Separators, electrodes, half-cells, and cells of electrical energy storage devices

Abstract

Electrodes, separators, half-cells, and full cells of electrical energy storage devices are made with electrospinning and isostatic compression. The electrical energy storage device may include electrochemical double layer capacitors (EDLCs, also known as supercapacitors), hybrid supercapacitors (HSCs), Li-ion capacitors and electrochemical storage devices, Na-ion capacitors and electrochemical storage devices, polymer electrolyte fuel cells, and still other capacitors and electrochemical storage cells.

Claims

1. A method of manufacturing a component for energy storage devices, the method comprising steps of: preparing a first solution of a first polymer in one or more solvents; electrospinning the first solution in a DC electric field between 0.5 kV/cm and 1.5 kV/cm using a pumping rate of between 0.5 ml/h per needle and 5 ml/h per needle; collecting fibers resulting from the step of electrospinning to obtain a separator; providing a charge carrier material; providing a second polymer binder selected from the group consisting of polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE) and Nafion; mixing the charge carrier material, the second polymer binder, and graphic powder in a second solvent for between 5 and 48 hours to form a suspension becoming microheterogeneous from about 2 to about 15 m suspension, where the second solvent is a mixture of dimethylformamide (DMF) and acetone, the concentration of the second solvent in the suspension is between about 15 and about 25 percent by weight, and the ratio of DMF to acetone in the second solvent is between 70/30 and 95/5 by weight and ratio of the charge carrier material to graphite powder is between 80/20 and 95/5 by weight; electrospinning the suspension onto the separator by drop-wise feeding the suspension in a DC electric field of between 1.0 kV/cm and 1.8 kV/cm, thereby depositing an electrode onto the separator and obtaining a separator-electrode combination; drying the electrode of the separator-electrode combination depositing a current collector layer onto the electrode, wherein the current collector layer and the separator are on opposite sides of the electrode; and isostatically compressing in three dimensions the separator-electrode combination at a temperature between 20 and 80 degrees Celsius with applied pressure of between 3 MPa to about 25 MPa, for between 0.5 minute and 20 minutes, thereby obtaining the component; wherein the step of providing the charge carrier material comprises: providing carbon powder; increasing porosity of the carbon powder; eliminating chlorine and chloride from the carbon powder by exposing the carbon powder to hydrogen for between one hour and two hours at a temperature of between 600 degrees Celsius and 1000 degrees Celsius; expelling adherent hydrogen from the carbon powder; and depositing onto the carbon powder at least one set of items selected from the group consisting of: redox-active catalytical d-metal centers, Pt-nanoclusters, Ir-nanoclusters, and PtRu-nanoclusters; wherein the step of increasing porosity comprises applying a micropores-mesopores forming agent and at least one step selected from the group consisting of: a. exposing the carbon powder to CO.sub.2 at a temperature between 500 degrees Celsius and 1200 degrees Celsius for a duration of between 2 and about 16 hours; b. exposing the carbon powder to gaseous HCl at a temperature between 600 degrees Celsius and 1200 degrees Celsius for between 0.5 hour and 10 hours; and c. exposing the carbon powder to at least one of gaseous CO.sub.2, H.sub.2O, and ZnCl.sub.2 at a temperature between 600 degrees Celsius and 1200 degrees Celsius for between 2 hours and 14 hours.

2. The method of claim 1, wherein: concentration of the first polymer in the first solution is between 5 and 35 percent by weight; the second solvent comprises a mixture of dimethylformamide (DMF) and acetone; and concentration of DMF in the second solvent is between 75 and 85 percent by weight.

3. The method of claim 2, wherein viscosity of the first solution is between about 1 and about 50 Pa*s.

4. The method of claim 2, wherein the DC electric field used in the step of electrospinning the solution is 0.9 kV/cm and 1.3 kV/cm.

5. The method of claim 2, wherein the step of collecting is performed so that thickness of the separator is between 10 m and 30 m.

6. The method of claim 1, wherein the step of depositing onto the carbon powder comprises depositing onto the carbon powder one or more of oxides of metals selected from the group consisting of Mn, Fe, Co, Ni, V.

7. A method of making an electrochemical double layer capacitor, the method comprising: a. manufacturing the component in accordance with claim 1; b. providing a second half-cell; and c. combining the component, the second half-cell, and electrolyte to obtain the electrochemical double layer capacitor.

8. A method of making a hybrid supercapacitor, the method comprising: a. manufacturing the component in accordance with claim 1; b. providing a second half-cell; and c. combining the component, the second half-cell, and electrolyte to obtain the hybrid supercapacitor.

9. A method of making an electrical energy storage device, the method comprising: a. manufacturing the component in accordance with claim 1; b. providing at least one other component; and c. combining the component and the at least one other component to obtain the electrical energy storage device.

10. The method of claim 9, wherein the electrical energy storage device is at least one of Li-ion capacitor, Li-ion electrochemical electrical energy storage device, Na-ion capacitor, Na-ion electrochemical electrical energy storage device, and polymer electrolyte fuel cell energy storage device.

11. The component manufactured in accordance with the method of claim 1.

12. A method of manufacturing a component for energy storage devices, the method comprising steps of: preparing a first solution of a first polymer in one or more solvents; electrospinning the first solution in a DC electric field between 0.5 kV/cm and 1.5 kV/cm using a pumping rate of between 0.5 ml/h per needle and 5 ml/h per needle; collecting fibers resulting from the step of electrospinning to obtain a separator; providing a charge carrier material; providing a second polymer binder selected from the group consisting of polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE) and Nafion; mixing the charge carrier material, the second polymer binder, and graphic powder in a second solvent for between 5 and 48 hours to form a suspension becoming microheterogeneous from about 2 to about 15 m suspension, where the second solvent is a mixture of dimethylformamide (DMF) and acetone, the concentration of the second solvent in the suspension is between about 15 and about 25 percent by weight, and the ratio of DMF to acetone in the second solvent is between 70/30 and 95/5 by weight and ratio of the charge carrier material to graphite powder is between 80/20 and 95/5 by weight; electrospinning the suspension onto the separator by drop-wise feeding the suspension in a DC electric field of between 1.0 kV/cm and 1.8 kV/cm, thereby depositing an electrode onto the separator and obtaining a separator-electrode combination; drying the electrode of the separator-electrode combination depositing a current collector layer onto the electrode, wherein the current collector layer and the separator are on opposite sides of the electrode; and isostatically compressing in three dimensions the separator-electrode combination at a temperature between 20 and 80 degrees Celsius with applied pressure of between 3 MPa to about 25 MPa, for between 0.5 minute and 20 minutes, thereby obtaining the component; wherein the step of providing the charge carrier material comprises: providing carbon powder; increasing porosity of the carbon powder; eliminating chlorine and chloride from the carbon powder by exposing the carbon powder to hydrogen for between one hour and two hours at a temperature of between 800 degrees Celsius and 900 degrees Celsius; expelling adherent hydrogen from the carbon powder; and depositing onto the carbon powder at least one set of items selected from the group consisting of: redox-active catalytical d-metal centers, Pt-nanoclusters, Ir-nanoclusters, and PtRu-nanoclusters; wherein the step of increasing porosity comprises applying a micropores-mesopores forming agent and at least one step selected from the group consisting of: a. exposing the carbon powder to CO.sub.2 at a temperature between 500 degrees Celsius and 1200 degrees Celsius for a duration of between 2 and about 16 hours; b. exposing the carbon powder to gaseous HCl at a temperature between 600 degrees Celsius and 1200 degrees Celsius for between 0.5 hour and 10 hours; and c. exposing the carbon powder to at least one of gaseous CO.sub.2, H.sub.2O, and ZnCl.sub.2 at a temperature between 600 degrees Celsius and 1200 degrees Celsius for between 2 hours and 14 hours.

13. The method of claim 12, wherein: concentration of the first polymer in the first solution is between 5 and 35 percent by weight; the second solvent comprises a mixture of dimethylformamide (DMF) and acetone; and concentration of DMF in the second solvent is between 75 and 85 percent by weight.

14. The method of claim 13, wherein viscosity of the first solution is between about 1 and about 50 Pa*s.

15. The method of claim 13, wherein the DC electric field used in the step of electrospinning the solution is 0.9 kV/cm and 1.3 kV/cm.

16. The method of claim 13, wherein the step of collecting is performed so that thickness of the separator is between 10 m and 30 m.

17. The method of claim 12, wherein the step of depositing onto the carbon powder comprises depositing onto the carbon powder one or more of oxides of metals selected from the group consisting of Mn, Fe, Co, Ni, V.

18. A method of making an electrochemical double layer capacitor, the method comprising: a. manufacturing the component in accordance with claim 12; b. providing a second half-cell; and c. combining the component, the second half-cell, and electrolyte to obtain the electrochemical double layer capacitor.

19. A method of making a hybrid supercapacitor, the method comprising: a. manufacturing the component in accordance with claim 12; b. providing a second half-cell; and c. combining the component, the second half-cell, and electrolyte to obtain the hybrid supercapacitor.

20. A method of making an electrical energy storage device, the method comprising: a. manufacturing the component in accordance with claim 12; b. providing at least one other component; and c. combining the component and the at least one other component to obtain the electrical energy storage device.

21. The method of claim 20, wherein the electrical energy storage device is at least one of Li-ion capacitor, Li-ion electrochemical electrical energy storage device, Na-ion capacitor, Na-ion electrochemical electrical energy storage device, and polymer electrolyte fuel cell energy storage device.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 illustrates selected steps of a process of manufacturing a separator and an electrode of an energy storage device;

(2) FIG. 2 illustrates selected steps of a process for preparing carbon charge material for use in the process of FIG. 1; and

(3) FIGS. 3A, 3B, 3C, 4, 5, 6A, 6B, 6C, 7A, 7B, 8A, 8B, 8C, 8D, 9, 10, 11A, 11B, 12A, 12B, 13, 14A, 14B, 14C, 15A, 15B, 15C, 16A, 16B, 16C, 16D, 17A, 17B, 18A, 18B, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30 illustrate certain experimental and calculated results relating to energy storage devices using the novel electrodes and separators manufactured with the processes of FIG. 1 and FIG. 2.

DETAILED DESCRIPTION

(4) In this document, the words embodiment, variant, example, and similar words and expressions refer to a particular apparatus, process, or article of manufacture, and not necessarily to the same apparatus, process, or article of manufacture. Thus, one embodiment (or a similar expression) used in one place or context may refer to a particular apparatus, process, or article of manufacture; the same or a similar expression in a different place or context may refer to a different apparatus, process, or article of manufacture. The expression alternative embodiment and similar words and expressions are used to indicate one of a number of different possible embodiments, variants, or examples. The number of possible embodiments, variants, or examples is not necessarily limited to two or any other quantity. Characterization of an item as exemplary means that the item is used as an example. Such characterization does not necessarily mean that the embodiment, variant, or example is preferred; the embodiment, variant, or example may but need not be a currently preferred embodiment, variant, or example. All embodiments, variants, and examples are described for illustration purposes and are not necessarily strictly limiting.

(5) Top, bottom, left, right and analogous directional indicators may be used for describing the embodiments in the Figures; such terms are intended to facilitate the description and not as substantive requirements, unless specifically noted or otherwise made clear.

(6) When the word selected is used with reference to an item (such as a component, embodiment, variant, element, step) and without mention of the specific selection process, the word signifies any one or more, but not necessarily all, of the items available for the purpose described. For example, selected components of the mixture include may be used in the sense that other components may be found in the referenced mixture, and some of the described components may be omitted in some other mixtures.

(7) The word about and similar expressions, are used to indicate the possibility of small deviations from a precise value or an exact range; but examples with the precise value or range are subsumed within the value or range qualified by the word about or by a similar expression.

(8) Other and further explicit and implicit definitions and clarifications of definitions may be found throughout this document.

(9) Reference will be made in detail to one or more embodiments (apparatus, methods, and/or articles of manufacture) that are illustrated in the accompanying drawings. Same reference numerals may be used in the drawings and this description to refer to the same apparatus or article of manufacture elements and method steps. The drawings may be in a simplified form, not to scale, and may omit apparatus elements and method steps that can be added to the described apparatus, articles of manufacture, and methods, while possibly including optional elements and/or steps.

(10) FIG. 1 illustrates selected steps of a process 100 for manufacturing a separator and an electrode of an energy storage device, such as an EDLC, HSC, LiB or NaB capacitor or battery, or another energy storage device mentioned in this document. Some additional details of the steps of this process may be described or detailed elsewhere in this document.

(11) In step 105, a polymer solution in DMF with acetone-mixed solvent is prepared. The polymer may be, for example, PVDF, Nafion, Nafion-H.sub.2O with isopropanol mixture, a Teflon suspension, or a combination of these and/or other polymers. The concentration of the polymer in the solution may be, for example, between about 5 and about 35 percent of PVDF by weight, and the concentration of DMF in the DMF-acetone solvent may be, for example, between 75 and 85 percent by weight. In selected examples, the concentration of PVDF is 17.5% (+/0.5%), 20.0% (+/0.5%), 22.5% (+/0.5%), and 25.5% (+/0.5%) by weight; and the concentration of DMF in the DMF-acetone solvent is 77.5% (+/1%), 80.0% (+/1%), 82.5% (+/1%), and 85.0% (+/1%). The viscosity of the solution may be in the range of between about 1 and about 50 Pa*s.

(12) In step 110, a high DC electric field is applied to the polymer solution so that dispersion of the solution and formation of polymer nano/microfibers take place. The strength of the field may be, for example, between 0.5 and 1.5 kV/cm; in selected examples, the strength of the field is between 0.8 and 1.5 kV/cm; in other selected examples, the strength of the field is between 0.9 and 1.3 kV/cm. The pumping rate of the solution may be, for example, from 0.5 to 5 ml/h per needle.

(13) In step 115, the nano/microfibers are collected onto a material collector, to obtain a nano/microfibre polymer separator or membrane with well-defined microporosity-mesoporostiy. The material collector may be, for example, stationary or rotating. It may be made from aluminum or some other metal. In some embodiments, the thickness of the separator/membrane thus obtained is from about 10 m to about 30 m.

(14) In step 120, carbon charge carrier material with high specific surface area is provided. Details of this step will be described below in connection with a process 200 of FIG. 2 and elsewhere in this document. The material may be mixed with graphite powder, for example, using a ratio from about 80/20 to about 95/5, by weight, where the lower percentage corresponds to the graphite powder. In examples, the percentage of graphite powder by weight is 20% (+/0.5%), 15 (+/0.5%), 10 (+/0.5%), and 5 (+/0.5%).

(15) In step 122, the charge carrier material from the previous step (e.g., the hierarchically porous carbon particles or d-metal, Pt-metal, Ir-metal and PtRu-alloy nanoclusters activated or non-activated composites with specific surface area from 100 to 2200 m.sup.2 g.sup.1) and a selected electronically non-conductive polymer binder (such as PVDF, PTFE, Nafion) are dissolved in a DMF-acetone mixed solvent, forming a suspension with variable viscosity depending on the amount of the binder in the solution. The concentration of the solvent by weight may be, for example, between about 15 and about 25 percent. In examples, the concentration is 15.0% (+/0.5%) 17.5% (+/0.5%), 20.0% (+/0.5%), 22.5% (+/0.5%), and 25.0% (+/0.5%) by weight; and the ratio of DMF to acetone is between about 70/30 and about 95/5, by weight, with the higher percentage corresponding to DMF.

(16) In step 125, the suspension from the previous step is thoroughly mixed at a temperature, for example, from about 20 to about 30 degrees Celsius, and for a time duration of, for example, between about 5 and 48 hours to form a viscous microheterogeneous from about 2 to about 15 m suspension (solution) of carbon particles, polymer, and solvent.

(17) In step 130, the solution from the step 125 is drop-wise fed and subjected to a DC electric field, so that the suspension is dispersed to form nano/micro carbon-polymer wires or particles. The strength of the electric field in this step may be, for example, between 1.0 and 1.8 kV/cm. The intermeshing nanowires or microwires in this step may be deposited directly onto the membrane from the step 115.

(18) In step 135, the material from the step 130 is dried, that is, solvent is quickly evaporated from the solution and the resulting fibers/particles are deposited onto electrospun separator materials (e.g., PVDF, Nafion, other polymers). The drying may take place at temperatures from about 20 to about 80 degrees Celsius. In examples, the drying takes place at a temperature between 20 and 30 degrees Celsius, for a period between 10 and 30 hours. A separator/carbon electrode combination is thus formed.

(19) In step 140, the separator/carbon electrode combination from the step 135 is isostatically compressed. For example, the isostatic compression may take place at a temperature from about 20 to about 80 degrees Celsius, with applied constant pressure from about 3 MPa to about 25 MPa, for a period of about 0.5 minute to about 20 minutes. This results in a flexible, compressed electrode/separator half-cell. In specific examples, a pressure of 8-12 MPa is applied for between 1 and 3 minutes. The isostatic compression described here (and elsewhere in this document) may be performed using fluid pressure, for example, by placing the objects being compressed in a flexible container (such as a thin polymer bag), placing the flexible container into another container (generally not a flexible one) with a fluid, such as water, and applying the required pressure to the fluid. Because the fluid surrounds the entire article, the pressure should be equal from all directions, and occurrences of unwanted distortions in the article may be avoided or reduced. Electrodes, half-cells (i.e., electrode/separator/membrane combinations), and full cells (electrode-separator-membrane-separator-electrode combinations) may be isostatically compressed in three dimensions in this way. In particular, complete electrodes, half-cells, and full cells may be isostatically compressed or hot pressed at an elevated temperature (e.g., >25 degrees Celsius), in one step.

(20) FIG. 2 illustrates selected steps of the process 200 for preparing the carbon charge carrier material used in the process 100. (The process 200 has already been mentioned above, in relation to the step 120 of the process 100.) Some additional details of the steps of this process may be described or detailed elsewhere in this document. The process 200 may result in an ultramicroporous-microporous-mesoporous carbon powder having well-developed hierarchical porous structure with specific surface area from 100 to 2200 m.sup.2 g.sup.1 The process 200 may use carbon particles preparation methods including high-temperature chlorination reaction with molecular Cl.sub.2 or gaseous HCl from Mo.sub.2C, TiC, VC, WC, SiC, Cr.sub.xC.sub.y (i.e., a binary metal carbide, carbide-derived carbon, or CDC), or from organic compounds applying thermal decomposition method (organic carbon powder or OCP), or from organic aerogels (OAG), resulting in ultramicroporous-microporous-mesoporous carbon particles.

(21) In step 205, an organic precursor material is provided. The material may be carbon powder.

(22) In step 210, mesoporosity is created in the precursor material by exposing it to CO.sub.2 under high temperature from about 500 to about 1200 degrees Celsius, for a duration of between about 2 and about 16 hours. Alternatively or additionally, the precursor material may be subjected to high temperature gaseous HCl treatment at from about 600 to about 1200 degrees Celsius for a period of time between about 0.5 hour and about 10 hours. Alternatively or additionally, this step may include conducting activation reaction of raw carbon particles with CO.sub.2, H.sub.2O, ZnCl.sub.2 or analogous treatment methods, at temperatures from about 600 to about 1200 degrees Celsius, for a period of between about 2 and about 14 hours. Also, this step may include application of a solvent mixture (e.g., water with organic solvents, such as DMF, isopropanol) as a micropores-mesopores forming agent during evaporation/thermal treatment, for obtaining highly ultramicroporous-microporous-mesoporous electrode material with hierarchical porous structure.

(23) In step 215, chlorine (Cl.sub.2) and chloride (Cl.sup.) content is eliminated by exposing the material to hydrogen for a time duration of between about one hour and about two hours, at a temperature of between about 600 and about 1000 degrees Celsius; in embodiments, the temperature range is between 750 and 1000 degrees Celsius; in embodiments, the temperature range is between 800 and 900 degrees Celsius. Surface-active oxygen-containing functional groups and/or other surface-active functional groups may thus be reduced.

(24) In step 220, adherent hydrogen is expelled from the material with nitrogen, argon, or another noble gas. This may be done by exposure to the gas for between about 0.5 and about 4 hours, at a temperature from about 300 to about 900 degrees Celsius. In variants, the carbon powder may be deactivated with argon gas at temperatures between about 20 and about 1000 degrees Celsius, for a period of between 0 to about 10 hours.

(25) In step 225, redox-active catalytical d-metal centers (Mn, Fe, Co, Ni, V, etc., as oxides), Pt or Ir nanoclusters or PtRu-nanoclusters (with Pt and Ir in PtRu-nanoparticles from about 0.01 percent to about 80 percent of the catalyst by weight) are deposited onto the microporous-mesoporous carbon particles from the previous steps.

(26) Step 230 includes thoroughly washing the d-metal-carbon, Pt-, Ir- or PtRu-carbon composites, and drying them at temperatures between about 20 and about 80 degrees Celsius.

(27) In embodiments, pairs of dried half-cells from the process 100 are isostatically compressed together to obtain complete single cells of two electrodes and a common separator between the electrodes.

(28) The electrode (carbon) side of a half-cell (or the electrode sides of a single cell) may be covered by a conductor, for example, Al, Ta, Ti, Ni, Cu, or another current collector thin film layer. The film may be deposited, for example, using magnetron sputtering method at a residual pressure of about 10.sup.8 Pa and at a power of between about 50 and about 80 Watts; in examples, the power is about 70 Watts. Other deposition methods (for example, chemical vapor deposition, pulsed laser deposition) may also be used.

(29) Other inventive applications of isostatic compression for electrical energy storage devices include methods of fabricating half-cells for Li-ion capacitors/batteries, Na-ion capacitors/batteries, hybrid supercapacitors, polymer electrolyte fuel cells (PEM), and polymer electrolyte membrane electrolysers (PEMEC). In selected embodiments, these methods include the steps of forming partially graphitized carbon particles and/or carbon acetylene black powder into an electrospun electrode structure, typically mixed together with one or more binders (which may be organic binders, for example, PVDF, Teflon suspension, Nafion), water, and organic solvent mixtures; drying the structure; isostatically compressing the dried structure at temperatures from about 20 to about 80 degrees Celsius and pressures from about 1 to about 25 MPa, for a time duration of between about 0.5 to about 20 minutes; and forming a highly ultramicroporous-microporous-mesoporous cathode/anode electrodes for Li-ion capacitors/batteries, Na-ion capacitors/batteries, HSCs, as well as cathode and anode electrodes for PEM and PEMEC. Li-ion and Na-ion battery electrodes may be deposited from, respectively, Li- and Na-containing salts in situ using electrochemical deposition methods. The PEM and PEMEC electrodes may be prepared using chemical, physical, or electrochemical in situ deposition methods.

(30) The Brunauer-Emmett-Teller (BET) analysis (using N.sub.2 gas adsorption measurement at the nitrogen boiling temperature) or CO.sub.2 adsorption analysis of certain ultramicroporous-microporous-mesoporous carbon powders shows that electrode materials with very large specific surface areas (e.g., from about 100 to about 2200 m.sup.2*g.sup.1) can be synthesized by using solution based D-glycose thermal decomposition and high temperature binary carbide decomposition (chlorination or HCl) methods followed by post-treatment activation with CO.sub.2, H.sub.2O or ZnCl.sub.2, and followed by H.sub.2 cleaning steps. The three-modal pore size distribution with medium pore diameter from 0.5 to 0.7 nm, 0.7 to 2.0 nm, and 2.0 to 10 nm has been calculated and a very large total pore volume (given in Table 1 below) has been obtained. Table 1 shows that the electrospun electrodes may have very high specific surface areas and there may be only weak blocking of ultramicropores, micropores, and mesopores with the organic binder (e.g., PVDF, Teflon, Nafion, other binders) used for electrospinning of nanowire based electrodes with very high specific surface areas. The additional isostatic compressing step generally should not noticeably reduce the specific surface area and total pore volume, often resulting in just a small decrease from 5 to 30% in macroporosity. Therefore, in addition to the ultramicropores and micropores there may be mesopores inside the hierarchically porous electrodes, characterized by a high ion transport rate and thus transport properties to the adsorption zone or reaction volume (triple phase boundary area). The Hg porosity data show that the porous PVDF membrane using electrospinning method from polymer solution (and similarly to electrodes) with well-established pore size distribution and large surface area values (e.g., from about 10 to about 148 m.sup.2*g.sup.1). The Hg porosimetry data, however, show that the surface area, porosity, and pore size distribution may depend noticeably on the electrospinning parameters used.

(31) TABLE-US-00001 TABLE 1 N.sub.2 adsorption data of different carbon powders. S.sub.BET S.sub.SAIEUS d.sub.pore-max V.sub.tot Carbon powder (m.sup.2/g) (m.sup.2/g) (nm) (cm.sup.3/g) GDAC-10 h 1540 1820 0.56 0.695 VCCDC 900 C. 1385 1352 0.57 0.66 (Cl.sub.2) WCCDC 1100 C. 1574 1267 0.71 0.78 (Cl.sub.2) Mo.sub.2CCDC 600 C. 1944 1605 0.60 1.12 (Cl.sub.2) Mo.sub.2CCDC 800 C. 1916 1574 0.82 1.83 (Cl.sub.2) Mo.sub.2CCDC 1000 C. 937 711 0.83 1.45 (Cl.sub.2) SiCCDC 1100 C. 1140 731 0.89 0.48 (CO2) TiCCDC 950 C. 1450 1618 0.59 0.63 (Cl.sub.2)

(32) Noticeable influences of electric field strength, feed rate, and PVDF concentration employed in fabricating membranes using electrospinning are shown by data in Table 2 and Table 3, below.

(33) TABLE-US-00002 TABLE 2 Detailed preparation conditions of different electrospun membranes Distance Polymer between Concen- Field solution tip and tration Solvent strength feed rate collector Sample (%) content (kV cm.sup.1) (mlh.sup.1) (cm) TUX1&TUX3 20 DMA 0.70 15.0 25 TUX5 25 DMA 0.75 15.0 20 TUX6 25 DMA 0.63 15.0 20 TUX7 25 DMF- 0.67 0.25 15 acetone (8:2) TUX8 20 DMF- 1.27 0.5 15 acetone (8:2) TUX9 20 DMF- 1.07 1.0 15 acetone (8:2) TUX10 22.5 DMF- 1.07 0.5 15 acetone (8:2)

(34) TABLE-US-00003 TABLE 3 Hg intrusion porosimetry measurement results of electrospun membranes Sample S.sub.Hg (m.sup.2 g.sup.1) Porosity (%) TUX1&TUX3 21.15 42 TUX5 56.00 18 TUX6 50.30 22 TUX7 37.84 23 TUX8 32.25 30 TUX9 26.50 26 TUX10 89.50 24

(35) Experimental results show that the amount of binder and particle size of carbon powders have a substantial effect on the sintered mechanical stability of microporous-mesoporous-macroporous structure of the electrode/separator structures.

(36) We now proceed to describe certain experimental and calculated results, in connection with a number of Figures. Some of the experimental results have been fitted to theoretical models, such as pore size distribution, sizes of catalyst nanoparticles established, XRD data, TEM data, and Raman data.

(37) FIGS. 3A, 3B, and 3C show gas adsorption isotherms and pore size distribution measurement data for ultramicroporous-microporous-mesoporous carbon powders, and FIGS. 4 and 5 show analogous data for electrospun carbon-PVDF composite electrodes, based on Brunauer-Emmett-Teller (BET) gas adsorption measurement method and calculated using density functional theory (DFT) (FIGS. 3B and 4) and SAIEUS model (FIGS. 3C and 5), explaining the pore size distribution and adsorption hysteresis (FIG. 3A) and condensation into mesopores. The medium pore diameter, total pore volume and surface area of carbons are given in Table 1 above. The corresponding carbon powders have been prepared by the thermal high temperature chlorination (noted as Cl.sub.2) of binary carbides (denoted as TiCCDC, VCCDC, Mo.sub.2CCDC, SiCCDC, and HCl methods (CDCHCl)) or high temperature decomposition method from d-glucose (denoted as GDAC) at T=800 degrees Celsius for 0 to 12 hours, activated through the reaction with CO.sub.2 and chemically reduced using H.sub.2 at fixed temperatures for 0, 4, 6, 8, 10, 12 hours, as noted in the Figures).

(38) FIGS. 6A, 6B, 6C, 7A, and 7B show mercury intrusion porosimetry measurement data for electrospun membranes from different raw solutions of PVDF in DMF with acetone mixture, with detailed data given in Tables 2 and 3 above. Based on the data in FIGS. 6A, 6B, 6C, 7A, and 7B and in Tables 2 and 3, the concentration, solvent composition, and electric field strength have large influence on the membrane porosity, surface area, and differential pore size distribution values.

(39) FIGS. 8A, 8B, 8C, and 8D show backscattered electron scanning electron microscopy (SEM) images for electrospun membranes prepared from different raw PVDF solutions in DMF with acetone mixture, electrospun at different electric field strengths (which are given in Table 2).

(40) FIGS. 9 and 10 show SEM data for the electrospun electrode layer deposited onto a PVDF membrane at electric field strength 1.33 kV*cm.sup.1. FIG. 9 illustrates the electrode structure without the compression step, and FIG. 10 illustrates the electrode structure with additional isostatic hot pressing at 5 MPa for 2 minutes.

(41) FIG. 11A illustrates SEM data for an electrospun membrane after isostatic hot pressing at 5 MPa for 2 min.

(42) FIG. 11B shows a photo image of an electrospun half-cell, where the active electrode layer is black and the separator layer is white/grey.

(43) FIGS. 12A and 12B illustrate infra-red (IR) spectra for electrospun PVDF membranes prepared from 20% PVDF solution in DMF-acetone mixtures (a) 8:2 and (b) 7:3, at different applied dc voltages, and at solution feed rate of 0.5 ml*h.sup.1. Based on the data of FIG. 12, different polymorphic , , and phases (as noted in the Figures) in electrospun membranes have been created.

(44) FIG. 13 illustrates the influence of the PVDF concentration in DMF-acetone mixture (given in the Figure) for polymorphic composition of PVDF membrane, analyzed using an infra-red (IR) spectroscopy method.

(45) FIGS. 14A, 14B, and 14C show Raman spectroscopy and X-ray diffraction data (inset) for different carbon powders (noted in Figures).

(46) FIGS. 15A, 15B, and 15C show high-resolution transmission electron microscopy (HRTEM) data and SEM image (inset) for porous D-glucose derived activated carbons prepared using different CO.sub.2 activation times (noted in Figures as GDAC-xh).

(47) FIGS. 16A, 16B, 16C, 16D, 17A and 17B show, respectively, cyclic voltammograms (i.e., current density vs. cell potential) and capacitance vs. cell potential plots for carbon electrode/membrane two half-cell structures (forming single cells). In FIGS. 16A and 16B, the structures had been isostatically compressed at 20 degrees Celsius for 2 minutes; in FIGS. 16C and 16D, the structures had not been compressed. Different potential scan rates are marked in the Figures. The data of FIGS. 16A, 16C, and 17A were obtained at 20 degrees Celsius; the data of FIGS. 16B, 16D, and 17B were obtained at 30 degrees Celsius.

(48) FIGS. 18A and 18B show constant current charge-discharge curves for EDLC cells (isostatically compressed at 20 degrees Celsius for 2 minutes) at testing temperature of 20 degrees Celsius (18A) and 30 degrees Celsius (18B).

(49) FIG. 19 shows discharge capacitance vs current density data for EDLC cells (isostatically compressed at 20 degrees C. for 2 minutes) at temperature 20 degrees Celsius and 30 degrees Celsius (as marked in the Figure).

(50) FIG. 20 shows complex impedance plane plots for two ultramicroporous-microporous-mesoporous electropun electrode/separator cells (isostatically compressed at 20 degrees Celsius for 2 minutes) at 20 degrees Celsius and at 30 degrees Celsius (as marked in the Figure).

(51) FIG. 21 shows Nyquist plots for non-compressed electrospun electrode/electrospun membrane based single cells measured at a temperature of 20 degrees Celsius and at a temperature of 30 degrees Celsius (as marked in the Figure).

(52) FIG. 22 shows phase angle vs. log ac frequency (log f) plots for two electrode-membrane combinations. One combination is an electrospun electrode with an electrospun membrane that were isostatically compressed at 20 degrees Celsius for 2 minutes; the other combination is an electrospun electrode with an electrospun membrane that were not isostatically compressed. Data at 20 and 30 degrees Celsius are provided in the Figure.

(53) FIG. 23 illustrates series capacitance vs. log ac frequency (log f) plots for isostatically compressed and not compressed single cells. Data at 20 and 30 degrees Celsius are provided in the Figure.

(54) FIG. 24 illustrates the ratio of parallel capacitance

(55) $C_p=C_s\left(1+{\tan }^2\left(\frac{Z^{}\left(\right)}{Z^{}\left(\right)}\right)\right),$
and series capacitance

(56) $C_s=\frac{1}{Z^{}\left(\right)},$
vs. log of ac frequency (log f) plots for electrospun cells in which the electrodes and separator were isostatically compressed, and electrospun cells in which the electrodes/separator were not isostatically compressed. Data at 20 and 30 degrees Celsius are provided in the Figure.

(57) FIG. 25 shows series resistance R.sub.sZ() and FIG. 26 shows parallel resistance

(58) $R_p=R_s\left(1+\frac{1}{{\tan }^2\left(\frac{Z^{}\left(\right)}{Z^{}\left(\right)}\right)}\right)$
plotted against log ac frequency (log f) for electrospun cells made with and without isostatic compression. Data at 20 and 30 degrees Celsius are provided in the Figures.

(59) FIG. 27 shows the complex power plots calculated from impedance plane plots for ultramicroporous-microporous-mesoporous electrospun single cells made with and without isostatic compression. The characteristic time constants for charging/discharging of an EDLC are given in seconds in this Figure. Data at 20 and 30 degrees Celsius are provided.

(60) FIG. 28 shows Ragone (energy density vs. power density) plots for microporous-mesoporous electrospun electrode/separator/electrode based single cells made with and without isostatic compression, calculated from the constant power discharge data at various temperatures. Plots at 20 and 30 degrees Celsius are provided in the Figure.

(61) FIG. 29 shows constant current charge/discharge (at current 2 A*g.sup.1) data for an EDLC made with electrospun cells at floating (time stability testing) conditions at 30 degrees Celsius, measured at fixed floating times, which are indicted in the Figure.

(62) FIG. 30 shows dependence of capacitance vs. floating time (calculated from constant current charge/discharge data) for electrospun cells containing half-cells made with and without isostatic compression.

(63) Finally, we list a number of publications to which a person skilled in the art may turn to understand better the present disclosure. Each of these publications is incorporated by reference in its entirety. The publications are: B. E. Conway, Electrochemical Supercapacitors, Scientific Fundamentals and Technological Applications, New York: Kluwer Academic/Plenum Publishers, 1999. F. Beguin, E. Frackowiak, Carbons for Electrochemical Energy Storage and Conversion Systems, New York: CRN Press, 2010. R. Ktz, M. Carlen, Principles and applications of electrochemical capacitors. Electrochim. Acta, vol. 45, p. 2483-2498, 2000. A. G. Pandolfo, A. F. Hollenkamp, Carbon properties and their role in supercapacitors. J. Power Sources, vol. 157, p. 11-27, 2006. P. Simon, Y. Gogotsi, Materials for electrochemical capacitors. Nature Materials, vol. 7, p. 845-854, 2008. E. Lust, A. Jnes, T. Prn, P. 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Soc., vol. 159, p. A208-A213, 2012. H. I. Becker, Low voltage electrolytic capacitor. U.S. Pat. No. 2,800,616 A, 1957. I. K. Yoshida Akihiko, Electric double layer capacitor and method for producing the same. U.S. Pat. No. 5,150,283, 1992. A. W. Roy Richner, Method for cross-linking carbon or carbon material such as industrial carbon black and active carbon, use thereof in the production of electrochemical double layer capacitor electrodes. Patent WO2001045121 A1, 2001. E. N. Mrotek, B. Reichman, M. P. Yin, Porous electrodes containing activated carbon powders and fibers in matrix of carbonized resin, high strength, low resistance. U.S. Pat. No. 5,776,633, 1998. M. Endo, K. Watanabe, K. Tanaka, H. Mukouyama, Method of manufacturing polarizable electrode for electric double-layer capacitor. U.S. Pat. No. 5,277,729, 1994. I. Tallo, T. Thomberg, H. Kurig, A. Janes, K. Kontturi, E. Lust, Supercapacitors based on carbide-derived carbons synthesised using HCl and Cl-2 as reactants. J. Solid State Electrochem., vol. 17, p. 19-28, 2013. I. Tallo, T. Thomberg, K. Kontturi, A. Jnes, E. Lust, Nanostructured carbide-derived carbon synthesized by chlorination of tungsten carbide. Carbon, vol. 49, p. 4427-4433, 2011. I. Tallo, T. Thomberg, H. Kurig, K. Kontturi, A. Jnes, E. Lust, Novel micromesoporous carbon materials synthesized from tantalum hafnium carbide and tungsten titanium carbide. Carbon, vol. 67, p. 607-616, 2014. T. Thomberg, T. Tooming, T. Romann, R. Palm, A. Jnes, E. Lust, High power density supercapacitors based on the carbon dioxide activated D-glucose derived carbon electrodes and acetonitrile electrolyte. J. Electrochem. Soc., vol. 160, p. A1834-A1841, 2013. T. Thomberg, H. Kurig, A. Jnes, E. Lust, Mesoporous carbide-derived carbons prepared from different chromium carbides. Microporous and Mesoporous Materials, vol. 141, p. 88-93, 2011. T. Thomberg, A. Jnes, E. 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(64) Although steps of various methods may have been described serially in this disclosure, some of the steps may be performed in conjunction or in parallel, asynchronously or synchronously, in a pipelined manner, or otherwise. There is no particular requirement that the steps be performed in the same order in which this description lists them and the accompanying Figures show them, except where explicitly so indicated, otherwise made clear from the context, or inherently required. It should be noted, however, that in selected examples the steps are performed in the particular progressions described in this document and/or shown in the accompanying Figures. Furthermore, not every illustrated step and decision may be required in every embodiment, while some steps that have not been specifically illustrated may be desirable or necessary in some embodiments.

(65) The features described throughout this document may be present individually, or in any combination or permutation, except where the presence or absence of specific features in a given combination or permutation is inherently required, explicitly indicated, or otherwise made clear from the context.

(66) The inventive methods for manufacturing electrodes, membranes, half-cells, and full cells, as well as the electrodes, membranes, half-cells, and full cells (electrode-separator/membrane-electrode) made using the methods have been described above in considerable detail. This was done for illustration purposes. Neither the specific embodiments of the disclosure as a whole, nor those of the features, necessarily limit the general principles underlying the disclosure of this document. In particular, the inventive methods and articles are not necessarily limited to double layer capacitors, but extend to other electrode applications. The specific features described herein may be used in some embodiments, but not in others, without departure from the spirit and scope of the invention(s) as set forth. Many additional modifications are intended in the foregoing disclosure, and it will be appreciated by those of ordinary skill in the art that, in some instances, some of the disclosed features may be used in the absence of a corresponding use of other features. The illustrative examples therefore do not necessarily define the metes and bounds of the invention (or the inventions, as the case may be) and the legal protection afforded the invention(s), which function is served by the claims and their equivalents.