Dispersant for cathode slurry with lithium iron phosphate

Abstract

The present disclosure provides a cathode slurry comprising a lithium iron phosphate (LFP) slurry, an organic solvent, a thermoplastic polymer binder, and a dispersant of Formula I: wherein n of Formula I is 1 to 10, and R1 of Formula I is selected from the group consisting of hydrogen, a C8 to C18 alkyl phenyl group, a straight chain or branched chain primary or secondary C1 to C18 alkyl chain, and R2 of Formula I is selected from the group consisting of hydrogen, a methyl group, an ethyl group, or a combination thereof.

Description

Technical Field

[0001] This disclosure relates in general to slurries, and more specifically to dispersants for cathode slurries containing lithium iron phosphate. Background Technology

[0002] The electric vehicle (EV) market has expanded rapidly over the past decade due to increasingly stringent global environmental policies and government commitments to sustainability, leading to a growing demand for better energy storage devices. Lithium-ion batteries (LiB), currently the dominant energy storage product, have thus become one of the most popular industrial applications.

[0003] Global EV sales continue to grow at an unprecedented rate. By 2030, battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) will account for >55% of new vehicle production in China, Europe, and North America. The global demand for LiB (Li-Bike) vehicles was 700 gigawatt-hours (GWh) by 2022 and is estimated to increase to 4.7 megawatt-hours (TWh) by 2030.

[0004] Of all the conventional cathode materials used in LiB, lithium iron phosphate (LiFePO4 or LFP) currently dominates the market due to its low cost, high stability, and high safety performance. However, with more and more manufacturers entering the market, competition among LFP manufacturers has intensified, and many key manufacturers are looking for new ways to not only commit to their sustainability goals but also reduce their production costs.

[0005] As the manufacturing process for LFP cathodes used in LiB becomes more sophisticated, many major LiB manufacturers are actively seeking new ways to improve their cell production efficiency in order to enhance their competitiveness in the LiB market. One way to achieve this is to reduce the viscosity of the cathode slurry and thus increase the maximum possible solids content during cathode production. Simultaneously, since the primary solvent used in LFP cathodes is NMP (a highly hazardous organic solvent), a higher solids content in the cathode slurry will allow manufacturers to reduce the consumption of hazardous materials and mitigate potential health risks to employees.

[0006] Currently, the most common cathode pastes used in this industry have a solids content of approximately 55% by weight. A typical all-cathode paste formulation includes LFP as the active material, PVDF as a binder, SP carbon as a conductive additive, and NMP as a solvent. The viscosity of the mixed cathode paste ranges from approximately 5,000 centipoise (cP) to greater than 10,000 cP, depending on the requirements of each manufacturer. Since any additives other than the active material (LFP) are essentially impurities for the cathode, they will affect the final performance of the battery. Therefore, manufacturers aim to increase the solids content of the active material while maintaining an acceptable viscosity of the cathode paste.

[0007] In summary, the market is actively seeking a new dispersant for LiB cathode paste that can help disperse the paste, reduce its viscosity, and increase the solids content of the active material for production. These shortcomings indicate a continued need in the art to increase the solids content of the active material while maintaining a viscosity below the threshold viscosity. Summary of the Invention

[0008] This disclosure provides a cathode paste and the production of a cathode paste containing LFP material. Increasing the LFP content in the cathode paste provides a higher quality cathode. However, increasing the LFP content in the cathode paste can increase viscosity, which can prevent the LFP content from adhering to the cathode substrate. Therefore, current cathode pastes contain 55 wt% LFP solids, corresponding to a viscosity of 5,000 cP to greater than 10,000 cP. The dispersant of this disclosure can be added to the cathode paste such that the LFP solids content can be increased to greater than 55 wt% while maintaining an acceptable viscosity (e.g., in the viscosity range of 5,000 cP to 10,000 cP).

[0009] This disclosure provides a cathode slurry comprising lithium iron phosphate (LFP) slurry, an organic solvent, a thermoplastic polymer binder, and a dispersant of formula I:

[0010]

[0011] In Formula I, n is 1 to 10, and R1 of Formula I is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, straight or branched primary or secondary C1 to C18 alkyl chains, and R2 of Formula I is selected from the group consisting of hydrogen, methyl groups, ethyl groups, or combinations thereof.

[0012] For the purposes of this disclosure, the cathode paste also comprises an alkanolamine of formula II:

[0013]

[0014] In Formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms. For the purposes of this disclosure, the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA). For the purposes of this disclosure, the composition of the dispersant is in the range of 500 ppm to 2000 ppm relative to the total mass of the cathode slurry.

[0015] For the purposes of this disclosure, the dispersant comprises 0.05 to 0.20% by weight of the total mass of the cathode slurry. For the purposes of this disclosure, the composition of the dispersant is less than 500 parts per million (ppm) of the cathode slurry. For the purposes of this disclosure, the LFP slurry has a solids content greater than 55% by weight, wherein the viscosity is less than 10,000 centipoise (cP). For the purposes of this disclosure, the organic solvent is N-methyl-2-pyrrolidone (NMP), and the thermoplastic polymer binder is polyvinylidene fluoride (PVDF).

[0016] This disclosure also includes a method for producing a cathode slurry comprising: a binder dissolved in an organic solvent; a lithium iron phosphate (LFP) slurry, the LFP slurry comprising more than 55% by weight of the total weight of the cathode slurry; and a dispersant of Formula I.

[0017]

[0018] Wherein n of Formula I is 1 to 10, and R1 of Formula I is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, straight or branched primary or secondary C1 to C18 alkyl chains, and R2 of Formula I is selected from the group consisting of hydrogen, methyl groups, ethyl groups or combinations thereof; and when the cathode paste is below the threshold viscosity, the cathode paste is applied to the substrate to produce an LFP layer on the substrate.

[0019] This disclosure includes a method wherein the cathode paste further comprises an alkanolamine of formula II:

[0020]

[0021] In Formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms. For this disclosure, the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA). For this disclosure, the alkanolamine is present in the slurry at a molar percentage of 10 to 120 mol% of the molar amount of the P(OH) site of the dispersant of Formula I. The method of this disclosure further includes: producing a cathode slurry having SP carbon and polyvinylpyrrolidone (PVP) dispersed in NMP. For this disclosure, the threshold viscosity is approximately 10,000 centipoise (cP). For this disclosure, the cathode slurry has a viscosity between 5,000 centipoise (cP) and 10,000 cP. Detailed Implementation

[0022] This disclosure provides a cathode paste and the production of a cathode paste containing LFP material. Increasing the LFP content in the cathode paste provides a higher quality cathode. However, increasing the LFP content in the cathode paste can increase viscosity, which can prevent the LFP from adhering to the cathode substrate. Therefore, current cathode pastes contain 55% by weight of LFP solids, corresponding to a viscosity of 5,000 cP to greater than 10,000 cP. The dispersant of this disclosure can be added to the cathode paste, such that the LFP solids content can be increased to greater than 55% by weight while maintaining an acceptable viscosity (e.g., in the viscosity range of 5,000 cP to 10,000 cP).

[0023] As further described herein, the composition of the phosphate dispersant can range from 0.05 wt% to 0.20 wt% relative to the total mass of the slurry. In a specific example, the composition of the phosphate dispersant can range from 0.05 wt% to 0.12 wt% relative to the total mass of the slurry. Furthermore, in a specific example, the composition of the phosphate dispersant can be 0.05 wt% relative to the total mass of the slurry. In another specific example, the composition of the phosphate dispersant can be 0.12 wt% relative to the total mass of the slurry. Moreover, in a specific example, the composition of the phosphate dispersant can be 0.20 wt% relative to the total mass of the slurry.

[0024] In some specific examples, the phosphate dispersant can be less than 500 parts per million (ppm) of the slurry. The phosphate groups in the dispersant have a strong affinity for LFP particles, while the remaining components can interact with the solvent. For example, LFP particles can have a strong affinity for the phosphate groups of the dispersant, while the remaining particles can have an affinity for N-methyl-2-pyrrolidone (NMP) when NMP is the solvent for the slurry. This structure of the phosphate dispersant facilitates easier dispersion of LFP particles during the mixing process in the production of cathode slurries. The cathode slurry can be used in the production of LFP cathodes. When using the cathode slurry to produce cathodes, the phosphate ester does not introduce unwanted elements into the cathode or battery system. This innovative dispersant has demonstrated its ability to reduce the viscosity of cathode slurries after mixing at both high and low shear rates, thereby contributing to an increase in the maximum possible solids content of cathode slurries used for cathode production. The shear rates of 6 rpm, 20 rpm, and 50 rpm in the examples represent low, medium, and high shear rates, respectively. These shear rate ranges can be the standard shear rates of a Brinell viscometer array (e.g., Brinell viscometer DV-II+Pro, etc.). As described herein, alkanolamines can be added together with phosphate ester dispersants to neutralize the phosphate ester groups (-P(OH)) of the dispersant. In some examples, the dispersant is effective with and without an alkanolamine.

[0025] This disclosure provides a cathode slurry comprising lithium iron phosphate (LFP) slurry, an organic solvent, a thermoplastic polymer binder, and a dispersant of formula I:

[0026]

[0027] In Formula I, n is 1 to 10, and R1 is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, and straight-chain or branched primary or secondary C1 to C18 alkyl chains, and R2 is selected from the group consisting of hydrogen, methyl groups, ethyl groups, or combinations thereof. In one embodiment, R1 of Formula I may be selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, and straight-chain or branched primary or secondary C8 to C18 alkyl chains.

[0028] For the purposes of this disclosure, the cathode paste also comprises an alkanolamine of formula II:

[0029]

[0030] In formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms.

[0031] In some examples, n in Formula I is an integer from 3 to 8. In other examples, n in Formula I is one of 5 or 7.5. In some examples, R1 in Formula I is a C10 to C16 alkylphenyl group. In a specific example, R1 in Formula I is a C14 alkylphenyl group. In a specific example, R2 in Formula I is hydrogen. For the purposes of this disclosure, R1 in the dispersant of Formula I is selected from alkylphenyl groups, straight-chain or branched groups, and primary or secondary alkyl chains having a total of 12 to 14 carbon atoms.

[0032] In some examples, at least one of the groups R1, R2, and R3 of Formula II includes a hydroxyalkyl group having one to four carbons. In some examples, at least two of the groups R1, R2, and R3 of Formula II include a hydroxyalkyl group having one to four carbons. In a specific example, the alkanolamine of Formula II is triisopropanolamine (TIPA), wherein each of the R1, R2, and R3 groups of Formula II is an isopropanolamine group. In a specific example, the alkanolamine of Formula II is triethanolamine (TEA), wherein each of the R1, R2, and R3 groups of Formula II is an ethanol group. In a specific example, the alkanolamine of Formula II is diethanolamine, wherein R1 is hydrogen, and R2 and R3 groups are ethanol groups. Furthermore, in a specific example, the alkanolamine of Formula II is ethanolamine (MEA), wherein R1 and R2 groups are hydrogen, and R3 group is an ethanol group. For the purposes of this disclosure, the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA). For the purposes of this disclosure, the composition of the dispersant is in the range of 500 ppm to 2000 ppm relative to the total mass of the cathode slurry.

[0033] For the purposes of this disclosure, the dispersant comprises 0.05 wt% to 0.20 wt% of the total mass of the cathode slurry. In a specific example, the composition of the phosphate dispersant may range from 0.05 wt% to 0.12 wt% relative to the total mass of the cathode slurry. Furthermore, in a specific example, the composition of the dispersant may be 0.05 wt% relative to the total mass of the cathode slurry. In another specific example, the composition of the dispersant may be 0.12 wt% relative to the total mass of the cathode slurry. Furthermore, in a specific example, the composition of the dispersant may be 0.20 wt% relative to the total mass of the cathode slurry.

[0034] For the purposes of this disclosure, the composition of the dispersant is less than 500 parts per million (ppm) of the cathode slurry. For the purposes of this disclosure, the LFP slurry has a solids content greater than 55% by weight, and a viscosity less than 10,000 centipoise (cP), wherein the viscosity is measured as described in the Examples section herein. For the purposes of this disclosure, the organic solvent is N-methyl-2-pyrrolidone (NMP), and the thermoplastic polymer binder is polyvinylidene fluoride (PVDF).

[0035] This disclosure also includes a method for producing a cathode slurry comprising: a binder dissolved in an organic solvent; a lithium iron phosphate (LFP) slurry, the LFP slurry comprising more than 55% by weight of the total weight of the cathode slurry; and a dispersant of Formula I.

[0036]

[0037] Wherein n of Formula I is 1 to 10, and R1 of Formula I is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, straight or branched primary or secondary C1 to C18 alkyl chains, and R2 of Formula I is selected from the group consisting of hydrogen, methyl groups, ethyl groups, or combinations thereof; and when the cathode paste is below the threshold viscosity, the cathode paste is applied to the substrate to produce an LFP layer on the substrate, wherein the viscosity is measured as described in the Examples section herein.

[0038] This disclosure includes a method wherein the cathode paste further comprises an alkanolamine of formula II:

[0039]

[0040] In Formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms. For the purposes of this disclosure, the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA). For the purposes of this disclosure, the alkanolamine is present in the slurry at a molar percentage of 10 to 120 mol% of the P(OH) site of the dispersant of Formula I. In some examples, the alkanolamine is present in the slurry at a molar percentage of 10 to 25 mol% of the P(OH) site of the dispersant of Formula I. In other examples, the alkanolamine is present in the slurry at a molar percentage of 25 to 50 mol% of the P(OH) site of the dispersant of Formula I. In still other examples, the alkanolamine is present in the slurry at a molar percentage of 75 to 100 mol% of the P(OH) site of the dispersant of Formula I. In other examples, alkanolamines are present in the slurry at a molar percentage of 100 to 120 mol% of the P(OH) site of the dispersant of Formula I.

[0041] The method of this disclosure also includes: producing a cathode paste having SP carbon and polyvinylpyrrolidone (PVP) dispersed in NMP. SP carbon black is a conductive agent and can be dispersed using PVP. SP carbon black can be replaced by carbon nanotubes (CNTs) or graphene. For this disclosure, the threshold viscosity is approximately 10,000 centipoise (cP), wherein the viscosity is measured as described in the Examples section herein. For this disclosure, the cathode paste has a viscosity between 5,000 centipoise (cP) and 10,000 cP, wherein the viscosity is measured as described in the Examples section herein.

[0042] In specific examples, the active solids content is greater than 55% by weight, and the viscosity is less than 10,000 cP at 6 rpm, less than 6,000 cP at 20 rpm, and less than 5,000 cP at 50 rpm, wherein the viscosity is measured as described in the Examples section herein. In specific examples, the active solids content is 60% by weight, and the viscosity is less than 10,000 cP at 6 rpm, less than 6,000 cP at 20 rpm, and less than 5,000 cP at 50 rpm, wherein the viscosity is measured as described in the Examples section herein. In specific examples, the active solids content is 65% by weight, and the viscosity is less than 24,000 cP at 6 rpm, less than 19,000 cP at 20 rpm, and less than 5,000 cP at 50 rpm, wherein the viscosity is measured as described in the Examples section herein. In a specific example, the active solids content is 60% by weight, and the viscosity is less than 8,000 cP at 6 rpm, less than 6,000 cP at 20 rpm, and less than 5,000 cP at 50 rpm, wherein the viscosity is measured as described in the Examples section herein.

[0043] Example

[0044] In the embodiments, various terms and names for materials are used, including, for example, the following:

[0045] Material

[0046] The materials used in the embodiments and / or comparative examples include the following.

[0047] Table 1. Ingredients of this Disclosure

[0048] Table 2. Chemical Formulas

[0049] Unneutralized Examples

[0050] Neutralization Examples

[0051] Preparation of cathode paste containing lithium iron phosphate (LFP) slurry

[0052] The total solid content of the active material (e.g., lithium iron phosphate (LFP)) varies between 60 wt% and 65 wt%. In these embodiments, N-methyl-2-pyrrolidone (NMP) is used as the solvent. In these embodiments, an all-cathode formulation is used, wherein LFP is used as the cathode active material, polyvinylidene fluoride (PVDF) is used as the binder, SP carbon is used as the conductive additive, and polyvinylpyrrolidone (PVP) is used as the dispersant for SP carbon within the NMP solvent.

[0053] The LFP precursor slurry was prepared as follows: PVDF was dissolved or pre-dissolved in NMP as a 10% by weight solution by placing it in a 40°C oven for a period of time (e.g., overnight). SP carbon and PVP were dispersed in NMP at 3000 rpm for 3 minutes. LiFePO4 was then added to the slurry and mixed at 2000 rpm for 3 minutes using a FlackTek SpeedMixer DAC 150.1FVZ. Pre-dissolved PVDF was added, and the mixture was then mixed at 2000 rpm for 2+2 minutes. A dispersant (of Formula 1) was added, and the entire slurry was mixed at 3000 rpm for 3 minutes. The viscosity of the cathode slurry was measured at different shear rates using a viscometer. The viscosity of the cathode slurry was measured using a Brookfield viscometer DV-II+Pro. During the measurements, the rotational speeds were set to 0.100 rpm, 0.333 rpm, and 0.833 rpm, corresponding to 6 rpm, 20 rpm, and 50 rpm, respectively. Three separate measurements were taken at each speed, and the values ​​were averaged to determine the viscosity at each speed. A No. 10 conical mandrel was used. Viscosities were measured at room temperature (23°C).

[0054] Data Analysis

[0055] CE1 represents a 60% by weight (active material content, LFP content) all-cathode formulation without dispersant. The final viscosities measured at 6 rpm, 20 rpm, and 50 rpm were 11750 cP, 8508 cP, and 5320 cP, respectively. Each rpm represents a different shear rate, with 6 rpm being the lowest shear rate and 50 rpm being the highest. This CE1 serves as a baseline for comparative studies on the viscosity reduction effect in LFP cathode slurries. CE1 will be used as a baseline for comparison with other 60% solids content samples.

[0056] CE2 represents a 65% by weight (active material content, LFP content) all-cathode formulation without dispersants. CE2 is similar to CE1, except that the LFP content is increased from 60% to 65%. CE2 will be used as a baseline for comparison with other 65% solids content samples.

[0057] IE1, IE2, and IE3 are embodiments of the present invention using dispersant 1 as a phosphate ester dispersant, and have different dispersant ratios (relative to total mass) ranging from 500 ppm, 1200 ppm to 2000 ppm, respectively. When compared to CE1, embodiments IE1, IE2, and IE3 effectively reduced the cathode slurry viscosity at both high and low shear rates. For example, CE1 has measured viscosities of 11750 cP, 8508 cP, and 5320 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively, and IE1 has measured viscosities of 10139 cP, 6983 cP, and 6147 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. Furthermore, IE2 has measured viscosities of 8583 cP, 5067 cP, and 4407 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. In addition, the IE3 has a measured viscosity of 9000 cP, 5258 cP, and 4397 cP, measured at 6 rpm, 20 rpm, and 50 rpm, respectively.

[0058] IE4 and IE5 are embodiments of the invention using dispersant 2 as a phosphate ester dispersant, each having a different dispersant ratio (relative to total mass) from 1200 ppm to 2000 ppm. Compared to CE1, both IE4 and IE5 embodiments are effective in reducing the viscosity of the cathode slurry. For example, CE1 has measured viscosities of 11750 cP, 8508 cP, and 5320 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively, and IE4 has measured viscosities of 9611 cP, 6367 cP, and 5320 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. Furthermore, IE5 has measured viscosities of 7889 cP, 5342 cP, and 4457 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively.

[0059] IE6, IE7, and IE8 are embodiments of the invention using 2000 ppm dispersant 1 as a phosphate ester dispersant, wherein additional alkanolamines are added to the formulation to neutralize the phosphate ester groups. For IE6 to IE8, the amines used are MEA, TEA, and TIPA, respectively. Compared to CE1, it was observed that IE6, IE7, and IE8 remained effective in reducing the viscosity of the LFP cathode slurry even with neutralized phosphate sites. For example, CE1 had measured viscosities of 11750 cP, 8508 cP, and 5320 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively, and IE6 had measured viscosities of 10361 cP, 6808 cP, and 5917 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. Furthermore, IE7 had measured viscosities of 9194 cP, 7133 cP, and 5413 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. In addition, the IE8 has a measured viscosity of 8166 cP, 5300 cP, and 5360 cP, respectively, measured at 6 rpm, 20 rpm, and 50 rpm.

[0060] IE9 and IE10 are embodiments of the invention with a higher active material content (LFP 65% by weight), using 2000 ppm dispersant 1 and dispersant 2 as dispersants, respectively. When compared with CE2, both IE8 and IE9 were observed to be effective in reducing the viscosity of the LFP cathode slurry. For example, CE2 had measured viscosities of 78708 cP, 19017 cP, and 3503 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively, while IE9 had measured viscosities of 23638 cP, 18033 cP, and 4787 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively. Furthermore, IE10 had measured viscosities of 37777 cP, 10367 cP, and 4443 cP measured at 6 rpm, 20 rpm, and 50 rpm, respectively.

[0061] Table 3 shows the effectiveness of phosphate ester dispersants in reducing viscosity at different dosage levels, different active material solid contents, and different neutralization levels, from IE1 to IE10.

Claims

1. A cathode paste, the cathode paste comprising: Lithium iron phosphate (LFP) slurry; Organic solvents; Thermoplastic polymer adhesives; and Dispersant of Formula I: In Formula I, n is 1 to 10, and R1 of Formula I is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, straight or branched primary or secondary C1 to C18 alkyl chains, and R2 of Formula I is selected from the group consisting of hydrogen, methyl groups, ethyl groups, or combinations thereof.

2. The cathode paste according to claim 1, wherein the cathode paste further comprises an alkanolamine of formula II: In formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms.

3. The cathode paste according to claim 2, wherein the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA).

4. The cathode slurry according to claims 1 to 3, wherein the composition of the dispersant is in the range of 500 ppm to 2000 ppm relative to the total mass of the cathode slurry.

5. The cathode slurry according to claims 1 to 4, wherein the dispersant accounts for 0.05 to 0.20% by weight of the total mass of the cathode slurry.

6. The cathode slurry according to claims 1 to 5, wherein the composition of the dispersant is less than 500 ppm of the cathode slurry.

7. The cathode paste according to claims 1 to 6, wherein the LFP paste has a solids content greater than 55% by weight and a viscosity less than 10,000 centipoise (cP).

8. The cathode paste according to claims 1 to 7, wherein the organic solvent is N-methyl-2-pyrrolidone (NMP) and the thermoplastic polymer binder is polyvinylidene fluoride (PVDF).

9. A method, the method comprising: A cathode slurry is produced, the cathode slurry comprising: An adhesive, wherein the adhesive is dissolved in an organic solvent; Lithium iron phosphate (LFP) slurry, wherein the lithium iron phosphate (LFP) slurry constitutes more than 55% by weight of the total weight of the cathode slurry; Dispersant of Formula I: Wherein n of formula I is 1 to 10, and R1 of formula I is selected from the group consisting of hydrogen, C8 to C18 alkylphenyl groups, straight-chain or branched primary or secondary C1 to C18 alkyl chains, and R2 of formula I is selected from the group consisting of hydrogen, methyl groups, ethyl groups, or combinations thereof; and When the cathode slurry is below the threshold viscosity, the cathode slurry is applied to the substrate to produce an LFP layer on the substrate.

10. The method of claim 9, wherein the cathode paste further comprises an alkanolamine of formula II: In formula II, R1, R2, and R3 are selected from hydrogen atoms or hydroxyalkyl groups having one to four carbon atoms.

11. The method of claim 10, wherein the alkanolamine is selected from ethanolamine (MEA), triethanolamine (TEA), and triisopropanolamine (TIPA).

12. The method according to claims 9 to 11, wherein the alkanolamine is present in the slurry at a molar percentage of 10 to 120 mol% of the molar amount of the P(OH) site of the dispersant of formula I.

13. The method according to claims 9 to 12, wherein the generation of the cathode slurry comprises SP carbon and polyvinylpyrrolidone (PVP) dispersed in the NMP.

14. The method according to claims 9 to 13, wherein the viscosity of the cathode slurry is determined, wherein the threshold viscosity is approximately 10,000 centipoise (cP).

15. The method according to claims 9 to 14, wherein the cathode paste has a viscosity between 5,000 centipoise (cP) and 10,000 cP.

Images