High density, low tortuosity electrode and compositions and methods for making the same

Abstract

Disclosed herein is an electrode film exhibiting high density and low tortuosity, along with an electrode-forming composition used to make the electrode film. Also disclosed is a method for making the electrode film, which comprises using a template component that can be removed after forming the electrode film to provide a hierarchical pore network throughout the electrode film. In addition to the template component and an electroactive material, some aspects of the disclosure utilize a binder. In some aspects, the binder becomes fibrillated during the method used to make the electrode, which further facilitates the hierarchical pore network in some aspects.

Description

HIGH DENSITY, LOW TORTUOSITY ELECTRODE AND COMPOSITIONS AND METHODS FOR MAKING THE SAMECROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to the earlier filing date of U.S. Provisional Application No. 63 / 632,666, filed on April 11 , 2024, the entirety of which is incorporated herein by reference.ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

[0002] This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.FIELD

[0003] The present disclosure is directed to an electrode that exhibits high density with low tortuosity and methods for making and using the same.BACKGROUND

[0004] Lithium-sulfur (Li-S) batteries are emerging as a promising next-generation energy storage technology due to their high theoretical energy density, low cost, and energy sustainability. Despite advancement in enhancing sulfur utilization and mass loading for high specific energy, enhancing the volumetric energy density (Ev) of Li-S full cells has been a main goal that has not yet been achieved, with most reported Evvalues being below 400 Wh L1. This is at least one limitation that restricts the deployment of Li-S batteries in space-constrained applications, such as electric vehicles and portable electronic devices. There exists a need in the art for improved Li-S battery systems, as well as other types of systems, that can exhibit high cell energy densities.SUMMARY

[0005] Aspects of the present disclosure concern an electrode-forming composition comprising: an electroactive material; a template component; and a binder component; wherein the electrodeforming composition has (i) a solids content above at least 60 wt% with respect to the total weight of the electrode-forming composition, and / or (ii) a viscosity greater than 10 Pa s at a shear rate of 1 s’1.

[0006] Further aspects of the present disclosure concern an electrode film, comprising: a binder; an electroactive material; and a pore network formed within the electrode film comprisinginterconnected pores, wherein the pore network is located throughout the volume of the electrode film and wherein more than 60% of a pore space of the pore network is interconnected.

[0007] Yet further aspects of the present disclosure concern a method for forming an electrode film, comprising: exposing an electrode-forming composition according to aspects of the present disclosure to compressive and / or shear forces to provide an electrode film precursor; and removing the template component from the electrode film precursor to provide the electrode film.

[0008] The foregoing and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGS. 1A and 1 B are schematic illustrations showing the closed pore structure of an electrode film made according to a conventional slurry coating process, referred to herein as an “CCS” electrode film (FIG. 1 A); and the vascular pore network of an electrode film according to aspects of the present disclosure obtained using a template component and processing method according to aspects of the present disclosure, referred to herein in examples of the disclosure as an “SDS” electrode film (FIG. 1 B).

[0010] FIG. 2 is a schematic illustration showing the influence of electrode porosity and sulfur content on the volume of (i) a sulfur electrode having high porosity and low sulfur content (left image) and (ii) a sulfur electrode having low porosity and high sulfur content (right image).

[0011] FIG. 3 is a graph showing an estimation of energy density (Ev) for a 2 Ah Li-S dry cell as a function of electrode porosity and sulfur content.

[0012] FIGS. 4A and 4B are scanning electron microscopy (SEM) images showing a sulfur electroactive material (FIG. 4A) and an electrode formed from an electrode-forming composition comprising the sulfur electroactive material using a method according to aspects of the present disclosure (FIG. 4B).

[0013] FIG. 5 is a schematic illustration of the electrode fabrication process according to aspects of the present disclosure using shear and compressive forces provided by an apparatus comprising rollers.

[0014] FIG. 6 is a schematic illustration of an electrode film made according to a conventional slurry coating process (top schematic) and an electrode film made according to a method according to aspects of the present disclosure (bottom schematic).

[0015] FIG. 7 is a schematic illustration of the electrode fabrication process according to aspects of the present disclosure using shear and compressive forces applied by pressing an electrodeforming composition between two plates in one direction while pulling / pushing the electrodeforming material in a different direction.

[0016] FIG. 8 shows an equivalent circuit for EIS spectra fitting and the schematic illustration of the transmission-line model.

[0017] FIG. 9 shows 1stdischarge and charge profiles of electrodes formed using a conventional slurry coating process with and without a calendering step (without calendering = “PCS” electrode) and (with calendering = “CCS” electrode) at E / S 10 mL g1, 0.05 C, 30 °C in CVE (CVE being an electrolyte prepared by dissolving 1 M lithium bis(trifluoromethane)sulfonimide (LiTFSI) in 1 ,3- dioxolane (DOL) and 1 ,2-dimethoxyethane (DME) (1 :1 , v / v) mixture with 0.3 M LiNOs as an additive).

[0018] FIG. 10 is a graph showing the cycle performance of the PCS electrode in CVE at E / S 10 mL g1, 0.1 C (first two cycles at 0.05 C).

[0019] FIG. 11 shows 1stdischarge and charge profiles of an SDS electrode at E / S 10 mL g1, 0.05 C, 30 °C in CVE.

[0020] FIGS. 12A and 12B are graphs showing viscosities of CVE (a) and LHCE (b) electrolytes at different temperatures, wherein LHCE is an electrolyte prepared by dissolving 7 M LiTFSI in a DOL and DME (1 :1 , v / v) mixture and adding TTFE as diluent at 2:1 , v / v.

[0021] FIG. 13 shows 1stdischarge and charge profiles of PCS and CCS electrodes at E / S 10 mL g1, 0.05 C, 30 °C in LHCE.

[0022] FIG. 14 shows 1 discharge and charge profiles of an SDS electrode at E / S 10 mL g1, 0.05 C, 30 °C in LHCE.

[0023] FIG. 15 is an SEM image of electroactive material used for electrode fabrication using a conventional slurry coating process.

[0024] FIG. 16A-16D are images providing a comparison of electrode film structures between an CCS electrode film and an SDS electrode film, wherein FIG. 16A shows an SEM surface image of the CCS electrode film; FIG. 16B shows an SEM surface image of the SDS electrode film; FIG. 16C shows an SEM cross-sectional image of the CCS electrode film; and FIG. 16D shows an SEM cross-sectional image of the SDS electrode film.

[0025] FIG. 17 is a graph showing pore size distribution of a CCS electrode and an SDS electrode, wherein the pore size was estimated by PFIB-SEM image analysis.

[0026] FIG. 18A-18D show (i) 3D reconstructed images of a CCS electrode (FIG. 18A) and an SDS electrode (FIG. 18B), with green representing the connected pores and brown representing closed pores; and (ii) a 3D pressure-volume visualization with illuminated streamlines over connected porosity for the CCS electrode (FIG. 18C) and the SDS electrode (FIG. 18D), showing that the pressure of the single-phase fluid flow is highest at the selected dimension of entry and relatively lower at the exit, represented by a physics colormap ranging from red (high) to blue (low) as continuous values.

[0027] FIG. 19 is a schematic illustration of S-electrode | S-electrode symmetric cells used for electrochemical impedance spectroscopy (EIS) measurements in CVE and LHCE.

[0028] FIGS. 20A-20D show results for a CCS electrode as compared with an SDS electrode, with FIG. 20A showing the EIS spectra of CCS and SDS electrodes in CVE and FIG. 20B showing the EIS spectra of CCS and SDS electrodes in LHCE; and FIGS. 20C and 20D showing the impedance-based tortuosity (r,) of CCS and SDS electrodes using CVE and LHCE, respectively.

[0029] FIG. 21 shows a schematic illustration of the S-electrode-host | S-electrode-host symmetric cells for cyclic voltammetry (CV) measurements in LHCE, with a scan rate of 1 -50 mV s'1, wherein “S-electrode host” refers the S-electrode after removing the active sulfur from the electrode.

[0030] FIGS. 22A-22C show (i) the CV profiles of an CCS electrode host (FIG. 22A); (ii) the CV profiles of an SDS electrode host (FIG. 22B); and (iii) a comparison of specific capacitance between CCS and SDS electrode hosts (FIG. 22C).

[0031] FIG. 23 shows a high-resolution cross-sectional SEM image of an SDS electrode.

[0032] FIG. 24 shows cycle performances of CCS and SDS electrodes in the LHCE at E / S 10 mL g1-

[0033] FIG. 25 shows cycle performances of CCS and SDS electrodes in the CVE at E / S 10 mL g1.

[0034] FIGS. 26A and 26B show cycle performances of CCS and SDS electrodes in the LHCE (FIG. 26A) and the CVE (FIG. 26B) at E / S 4 mL g1.

[0035] FIGS. 27A-27D show (i) the first discharge and charge profile of a high-S-loading (7.1 mg cm2) SDS electrode at E / S 4 mL g1(FIG. 27A); (ii) cycle performance of the high-S-loading SDSelectrode at E / S 4 mL g1in a plot of areal capacity versus cycle plot (FIG. 27B); (Hi) the second discharge and charge profiles of high-S-content SDS electrodes comprising the different sulfur contents summarized in Table 1 herein at E / S 4 mL g1(FIG. 27C); and (iv) the cycle performances of the high-S-content SDS electrodes with the varying sulfur content (FIG. 27D), wherein current density is 0.1 C (10=1000 mA g1, first two cycles at 0.05 C).

[0036] FIGS. 28A and 28B show 0.7 Ah pouch cell cycle performance of an SDS electrode at an electrode porosity of 14% (density of 1 .8 g cm3), a sulfur loading of 5.6 mg cm2, E / S of 4 mL g1, and a current density of 0.1 mA cm2(0.02 C) (FIG. 28A); and the 1stand 4thcycle discharge and charge profiles of a 0.7 Ah Li-S (SDS / CVE) pouch cell (FIG. 28B).

[0037] FIG. 29 shows 2.1 Ah pouch cell cycle performance of an SDS electrode at an electrode porosity of 62% (density of 0.8 g cm3), a sulfur loading of 4.2 mg cm2, E / S of 5 mL g1, a current density of 0.14 mA cm2(0.03 C) for cycles 1 -7, 0.28 mA cm2(0.06 C) for cycles 8-31 , and 0.42 mA cm2(0.1 C) for cycles 32-100.

[0038] FIG. 30 shows 1stand 4thcycle discharge and charge profiles of a 2.1 Ah Li-S (SDS / LHCE) pouch cell.

[0039] FIG. 31 compares the relationship between E,, and S-electrode E„at different cell capacities based on a sulfur loading of 5 mg cm2and a specific capacity of 1000 mAh g1and also provides an Evcomparison between an electrode of the present disclosure and comparison electrodes.DETAILED DESCRIPTIONI. Overview of Terms

[0040] The following explanations of terms and abbreviations are provided to better describe the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure. As used herein, “comprising” means “including” and the singular forms “a” or “an” or “the” include plural references unless the context clearly dictates otherwise. The term “or” refers to a single element of stated alternative elements or a combination of two or more elements, unless the context clearly indicates otherwise.

[0041] Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and not intended tobe limiting. Other features of the disclosure are apparent from the following detailed description and the claims.

[0042] Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, molarities, voltages, capacities, and so forth, as used in the specification or claims are to be understood as being modified by the term “about.” Accordingly, unless otherwise implicitly or explicitly indicated, or unless the context is properly understood by a person of ordinary skill in the art to have a more definitive construction, the numerical parameters set forth are approximations that may depend on the desired properties sought and / or limits of detection under standard test conditions / methods as known to those of ordinary skill in the art. When directly and explicitly distinguishing aspects of the disclosure from discussed prior art, the numbers are not approximates unless the word “about” is recited.

[0043] Although the operations of some of the aspects of the disclosure are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods can be used in conjunction with other methods. Additionally, the description sometimes uses terms like “introduce,” “flow,” or “provide” to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations that correspond to these terms may vary depending on the particular implementation and are readily discernible by one of ordinary skill in the art.

[0044] Although there are alternatives for various components, parameters, operating conditions, etc. set forth herein, that does not mean that those alternatives are necessarily equivalent and / or perform equally well. Nor does it mean that the alternatives are listed in a preferred order unless stated otherwise.

[0045] Directions and other relative references (e.g., inner, outer, upper, lower, etc.) may be used to facilitate discussion of the drawings and principles herein, but are not intended to be limiting. For example, certain terms may be used such as “inside,” “outside,” “top,” “down,” “interior,” “exterior,” and the like. Such terms are used, where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated aspects of the disclosure. Such terms are not, however, intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, an “upper” part can become a “lower” part simply by turning the object over. Nevertheless, it is still the same part and the object remains the same.

[0046] In order to facilitate review of the various aspects of the disclosure, the following explanations of specific terms are provided:

[0047] Average Particle Size: A mathematical average diameter of a plurality of particles, wherein diameters of individual particles are considered in arriving at the average. Particle diameter may be determined by any suitable method including, but not limited to, scanning electron microscopy.

[0048] Binder: A component that is used to bind particles together through chemical binding between functional groups of the binder (e.g., -OH, -OOH, or anions thereof) and the particles. Binders, as described herein, are typically separate and distinct from a conductive carbon material that is used to join nanoparticles into aggregates that form particles.

[0049] Capacity: The capacity of a cell is the amount of electrical charge a cell can deliver. The capacity is typically expressed in units of mAh, or Ah, and indicates the maximum constant current a cell can produce over a period of one hour. For example, a cell with a capacity of 100 mAh can deliver a current of 100 mA for one hour or a current of 5 mA for 20 hours.

[0050] Cell: As used herein, a cell refers to an energy storage device used for generating a voltage or current from electrochemical reactions, or the reverse in which electrochemical reactions are induced by a current. Examples include voltaic cells, electrolytic cells, and fuel cells, among others. A battery typically includes one or more cells.

[0051] Conductive Additive: This term refers to an electrode component that provides additional electronic and / or ionic conductivity to enable electrochemical reactions of the electrode.

[0052] Electroactive Material: A material (e.g., an element, an ion, an organic compound, or an inorganic compound) that is capable of forming redox pairs having different oxidation and reduction states (e.g., ionic species with differing oxidation states or a metal cation and its corresponding neutral metal atom). Conversions between chemical energy and electricity energy occur with an accompanying change in oxidation state these ions or compounds. In a flow battery, an electroactive material refers to the chemical species dissolved in certain solutions that participate(s) in the redox reaction during the charge and discharge processes, significantly contributing to the energy conversions that ultimately enable the battery to deliver / store energy. By “significantly contributing” is meant that a redox pair including the electroactive material contributes at least 10% of the energy conversions that ultimately enable the battery to deliver / store energy. In some aspects of the disclosure, the redox pair including the electroactive material contributes at least 50%, at least 75%, at least 90%, or at least 95% of the energy conversions of a cell comprising the electroactive material in a catholyte or anolyte.

[0053] Electrode-Forming Composition: A composition as disclosed herein that comprises a template component in combination with at least one electroactive material and at least one binder. An electrode-forming composition according to the present disclosure is distinct from a slurry comprising an electroactive material and a binder in a solvent as the electrode-forming composition has a solids content above at least 60 wt% with respect to the total weight of the electrode-forming composition.

[0054] Electrode Film: As used herein, this term refers to a material used in an electrode. The electrode film of the present disclosure is formed from an electrode-forming composition according to aspects of the present disclosure using a method according to aspects of the present disclosure. The electrode film typically comprises a mixture of at least an electroactive material and a binder.

[0055] Electrode Film Precursor: As used herein, this term refers to a material that is formed after having exposed an electrode-forming composition to compressive and / or shear forces but before removing a template component of the electrode-forming composition. The electrode film precursor typically comprises a uniform mixture of at least an electroactive material, a binder, and a template component, which have been exposed to compressive and / or shear forces.

[0056] Electrode Porosity: A measurement of the porosity exhibited by a layer of electrode film according to aspects of the present disclosure. In some aspects, the layer of electrode film is formed on a substrate to provide an assembled electrode.

[0057] Electrode Tortuosity: A measurement of the tortuosity exhibited by a layer of electrode film according to aspects of the present disclosure.

[0058] Electronic Conductive Additive: A conductive additive that provides additional electronic conductivity. An exemplary electronic conductive additive can include, but is not limited to, conductive carbon materials (e.g., amorphous carbon; carbon black; carbon nanofibers (CNF); carbon nanotubes (CNT); graphene; reduced graphene oxide; carbon products formed from decomposing organic precursors; metal particles, such as silver, copper, and the like; conductive polymers, such as poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, and polyaniline; and combinations thereof).

[0059] Fibrillated Binder: A binder that has been treated so as to exhibit a fibril-like morphology rather than a particle or other non-fibri Hated state.

[0060] Gel: A semi-solid that can have properties ranging from soft and weak to hard and tough and typically exists as a substantially dilute cross-linked system, which exhibits no flow when in the steady state.

[0061] Ionic conductive additive: An additive added to an electrode-forming composition to enhance lithium-ion transport within the electrode and / or electrolyte phase. Exemplary ionic conductive additives include, but are not limited to, lithium salts (e.g., LiTFSI, LiFSI, and LiBF4), lithium-ion conductive ceramics (e.g., Li7La3Zr20i2 (LLZO), Lii.3Alo.3Tii.7(P04)3 (LATP), and Lii.5Alo.5Gei.5(P04)3 (LAGP)), ionic conductive polymers (e.g., polyethylene oxide (PEO), and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) with lithium salts), inorganic ion conductors (e.g., Li3PO4, UPON, LiioGeP2Si2, LiaPSsCI, and LisZrCle), and combinations thereof.

[0062] Liquid: A fluid substance that flows freely but is of constant volume, having a consistency like that of water or oil.

[0063] Pore: In electrode films of the present disclosure, a pore is an opening or void space formed within the volume of the electrode film. Pores may be formed between individual electroactive material particles and within such particles. In electrode films of the present disclosure, pores can be interconnected with one another to provide channels through which electrolyte can flow.

[0064] Slurry: A flowable composition typically comprising a liquid solvent and exhibiting a solids content typically lower than 65 wt% by weight of total composition and exhibiting a viscosity value that is less than 10 Pa s at a shear rate of I s'1. A slurry also typically exhibits a low yield stress (e.g., less than 10 Pa) and can be disposed using a liquid-phase coating method, such as blade coating, slot die- coating, or the like.

[0065] Solid: A material / compound that is firm and stable in shape and is not a liquid or fluid.

[0066] Specific capacity: A term that refers to capacity per unit of mass. Specific capacity may be expressed in units of mAh / g.

[0067] Substrate: A material upon which a layer of (at least) an electrode film according to the present disclosure is deposited, the electrode film being provide by an electrode-forming composition according to the present disclosure. A substrate typically has a deposition surface upon which the electrode film is deposited. The substrate can comprise a material that is suitable for use in an electrode, such as in an anode or a cathode (or both). Suitable substrate materials are described herein.

[0068] Template Component: A component of the electrode-forming composition according to aspects of the disclosure that is removed from the electrode film formed therefrom and thus is not present in the resulting electrode. In some aspects, the template component is a sacrificial component that can be of solid, liquid, or gel form. The template component is not functionally equivalent to a solvent used in a conventional slurry coating process.II. Introduction

[0069] A main challenge in achieving high cell energy density in Li-S batteries is the significant volume occupied by conventional highly porous sulfur electrodes within a cell. The high electrode porosity reduces cell volumetric energy and requires a substantial amount of electrolyte for full pore filling. Traditionally, sulfur electrodes are fabricated using nanosized or highly porous sulfur host materials using a conventional slurry coating process. However, such methods encounter several practical challenges, such as cohesion and adhesion failures due to the highly porous structure and large surface area of the nanomaterials. Toward achieving high cell level Ev, it is important to note that the preparation of a high sulfur mass loading electrode represents only the initial step. Another challenge is reducing electrode porosity to meet the high Evdesign. Without addressing this challenge, a sulfur electrode with extremely low density could result in a diminished cell-level energy density. One conventional approach to reduce electrode porosity is performing post-drying calendering (that is, calendering performed after drying a film made from a slurry containing the electroactive material, binder, and any conductive additives, such as electronic and / or ionic conductive additives). While direct calendering of a dried sulfur electrode enhances electrode density, it can cause compromised electrode wetting and low sulfur utilization due to the low porosity and exaggerated tortuosity. Additionally, alternative densification methods, such as capillary pressure-driven densification, sintering, solvent-assist reshaping, and selfassembly have been explored; however, these approaches either fail to achieve sufficient densification or present challenges for large-scale implementation. Few experimental solutions reported so far can effectively maintain the cell performance under conditions of low electrode porosity.

[0070] Furthermore, by way of example, high-S-loading electrodes prepared through conventional slurry coating frequently exhibit low sulfur content with inert materials like binders, sulfur hosts, and conductive agents accounting for approximately 40 wt.% or more, which is much higher than that in lithium-ion batteries (<10 wt.%). This limits the improvement of practical energy density with conventional methods.

[0071] Many of the above-described drawbacks associated with conventional materials often relate to (or stem from) the electrode fabrication process. For example, the conventional slurry coating method results in a highly porous electrode structure, primarily due to the removal of solvents, which typically constitute >75 wt.% of the slurry, particularly in a sulfur slurry. And, any attempt to achieve a high-density electrode film without relying on dry calendering by increasing the solid content of the slurry is typically constrained by the binder solubility and slurry viscosity.

[0072] The electrode described herein exhibits high density, low tortuosity, and minimal binder content (e.g., as low as 1 wt.% in some aspects). The electrode according to aspects of thepresent disclosure is prepared using a new shear force-driven fabrication method in combination with an electrode-forming composition comprising a template component. The disclosed method overcomes the limitations of traditional slurry coating techniques and enhances electrode cohesion. The electrode-forming composition according to aspects of the present disclosure provides a unique mixture of a template component, electroactive material(s), binder(s), and optional additives that can be exposed to processing steps that facilitate forming thinner electrodes with decreased porosity, but without sacrificing cell-level Evvalues and / or electroactive material utilization rates. Additionally, electrodes formed with the electrode film according to the present disclosure avoid cracking and / or cohesion failure, which often cannot be avoided in electrodes made using a conventional slurry / calendering process (wherein the material is first dried and then calendered) and a low amount of binder.III. Electrode-Forming Composition, Electrode Film, Electrode, and Cell

[0073] Disclosed herein is an electrode-forming composition useful for making the electrode film and assembled electrodes according to the present disclosure. The electrode-forming composition is a mixture comprising an electroactive material, a template component, and a binder component. In some aspects, the electrode-forming composition can further comprise one or more additional materials, such as a conductive additive (e.g., , a solvent, or a combination thereof. The components of the electrode-forming composition are discussed in more detail below.

[0074] In some aspects, the electroactive material component of the electrode-forming composition can be a cathode-forming electroactive material. In some such aspects, the electroactive material can be selected from sulfur-containing materials (including sulfur-carbon composite materials, sulfides, and sulfates), sodium-containing materials (including Prussian white analogues, Na2Fe[Fe(CN)6], NASICON-type phosphate (Na3V2(PO4)3), zinc-containing materials (including ZnMn2C>4 and ZnFe[Fe(CN)6]), phosphorus-containing materials (including phosphates, such as lithium iron phosphates), transition metal oxides (including oxides comprising lithium, sodium, potassium, calcium, zinc, or magnesium, and one or more of cobalt, manganese, nickel, aluminum, or iron), or combinations thereof. Exemplary electroactive materials for use in cathodes can include, but are not limited to, sulfur materials (including sulfur-carbon composites), lithium cobalt oxide (having a formula LiCoO2, and also referred to as “LCO”), lithium nickel cobalt aluminum oxide (or “NCA”), lithium iron phosphate (having a formula LiFePC and also referred to as “LFP”), lithium nickel manganese cobalt oxide (having a formula LiNixMnyCozO2, wherein x + y + z = 1 , also referred to as “NMC”), lithium nickel manganese cobalt oxide (or “LNMO”), olivine, lithium manganese oxide (or “LMO”), and lithium manganese iron phosphate materials (having a formula LiMnxFeixPO4, wherein x is 0<x<1 , also referred to as “LMFP”), MnO2, and V2Os. In someaspects, mixtures of such materials can be used. In some representative aspects, the electroactive material is sulfur, including sulfur / carbon composites (e.g., sulfur-Ketjen Black composites).

[0075] In some aspects, the electroactive material component of the electrode-forming composition can be an anode-forming electroactive material. In some such aspects, the electroactive material can be selected from a metal material (e.g., lithium, sodium, potassium, tin, aluminum, magnesium, silver, antinomy, tin, selenium, and any alloys thereof), a carbon-based material (e.g., graphite, graphene, activated carbon, hard carbon, carbon nanotubes or nanoparticles, and the like), a silicon-based material (e.g., silicon, silicon oxides, or silicon / carbon composites), or combinations thereof. In some aspects, mixtures of such materials can be used.

[0076] The electroactive material component can be present in an amount ranging from 10 wt% to 99 wt%, such as 50 wt% to 99 wt%, or 60 wt% to 99 wt%. In particular aspects, the electroactive material is a sulfur / carbon (S / C) composite material wherein the sulfur content ranges from 70 wt% to 90 wt%, such as 72 wt% to 90 wt%, or 74 wt% to 90 wt%, or 75 wt% to 90 wt%, or 80 wt% to 90 wt%, or 81 wt% to 90 wt%, or 83 wt% to 90 wt%, or 85 wt% to 90 wt%. In some such aspects, the sulfur content is about 80 wt%.

[0077] The template component of the electrode-forming composition is used to provide a vascular-like pore network within the electrode film formed from the electrode-forming composition. The template component also can facilitate connecting pores of the vascular-like pore network and further can reduce the tortuosity of the electrode. For example, the template component may improve flowability of components of the electrode-forming composition, such as solid components of the electrode-forming compositions. Without being limited to a single theory, it currently is believed that improved flowability is at least one factor that can contribute to connecting pores formed within the electrode film obtained from the electrode-forming composition.

[0078] The template component is typically removed from the final electrode film and typically is removed in its entirety or such that at least 80 wt% or more of the template component is removed from the final electrode film, such as at least 85 wt% or more, or 90 wt%, or 95 wt%, or 99 wt%, or more of the template component is removed from the final electrode film. Upon removing the template component, void spaces / connections are created in the electrode film, which form the vascular-like pore network of the final electrode film. In some aspects, the internal pore connectivity and pore distribution of the electrode film made using the template component is uniform across the electrode and includes an even distribution of small and large interconnected pores, wherein both large and small pores are connected. In some aspects, more than 60% of the pore space of the electrode film is interconnected, such as more than 65%, or more than 70%, or more than 75%, or more than 80% of the pore space of the electrode film is interconnected. Theincreased interconnectivity of the disclosed electrode film made with the template component (as opposed to an electrode made with a conventional slurry composition) facilitates electrolyte wetting of the electrode and decreases impedance-based tortuosity, thereby enhancing electrolyte flow and accessibility. In aspects of the present disclosure, impedance-based tortuosity is measured using the transmission-line model by Landesfeind et al, which is discussed herein in detail in the Examples. In particular aspects, the impedance-based tortuosity exhibits a value less than 2.5 (such as less than 2.25 or less than 2) according to the transmission-line model. The template component also is selected to exhibit a level of flowability (either inherently or through assistance by pairing with a solvent) that, when paired with shear and compressive forces used during fabrication, can facilitate forming the interconnected pore structures contained within electrodes made from the electrode-forming composition.

[0079] The template component of the electrode-forming composition can be a solid (e.g., a powder), a gel, or a liquid. In some aspects, the template component is a solid material that can be selected from an inorganic material, an organic material, or a combination thereof. In some such aspects, the inorganic material can be an inorganic salt, such as a sodium salt, a calcium salt, an ammonium salt, a phosphate salt, a lithium salt, or the like. In some particular aspects, the inorganic salt can be selected from sodium bis(trifluoromethane)sulfonimide, calcium bis(trifluoromethane)sulfonimide, ammonium bicarbonate, tris(trimethylsilyl)phosphate, lithium bis(trifluoromethane)sulfonimide, and the like. In some other such aspects, the organic material can be an organic molecule (e.g., glucose and other sugars) or an organic polymer material, such as poly(ethylene oxide), polyethylene glycol) dimethyl ether, polyvinylpyrrolidone, poly(acrylonitrile), poly(vinyl alcohol). In some aspects, the template component is a gel material. In such aspects, the gel material can be a material having a melting point lower than 100 °C, such as a melting point lower than 90 °C, or lower than 70 °C, or lower than 50 °C. In some aspects, the gel material can be selected from agarose gel, gelatin, xanthan gum, alginate, and polyacrylamide gel. In some aspects, the template component can be a liquid. In some such aspects, the liquid can be a liquid that has a boiling point lower than 200 °C, such as a boiling point lower than 150 °C, or lower than 100 °C, or lower than 90 °C. In some aspects, the liquid is an alcohol, such as a lower alcohol (e.g., methanol, 2-propanol, ethanol, butanol, pentanol, and the like). In yet additional aspects, the liquid can be an ionic liquid (e.g., 1-ethyl-3-methylimidazolium [TFSI]). In particular aspects, 2-propanol is used as the liquid template component. The template component can be present in an amount ranging from 0.1 wt% to 40 wt%, such as 1 wt% to 30 wt%, or 10 wt% to 30 wt%.

[0080] The electrode-forming composition further comprises a binder material. In some aspects, the binder material can be a polymer material. In particular aspects, the binder material can be a fluorinated polymer, such as poly(vinylidene fluoride) (“PVDF”), poly(tetrafluoroethylene) (“PTFE”),polyvinyl fluoride, or mixtures thereof. In some particular aspects, the binder material can be selected from a polyacrylate (e.g., lithium polyacrylate, LiPAA), a polyimide (PI), a polyvinyl alcohol, a polyvinyl chloride, an ethylene oxide, a polyvinylpyrrolidone, a polyurethane, a polyethylene (PE), a polypropylene (PP), a styrene-butadiene rubber, an epoxy resin, a nylon, and mixtures thereof. In particular aspects, the binder material is PTFE. The binder material of the disclosed electrode-forming composition can be used at low amounts, such as below 10 wt%, such as 9 wt%, or 8 wt%, or 7 wt%, or 6 wt%, or 5 wt%, or 4 wt%, or 3 wt%, or 2 wt%, or 1 wt%, or lower, based on the total weight percent of the electrode-forming composition, excluding any template component.

[0081] In some aspects, the electrode-forming composition can further comprise one or more conductive additives. In some aspects, the conductive additive can be an electronically conductive additive, such as carbon material, a conductive polymer, a metal material, or a mixture thereof. In some particular aspects, the conductive additive can be carbon black, acetylene black, Ketjen Black, carbon fibers (e.g., vapor-grown carbon fiber), metal powders or fibers (e.g., Cu, Ni, Al), and conductive polymers (e.g., polyphenylene derivatives). In yet additional aspects, the conductive additive can be an ionic conductive additive. In some such aspects, the ionic conductive additive can be selected from Li7La3Zr20i2 (LLZO), Alo.3Lii.3Tii.7(P04)3 (LATP), Lii.5Alo.5Gei.5(P04)3 (LAGP), U3PO4, LiPON, Li GePzSis, Li6PS5CI, Li2ZrCl6, and combinations thereof.

[0082] The electrode-forming composition is prepared as a solid composition or as a viscous paste composition, thereby allowing the composition to maintain shape without external support and also be processed by method disclosed herein. In particular aspects, the electrode-forming composition is not prepared as a slurry. In some particular aspects, the electrode-forming composition is not an aqueous slurry. In such aspects, the electrode-forming composition takes the form of a semi-solid composition with a solids content greater than 60 wt% (based on the total weight of the composition) and / or exhibiting a viscosity greater than 10 Pa s at a shear rate of 1 s’1, such as greater than 15 Pa s at a shear rate of 1 s’1, or greater than 20 Pa s at a shear rate of 1 s’1. The electrode-forming composition of the present disclosure also exhibits high yield stress, such as greater than 10 Pa, or greater than 15 Pa, or greater than 20 Pa. The electrode-forming composition according to the present disclosure can have a solids content above 60 wt% based on the total weight of the composition, such as above 65 wt%, or above 70 wt%, or above 75 wt%, or above 80 wt%, or above 85 wt%. The solids content represents the amount of all solid components present in the electrode-forming composition (e.g., any electroactive material, binder, conductive additive, and solid / gel template component that is present in the composition).

[0083] In some particular aspects, the electrode-forming composition comprises (i) a sulfur / carbon composite material as the electroactive material; (ii) 2-propanol as the templatecomponent; (iii) a PTFE, PP, or PE binder material; and (iv) a conductive carbon additive. In some such aspects, the S / C composite, conductive carbon additive, and binder are present in amounts providing a weight ratio of S / C composite:conductive carbon additive:binder ranging from 88:7:5 to 93:6:1. In some representative aspects, the weight ratio of this combination is 88:7:5 or 93:6:1 (S / C composite : conductive carbon additive : binder).

[0084] Also disclosed herein is an electrode made using an electrode-forming composition according to the present disclosure. The electrode comprises an electrode film layer comprising an electroactive material and a binder and may further comprise a conductive additive component, a support substrate, or a combination thereof. The electroactive material and binder can be as described herein for the electrode-forming composition. In some aspects, the binder component of the electrode film can exist in a different form compared to the form of the binder as it exists in the electrode-forming composition. For example, in some aspects, the binder component of the electrode film can be in a fibrillated state (such as existing as fibers) as compared to its state when present in the electrode-forming composition (such as existing as particles). Fibrillation of the binder component can result from the method used to make the electrode according to aspects of the present disclosure. The electrode film typically is free of the template component; however, trace amounts of the template component may be present in the electrode film without harming efficiency. Such trace amounts usually are amounts that are less than 20 wt%, such as less than 15%, or less than 10 wt%, or less than 5 wt%, or less than 1%.

[0085] The electrode of the present disclosure exhibits properties and structural features that are not present in electrodes made from conventional methods (e.g., post-drying calendering methods wherein calendering occurs after drying a slurry mixture; or other densification methods, like capillary pressure-driven densification, sintering, solvent-assist reshaping, and self-assembly). As described herein, the template component can be used to leave behind a vascular network of pores and channels upon its removal from the electrode film component of the electrode. As such, the electrode film exhibits a vascular network of interconnected hierarchical pores and / or channels that are not obtained through a conventional process, such as slurry formation, drying, and calendering, which produces a closed pore network wherein pores are not interconnected over the majority of the electrode film. FIGS. 1 A and 1 B show schematic illustrations of an electrode film with a closed pore network obtained from a conventional slurry drying / calendering process (FIG. 1 A) and an electrode film with a vascular pore network according to the present disclosure (FIG. 1 B). As illustrated in FIG. 1A, isolated small pores (102) of the closed pore electrode (100) are not connected with the large channels / pores (104), which creates local regions distant from the large channels that are bypassed during electrolyte permeation, hindering their participation in reactions, which leads to poor performance. Poor connectivity of pores of the electrode film of FIG. 1 A is attributed, at least in part, to structure damage that occurs from dry calendering. Further, the lackof large channels throughout the electrode film can result in very low permeability at the global scale, impeding electrolyte distribution and causing reaction heterogeneity. In contrast, as seen in FIG. 1 B, the electrode film (106) of the present disclosure comprises internal structural features that facilitate the rapid and thorough permeation of electrolyte throughout the electrode. The electrode film comprises interconnected large pores (108), which can function as major vessels, swiftly transporting electrolyte to subregions, while the connected small pores (110) act as capillaries, uniformly distributing electrolyte to individual particles.

[0086] In some aspects, the electrode film according to the present disclosure exhibits average porosity values below 70%, such as below 65%, or below 60%, or below 55%, or below 50%. In some aspects, the electrode film exhibits an average porosity value as low as 15%. The ability to achieve the average porosity values according to the disclosed electrode film can contribute to the ability of achieving electrodes that exhibit reduced thicknesses. In some aspects, electrode film layer of the present disclosure present in an assembled electrode can exhibit a thickness below 100 pm without decreasing areal mass loading values below 4 mg cm2. In some aspects, electrode film layer exhibits a thickness below 80 pm, such as below 75 pm, or below 70 pm without decreasing areal mass loading values below 4 mg cm2.

[0087] By achieving such thicknesses without decreasing areal mass loading, the disclosed electrode avoids the diminished electroactive material packing density that often is associated with electrodes having high electrode porosity. At least some of these features are illustrated schematically in FIG. 2, which depicts sulfur-based electrodes as examples. In particular, FIG. 2 compares (i) a conventional sulfur electrode (200) having a high porosity value and an electrode film layer thickness of approximately 200 pm with (ii) an electrode according to the present disclosure (202). As shown in FIG. 2, the electrode film layer (202) of the present disclosure has a resulting thickness (e.g., 65 pm), which can be, at least in part, attributed to lower porosity (e.g., lower than 50%). The disclosed electrode can exhibit a two-thirds reduction in electrode volume by using the method and electrode-forming composition disclosed herein. Additionally, the disclosed electrode’s design facilitates elevated cell-level Evvalues, as shown in FIG. 3, which shows results from modeling a 2 Ah Li-S pouch cell configuration using sulfur electrode with a loading of 5 mg cm2for estimation and considering all cell components, such as electrode film layers (e.g., electrode film layers 204 of FIG. 2, substrate 206 of FIG. 2, separator 208 of FIG. 2, anode 210 of FIG. 2, and any current collectors). As compared with a conventional electrode having 70% porosity and 50 wt% sulfur, which is estimated to exhibit an Evof 332 Wh L1, an electrode according to the disclosure having low average porosity (e.g., 47% porosity) and high sulfur content (e.g., 70 wt% sulfur) can exhibit an E„ of 612 Wh L1, provided the sulfur utilization rate is maintained.

[0088] As discussed herein, the electrode film of the present disclosure can avoid issues like cracking and cohesion failure. FIGS. 4A and 4B provide SEM images of a sulfur electroactive material (FIG. 4A) and an electrode prepared from an electrode-forming composition according to aspects of the present disclosure comprising the sulfur electroactive material and that was formed using a method disclosed herein (FIG. 4B). FIGS. 4A and 4B confirm that no significant particle breakage occurs when forming the electrode using a method according to the present disclosure. Additionally, the electrode film comprises a uniform distribution of elements provided by the electrode-forming composition materials (e.g., carbon, fluorine, sulfur, and the like), which provides additional confirmation of the structural integrity of the electrode film. This homogenous distribution of elements can be confirmed using energy dispersive X-ray (EDX) mapping.

[0089] The electrode of the present disclosure can be used in a cell, such as a coin cell or a pouch cell. The cell can further comprise a second electrode and an electrolyte. Electrolytes known to those in the art in view of the type of electroactive material that is used for the electrode(s) can be used in the cell. The cell may also further comprise a membrane or separator. A plurality of cells comprising multiple electrodes according to the present disclosure can be assembled and used in combination with one another.IV. Method

[0090] Also disclosed herein is a method for making an electrode from an electrode-forming composition according to the present disclosure. In aspects of the present disclosure, the method comprises exposing the electrode-forming composition to a shear force to provide an electrode film precursor and then removing the template component from the electrode film precursor to provide the electrode film. In some aspects, the shear force used in the method is paired with a compressive force. In some aspects, the method can further comprise preparing the electrodeforming composition by combining an electroactive material, a binder, and a template component. In yet additional aspects, the method can further comprise coupling the electrode film with a substrate or other electrode component for form the final electrode. In some aspects, the electrode film may be formed while already present on a substrate, such as by performing the template component removal step after having deposited a layer of electrode-forming composition on the substrate.

[0091] According to aspects of the present disclosure, an electrode-forming composition described herein can be exposed to a shear force produced by an apparatus to which the electrode-forming composition is exposed. In some aspects, the shear force can be coupled with a compressive force. The force(s) applied during the method according to aspects of the disclosure facilitate modifying the binder particles to have fibril-like morphologies. The compressive and / or shear forces can be applied to the electrode-forming composition using asuitable apparatus that can apply force against the composition such that component of the composition, particularly the binder component, is compressed and stretched simultaneously. In some aspects, the apparatus used to apply the compressive and / or shear forces to the electrodeforming composition is a roller apparatus, a press apparatus, an extrusion apparatus, or a combination thereof. In some particular aspects, exposing the electrode-forming composition to compressive and / or shear forces comprises passing the electrode-forming composition through rollers positioned near opposing surfaces of the electrode-forming composition (e.g., such that the electrode-forming composition passes through a space formed between at least two oppositely positioned rollers that roll in opposite directions). A schematic illustration of this exemplary configuration (500) is shown by FIG. 5. As shown in FIG. 5, electrode-forming composition 502 comprising binder particles 504, conductive additive 506, electroactive material 508, and template component 510 is positioned between oppositely-positioned rollers 512 and 514, which are configured to roll / move in opposite directions (e.g., roller 512 rolls counter-clockwise, while roller 514 rolls clockwise). More than one set of oppositely-positioned rollers can be used, as shown in FIG. 5.

[0092] Continuing with reference to FIG. 5, by passing the electrode-forming composition through the rollers, compressive and / or shear forces can be created and applied to the components of the electrode-forming composition, which can facilitate forming electrode film 516 comprising a fibrillated binder component 518, which is formed from the initial binder particles 504 included in the composition prior to rolling. Thickness of the resulting electrode film can be controlled by changing the gap between the oppositely-positioned rollers.

[0093] FIG. 6 provides a comparative illustration showing certain differences between a conventional slurry coating process (top scheme showing the process from slurry 600 to closed pore network material 608) and a method according to the present disclosure (bottom scheme showing the process from electrode-forming composition 610 to electrode film 622). In the conventional process, slurry 600 comprising electroactive material 602 and solvent 604 is dried to remove the solvent, providing dried composition 606, which is then calendered to provide closed pore material 608. In contrast, a method of the present disclosure utilizes electrode-forming composition 610, which comprises template component 612, binder particles 614, and electroactive material 616. The electrode-forming composition is first exposed to compressive and / or shear forces to provide electrode film precursor 616, comprising large pores 618 and fibrillated binder 620. Upon removing template component 612, electrode film 622 is formed, which comprises a vascular hierarchical pore network.

[0094] Similar compressive and / or shear force effects can be provided using other apparatuses, such as by pressing the electrode-forming composition between oppositely-positioned plates (e.g.,plates of a hydraulic press), while simultaneously pushing or pulling the electrode-forming composition from between the plates. Such an exemplary set-up is illustrated schematically in FIG. 7, which shows the conversion of electrode-forming composition 700 (which comprises electroactive material 704, binder particles 706, and template component 708) to electrode film 702 (comprising electroactive material 704 and fibrillated binder 710) using two oppositely- positioned plates (712 and 714) that can be pressed together so as to apply a compressive force against the electrode-forming material, while simultaneously pulling (or extruding / pushing) the electrode-forming material through the plates in an orthogonal direction to the force being applied by the plates. In some aspects of the disclosure, one of the plates could be replaced with a roller, which, in conjunction with one plate, could be used to apply the compressive and / or shear forces.

[0095] In some aspects, the method can comprise controlling the rate at which the electrodeforming composition is passed through the apparatus used to provide the compressive and / or shear forces. For example, in some aspects, the rate at which the electrode-forming composition is passed through a roller apparatus can be controlled so as to ensure that a sufficient amount of force is provided over the surface area of the electrode-forming composition such that the binder component can become fibrillated. In some aspects, the rate at which the electrode-forming composition is passed through the apparatus used in the method (e.g., a roller apparatus, a press, or the like) can be 1 mm s1to 500 mm s1, with particular aspects using 8 mm s1. In some aspects, spacing between any rollers and / or plates used to apply the compressive and / or shear forces may be nominally set by using a mode of compliant biasing (e.g., spring biasing) and multiple passes through the rollers and / or plates can be used to set thickness of the resulting layer of the electrode film precursor.

[0096] The method further comprises removing the template component from the electrode film precursor formed from the electrode-forming composition. In some aspects, removing the template component can comprise exposing the electrode film precursor to a drying step wherein the template component is removed. In some aspects, drying can comprise heating the electrode film precursor at a temperature sufficient to evaporate the template component after the compressive and / or shear forces have been applied. In some such aspects, the temperature at which the electrode film precursor is treated can range from greater than ambient temperature to 200 °C, such as 30 °C to 100 °C, or 30 °C to 60 °C. In some other aspects, drying can comprise exposing the electrode-forming composition to an external pressure (e.g., a vacuum) so as to remove the template component. Such a drying step can be employed when, for example, the template component is a liquid or gel. In yet additional aspects, a combination of drying and external pressure can be used to dry the electrode film precursor.

[0097] In some other aspects, removing the template component can comprise exposing the electrode film precursor to a solution in which the template component is soluble. Such a removal step can be employed when, for example, the template component is a gel or a solid. In some such aspects, the template component can be a solid, such as an inorganic salt, and it can be exposed to an aqueous solution to thereby dissolve the solid in the solution. In other aspects, the template component may be a gel material that can be exposed to an aqueous or organic solution to thereby dissolve the gel. In such aspects, the solution and dissolved solid or gel can be removed by any suitable means, such as drying or otherwise physically removing the liquid (e.g., blotting).

[0098] In yet some other aspects, removing the template component can comprise exposing the electrode film precursor to a temperature sufficient to thermally degrade the template component. In some such aspects, the template component may be a polymer or other material that can be thermally degraded to by-products that are easily removed from the electrode, such as by dissolution and / or drying (using heat or vacuum pressure). In some aspects, thermal treatment used to remove the template component can be performed at a temperature that will thermally decompose the template component without deleteriously affecting other components of the electrode film precursor, such as the electroactive material, binder, any other components. As an example, thermal degradation of a template component can be carried out in a sulfur-containing electrode film precursor at temperatures below the melting point of sulfur (e.g., at temperatures below 155 °C, such as below 150 °C, or below 140 °C).

[0099] An exemplary method for making a sulfur-containing electrode is described for illustrative purposes. In such a method, a mixture comprising a sulfur-containing component (e.g., provided as a sulfur-carbon composite comprising a carbon component, such as Ketjen Black, which could be native Ketjen Black, calcined Ketjen Black, or a mixture thereof) and a conductive carbon additive is combined with a mixture comprising a binder (e.g., PTFE) and a template component (e.g., 2-propanol) to form an electrode-forming composition in the form of a viscous paste. The electrode-forming mixture is then passed through an apparatus capable of applying compressive and / or shear forces on the electrode-forming composition, such as a roller apparatus. The electrode-forming composition is passed through the apparatus at a rate of 8 mm s1to provide a layer of the electrode-forming composition. This process can be repeated any number of times until a desired thickness is obtained. The resulting layer of electrode-forming composition is then exposed to conditions suitable to remove the template component from the mixture, such as by heating the layer of the electrode-forming composition at a temperature suitable to evaporate the 2-propanol (e.g., 60 °C) while under vacuum. After removing the template component, the resulting electrode film is combined with a substrate (e.g., an aluminum foil) to provide an electrode comprising a single layer of the electrode film (e.g., a layer formed on one surface of thesubstrate, such as for use in a coin cell) or a dual layer of the electrode film (e.g., layers formed on opposing surfaces of the substrate, such as for use in a pouch cell).V. Overview of Several Aspects

[0100] Aspect 1. An electrode-forming composition, comprising: an electroactive material; a template component; and a binder component; wherein the electrode-forming composition has (i) a solids content above at least 60 wt% with respect to the total weight of the electrode-forming composition, and / or (ii) a viscosity greater than 10 Pa s at a shear rate of 1 s’1.

[0101] Aspect 2. The electrode-forming composition according to Aspect 1 , the electroactive material comprises a sulfur-containing material, a lithium-containing material, a sodium-containing material, a potassium-containing material, a zinc-containing material, a magnesium-containing material, a calcium-containing material, an aluminum-containing material, a phosphorus-containing material, a transition metal oxide, or a mixture thereof.

[0102] Aspect 3. The electrode-forming composition according Aspect 1 or 2, wherein the electroactive material comprises a sulfur-carbon composite and the binder component comprises a polymer material selected from a fluorinated polymer, a polyacrylate, a polyimide, a polyvinyl alcohol, a polyvinyl chloride, an ethylene oxide, a polyvinylpyrrolidone, a polyurethane, a polyethylene, a polypropylene, a styrene-butadiene rubber, an epoxy resin, a nylon, and mixtures thereof.

[0103] Aspect 4. The electrode-forming composition according Aspect 3, wherein the sulfurcarbon composite comprises a sulfur content ranging from 10 wt% to 90 wt% of the total weight of the sulfur-carbon composite.

[0104] Aspect 5. The electrode-forming composition according any one or all of Aspects 1 -4, wherein the template component is a liquid, a solid, or a gel.

[0105] Aspect 6. The electrode-forming composition according any one or all of Aspects 1 -5, wherein the template component comprises an inorganic material, an organic polymer material, or an alcohol.

[0106] Aspect 7. The electrode-forming composition according any one or all of Aspects 1 -6, wherein the template component comprise an alcohol selected from methanol, 2-propanol, ethanol, butanol, pentanol, or combinations thereof.

[0107] Aspect 8. The electrode-forming composition according any one or all of Aspects 1 -7, wherein the electroactive material comprises a sulfur-carbon composite; the binder comprises afluorinated binder, a polyethylene, or a polypropylene; and the template component comprises 2- propanol.

[0108] Aspect 9. The electrode-forming composition according any one or all of Aspects 1 -8, further comprising a conductive additive.

[0109] Aspect 10. An electrode film, comprising: a binder; an electroactive material; and a pore network formed within the electrode film comprising interconnected pores, wherein the pore network is located throughout the volume of the electrode film and wherein more than 60% of a pore space of the pore network is interconnected.

[0110] Aspect 11. The electrode film according Aspect 10, wherein the electrode film exhibits a measured impedance-based tortuosity ( ) value of less than 2.5.

[0111] Aspect 12. The electrode film according Aspect 10 and / or Aspect 11 , wherein the electrode film exhibits an areal capacity greater than 3 mAh cm2.

[0112] Aspect 13. The electrode film according to any one or all of Aspects 10-12, wherein the electrode film exhibits an average porosity value of less than 70% and the electroactive material is present in an amount of at least 70 wt%.

[0113] Aspect 14. The electrode film according to any one or all of Aspects 10-13, wherein the binder is fibrillated.

[0114] Aspect 15. A method for forming an electrode film, comprising: exposing an electrodeforming composition according to any or all of Aspects 1-10 to compressive and / or shear forces to provide an electrode film precursor; and removing the template component from the electrode film precursor to provide the electrode film.

[0115] Aspect 16. The method according to Aspect 15, wherein the compressive and / or shear forces are provided by (i) passing the electrode-forming composition through rollers or (ii) pressing the electrode-forming composition while simultaneously extruding or pulling the electrode-forming composition.

[0116] Aspect 17. The method according to Aspect 16, wherein passing the electrode-forming composition through rollers comprises passing the electrode-forming composition through two rollers, wherein (i) the rollers are positioned opposite one another and separated by a preselected distance such that the electrode-forming composition passes between them, and (ii) the rollers are rotated in opposite directions.

[0117] Aspect 18. The method according to any or all of Aspects 15-17, wherein the template component is removed by drying the electrode film precursor or exposing the electrode film precursor to a solution in which the template component is soluble.

[0118] Aspect 19. The method according to Aspect 18, wherein drying comprises: (i) heating the electrode film at a temperature ranging from greater than ambient temperature to a temperature of 200 °C; (ii) exposing the electrode film precursor to an external pressure; or (iii) both (i) and (ii).

[0119] Aspect 20. The method according to any or all of Aspects 15-19, wherein the method further comprises preparing the electrode-forming composition by combining the electroactive material, the binder, and the template component.VI. Examples

[0120] Preparation of S / C composite - All the chemicals were used as received. For the preparation of SDS, besides KB (EC-600JD, AkzoNobel), pore volume-expanded KB (EKB) was also used as sulfur (denoted as “S” hereinafter) host materials to increase the sulfur content in the S / C materials. EKB was prepared by calcining KB under CO2 gas in a tube furnace at 980 °C for 3 hours. For the preparation of CCS, integrated KB (IKB) was prepared and used as the sulfur host materials. In brief, KB and citric acid (Sigma-Aldrich) were first mixed in water at a weight ratio of 1 :1 and stirred at 60 °C for 2 hours. Then ethylene glycol (Sigma-Aldrich) was added to the mixture at a ratio of ethylene glycol / citric acid = 2:1 mol / mol and stirred at 130 °C for 6 hours. The mixture was dried overnight and calcined in a tube furnace at 800 °C for 10 h at an argon atmosphere. The IKB obtained was ground and sieved using a 100-mesh screen.

[0121] To prepare the S / C composite, sulfur powder (Alfa Aesar) was loaded into the pores of the carbon host materials (KB, EKB, or IKB) using a melt-impregnation process at 155 °C for 12 hours, resulting in xS / C composites, where x represents the sulfur content in the S / C composite. The obtained xS / C composites were 80S / KB, 87S / EKB, 90S / EKB, and 80S / IKB, with a basic particle size of 30-50 nm.

[0122] Preparation of the sulfur electrode - SDS electrode was prepared by a rolling method under shear force at room temperature. The electroactive material (80S / KB, 87S / EKB, or 90S / EKB) and the conductive carbon additive Super P (MTI Corporation) were thoroughly mixed using a mortar-pestle. The PTFE suspension (60 wt%, Sigma-Aldrich) served as the binder and 2- propanol (Sigma-Aldrich) as the template component and these were added at different weight ratios to form a uniform paste under continuous stirring. The electrode compositions are listed in Table 1 where y in SDSy represents the sulfur content in the whole electrode. The paste was sent through the roller and calendered to an electrode film at a loading rate 8 mm s1. The electrode film was rolled up and sent through the roller again at a reduced gap. Sulfur loading wascontrolled by film area. Electrode film solid content was increased by repeated rolling. By adjusting the roller gap and rolling repeatedly, free-standing SDS electrode films with different sulfur loadings and solid contents were obtained. The electrode film was dried at 60 °C under vacuum for 12 hours to remove the template component. The electrode film was single-sided (for coin cell) and double-sided (for pouch cell) attached on the carbon-coated aluminum (Al) foil (Guangzhou Nano New Material Technology Co., Ltd) prior to use by a mild calendering. The SDS electrode film had a sulfur loading of 4-7 mg cm2, average electrode porosity of 62-14% (density of 0.8-1 .8 g cm3). Without further annotation, SDS70, a sulfur loading of 4.5 mg cm2, a thickness of 58 pm, and an average electrode porosity of 47% (density 1.1 mg cm2) were used as the SDS platform electrode.

[0123] For comparison, the CCS electrode was prepared by the conventional slurry coating method and post-drying calendering. 80S / IKB, Super P, and CMC (Sigma-Aldrich) as binder were mixed with water as a solvent to form a uniform slurry. Then the slurry was coated on a carbon- coated Al foil. The sulfur electrode was dried at 60 °C under vacuum conditions for 12 hours. The obtained PCS electrode has a sulfur loading of 4.5 mg cm2, a thickness of 128 pm, and an average pristine porosity of 76% (density of 0.5 g cm3). It was pressed to the same average porosity of SDS electrode (47%) to obtain CCS electrode by dry calendering prior to use.

[0124] The sulfur electrode density was calculated by pcnthorfe= - —mcathoie- =^cathode ^cathode- -where pcathOde is the sulfur cathode density in g cm3, mcathodeis thecathode mass in g, Acath odeis the cathode area in cm2, lcathode is the cathode thickness in cm. The sulfur loading, Ls, is defined as the mass of sulfur per unit area of the electrode in mg cm2, while <DSis the sulfur content in the whole electrode as a dimensionless fraction (e.g. 0.7 for 70% sulfur content). The sulfur electrode porosity was estimated by ^cathode = 1 -Pcathode 33wherePo the cathode porosity, p0is the sulfur cathode density at 0% porosity. The equationwas used wh e rePiisthe true density of S, carbon, and binder Ps Pcarbon Pbinderis 2.07 g cm3. pcarbon is 2.2 g cm3. pfoinrferis 2.2 g cm3. co, is the mass fraction of S, carbon, and binder in the whole electrode. The estimated p0is 2.1 g cm3.Table 1. Sulfur electrode compositionS electrode S / C Weight ratio of S content Electrode Average type composite S / C composite: (wt%) density (g ElectrodeSuper P: binder cm3) porosity (%)SDS70b80S / KBa88:7:5 70 1 .1 (coin cell), 47,1.8 and 0.8 14 and 62(pouch cell)Table 1. Sulfur electrode compositionS electrode S / C Weight ratio of S content Electrode Average type composite S / C composite: (wt%) density (g ElectrodeSuper P: binder cm3) porosity (%)SDS74 80S / KB 93:6:1 74 1.1 47SDS81 87S / EKB 93:6:1 81 1.1 47SDS83 90S / EKB 93:6:1 83 1.1 47PCS 80S / IKB 88:7:5 70 0.5 76CCS 80S / IKB 88:7:5 70 1.1 47Notes: (a) xS / C composites, where x represents the sulfur content in the S / C composite, expressed as a numerical value before the “%” (e.g. x=80 for 80 wt% sulfur in S / C); and (b) SDSy, where y represents the sulfur content in the whole electrode, also expressed as the numerical value before the

[0125] The sulfur electrode host was prepared through heat treatment of the sulfur electrode at 110 °C under vacuum for 48 hours to eliminate the elemental S. To confirm the removal of elemental S, the electrode mass was compared before and after heat treatment.

[0126] Assembly of coin cell - The 2032-type (MTI Corp.) coin cell was assembled in a glovebox filled with argon with both the oxygen and moisture levels below 1 ppm. 250 pm Li chips (Xiamen Tmax Battery Equipments Ltd.) were used as the anode with Celgard 2400 with a thickness of 20 pm as the separator. The diameter of the sulfur cathode and Li anode were 12.7 mm and 16 mm, respectively. The electrolyte referred to herein as the “CVE” was prepared by dissolving 1 M LiTFSI (Solvionic) in DOL (Gotion) and DME (Gotion) (1 :1 , v / v) mixture with 0.3 M LiNOs (Sigma Aldrich) as additive. The electrolyte referred to herein as “LHCE” was prepared by dissolving 7 M LiTFSI in DOL and DME (1 :1 , v / v) mixture and adding TTFE (SynQuest Labs, Inc.) as diluent at 2:1 , v / v. In this context, “M” denotes the salt molar to solvent volume ratio. The E / S ratio means the ratio of electrolyte volume (mL) to the sulfur mass (g) in the cell assembly. The electrolyte volume used for sulfur cathode | sulfur cathode symmetric coin cells, sulfur electrode host | sulfur electrode host symmetric coin cells was 100 pL. The cells were rested 24 hours before test to ensure the complete wetting of electrolyte.

[0127] Assembly of the pouch cell - A double-sided SDS electrode was punched into rectangular pieces (54 mm x 36 mm) for pouch cell use. Double-sided 50 pm Li on an 8 pm Cu foil (China Energy Lithium Co., Ltd.) was punched into rectangular pieces (55.5 mm x 37.5 mm) as the Li anode of pouch cell. Celgard 2400 was used as the separator. A double-sided sulfur cathode, separator, and double-sided Li anode were alternatively stacked together with two pieces of single-sided sulfur cathode as the outermost layer. The pouch cells with a cell capacity of 0.7 Ah and 2.1 Ah were assembled in a dry room (0.1 RH%, 19 °C) of the Advanced Battery Facility Laboratory at PNNL. The electrolyte injection and pouch cell sealing were carried out in the Ar- filled glovebox.

[0128] The parameters of 0.7 Ah and 2.1 Ah Li-S pouch cells are listed in Table 2.

[0129] Cell-level Evwas calculated by Equation (1 ).where Eoutis the output energy of pouch cell, Aanodeis the area of Li anode, lcellis the measured cell thickness. Full cell included all the cell components, the sulfur cathode, Li anode, electrolyte, current collectors, separator, and packaging. Dry cell included all the cell components except the electrolyte.

[0130] Electrochemical test - The electrochemical performance of the coin cells was tested galvanostatically using a LANHE battery tester CT2001 A at 30 °C. Similarly, the electrochemical performance of the pouch cells was tested using a LANHE battery tester (CT2001 B) at 25 °C. For the Li-S pouch cell with CVE, testing was conducted at a current density of 0.1 mA cm2(0.02 C). The Li-S pouch cell with LHCE electrolyte was tested at a current density of 0.14 mA cm2(0.03 C) for cycles 1-7, 0.28 mA cm2(0.06 C) for cycles 8-31 , and 0.42 mA cm2(0.1 C) for cycles 32-100. Prior to pouch cell testing, the cell was sandwiched between two foam pads and fixed between twopolyether ether ketone plates using four sets of screws / springs, applying an initial pressure of 20 psi. For Li— S batteries with CVE, testing was conducted within a voltage range of 1 .8-2.8 V, while Li-S batteries with LHCE electrolyte were tested in a voltage range of 1 .2-3.0 V. EIS tests of sulfur cathode | sulfur cathode symmetric cells were measured and fitted by an EC-Lab Bio-logic workstation, over a frequency range of 1 MHz-0.1 Hz with an amplitude voltage of 5 mV. The semicircle in the EIS spectra was assigned to the contact impedance, while the high frequency impedance (Rh) and low frequency impedance (F? / ) were fitted using the equivalent circuit shown in FIG. 8, where C is the constant phase element. The ionic resistance (F?,on) was estimated by R= Ri ~ Rh. Impedance-based tortuosity was estimated by— where A is the cross- sectional area, K is the electrolyte ionic conductivity, a is the electrode porosity, and dis the electrode distance including twice the electrode thickness plus the separator thickness. CVs for sulfur electrode host | sulfur electrode host symmetric cells were conducted using a Bio-Logic electrochemical workstation over the voltage range of 0-1 .0 V, with varying scan rates from 1 to 50 mV s1. The sulfur utilization rate mentioned in this paper denotes the specific discharge capacity calculated based on the sulfur weight, excluding the carbon content.

[0131] Characterization - Samples transferred to characterization instruments were sealed in airproof containers filled with Ar to avoid air contamination. XRD measurements were performed using a Rigaku Miniflex II diffractometer with Cu Ka radiation (A = 1.541 A) at a scanning speed of 2°min~1(20). The electrode sample morphology analysis was performed by means of serial- sectioning-tomography using a Thermo Scientific™ Helios(tm) 5 Hydra UX Dual Beam. The microscope used a Xe+plasma ion-source focused ion beam to sputter material to section a piece of material. An accelerating voltage of 30 keV and an ion beam of 15 nA were used for the sectioning. The resulting “cut-face” was then imaged in cross section using a high-resolution SEM at nanometer scale creating an image (slice) representing a specific volume defined by area of the SEM image and the thickness of the section. An accelerating voltage of 1 keV and a 25 pA aperture was used for the SEM image. 600 SEM images were collected and converted from a 2D- image stack to a 3D reconstructed volume of 65 pm x 43 pm x 30 pm with a 21 .2 nm x 21 .2 nm x 50 nm voxel size. Each image was taken after removal of a 50 nm section. The 3D-visualization, image analysis, and the fluid flow simulation were performed with Thermo Scientific™ Avizo(tm) Software. The viscosity of the electrolytes as a function of temperature was measured using an Anton Paar rheometer (MCR-101 ; Ashland, VA, USA). Measuring system DG26.7 SS coupled with a C-PTD200 cell was used. A Peltier system built in the rheometer was employed for temperature control. A performance check was conducted to the rheometer and measuring system using a certified viscosity standard S60 (Cannon Instrument Co., State College, PA, USA) before the sample measurements to ensure measurement quality. The viscosity of the standard was measured at temperatures of 20, 25, 40 and 50±0.1 °C. The measured values werecompared to the real viscosity values of the standard at these temperatures to evaluate the performance of the system. A temperature ramp was applied to the electrolyte samples during measurements. The temperature was set at 0 °C to start the measurements. Once a measurement was started, temperature was increased linearly over time from 0 °C to 60 °C in a duration of 45 minutes while the viscosity was measured and recorded with the values logged in every 30 seconds. A constant shear rate of 50 1 / s was used for all measurements. After each sample measurement, the DG26.7 measuring system was dissembled for cleaning and drying before used for a new sample. A nitrogen flow through the measuring system was established to minimize the sample exposure to air.

[0132] Image segmentation, structural quantification, and flow simulation on the sulfur electrode - The segmentation process used image processing tools in the Avizo software. The data were first smoothed using a Non-Local Means filter to remove noise. Then an automatic split of phases was applied using kMeans algorithm with a module called Intensity Auto Classification. This process was followed by applying a Watershed Transform tool to segment the phases using precise boundaries. The volume fraction was calculated by counting the voxel numbers of each segmented phase and dividing them by the total number of the voxels in the volume. The connectivity was defined as the ratio between the connected pore volume and total porosity. Size distribution was calculated by the pore space separation in Avizo using a high-level combination of Watershed Transform, distance transform, and numerical reconstruction. Pore space was split into morphological structures in 3D in order to get the best separation.

[0133] Evestimation of sulfur cathode and dry pouch cell - The 2 Ah Li-S pouch Evestimation was performed by Equation (2),

[0134] where CcMis the cell capacity, Vcellis the cell voltage of 2.1 V, ltis the thickness of the cell components including sulfur cathode, Li anode, carbon coated Al foil as cathode current collector, Cu foil as anode current collector, separator, and cell packaging, N is the layer number. Electrolyte was not taken into account. The cell parameters are listed in Table 3.

[0135] For estimation of 0.6 Ah, 1 .0 Ah, 1 .5 Ah, 2.5 Ah, and 3 Ah pouch cells, the layer number were 3, 5, 8, 13, and 16, respectively.

[0136] The S-cathode Evestimation was performed by Equation (3),where Carealis the areal capacity of sulfur cathode, Cspis the sulfur specific capacity. The results are summarized in Table 4.

[0137] Eg calculation of 0.7 Ah and 2.1 Ah Li-S pouch cell

[0138] The full-cell gravimetric energy density (Eg) of the pouch cells including all the cell components were calculated using the following Equation (4):

[0139] is the mass of the cell components. The full-cell Eg of 0.7 Ah and 2.1 Ah Li-S pouch cells were 221 Wh kg1and 204 Wh kg1, respectively.Example 1

[0140] In this example, the electrochemical performance of sulfur electrodes with varying porosities was evaluating using the CVE. This evaluation was conducted under flooded electrolyte conditions, with an electrolyte volume / sulfur (E / S) ratio of 10 mL g1. An electrode made according to the method of the present disclosure (comprising a sulfur-carbon composite as the electroactive material, a PTFE binder, and a conductive carbon additive) was evaluated (referred to herein as the “shear-force densified sulfur” or “SDS” electrode) and compared with an electrode made according to a conventional slurry coating technique using carboxymethyl cellulose (CMC) as a binder and an integrated KB / S (IKB / S) material. After drying, the coated electrode had an average porosity of 76% and is referred to herein as the “pristine coated S” (or “PCS”) electrode. The PCS electrode was subsequently calendered to match the average porosity of the SDS electrode (which had an average porosity of 47%). This calendered version of the electrode is referred to herein as the “calendered coated S” (or “CCS”) electrode. All sulfur-containing electrodes used in this example had a mass loading >4 mg cm2.

[0141] The high-porosity PCS electrode (average porosity of 76%) exhibited a commendable specific capacity of 955 mAh g“1, characterized by two distinct plateaus at 2.3 V and 2.1 V (FIGS.9 and 10), attributed to its good electrolyte wetting capability due to high porosity. However, a reduction in electrode porosity (e.g., by calendering the PCS electrode to provide the CCS electrode) led to a decline in electrochemical performance. In particular, the CCS electrode, with an average porosity of 47%, displayed a lower specific capacity of 804 mAh g-1and a large overpotential of 0.4 V indicating adverse effects of dry calendering on electrode structure, resulting in reduced average porosity and increased polarization. In contrast, the SDS electrode according to aspects of the present disclosure demonstrated a markedly higher specific capacity of 1165 mAh g-1and a minimal overpotential of 0.2 V (FIG. 11 ), indicating a superior electrode structure compared to the CCS electrode. To enhance cell cycle life, the PCS, CCS, and SDS electrodes were evaluated in a localized highly concentrated electrolyte (LHCE) comprising 7 M LiTFSI / (DOL+DME), with 2,2,2-trifluoroethyl 1 ,1 ,2,2-tetrafluoroethyl ether (TTFE) as diluent at a 2:1v / v ratio. With LHCE, the PCS exhibited a low specific capacity of 494 mAh g“1, despite its high porosity, possibly attributed to the increased electrolyte viscosity (FIGS. 12A and 12B). The CCS with calendering further reduced the specific capacity to 292 mAh g-1, accompanied by exaggerated overpotential (FIG. 13). Conversely, the SDS electrode demonstrated a significantly improved specific capacity of 1276 mAh g-1and minimized overpotential (FIG. 14).Example 2

[0142] In this example, the structures of high-density CCS and SDS electrodes were examined using SEM, plasma focused ion beam (PFIB)-SEM, and electrochemical methods. Although boththe electrodes share similar active material (S / KB), their particle size differs: the CCS electrode uses larger secondary particles (10-40 pm, FIG. 15), whereas the SDS electrode employs nanosized material directly (FIG. 4A). SEM images reveals that both electrodes exhibit similar morphologies, with flat surfaces (FIGS. 16A and 16B) and compact cross sections (FIGS. 16C and 16D). However, their internal pore connectivity and distribution, as revealed by PFIB-SEM, show different features. In the CCS electrode, pore distribution is highly uneven, with small pores (<5 pm) and large pores (5-20 pm) (FIG. 17) concentrated on one side, leaving the other side devoid of large pores (FIG. 18A, see dashed box). The 3D reconstruction showed that interconnected pore space is only 59.7%, severely limiting electrolyte transport. Fluid flow simulations confirm that electrolyte diffusion pathways are restricted with limited streamlines observed in the unconnected regions (FIG. 18C). In contrast, the SDS electrode exhibits a more uniform distribution of both small and large pores, forming a highly connected vascular porous network. Approximately 79.9% of the pore space is interconnected (FIG. 18B), facilitating electrolyte flow through the structures (FIG. 18D). This well-connected pore network facilitates efficient electrolyte diffusion, particularly using viscous electrolytes like LHCE.

[0143] To elucidate the impact of electrode structure on electrolyte wetting, electrochemical impedance spectroscopy (EIS) was performed in S-electrode | S-electrode symmetric cells. FIG. 19 provides a schematic illustration of the S-electrode | S-electrode symmetric cell (1900), which comprises two separated layers of electroactive material 1902 and conductive additive 1904 in electrolyte 1906. Separation of the layers is achieved using separator 1908. In the CVE, the CCS electrodes exhibited three times higher impedance than the SDS electrodes (FIG. 20A), indicating poor wetting of the CCS electrodes. In the LHCE, the higher viscosity increased impedance for both electrodes, but the CCS electrode impedance was 16 times higher than the SDS electrode (FIG. 20B). This result highlights the challenges of electrolyte transport in the closed-pore CCS structure and further confirms that the vascular pore network of the electrode film can improve wetting, particularly with viscous electrolytes.

[0144] The impedance-based tortuosity (r,) of the electrodes was also evaluated using the transmission-line model by Landesfeind et al., with results summarized in FIGS. 20C and 20D. As described herein, the transmission-line model involves estimating impedance-based tortuosity byTi=R10”Ak£where A is the cross-sectional area, K is the electrolyte ionic conductivity, E is the electrode porosity, and d is the electrode distance including twice the electrode thickness plus the separator thickness. The semicircle in the EIS spectra was assigned to the contact impedance, while the high frequency impedance (F? / >) and low frequency impedance ( / =? / ) were fitted using the equivalent circuit shown in FIG. 8, where C is the constant phase element. The ionic resistance (F?,On) was estimated by ^2- = Ri - Rh.

[0145] For the CCS electrode, T, increased significantly from 2.6 in CVE to 24.9 in the LHCE, reflecting severe resistance to electrolyte transport. In contrast, the SDS electrode maintained low and consistent r values of 1 .6 to 1 .7, demonstrating superior permeability. Since both electrodes shared the same electroactive materials, these differences are believed to be attributable to variations in active surface area. Cyclic voltammetry (CV) was performed on S-electrode-host | S- electrode-host symmetric cells after removing sulfur by vacuum sublimation to measure the specific capacitance (FIG. 21 ). With reference to FIG. 21 , the electrode-host | S-electrode-host symmetric cell 2100 comprises conductive additive 2102, electrolyte 2104, and separator 2106. In the LHCE, the CCS-electrode-host exhibited low response current even at 50 mV s1(FIG. 22A) whereas the SDS-electrode-host showed much higher currents (>1 .5 mA, FIG. 22B). The SDS electrode host's specific capacitance was three times that of the CCS electrode (FIG. 22C), confirming a larger active surface area. Both PFIB-SEM and electrochemical analysis indicate that the SDS electrode has a superior electrolyte accessibility compared to the CCS electrode.Example 3

[0146] As discussed herein, the formation of the vascular pore structure in the SDS electrode film facilitates improvements in electrode performance. Without being limited to a single theory, it currently is believed that the vascular pore structure is attributed to, at least in part, the notably high solid content of the disclosed electrode-forming compositions and the presence of the template component. In the case of the SDS electrode described in examples disclosed herein, densification of the electrode-forming composition occurs in the presence of the template component, which is then removed to provide the electrode film. The application of compressive and / or shear forces used in the method for making the electrode film leads to the fibrillation of PTFE particles into elongated fibers (FIG. 23), establishing connections among the electrode particles. Simultaneously, the template component acts as a tortuosity control agent during electrode densification, promoting the formation of hierarchical and interconnected pores upon solvent removal. The hierarchical architecture of the SDS electrode film, characterized by large global channels and locally connected small pores, generates interconnected flow paths within the electrode, which facilitate rapid and thorough permeation of electrolyte. The interconnected large pores functions as major vessels, swiftly transporting electrolyte to subregions, while the connected small pores act as capillaries, uniformly distributing electrolyte to individual particles. In the absence of small pores or if small pores are isolated from the large channels / pores (such as in the CCS electrode described in examples herein), local regions distant from the large channels may be bypassed during electrolyte permeation, hindering their participation in reactions. And, the lack of large channels in the CCS electrode could result in very low permeability at the global scale, impeding electrolyte distribution and causing reaction heterogeneity. Therefore, the unique architecture of the electrode film according to the present disclosure plays a role in facilitatingelectrolyte permeation and ensuring reaction homogeneity, leading to enhanced electrode performance.Example 4

[0147] In this example, effects of electrode structure on sulfur utilization and cycle stability were evaluated. The results of this example illustrate that the interconnected and hierarchical vascular pore network exhibited by the electrode according to the present disclosure enhances sulfur utilization and cycle stability in highly dense electrodes.

[0148] Under flooded electrolyte conditions (E / S ratio of 10 mL g-1 ), the SDS electrode exhibits a stable cycling performance, achieving a specific discharge capacity of 693 mAh g-1 after 100 cycles in the LHCE electrolyte (FIG. 24), comparable to its performance in the CVE (709 mAh g-1 after 100 cycles, FIG. 25). In contrast, the CCS electrode shows much lower capacities in both the LHCE (57 mAh g-1 after 100 cycles) and the CVE (332 mAh g-1 after 100 cycles). This performance degradation of the CCS electrode is attributed to the structure damage from dry calendering, which compromises pore connectivity and blocks electrolyte wetting. The issue is exacerbated in the high-viscosity LHCE electrolyte, further reducing the CCS electrode’s capacity. Under lean electrolyte conditions (E / S 4 mL g-1 ), the advantages of the LHCE electrolyte becomes more pronounced. The SDS electrode delivered a high reversible specific capacity of 1311 mAh g 1 and cycles stably for 100 cycles without cell failure (FIG. 26A), whereas performance in the CVE was only exhibited for 32 cycles (FIG. 26B). The CCS electrode performs poorly in both electrolytes under these harsher conditions (see FIGS. 26A and 26B).Example 5

[0149] In this example, sulfur loading and sulfur content in electrodes was evaluated. To enhance cell energy density, both sulfur loading and sulfur content were further increased in the SDS electrode of the examples described herein. Even at a high sulfur loading of 7.1 mg cm2, the SDS electrode exhibits a remarkable areal capacity of 9.6 mAh cm2in the initial cycle (FIG. 27A) and maintains a capacity of 4.6 mAh cm2after 60 cycles at E / S 4 mL g1(FIG. 27B). Moreover, increasing the sulfur content in the electrode by augmenting the sulfur content in the S / C composite used for the electroactive material and reducing the binder content in the electrode was demonstrated. As shown in Table 1 herein, when the binder content was reduced to 1% while maintaining 80% sulfur content in the S / C composite, the sulfur content in the electrode increased from 70% to 74%, and electrode cohesiveness was maintained by modifying the rolling process used to make the electrode. To further increase the sulfur content in the S / C composite, while maintaining the electrochemical performance, the distribution of sulfur within the carbon host was modified to enhance electron transport and electrolyte wetting. The activated EKB, with a porevolume of 10.5 cm3g1(twice that of pristine KB, 4.8-5.1 cm3g1), theoretically allows for 87% of sulfur infiltration into the carbon host. For the S / EKB-SDS electrode, the sulfur content in the electrode reached 81%. As such, the high-sulfur-content electrodes according to the present disclosure demonstrate both high sulfur utilization rate and stable cycling in LHCE as can be seen in the “SDS70,” “SDS74,” “SDS81 ” and “SDS83” plots shown in FIGS. 27C and 27D.Example 6

[0150] To validate the practical viability of the SDS electrode according to examples herein, prototype Li-S pouch cells were fabricated using certain electrode and electrolyte examples described herein (see Table 2). The average electrode porosity was reduced to as low as 14%, resulting in an electrode density of 1.8 g cm3. Using the CVE at E / S 4 mL g1, the assembled 0.7 Ah Li-S pouch cell demonstrated an impressive Evof 668 Wh L1(FIGS. 28A and 28B). After the injection of the electrolyte, the practical cell energy density Evreduces to 417 Wh L1. This cell cycled for 25 cycles before decay occurred due to depletion of the CVE. To extend the cycle life, a 2.1 Ah Li-S pouch cell was assembled using an LHCE electrolyte (FIG. 29), with the average electrode porosity adjusted to 62% to accommodate the challenge of electrolyte wetting in large size and multilayer pouch cells. This pouch cell delivered a high specific capacity of 1304 mAh g1(FIG. 30), achieving measured Evvalues of 571 Wh L1based on dry cell volume and 423 Wh L1if including the electrolyte volume. Remarkably, this pouch cell exhibited over 100 cycles without early failure or short-circuiting. The pouch-cell-level Evachieved with SDS electrodes ranks among the highest reported values for Li-S pouch cells, demonstrating the potential of the SDS electrode for high energy density Li-S batteries. To compare with other high-sulfur-loading cathodes, the electrode-level Evwas calculated using reported areal capacity and cathode thickness values (FIG. 31 and Table 4). In comparison to the 200-1400 Wh L1at the electrode level reported in the various comparative examples from Table 4, the SDS electrode offers a significantly higher Evof 2460 Wh L1. Without being limited to a single theory, it currently is believed that this is attributed to, at least in part, the high sulfur content and electrode density of the SDS electrodes. The projected cell-level Evas a function of electrode Evat different cell capacities was also evaluated. The projection suggests that if the electrode-level Evis below 560 Wh L1, which is typical in reported studies, it would be hard to achieve a cell-level Ev> 350 Wh L1, even with a cell capacity as high as 3 Ah. The demonstrated high cell-level E^ and long cycling life of the SDS electrode under practical conditions indicate that the SDS electrode and its processing method represent a viable pathway for the development of realistic Li-S pouch cells.

[0151] In view of the many possible embodiments to which the principles of the present disclosure may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the disclosure and should not be taken as limiting the scope of the presentdisclosure. Rather, the scope is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.

Claims

We claim:

1. An electrode-forming composition, comprising: an electroactive material; a template component; and a binder component; wherein the electrode-forming composition has (i) a solids content above at least 60 wt% with respect to the total weight of the electrode-forming composition, and / or (ii) a viscosity greater than 10 Pa s at a shear rate of 1 s '.

2. The electrode-forming composition of claim 1 , wherein the electroactive material comprises a sulfur-containing material, a lithium-containing material, a sodium-containing material, a potassium-containing material, a zinc-containing material, a magnesium-containing material, a calcium-containing material, an aluminum-containing material, a phosphorus-containing material, a transition metal oxide, or a mixture thereof.

3. The electrode-forming composition of claim 1 , wherein the electroactive material comprises a sulfur-carbon composite and the binder component comprises a polymer material selected from a fluorinated polymer, a polyacrylate, a polyimide, a polyvinyl alcohol, a polyvinyl chloride, an ethylene oxide, a polyvinylpyrrolidone, a polyurethane, a polyethylene, a polypropylene, a styrene-butadiene rubber, an epoxy resin, a nylon, and mixtures thereof.

4. The electrode-forming composition of claim 3, wherein the sulfur-carbon composite comprises a sulfur content ranging from 10 wt% to 90 wt% of the total weight of the sulfur-carbon composite.

5. The electrode-forming composition of claim 1 , wherein the template component is a liquid, a solid, or a gel.

6. The electrode-forming composition of claim 1 , wherein the template component comprises an inorganic material, an organic polymer material, or an alcohol.

7. The electrode-forming composition of claim 1 , wherein the template component comprise an alcohol selected from methanol, 2-propanol, ethanol, butanol, pentanol, or combinations thereof.

8. The electrode-forming composition of claim 1 , wherein the electroactive material comprises a sulfur-carbon composite; the binder comprises a fluorinated binder, a polyethylene, or a polypropylene; and the template component comprises 2-propanol.

9. The electrode-forming composition of claim 1 , further comprising a conductive additive.

10. An electrode film, comprising: a binder; an electroactive material; and a pore network formed within the electrode film comprising interconnected pores, wherein the pore network is located throughout the volume of the electrode film and wherein more than 60% of a pore space of the pore network is interconnected.11 . The electrode film of claim 10, wherein the electrode film exhibits a measured impedance-based tortuosity (r,) value of less than 2.5.

12. The electrode film of claim 10, wherein the electrode film exhibits an areal capacity greater than 3 mAh cm2.

13. The electrode film of claim 10, wherein the electrode film exhibits an average porosity value of less than 50% and the electroactive material is present in an amount of at least 70 wt%.

14. The electrode film of claim 10, wherein the binder is fibrillated.

15. A method for forming an electrode film, comprising: exposing an electrode-forming composition according to any one of claims 1 -9 to compressive and / or shear forces to provide an electrode film precursor; and removing the template component from the electrode film precursor to provide the electrode film.

16. The method of claim 15, wherein the compressive and / or shear forces are provided by (i) passing the electrode-forming composition through rollers or (ii) pressing the electrodeforming composition while simultaneously extruding or pulling the electrode-forming composition.

17. The method of claim 16, wherein passing the electrode-forming composition through rollers comprises passing the electrode-forming composition through two rollers, wherein(i) the rollers are positioned opposite one another and separated by a preselected distance such that the electrode-forming composition passes between them, and (ii) the rollers are rotated in opposite directions.

18. The method of claim 15, wherein the template component is removed by drying the electrode film precursor or exposing the electrode film precursor to a solution in which the template component is soluble.

19. The method of claim 18, wherein drying comprises:(i) heating the electrode film at a temperature ranging from greater than ambient temperature to a temperature of 200 °C;(ii) exposing the electrode film precursor to an external pressure; or(iii) both (i) and (ii).

20. The method of claim 15, wherein the method further comprises preparing the electrode-forming composition by combining the electroactive material, the binder, and the template component.

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