid is complete, the reaction solution is then dried to form a dry powder referred to herein as a precursor. Thin film drying is preferred.

[0041] If desired, the precursor can optionally be ball milled for a shorter time, such as less than 4 hours, to produce a more uniform and higher tap density powder. Ball milling can be accomplished using alumina; however, when using alumina, the material may be contaminated with small amounts of material from the ball media and the jar. Zirconia is a particularly preferred ball media for ball milling.

[0042] The precursor is fired to obtain LMP / C, and preferably LiFePO4 / C. Under an inert gas, a calcination temperature of 620 °C to 740 °C is preferred. Above about 740 °C, Fe3P impurities can be observed. As an example demonstrating the present invention, it is preferred to fire or calcine the powder at about 660 °C to 700 °C for 1 hour to 10 hours, and preferably under N 2(g) atmosphere. If less than about 1 hour, the calcination is incomplete. If more than about 10 hours, the oxide begins to degrade. A calcination time of about 4 hours to about 10 hours is preferred.

[0043] Since at the calcination temperature, the main decomposition products are gases, there is no need to monitor the decomposition products. The expected decomposition products include NH3, CO2, CO, and H2O.

[0044] For convenience, a method for forming lithium iron phosphate is described herein. It should be understood that iron can be replaced by an equimolar nickel salt, manganese salt, cobalt salt, or a combination thereof by the same method to obtain an olivine-type lithium metal phosphate referred to herein as LMP, with the chemical formula:

[0045] LiFe x Ni a Mn y Co z PO4, where x + a + y + z = 1 [[ID=二十一]]

[0046] [[ID=二十二]]Where: [[ID=二十三]] [[ID=二十四]]

[0047] [[ID=二十五]]0 ≤ x ≤ 1, more preferably 0.5 ≤ x ≤ 1, and most preferably 0.9 ≤ x ≤ 1; [[ID=二十六]] [[ID=二十七]]

[0048] [[ID=二十八]]0 < y ≤ 1, more preferably 0 ≤ y ≤ 0.5; [[ID=二十九]] [[ID=三十]]

[0049] [[ID=三十一]]?0 < z ≤ 1, more preferably 0 ≤ z ≤ 0.5; and [[ID=三十二]] [[ID=三十三]]

[0050] [[ID=三十四]]0 < a ≤ 0.1. [[ID=三十五]] [[ID=三十六]]

[0051] [[ID=三十七]]Iron oxide (Fe2O3) (where iron is Fe[[ID=三十八]] +3 [[ID=三十九]]) is the preferred iron source for the reaction. Compared with iron oxalate or iron sulfate, iron oxide is generally widely available and has a lower cost per mole of iron. In iron oxide, iron is in the Fe(III) oxidation state, thus minimizing the need for inert air purification during the synthesis process, and Fe(III) has a lower sensitivity to pH. A specific feature of using iron oxide is that less water is required for the synthesis. For example, compared with the synthesis using iron oxalate, only about 33% by volume of water is required to synthesize the oxide precursor using iron oxide. On a commercial scale, using less water reduces the drying requirement compared to the case with a higher water content, thus enabling evaporation drying or thin-film drying on a much larger scale. [[ID=四十]]

[0052] If nickel, manganese and / or cobalt are present, acid salts of nickel, manganese and cobalt in which the metal is in the +2 oxidation state are preferred metal sources. By way of example, oxalates of manganese, nickel and / or cobalt may be cited.

[0053] When iron oxide is used, post-calcination grinding is usually not required.

[0054] In order to obtain good electrochemical properties (such as conductivity), tap density, lithium ion diffusivity, optimal particle size and phase purity, carbon is preferably used as a coating. The carbon content can also control the crystal growth of LMP during calcination, where the particle size is inversely proportional to the carbon content. The tap density is also inversely proportional to the carbon content. In addition, at high carbon contents, impurities appear due to the reduction of iron. If the carbon content is insufficient, impurities are formed due to the oxidation of iron. In order to obtain optimal conductivity and sufficient tap density and particle size, the preferred final carbon content is at least 1 wt% to no more than 3 wt%. Most preferably, the carbon content is at least 1.5 wt% to no more than 2.5 wt%, with about 2 wt% being optimal. When the carbon content exceeds about 2 wt%, there is no significant improvement in conductivity, and the lithium ion diffusion rate may decrease as the thickness of the carbon coating increases. For these reasons, and in order to maximize the tap density, it is preferred to limit the carbon content to no more than about 2 wt%.

[0055] The particle size obtained by synthesis is generally about 200 nm to 400 nm in diameter, and the particle size distribution is sufficiently uniform.

[0056] Particularly preferred carbon sources are organic acids, particularly carboxylic acids, and especially dicarboxylic acids or tricarboxylic acids. Dicarboxylic acids and tricarboxylic acids having less than about 10 carbon atoms (preferably with an alkyl group) are most preferred. Particularly preferred acids are selected from the group consisting of: citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecane dioic acid, dodecanedioic acid, isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid and sucrose. Citric acid and oxalic acid are preferred because they are low in cost and widely available.

[0057] There are no particular limitations on the drying method. Thin-film drying and evaporative drying are particularly preferred for production efficiency, as both provide final products with electrochemical properties that are not significantly altered by the drying method. However, due to the varying solubilities of the reaction components, evaporative drying is advantageous, and mixing of the precursor solution during drying is preferred.

[0058] The reaction of the iron salt and the phosphate can be carried out in an inert gas to prevent oxidation of the Fe(II). For the purposes of the present invention, an inert gas is defined as a gas that does not oxidize the Fe(II). Suitable gases include, but are not limited to, N2 and rare gases. N2 is particularly preferred due to its relatively low cost and wide availability.

[0059] Throughout this specification, stoichiometric means adding reactants in amounts sufficient to form a final product of appropriate stoichiometry within experimental error. As defined herein, stoichiometry is at least within 5 mole percent of the desired theoretical stoichiometric equivalent, and preferably within 1 mole percent of the desired theoretical stoichiometric equivalent. For example, the stoichiometric equivalents of lithium and phosphate preferably have a molar ratio of lithium to phosphate of 0.95:1 to 1.05:1, and preferably 0.99:1 to 1.01:1.

[0060] By using currently available equipment and / or innovations in existing industrial equipment, this method can be easily expanded for large-scale production. The positive electrode of the present invention is combined into a battery, wherein the battery includes a negative electrode (which is not limited herein), a separator (which is not limited herein) and a dielectric (which is not limited herein). Forming a battery from the positive electrode, negative electrode, separator and dielectric of the present invention as described herein is well known to those skilled in the art and does not require further elaboration herein.

[0061] Example

[0062] Solution 1 was prepared by adding 230.5 g of H3PO4 to 0.7 L of deionized water and mixing the solution for 20 minutes. 159.7 g of Fe2O3, 126.0 g of oxalic acid, and 52.5 g of citric acid were added to the solution and stirred for 1 to 2 hours. The pH of the solution was approximately 1.3 to 1.5.

[0063] Solution 2 was prepared by adding 77.6 grams of Li2CO3 to 0.8 mL of deionized water in a separate beaker and mixing the solution for about 20 minutes.

[0064] Solution 2 is added dropwise to solution 1 over a period of about 1 hour. The solution containing lithium carbonate is preferably added slowly to avoid foaming due to the release of CO 2. Preferably, the combined solutions are vigorously mixed at 40° C. for 24 hours while covering to prevent water evaporation to form a reaction solution.

[0065] The reaction solution was dried by thin film drying at a temperature of about 200° C. X-ray diffraction (XRD) of the dried powder showed the presence of Fe2O3 and Li x C y O zOther lithium compounds are converted into the final LiFePO4 / C during calcination. Then, in a tube furnace, 2(g) The powder was calcined at about 670° C. for about 4 hours to obtain LiFePO 4 / C.

[0066] While not being bound by theory, it is hypothesized that H2C2O4 acts as a reducing agent and dispersant for Fe2O3 and Li2CO3 in water. The particle size, morphology, and surface area of ​​the final LiFePO4 / C material can be controlled by varying synthesis conditions such as time, temperature, and duration.

[0067] Figure 1 The XRD pattern of the evaporated precursor material before calcination is shown. The main diffraction peaks indicate iron oxide (Fe2O3) and other lithium compounds, which are converted into the final LiFePO4 / C cathode material during calcination.

[0068] Figure 2 The powder XRD pattern of the LiFePO4 / C material is shown. All major peaks are associated with an orthorhombic olivine structure, indicating the presence of a standard LiFePO4 phase. No visible peaks associated with harmful impurity phases commonly found in traditional hydrothermal or solid-phase methods, such as Li4P2O7, Fe2P, or Fe2P2O7, were detected.

[0069] Figure 3 The charge / discharge curves of LiFePO4 / C versus commercial LFP Li half-cell at 0.1C rate are shown. The voltage plateau of about 3.4V is due to the fact that Fe 2+ / Fe 3+ Redox couple and Li + At a rate of 0.1C, a discharge capacity of 162 mAh / g can be achieved. Figure 3 It also shows that the difference between the charge and discharge voltage plateaus is small, indicating low polarization and good reversibility.

[0070] Figure 4 The cycling performance of LiFePO4 / C cathode materials compared to commercially available materials at a rate of 1C is shown. The cycling performance at 1C is very stable with almost no capacity fade. Figure 5 Improved rate performance of the inventive material relative to commercially available materials is shown, with the inventive material shown to achieve approximately 150 mAh / g at a 1C rate and 110 mAh / g at a 10C rate.

[0071] The present invention has been described with reference to preferred embodiments, but is not limited thereto. Additional embodiments and modifications not specifically described herein may be implemented, but are within the scope of the invention as more particularly described in the appended claims.

Claims

1. A method for forming a lithium metal phosphate positive electrode material, the method comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; The second molar concentration of PO4 3- , the third molar concentration of Fe 3+ and an organic acid or an organic acid salt are added to water to form a second aqueous solution; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ a reaction product with the organic acid or a salt of the organic acid; drying the precipitate to form a precursor comprising the reaction product and a lithium salt; as well as The precursor is calcined to form the lithium metal phosphate cathode material having a chemical formula represented by LiMPO 4 / C, wherein the lithium metal phosphate cathode material includes up to 3 wt % of carbon. 2 . The method for forming a lithium metal phosphate cathode material according to claim 1 , wherein the ratio of the first molar concentration to the second molar concentration is 0.95:1 to 1.05:

1. 3 . The method for forming a lithium metal phosphate cathode material according to claim 1 , wherein a ratio of the first molar concentration to the third molar concentration is 0.95:1 to 1.05:

1. 4 . The method of forming a lithium metal phosphate cathode material according to claim 1 , wherein forming the first aqueous solution comprises adding a lithium material comprising lithium and carbonate.

5. The method of forming a lithium metal phosphate cathode material according to claim 4, wherein the lithium material is selected from the group consisting of LiHCO3 and Li2CO3.

6. The method for forming a lithium metal phosphate cathode material according to claim 5, wherein the LiHCO3 is an in-situ reaction product of Li2CO3 and CO2.

7. The method for forming a lithium metal phosphate positive electrode material according to claim 1, wherein forming the first aqueous solution comprises adding a + and H + The at least one counter ion in the group consisting of a phosphate material.

8. The method of forming a lithium metal phosphate positive electrode material according to claim 7, wherein the phosphate material is selected from the group consisting of H3PO4, NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4. 9 . The method for forming a lithium metal phosphate positive electrode material according to claim 8 , wherein the phosphate material is H 3 PO 4 or (NH 4 ) 2 HPO 4 .

10. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the organic acid comprises at least one carboxyl group.

11. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the organic acid is selected from the group consisting of citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, citric acid, isocitric acid, aconitic acid, and propane-1,2,3-tricarboxylic acid.

12. The method of forming a lithium metal phosphate cathode material according to claim 11, wherein the organic acid is selected from the group consisting of oxalic acid and citric acid. 13 . The method for forming a lithium metal phosphate positive electrode material according to claim 12 , wherein the reaction product is iron oxalate.

14. The method for forming a lithium metal phosphate positive electrode material according to claim 1, wherein the metal further comprises a metal selected from the group consisting of Ni 2+ 、Mn 2+ and Co 2+ At least one element in the group consisting of. 15 . The method for forming a lithium metal phosphate cathode material according to claim 14 , wherein forming the second aqueous solution comprises adding a metal salt, wherein the metal salt is a salt of the organic acid.

16. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the LiMPO4 / C has a chemical formula: LiFe x Ni a Mn y Co z PO4, where x+a+y+z=1 in: 0≤x≤1； 0≤y≤1； 0≤z≤1; and 0≤a≤0.1。 17 . The method for forming a lithium metal phosphate positive electrode material according to claim 16 , wherein 0.5≤x≤1. 18 . The method for forming a lithium metal phosphate positive electrode material according to claim 17 , wherein 0.9≤x≤1.

19. The method for forming a lithium metal phosphate positive electrode material according to claim 16, wherein 0≤y≤0.

5. 20 . The method for forming a lithium metal phosphate positive electrode material according to claim 16 , wherein 0≤z≤0.

5.

21. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the carbon is a coating.

22. The method of forming a lithium metal phosphate cathode material of claim 1, comprising at least 1 wt% carbon.

23. The method of forming a lithium metal phosphate cathode material of claim 1, comprising at least 1.5 wt% to 2.5 wt% carbon. 24 . The method of forming a lithium metal phosphate cathode material according to claim 1 , wherein allowing the precipitate to form comprises reacting for 5 to 24 hours.

25. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the drying is selected from thin film drying and evaporative drying.

26. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the calcination is performed at a temperature of 620°C to 740°C.

27. The method of forming a lithium metal phosphate cathode material according to claim 1, wherein the metal further comprises at least one element selected from the group consisting of nickel, manganese and cobalt.

28. A method for forming a lithium metal phosphate cathode precursor material, the method comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; The second molar concentration of PO4 3- , organic acids or organic acid salts, and Fe 3+ adding a metal to water to form a second aqueous solution, wherein the metal is present at a third molar concentration; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ reaction products with said organic acid and said organic acid salt; as well as The precipitate is dried to form a precursor comprising the reaction product and a lithium salt. 29 . The method for forming a lithium metal phosphate cathode precursor material according to claim 28 , wherein the ratio of the first molar concentration to the second molar concentration is 0.95:1 to 1.05:

1. 30 . The method for forming a lithium metal phosphate cathode precursor material according to claim 28 , wherein a ratio of the first molar concentration to the third molar concentration is 0.95:1 to 1.05:

1.

31. The method of forming a lithium metal phosphate cathode precursor material according to claim 28, wherein forming the first aqueous solution comprises adding a lithium material comprising lithium and carbonate.

32. The method of forming a lithium metal phosphate cathode precursor material according to claim 31, wherein the lithium material is selected from the group consisting of LiHCO3 and Li2CO3.

33. The method for forming a lithium metal phosphate cathode precursor material according to claim 32, wherein the LiHCO3 is an in-situ reaction product of Li2CO3 and CO2.

34. The method for forming a lithium metal phosphate positive electrode precursor material according to claim 28, wherein the forming the first aqueous solution comprises adding a + and H + The at least one counter ion in the group consisting of a phosphate material.

35. The method of forming a lithium metal phosphate cathode precursor material according to claim 34, wherein the phosphate material is selected from the group consisting of H3PO4, NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4.

36. The method for forming a lithium metal phosphate positive electrode precursor material according to claim 35, wherein the phosphate material is H3PO4 or (NH4)2HPO4.

37. The method of forming a lithium metal phosphate cathode precursor material according to claim 28, wherein the organic acid comprises at least one carboxyl group.

38. The method of forming a lithium metal phosphate cathode precursor material according to claim 28, wherein the organic acid is selected from the group consisting of citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, citric acid, isocitric acid, aconitic acid, and propane-1,2,3-tricarboxylic acid.

39. The method of forming a lithium metal phosphate cathode precursor material according to claim 38, wherein the organic acid is selected from the group consisting of oxalic acid and citric acid.

40. The method for forming a lithium metal phosphate cathode precursor material according to claim 39, wherein the reaction product is iron oxalate.

41. The method for forming a lithium metal phosphate positive electrode precursor material according to claim 28, wherein the metal further comprises a metal selected from the group consisting of Ni 2+ 、Mn 2+ and Co 2+ At least one element in the group consisting of.

42. The method for forming a lithium metal phosphate cathode precursor material according to claim 41, wherein forming the second aqueous solution comprises adding a metal salt, wherein the metal salt is a salt of the organic acid.

43. The method for forming a lithium metal phosphate cathode precursor material according to claim 28, wherein the forming the precipitate comprises reacting for 5 hours to 24 hours.

44. The method of forming a lithium metal phosphate cathode precursor material according to claim 28, wherein the drying is selected from thin film drying and evaporative drying.

45. The method of forming a lithium metal phosphate cathode precursor material according to claim 28, wherein the calcination is performed at a temperature of 620°C to 740°C.

46. ​​The method of forming a lithium metal phosphate cathode precursor material of claim 28, wherein the metal is selected from the group consisting of nickel, manganese, and cobalt.

47. A method of forming a battery, the method comprising: A lithium metal phosphate cathode material is formed, comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; The second molar concentration of PO4 3- , an organic acid or a salt of an organic acid, and a metal are added to water to form a second aqueous solution, wherein the metal comprises Fe 3+ wherein the metal is present at a third molar concentration; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ a reaction product with the organic acid or a salt of the organic acid; drying the precipitate to form a precursor comprising the reaction product and a lithium salt; calcining the precursor to form the lithium metal phosphate cathode material having a chemical formula represented by LiMPO4 / C, wherein the lithium metal phosphate cathode material comprises up to 3 wt% of carbon; and The lithium metal phosphate cathode material is combined with an anode, a separator, and a dielectric in a battery.

48. The method of forming a battery according to claim 47, wherein the ratio of the first molar concentration to the second molar concentration is from 0.95:1 to 1.05:

1.

49. The method of forming a battery according to claim 47, wherein the ratio of the first molar concentration to the third molar concentration is from 0.95:1 to 1.05:

1.

50. The method of forming a battery according to claim 47, wherein said forming said first aqueous solution comprises adding a lithium material comprising lithium and carbonate.

51. The method of forming a battery according to claim 50, wherein the lithium material is selected from the group consisting of LiHCO3 and Li2CO3.

52. The method of forming a battery according to claim 51, wherein the LiHCO3 is an in situ reaction product of Li2CO3 and CO2.

53. The method of forming a battery according to claim 47, wherein forming the first aqueous solution comprises adding a + and H + The at least one counter ion in the group consisting of a phosphate material.

54. The method of forming a battery according to claim 53, wherein the phosphate material is selected from the group consisting of H3PO4, NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4.

55. The method of forming a battery according to claim 54, wherein the phosphate material is H3PO4 or (NH4)2HPO4.

56. The method for forming a battery of claim 47, wherein the organic acid comprises at least one carboxyl group.

57. The method of forming a battery according to claim 47, wherein the organic acid is selected from the group consisting of citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, citric acid, isocitric acid, aconitic acid, and propane-1,2,3-tricarboxylic acid.

58. The method of forming a battery according to claim 57, wherein the organic acid is selected from the group consisting of oxalic acid and citric acid.

59. The method of forming a battery according to claim 58, wherein the reaction product is ferric oxalate.

60. The method of forming a battery according to claim 47, wherein the metal further comprises a metal selected from the group consisting of Ni 2+ 、Mn 2+ and Co 2+ At least one element in the group consisting of.

61. The method of forming a battery according to claim 60, wherein said forming the second aqueous solution comprises adding a metal salt, wherein said metal salt is a salt of said organic acid.

62. The method of forming a battery according to claim 47, wherein the LiMPO4 / C has the formula: LiFe x Ni a Mn y Co z PO4, where x+a+y+z=1 in: 0≤x≤1； 0≤y≤1； 0≤z≤1; and 0≤a≤0.1。 63. The method of forming a battery according to claim 62, wherein 0.5≤x≤1.

64. The method for forming a battery according to claim 63, wherein 0.9≤x≤1.

65. The method for forming a battery according to claim 62, wherein 0≤y≤0.

5.

66. The method of forming a battery according to claim 62, wherein 0≤z≤0.

5.

67. The method of forming a battery according to claim 47, wherein the carbon is a coating.

68. The method of forming a battery of claim 47 comprising at least 1 wt% carbon.

69. The method of forming a battery of claim 47 comprising at least 1.5 wt% to 2.5 wt% carbon.

70. The method for forming a battery of claim 47, wherein said allowing the precipitate to form comprises reacting for 5 hours to 24 hours.

71. The method of forming a battery according to claim 47, wherein the drying is selected from the group consisting of spray drying and evaporative drying.

72. The method of forming a battery according to claim 47, wherein the calcining is performed at a temperature of 620°C to 740°C.

73. The method of forming a battery according to claim 47, wherein the metal is selected from the group consisting of nickel, manganese, and cobalt.

74. A method of forming a lithium metal phosphate cathode material, the method comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; A second aqueous solution is formed, which contains a second molar concentration of PO4 3- , the third molar concentration of Fe 3+ , and organic acids or salts of organic acids; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ a reaction product with the organic acid or a salt of the organic acid; drying the precipitate to form a precursor comprising the reaction product and a lithium salt; as well as The precursor is calcined to form the lithium metal phosphate cathode material having a chemical formula represented by LiMPO4 / C, wherein the lithium metal phosphate cathode material comprises up to 3 wt% carbon, wherein forming the second aqueous solution includes adding Fe2O3.

75. A method of forming a lithium metal phosphate cathode precursor material, the method comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; A second aqueous solution is formed, which contains a second molar concentration of PO4 3- , organic acids or organic acid salts, and Fe 3+ a metal, wherein the metal is present at a third molar concentration; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ a reaction product with the organic acid or a salt of the organic acid; and The precipitate is dried to form a precursor comprising the reaction product and a lithium salt, wherein forming the second aqueous solution comprises adding Fe2O3.

76. A method of forming a battery, the method comprising: A lithium metal phosphate cathode material is formed, comprising: A first aqueous solution is formed, comprising a first molar concentration of Li + ; A second aqueous solution is formed, which contains a second molar concentration of PO4 3- , an organic acid or a salt of an organic acid, and a metal, wherein the metal comprises Fe 3+ wherein the metal is present at a third molar concentration; The first aqueous solution and the second aqueous solution are combined, and a precipitate is formed at ambient pressure, wherein the precipitate comprises the Fe 3+ a reaction product with the organic acid or a salt of the organic acid; drying the precipitate to form a precursor comprising the reaction product and a lithium salt; calcining the precursor to form the lithium metal phosphate cathode material having a chemical formula represented by LiMPO4 / C, wherein the lithium metal phosphate cathode material comprises up to 3 wt% of carbon; and The lithium metal phosphate cathode material is combined with an anode, a separator, and a dielectric in a battery, wherein forming the second aqueous solution includes adding Fe2O3.

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