Battery electrode coatings applied by waterborne electrodeposition

Abstract

The present invention is directed towards an electrodepositable coating composition comprising (a) a fluoropolymer; (b) an electrochemically active material and/or electrically conductive agent; (c) a pH-dependent rheology modifier; and (d) an aqueous medium comprising water; wherein water is present in an amount of at least 45% by weight, based on the total weight of the electrodepositable coating composition. Also disclosed herein is a method of coating a substrate, as well as coated substrates and electrical storage devices.

Claims

1. An electrodepositable coating composition comprising: (a) a fluoropolymer; (b) an electrochemically active material and/or electrically conductive agent; (c) a pH-dependent rheology modifier; and (d) an aqueous medium comprising water; wherein water is present in an amount of at least 45% by weight, based on the total weight of the electrodepositable coating composition, wherein the electrodepositable coating composition has a solids content of no more than 30% by weight, based on the total weight of the electrodepositable coating composition.

2. The electrodepositable coating composition of claim 1, wherein the fluoropolymer comprises a (co)polymer comprising the residue of vinylidene fluoride.

3. The electrodepositable coating composition of claim 2, wherein the fluoropolymer comprises a (co)polymer comprising the residue of tetrafluoroethylene.

4. The electrodepositable coating composition of claim 1, wherein the electrochemically active material comprises LiCoO.sub.2, LiNiO.sub.2, LiFePO.sub.4, LiFeCoPO.sub.4, LiCoPO.sub.4, LiMnO.sub.2, LiMn.sub.2O.sub.4, Li(NiMnCo)O.sub.2, Li(NiCoAl)O.sub.2, carbon-coated LiFePO.sub.4, or a combination thereof.

5. The electrodepositable coating composition of claim 1, wherein the electrochemically active material comprises sulfur, LiO.sub.2, FeF.sub.2 and FeF.sub.3, Si, aluminum, tin, SnCo, Fe.sub.3O.sub.4, or combinations thereof.

6. The electrodepositable coating composition of claim 1, wherein the electrochemically active material comprises graphite, lithium titanate, lithium vanadium phosphate, silicon, silicon compounds, tin, tin compounds, sulfur, sulfur compounds, lithium metal, graphene, or a combination thereof.

7. The electrodepositable coating composition of claim 1, wherein the pH-dependent rheology modifier comprises an alkali-swellable rheology modifier.

8. The electrodepositable coating composition of claim 7, wherein a composition of water and the alkali-swellable rheology modifier at 4.25% by weight of the total composition of water and the alkali-swellable rheology modifier has an increase in viscosity of at least 500 cps over an increase in pH value of 1 pH unit, as measured using a Brookfield viscometer using a #4 spindle and operated at 20 RPMs.

9. The electrodepositable coating composition of claim 1, wherein the pH-dependent rheology modifier comprises an acid-swellable rheology modifier.

10. The electrodepositable coating composition of claim 1, further comprising a dispersant.

11. The electrodepositable coating composition of claim 10, wherein the dispersant comprises a (meth)acrylic polymer dispersant.

12. The electrodepositable coating composition of claim 10, further comprising a crosslinking agent.

13. The electrodepositable coating composition of claim 11, wherein the electrically conductive agent comprises conductive carbon black, carbon nanotubes, graphene, graphite, carbon fibers, fullerenes, and combinations thereof.

14. The electrodepositable coating composition of claim 1, wherein the electrodepositable coating composition comprises: (a) 0.1% to 10% by weight of the fluoropolymer; (b) 45% to 99% by weight of the electrochemically active material; (c) 0.1% to 10% by weight of the pH-dependent rheology modifier; and (d) optionally 0.5% to 20% by weight of the electrically conductive agent; the % by weight based on the total solids weight of the electrodepositable composition.

15. The electrodepositable coating composition of claim 1, wherein the VOC of the electrodepositable coating composition is no more than 300 g/L.

16. The electrodepositable coating composition of claim 1, wherein the electrodepositable coating composition is substantially free of fugitive adhesion promoter.

17. The electrodepositable coating composition of claim 1, wherein a coating produced by electrodepositing the electrodepositable coating composition of claim 1 to a substrate has a 90° peel strength at least 20% greater than a comparative coating composition that does not include the pH-dependent rheology modifier, the 90° peel strength measured according to PEEL STRENGTH TEST METHOD.

18. The electrodepositable coating composition of claim 1, wherein a coating produced by electrodepositing the electrodepositable coating composition of claim 1 to a substrate has a 90° peel strength of at least 5 N/m, as measured according to PEEL STRENGTH TEST METHOD.

19. A method of coating a substrate, the method comprising: electrocoating the electrodepositable coating composition of claim 1 onto a substrate.

20. The method of claim 19, wherein the method has a mass deposition rate of the electrodepositable coating composition of at least 0.5 mg/cm.sup.2/s.

Description

EXAMPLES

Example 1: Preparation of Dispersant

(1) 427.2 grams of diacetone alcohol was added to a four-neck round bottom flask equipped with a mechanical stir blade, thermocouple, and reflux condenser. The diacetone alcohol was heated to a set point of 122° C. under a nitrogen atmosphere. A monomer solution containing 317.3 grams of methyl methacrylate (“MMA”), 479 grams of butyl acrylate (“BA”), 104.4 grams of ethyl acrylate (“EA”), and 122.8 grams of methacrylic acid (“MAA”) was thoroughly mixed in a separate container. An initiator solution of 9.95 grams of tert-amyl peroctoate and 179 grams of diacetone alcohol was also prepared in a separate container. The initiator and monomer solutions were co-fed into the flask at the same time using addition funnels over 210 and 180 minutes, respectively. After the initiator and monomer feeds were complete, the monomer addition funnel was rinsed with 51.1 grams of diacetone alcohol and the resulting solution was held at 122° C. for 1 hour. Then a second initiator solution of 3.1 grams of tert-amyl peroctoate and 53.7 grams of diacetone alcohol was added over 30 minutes. After this second initiator feed was complete, the initiator addition funnel was rinsed with 25 grams of diacetone alcohol. The solution was then held at 120° C. for 90 minutes. After the 90-minute hold, the solution was cooled to 100° C. and then 139.9 grams of dimethyl ethanolamine was added over 10 minutes. After the addition, the solution was held at 100° C. for 15 minutes and then cooled to 70° C. Once the solution reached 70° C., 2,593.4 grams of warm (70° C.) deionized water was added over 60 minutes and was mixed for 15 minutes to form a dispersion. After mixing, the resin dispersion was poured into a suitable container. The total solids of the resin dispersion were measured to be 23.5% solids. The solids content was determined by adding a quantity of the resin dispersion to a tared aluminum dish, recording the weight of the dispersant and dish, heating the test specimen in the dish for 60 minutes at 110° C. in an oven, allowing the dish to cool, reweighing the dish to determine the amount of non-volatile content remaining, determining the solids content for each sample by dividing the weight of the non-volatile content by the total sample weight and multiplying by 100. This measurement was completed twice and the final number is an average of the two measured values.

Example 2: Preparation of Dispersion of PVDF and Dispersant

(2) 92.3 grams of deionized water, 134.4 grams (31.52 grams of solid material) of dispersant prepared using the method of Example 1 and 0.23 grams of a de-foaming agent (Drewplus™) were combined in a plastic cup. The resultant mixture was stirred vigorously using a Cowles blade while maintaining a modest vortex at 1200 RPMs. The mixing was continued while 73.5 grams of polyvinylidene difluoride powder (RZ-49 available from Asambly Chemical) was added in small portions of about 0.5 grams over 5 minutes. Mixing was continued for an additional 45 minutes after all the polyvinylidene difluoride powder was added.

Example 3: Preparation of Dispersion of PVDF without Dispersant

(3) 286.0 grams of deionized water, 98.4 grams of ACRYSOL™ ASE-60 (3.33 grams of solid material) and 0.16 grams of a de-foaming agent (Drewplus™) were combined in a plastic cup. The resultant mixture was stirred vigorously using a Cowles blade while maintaining a modest vortex at 1200 RPMs. This mixing was continued while 64.3 grams of polyvinylidene difluoride powder, RZ-49 (available from Asambly Chemical) was added in small portions of about 0.5 grams over 5 minutes. Mixing was continued for an additional 45 minutes at a constant speed of 1200 RPMs after all the polyvinylidene difluoride powder was added. During the mixing, pH was adjusted to a value of 6.68 using dimethylethanolamine (DMEA) to facilitate the dispersion of the PVDF powder.

Preparation of Electrodepositable Coating Compositions for Producing Positive Electrodes and Evaluation Thereof

Examples 4-9: Preparation of Electrodepositable Coating Compositions and Positive Electrodes Produced by Electrodeposition Thereof

(4) TABLE-US-00002 TABLE 2 Example # and Amount of Ingredient Charge # Ingredient 4 5 6 7 8 9 1 ACRYSOL  2.67 g  8.01 g 13.35 g — — — ASE-60.sup.1  (0.11 g  (0.33 g  (0.54 g solids, solids, solids, 0.4% by 1.2% by 2% by weight weight weight of total of total of total solids) solids) solids) ACRYSOL — — —  2.56 g — — HASE TT-  (0.11 g 615.sup.2 solids, 0.4% by weight of total solids) ATRP Star — — — — 13.15 g — Polymer.sup.3  (0.11 g solids, 0.4% by weight of total solids) ACRYSOL — — — — —  2.56 g HASE-  (0.11 g DR180.sup.4 solids, 0.4% by weight of total solids) 2 Dispersion  2.8 g  2.18 g  1.55 g  2.8 g  2.8 g  2.8 g of PVDF  (0.98 g  (0.76 g  (0.54 g  (0.98 g  (0.98 g  (0.98 g and solids, solids, solids, solids, solids, solids, Dispersant 3.6% by 2.8% by 2% by 3.6% by 3.6% by 3.6% by of Example weight weight weight weight weight weight 2 of total of total of total of total of total of total solids) solids solids) solids) solids) solids) 3 Ethanol 1.702 g 1.702 g  1.73 g  1.73 g  1.73 g  1.73 g 4 DI Water 22.05 g 17.28 g 12.56 g 22.45 g 12.23 g 22.45 g 5 Electrochem.   25 g   25 g   25 g   25 g   25 g   25 g Active (92% by (92% by (92% by (92% by (92% by (92% by Material weight weight weight weight weight weight of total of total of total of total of total of total solids) solids) solids) solids) solids) solids) 6 Electrically  1.09 g 1.09 g  1.09 g 1.09 g  1.09 g  1.09 g Conductive (4% by (4% by (4% by (4% by (4% by (4% by Agent weight weight weight weight weight weight of total of total of total of total of total of total solids) solids) solids) solids) solids) solids) 7 Organic 2.257 g 2.257 g 2.257 g 2.301 g 2.301 g 2.301 g Solvent 8 Organic 0.705 g 0.705 g 0.705 g 0.719 g 0.719 g 0.719 g Solvent 9 DI Water   214 g   213 g   212 g   213 g   203 g   213 g .sup.1Commercially available from Dow Chemical Co. .sup.2Commercially available from Dow Chemical Co. .sup.3fracAS SIST ® prototype 2 commercially available from ATRP Solutions. .sup.4Commercially available from Dow Chemical Co.

(5) Electrodepositable coating compositions were produced by combining the ingredients identified in Table 2 as follows: To a plastic cup was added a dispersion of an alkali swellable rheology modifier (Charge 1), a dispersion of PVDF and dispersant (Charge 2), ethanol (Charge 3), and deionized water (Charge 4). This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture (Charge 5), and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Next, an electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture (Charge 6), and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, organic co-solvents Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. (Charge 7) and DOWANOL™ PnB glycol ether from DOW Chemical Co. (Charge 8) were added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The composition was diluted to 10% total solids by addition of deionized water under constant stirring using a magnetic stir bar at 800 RPMs (Charge 9). The pH of each fully formulated electrodepositable coating composition is reported in Table 3. After 30 minutes of stirring, anionic electrodeposition was performed for each composition. A 4 cm by 6 cm carbon-coated aluminum foil immersed 3 cm into the electrodepositable coating composition served as the anode to be coated with a separation of 2.7 cm from a 4 cm by 6 cm aluminum foil as a counter electrode immersed 3 cm into the electrodepositable coating composition serving as the cathode. The electrodepositable coating composition was stirred using a magnetic stirrer throughout the duration of the electrodeposition, and a 100V electrical potential was applied across the electrodes using a direct current rectifier for three different time durations for each composition. After deposition, the films were rinsed with deionized water, left to dry overnight and then weighed to determine the amount of material that was deposited during electrodeposition. Depositions at durations of 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of each electrodepositable coating composition as calculated by a linear fit to the measured deposited mass at each time and including the point (0,0). The mass deposition rate for each composition is included in Table 3.

(6) TABLE-US-00003 TABLE 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 pH 8.11 8.8  8.9  8.92 8.77 9.13 Mass 1.02 0.97 0.97 1.02 0.73 0.93 Deposition Rate (mg/cm.sup.2/s)

Example 10: Preparation of Electrodepositable Coating Composition and Positive Electrodes Produced by Electrodeposition Thereof

(7) To a plastic cup was added 6.37 g of the PVDF dispersion from Example 3 (1.09 g of solid material, 4 wt. % of the total solids content; 0.05 g ACRYSOL ASE-60, 0.20 wt % of the total solids; 1.04 g PVDF, 3.80 wt. % of the total solids), 1.02 g of ethanol, and 23.00 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 25 g (92 wt. % of the total solids content) of electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2000 RPMs for 5 minutes. Next, 1.09 g (4 wt. % of the total solids content) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, 1.00 g of Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. and 0.30 g of DOWANOL PnB glycol ether from DOW Chemical Co. was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The composition was diluted to 10% total solids by the addition of 214 g of deionized water under constant stir using a magnetic stir bar at 800 RPMs. The pH of the fully formulated electrodepositable coating composition was 9.25. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 3.52 mg/cm.sup.2/s according to the procedure described in Examples 4-9.

Comparative Example 11: Preparation of Comparative Electrodepositable Composition without a pH-Dependent Rheology Modifier

(8) To a plastic cup was added 9.33 g (3.26 g solids; 4 wt. % of the total solids content of composition) of a dispersion of PVDF and dispersant as prepared in Example 2, 5.136 g of ethanol, and 66.03 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 75 g (92 wt. % of the total solids content of composition) of electrochemically active material (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 3.26 g (4 wt. % of the total solids content of the composition) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture and mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, 6.76 g of Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. and 2.12 g of DOWANOL™ PnB glycol ether from the DOW Chemical Co. was added to the mixture and mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The electrodepositable coating composition was diluted to 10% total solids by the addition of deionized water under constant stir using a magnetic stir bar at 800 RPMs. The pH of the comparative electrodepositable coating composition was 10.13. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 0.24 mg/cm.sup.2/s according to the procedure described in Examples 4-9. This mass deposition rate under this procedure is not acceptable to produce a continuous coating sufficient to allow the coated substrate to serve as an electrode in an electrical storage device.

Comparative Example 12: Preparation of Comparative Electrodepositable Composition with a Non-pH-Dependent Rheology Modifier

(9) To a plastic cup was added 2.56 g (0.11 g solids, 0.4 wt. % of the total solids of the composition) of a dispersion of hydroxyethyl cellulose rheology modifier (HEC QP-300 from DOW Chemical Co.), 2.8 g (0.98 g solid, 3.6 wt. % of the total solids of the composition) of the PVDF dispersion of Example 2, 1.73 g of ethanol, and 22.45 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 25 g (92 wt. % of the total solids content) of electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2000 RPMs for 5 minutes. Next, 1.09 g (4 wt. % of the total solids content) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, 2.3 g of Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. and 0.719 g of DOWANOL™ PnB from DOW Chemical Co. was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The composition was diluted to 10% total solids by the addition of deionized water under constant stir using a magnetic stir bar at 800 RPMs. The pH of the fully formulated electrodepositable coating composition was 9.54. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 0.16 mg/cm.sup.2/s according to the procedure described in Examples 4-9. This mass deposition rate is not acceptable to produce a continuous coating sufficient to allow the coated substrate to serve as an electrode in an electrical storage device.

Evaluation of Electrodes Produced by Electrodeposition in Coin Cells

(10) Coin cells were fabricated from the positive electrodes prepared by electrodeposition for a duration of 10 seconds as described above for each example. The coated substrates of Examples 4-10 were baked at 245° C. for 10 minutes, and then substrates were pressed to 35% porosity after baking using a calendar press provided by Innovative Machine Corporation before use as a positive electrode in the coin cell. The positive electrodes were paired with a lithium metal negative electrode. A ceramic coated 20 μm thick Celgard separator was used as the separator. The electrolyte was comprised of 1.2 M LiPF.sub.6 in a solvent mixture of ethylene carbonate (“EC”) and ethyl methyl carbonate (“EMC”) at a 3:7 ratio of EC:EMC. The coin cell was fabricated using 316 stainless steel casings and pairing a 1 cm diameter positive electrode with a 1.5 cm diameter lithium negative electrode and 60 μL of electrolyte solution. Testing of the batteries was performed on an Arbin battery tester using a single formation step at 0.1C followed by three cycles at each rate specified in Table 4 below. Battery cycling was characterized by cycling the batteries at 1C after the rate study was completed.

(11) TABLE-US-00004 TABLE 4 Capacity at 1C Capacity Capacity Capacity Capacity Capacity after Example at 0.1C at 0.2C at 0.4C at 0.8C at 1.6C 20 cycles  4 164 157 144 138 121 137  5 128 100  89  73  61  74  6 122 107  98  89  79  84  7 165 125  94  0  0  0  8 158 139 122  96  42  80  9 137 114  93  63  0  43 10 148 134 122  91  41  73

(12) These examples demonstrate that the positive electrodes produced by electrodeposition are able to provide acceptable performance when used in a coin cell. In particular, the examples that included the pH-dependent rheology modifier ACRYSOL™ ASE-60 and the dispersant provided good performance.

Evaluation of Adhesion of Electrodes Produced by Electrodeposition and Comparative Electrode Prepared by Drawdown Method

Example 13: Preparation of Electrodepositable Coating Composition for Producing a Positive Electrode by Electrodeposition, Preparation of Positive Electrode by Electrodeposition and Evaluation of Adhesion

(13) To a plastic cup was added 7.69 g (0.33 g solid, 0.4 wt. % of the total solids of the composition) of a dispersion of an alkali swellable rheology modifier (ACRYSOL™ ASE-60 from DOW Chemical Co.), 8.39 g (2.93 g solids, 3.6 wt. % of the total solids of the composition) of the PVDF dispersion of Example 2, 5.136 g of ethanol, and 66.03 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 75 g (92 wt. % of the total solids of the composition) of electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2000 RPMs for 5 minutes. Next, 3.26 g (4 wt. % of the total solids content) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, 6.768 g of Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. and 2.115 g of DOWANOL™ PnB glycol ether from DOW Chemical Co. was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The composition was diluted to 10% total solids by the addition of deionized water under constant stirring using a magnetic stir bar at 800 RPMs. The pH of the fully formulated electrodepositable coating composition was 9.79. After 30 minutes of stirring, anionic electrodeposition was performed. A 5.5 cm by 11 cm carbon-coated aluminum foil immersed 8 cm into the electrodepositable coating composition served as the anode to be coated with a separation of 2.7 cm from a 5.5 cm by 11 cm aluminum foil serving as a counter-electrode, each aluminum foil commercially available from MTI. The electrodepositable coating composition was stirred using a magnetic stirrer throughout the duration of the electrodeposition, and a 30V electrical potential was applied across the electrodes using a direct current rectifier for a duration of 40 seconds. The coated substrate had an electrodeposited film having a loading of 11.2 mg/cm.sup.2. The coated substrate was baked at 245° C. for 10 minutes, and then substrate was pressed to 35% porosity after baking using a calendar press provided by Innovative Machine Corporation. The adhesion of the coating to the substrate was measured using the PEEL STRENGTH TEST METHOD, described above. The adhesion testing yielded a peel strength value of 19.0 N/m.

Comparative Example 14: Preparation of Positive Electrode by Drawdown Method and Evaluation of Adhesion

(14) To a plastic cup was added 1.602 g (0.068 g solids, 0.4 wt. % of the total solids of the composition) of a dispersion of an alkali swellable rheology modifier (ACRYSOL™ ASE-60 from DOW Chemical Co.), 1.79 g (0.63 g solids, 3.6 wt. % of the total solids of the composition) of the PVDF dispersion of Example 2, 1.02 g of ethanol, and 13.20 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 15 g (92 wt. % of the total solids of the composition) of electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2000 RPMs for 5 minutes. Next, 0.65 g (4 wt. % of the total solids of the composition) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. Finally, 1.35 g of Hexyl CELLOSOLVE™ glycol ether from DOW Chemical Co. and 0.42 g of DOWANOL™ PnB glycol ether from DOW Chemical Co. was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The pH of the fully formulated electrodepositable coating composition was 9.79. Films were cast onto an aluminum foil substrate identical to the substrate used in Example 13 using an AFA-II automatic thick film coater from MTI systems and a drawdown bar with a gap thickness of 150 μm moving at a rate of 30 mm/sec. A film with a loading of 9.2 mg/cm.sup.2 and a porosity of 35% was used for evaluating adhesion. The coated substrate was baked at 245° C. for 10 minutes, and then substrate was pressed to 35% porosity after baking using a calendar press provided by Innovative Machine Corporation. The adhesion was measured using the PEEL STRENGTH TEST METHOD, and yielded a peel strength value of 4.3 N/m.

(15) Example 13 and Comparative Example 14 demonstrate that the electrodes produced by electrodeposition had significantly improved adhesion of the deposited film to the underlying substrate compared to similar coating compositions applied by conventional methods, such as a drawdown method.

Preparation of Electrodepositable Coating Compositions for Producing Negative Electrodes and Evaluation Thereof

Example 15: Preparation of Electrodepositable Coating Composition for Producing a Negative Electrode and Electrodeposition Thereof

(16) To a plastic cup was added 0.09 g (0.40 wt. %, based on total solids) of an alkali swellable rheology modifier dispersion (ACRYSOL ASE-60 from DOW Chemical Co.), 0.80 g (3.60 wt. %, based on total solids) of the dispersion of PVDF and dispersant from Example 2, 1.354 g of ethanol, and 28.09 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 20 g (90 wt. %, based on total solids) of electrochemically active material (artificial graphite powder, available from MTI Corp.) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 1.33 g (6.0 wt. %, based on total solids) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Finally, 0.801 g of Hexyl CELLOSOLVE from DOW Chemical Co. and 0.246 g of DOWANOL PnB from DOW Chemical Co. were added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. The electrodepositable coating composition was diluted to 10% total solids by the addition of 173 g of deionized water under constant stirring using a magnetic stir bar at 800 RPMs. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 0.774 mg/cm.sup.2/s according to the procedure described in Examples 4-9.

Comparative Example 16: Preparation of Comparative Electrodepositable Coating Composition for Producing a Negative Electrode and Electrodeposition Thereof

(17) To a plastic cup was added 0.44 g (2 wt. %, based on total solids) of the dispersion of PVDF and dispersant from Example 2, 1.702 g of ethanol, and 24.53 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 20.02 g (90 wt. %, based on total solids) of electrochemically active material (artificial graphite powder, available from MTI Corp.) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 1.78 g (8 wt. %, based on total solids) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Finally, 2.257 g of Hexyl CELLOSOLVE from DOW Chemical Co. and 0.704 g of DOWANOL PnB from DOW Chemical Co. were added to the mixture, and the mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. The electrodepositable coating composition was diluted to 10% total solids by the addition of 173 g of deionized water under constant stirring using a magnetic stir bar at 800 RPMs. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 0.19 mg/cm.sup.2/s according to the procedure described in Examples 4-9. This mass deposition rate is not acceptable to produce a continuous coating sufficient to allow the coated substrate to serve as an electrode in an electrical storage device.

Preparation of VOC-Free Electrodepositable Coating Compositions for Producing Positive Electrodes and Evaluation Thereof

Example 17: Preparation of a VOC-Free Electrodepositable Coating Composition

(18) To a plastic cup was added 1.83 g (0.54 g solids, 2.0 wt. % of the total solids of the composition) of a dispersion of an alkali swellable rheology modifier (ACRYSOL™ HASE TT-615 from DOW Chemical Co.), 1.67 g (0.54 g solids, 2.0 wt. % of the total solids of the composition) of the PVDF dispersion of Example 2, and 23.0 g of deionized water. This mixture was mixed in a centrifugal mixer at 2,000 RPMs for 5 minutes. Next, 25 g (92 wt. % of the total solids of the composition) of electrochemically active material for a positive electrode (“NMC”, LiNi.sub.0.3Co.sub.0.3Mn.sub.0.3O.sub.2 commercially available from MTI) was added to the mixture, and the mixture was mixed in centrifugal mixer at 2000 RPMs for 5 minutes. Next, 1.09 g (4 wt. % of the total solids content) of electrically conductive agent (“Super P” carbon black commercially available from Imerys) was added to the mixture, and the mixture was mixed in a centrifugal mixer at 2000 RPMs for 5 minutes. The composition was diluted to 10% total solids by the addition of 219 g of deionized water under constant stirring using a magnetic stir bar at 800 RPMs. The pH of the fully formulated electrodepositable coating composition was 8.57, and the electrodepositable coating composition was VOC-free, i.e., had 0 g of VOC. After 30 minutes of stirring, anionic electrodeposition was performed using the same procedure as described in Examples 4-9. Depositions at 10 s, 20 s, and 30 s were measured to determine a mass deposition rate of 1.35 mg/cm.sup.2/s according to the procedure described in Examples 4-9.

(19) It will be appreciated by skilled artisans that numerous modifications and variations are possible in light of the above disclosure without departing from the broad inventive concepts described and exemplified herein. Accordingly, it is therefore to be understood that the foregoing disclosure is merely illustrative of various exemplary aspects of this application and that numerous modifications and variations can be readily made by skilled artisans which are within the spirit and scope of this application and the accompanying claims.