Cathode material for lithium- or sodium-sulfur battery

Abstract

A porous composite cathode active material for lithium- of sodium-sulfur batteries is provided. The porous composite cathode active material includes an interconnected framework of metal sulfide particles in a conductive binder. The porous composite cathode active material contains between 50 and 75 mass % of an electroactive chalcogen conversion cathode material and between 10 and 35 mass % metal sulfide(s). Methods of making the material can include forming a slurry and drying under controlled conditions.

Description

Attorney Docket No.: CONA-OOOl-WO (1340.0010)CATHODE MATERIAL FOR LITHIUM- OR SODIUM-SULFUR BATTERYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is related to, claims priority to, and incorporates herein by reference for all purposes U.S. Provisional Patent Application No. 63 / 667,448, filed July 3, 2024.BACKGROUND

[0002] For reasons including material scarcity, alternatives to conventional lithium ion batteries are required. One possible alternative is lithium-sulfur or sodium-sulfur batteries. While lithium-sulfur batteries are a promising technology, the field remains nascent and the likelihood of future progress is unclear. The use of sulfur in lithium-ion secondary battery cathodes has been under development for some time but has yet to achieve wide commercial adoption. The situation with sodium-sulfur batteries is even less advanced, as the possibility of replacing lithium with sodium is itself just starting to become technically feasible.

[0003] At the time of writing, conventional lithium ion cathode materials include one or more expensive or rare components, such as cobalt or nickel. Cobalt is an expensive and toxic material whose availability is highly concentrated in developing countries, where environmental protections are typically weaker. Nickel also has long term supply concerns. A need exists for cathode materials that do not require one or more of the expensive or rare components that are currently required in a lithium ion cathode material.

[0004] Lithium-sulfur batteries are one emerging alternative to conventional lithium ion batteries. While they have some anticipated advantages relative to their conventional counterparts (e.g., more abundant and lower cost source materials; theoretically expected higher energy density; etc.), "there are some essential problems that must be solved for practical use. Specifically, Sg and U2S have low ion / electron conductivities, resulting in poor discharge rate characteristics. In addition, the large volume expansion (~80%) of lithium conversion makes it difficult to maintain the conduction path in the electrode. The most serious problem is that the intermediate product, lithium polysulfide ( LizSx, 4 < x < 8), dissolves in a general organic electrolyte solution, reducing the charge / discharge efficiency and cycling characteristics." Nakamura et al., "Future potential for lithium-sulfur batteries", J. Power Sources, Vol. 558, 2023, 232566 at p. 4, paragraph abridging left and right columns, which is incorporated herein by reference in its entirety for all purposes. "The practical implementation of lithium-sulfur (Li-S) batteries is greatly hampered by the low sulfur utilization and limited battery lifespan stemming from the complexity of the sulfur conversionAttorney Docket No.: CONA-OOOl-WO (1340.0010) reactions." Jiao et al., "Molecular engineering of sulfur-providing materials for optimized sulfur conversion in Li-S chemistry", EcoMat, 2022; 4(6):el2262 at Abstract, which is incorporated herein by reference for all purposes. "Despite their favorable features, the commercialization of Li-S batteries is still plagued by some fundamental challenges involving the insulating nature of elemental sulfur and lithium sulfides (e.g., U2S2 and U2S), large volume expansion (up to 80%) of sulfur during cycling, dissolution of lithium polysulfides (LiPSs) in electrolyte, and lithium dendrite formation at the anode side." Jiao at p. 2, left column, second paragraph (internal citations omitted). "The emerging challenge of LiPS saturation and premature precipitation requires new insights regarding the fundamental understanding and effective regulation strategies...." Zhao et al. "A perspective toward practice lithium-sulfur batteries", ACS Cent. Sci. 2020, 6, 1095-1104 at paragraph abridging pp. 1098-9, which is incorporated herein in its entirety by reference.

[0005] In most existing approaches to a lithium sulfur battery, carbon is used as a "host" material for active components of batteries, due to its ability to adopt high surface area conformations while maintaining conductivity. It was generally believed that high surface area was important for this host material. It was also generally believed that low dimensionality was important for this host material. For these reasons, materials like graphene, carbon nanotubes, and other advanced materials are the principal candidates for next-generation sulfur host materials. These materials have disadvantages, including high cost.

[0006] The end goal with most battery technologies is achieving certain performance benchmarks under certain operating conditions. Performance against individual benchmarks can be "gamed" to some degree by utilizing laboratory conditions that do not realistically reflect practical operating conditions. Under these unrealistic laboratory conditions, some of these benchmarks have been approached and even achieved under manipulated conditions. One approach to producing improved laboratory performance involves use of a low sulfur content in the cathode. Another approach to improving laboratory performance involves use of a high electrolyte ratio (E / S). In one particular case, low sulfur content and a high electrolyte ratio were used in U.S. Patent No. 11,417,884, which is incorporated herein in its entirety by reference for all purposes. While these results showed a significant improvement relative to the state of the art, they were not achieved under realistic (e.g. commercially relevant) operating conditions. A need exists for cathode materials capable of achieving relevant performance benchmarks under real world operating conditions.

[0007] One particularly relevant battery environment is the automotive battery, which requires high power. While high power may have been previously achieved under laboratory conditions, a needAttorney Docket No.: CONA-OOOl-WO (1340.0010) exists for a functioning high power alternative to lithium ion batteries that are capable of functioning in the real world. While limited sulfu r-lithium batteries are commercially available, their performance quality is extremely low. In general, the best-reported cells provide 1400 mAh at 2.1 V nominal, which generates a cell that is approximately 3 Wh, as compared to existing Li-ion batteries of the same form factor that are capable of achieving >10 Wh. In addition, cycle life is generally lower with sulfur-lithium batteries.

[0008] Most battery processing technologies utilize harsh chemicals, such as N-methyl-2- pyrrolidone (NMP) or the like. Researchers have observed that "...the toxicity of NMP has come under increasing environmental scrutiny by regulatory bodies in various countries. The United States Environmental Protection Agency labeled NMP as a developmental toxicant. In Europe, due to its classification as a reproductive toxin, NMP is regarded as a substance of very high concern. In 2018, NMP was added to the Registration, Evaluation and Authorization of Chemicals (REACH) list, restricting its consumer application usage to <0.3%." Sliz et al., "Suitable cathode NMP replacement for efficient sustainable printed Li-Ion batteries," ACS Appl. Energy Mater. 2022, 5, 4047-4058 at paragraph abridging left and right columns of p. 4048, which is incorporated herein in its entirety by reference. It would be advantageous to be able to eliminate the use of such harsh chemicals when making lithium-sulfur batteries.

[0009] A need exists for an improved cathode material for a lithium-sulfur battery, which overcomes one or more of the aforementioned shortcomings.SUMMARY

[0010] The present disclosure provides, among other things, cathode compositions and batteries that include the same.

[0011] In particular, the inventors have discovered that sulfur batteries constructed from cathodes containing a mixture of elemental sulfur, metal chalcogenides (such as titanium disulfide) and carbon at particular mass fractions can provide unexpectedly improved performance. The inventors have discovered that battery performance is sensitive to small compositional changes in the mass ratios of these three components and have identified particular ranges of compositional makeup that provide unexpectedly improved battery performance (see Figs. 4-7). Among the unexpected features of the compositions described herein is the discovery that high performance, high energy density cathodes can be constructed using compositions in which there is a relatively low carbon content relative to sulfur. As noted above, carbon is typically regarded as a host material requiredAttorney Docket No.: CONA-OOOl-WO (1340.0010) for conversion of cathodic sulfur and for this reason prior art cathode compositions have favored relatively high mass fractions of carbon vs. sulfur and / or carbon compositions with low- dimensionality or high porosity.

[0012] Surprisingly, the compositional ranges described herein allow construction of cathodes that can simultaneously deliver high performance across several important battery metrics necessary to address the needs of commercial applications such as batteries for E-powered transportation. For example, Figures 4-7 show how modeled energy density (Wh / kg) and discharge pulse efficiency at various states of charge, vary over a compositional range of mass fractions of carbon, sulfur and titanium disulfide in the cathode. The shaded range in these diagrams demonstrates a previously un-recognized compositional space in which these performance characteristics can be co-optimized to provide cathodes capable of high performance in lithium sulfur batteries. In some instances, batteries containing cathodes conforming to these design principles have also been demonstrated to be operable at surprisingly low electrolyte ratios and / or to have the ability to achieve higher cycle life than similar batteries constructed with cathodes having compositions falling outside of this range.

[0013] In an aspect, the present disclosure provides a porous composite cathode active material. The porous composite cathode active material includes an interconnected framework of metal sulfide particles in a conductive binder. The porous composite cathode active material contains between 50 and 75 mass % of an electroactive chalcogen conversion cathode material and between 10 and 35 mass % metal sulfide(s).

[0014] In another aspect, the present disclosure provides a method of making a cathode active material. The method includes: a) forming a slurry into a film optionally in contact with a current collector, the slurry including insoluble metal sulfide particles, an electroactive chalcogen conversion cathode material, and a solution containing soluble conductive binder precursors; b) drying the film under controlled conditions to produce a cathode active material comprising a porous composite cathode active material comprising an interconnected framework. The electroactive chalcogen conversion cathode material is present in the porous composite cathode active material in an amount between 50 and 75 mass %. The interconnected framework comprises the metal sulfide particles and the conductive binder.

[0015] Any two or more of the features described in this specification, including in this summary section, may be combined to form implementations of the disclosure, whether or not specifically expressly described as a separate combination in this specification.Attorney Docket No.: CONA-OOOl-WO (1340.0010)BRIEF DESCRIPTION OF THE DRAWING

[0016] The present teachings described herein will be more fully understood from the following description of various illustrative embodiments, when read together with the accompanying drawings. It should be understood that the drawings described below are for illustration purposes only and are not intended to limit the scope of the present teachings in any way. The foregoing and other objects, aspects, features, and advantages of the disclosure will become more apparent and may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which:

[0017] FIG. 1 illustrates a cross section of an electrochemical cell 800 in accordance with exemplary embodiments of the disclosure.

[0018] FIG. 2 illustrates an example of a battery according to various embodiments described herein.

[0019] FIG. 3 includes plots of the pulse average efficiency, pulse end of plateau efficiency, and pulse end of discharge efficiency versus proportional chalcogen content, as described in Example la, in accordance with aspects of the present disclosure.

[0020] FIG. 4 is a ternary plot of energy density against composition for the three main ingredients of the cathode active material, as described in Example la, in accordance with aspects of the present disclosure.

[0021] FIG. 5 is a ternary plot of pulse average efficiency against composition for the three main ingredients of the cathode active material, as described in Example la, in accordance with aspects of the present disclosure.

[0022] FIG. 6 is a ternary plot of pulse end of first plateau efficiency against composition for the three main ingredients of the cathode active material, as described in Example la, in accordance with aspects of the present disclosure.

[0023] FIG. 7 is a ternary plot of pulse end of discharge efficiency against composition for the three main ingredients of the cathode active material, as described in Example la, in accordance with aspects of the present disclosure.

[0024] FIG. 8 is a plot of capacity versus cycle number for a variety of test cells, as described in Example lb, in accordance with aspects of the present disclosure.

[0025] FIG. 9 is a plot showing capacity versus cycle number for sodium sulfur battery described in Example lc, in accordance with aspects of the present disclosure.Attorney Docket No.: CONA-OOOl-WO (1340.0010)DEFINITIONS

[0026] About / Approximately: The term "about" or "approxi ately", when used herein in reference to a value, refers to a value that is similar, in context, to the referenced value. In general, those skilled in the art, familiar with the context, will appreciate the relevant degree of variance encompassed by "about" or "approximately" in that context. For example, in some embodiments, e.g., as set forth herein, the term "about" can encompass a range of values that within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or within a fraction of a percent, of the referred value.

[0027] Carbon: As used herein in connection with cathode materials, refers to elemental carbon or materials that are substantially composed of elemental carbon, examples include graphite, carbon black, graphene, carbon nanotubes and derivatives of such materials (e.g. oxidized, nitrogen-doped, or carboxylated graphene derivatives). Carbon-containing organic molecules such as hydrocarbons, polymers, solvents and the like are not encompassed by this term unless otherwise indicated.Similarly, in the context of terms such as "Carbon Free" and "Non-Carbon Materials" it is these elemental forms of carbon that are to be understood to be excluded.

[0028] Electroactive Material: As used herein, the term "electroactive material" refers to a composition of matter with one or more components capable of changing its oxidation state in a charge-transfer step of an electrochemical reaction.

[0029] Electrolyte to chalcogenide: As used herein, an "electrolyte to chalcogenide" ratio refers to a weight ratio of the electrolyte components of the battery to the elemental chalcogen components of the battery.

[0030] Electrolyte to selenium: As used herein, an "electrolyte to selenide" ratio refers to a weight ratio of the electrolyte components of the battery to the elemental selenium components of the battery.

[0031] Electrolyte to sulfur: As used herein, an "electrolyte to sulfide" ratio refers to a weight ratio of the electrolyte components of the battery to the elemental sulfur components of the battery.

[0032] Electrolyte to tellurium: As used herein, an "electrolyte to telluride" ratio refers to a weight ratio of the electrolyte components of the battery to the elemental tellurium components of the battery.

[0033] Intercalation Material: As used herein, the term "intercalation material" refers to a substance into which another substance or species (e.g. ion, metal ion) is reversibly inserted orAttorney Docket No.: CONA-OOOl-WO (1340.0010) included in vacancies, interstitial sites, voids, or between layers of the intercalation material, or some combination thereof.

[0034] Lithium alloy: As used herein, the term lithium alloy refers to substances formed by combinations of lithium and other metals or semimetal elements: non-limiting examples include lithium silicon compounds, and alloys of lithium with metals such as sodium, cesium, indium, aluminum, zinc and silver.

[0035] Metal chalcogenide: As used herein, a "metal chalcogenide" refers to a metal sulfides, selenides, and tellurides. Unless specifically stated otherwise, lithium sulfide and sodium sulfide (e.g. such as is formed during the discharge of a lithium sulfur or sodium sulfur battery) is not intended to be captured by the term metal chalcogenide and discussions of for example the mass fractions of metal chalcogenides in a composition are understood not to include lithium or sodium sulfides.

[0036] Mixed metal chalcogenide thereof: As used herein, a "mixed metal chalcogenide thereof" refers to a metal chalcogenide that includes at least two different metals from separate metal chalcogenides to which the phrase references. For example, a mixed metal chalcogenide of TiS? and M0S2 can be TiMoS2. This definition is applicable to sulfides, selenides, and tellurides.

[0037] Nanoparticle, Nanostructure, Nanomaterial: As used herein, these terms may be used interchangeably to denote a particle of nanoscale dimensions or a material having nanoscale structures. The nanoparticles can have essentially any shape or configuration, such as a tube, a wire, a laminate, sheets, lattices, a box, a core and shell, or combinations thereof.

[0038] Operable: As used herein, a battery or battery component is "operable" when a test cell is capable of operation at a minimum threshold of operability.

[0039] Pulse Average Efficiency: As used herein, a "pulse average efficiency" refers to an arithmetic mean of the pulse efficiency across the entire state of charge, where the pulse efficiency is the ratio of the voltage during a 1000 mA / gS pulse to the voltage immediately preceding / fol lowing the pulse during a 100 mA / gS discharge. For the specific experiments conducted herein, pulses were 5 seconds at 1000 mA / gS every 30 minutes during a 100 mA / gS discharge. For compositions including Se, the values described herein consider the mass of Se as mass of S for the purposes of computing the pulse average efficiency.

[0040] Pulse End of Discharge Efficiency: As used herein, a "pulse end of discharge efficiency" refers to an average pulse efficiency of a 1000 mA / gS discharge pulse in the portion of the dischargeAttorney Docket No.: CONA-OOOl-WO (1340.0010) cycle where the discharge specific capacity is greater than 600 mAh / gS and the fraction discharge is greater than 75%.

[0041] Pulse End of Plateau Efficiency. As used herein, a "pulse end of plateau efficiency" refers to a pulse efficiency value of the first pulse immediately following the discharge specific capacity exceeding 300 mAh / gS and the fraction discharge is greater than 25% during a 1000 mA / gS pulse.

[0042] Substantially: As used herein, the term "substantially" refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0043] Elements of different implementations described herein may be combined to form other implementations not specifically set forth above. Certain elements may be left out of the devices described herein without adversely affecting their operation. Various separate elements may be combined into one or more individual elements to perform the functions described herein.

[0044] It is contemplated that articles, devices, compositions, systems, methods, and processes of the claimed invention encompass variations and adaptations developed using information from the embodiments described herein. Adaptation and / or modification of the articles, devices, compositions, systems, methods, and processes described herein may be performed, as contemplated by this description.

[0045] Throughout the description, where articles, devices, compositions, and systems are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are articles, devices, compositions, and systems of the present invention that consist essentially of, or consist of, the recited components, and that there are processes and methods according to the present invention that consist essentially of, or consist of, the recited processing steps.

[0046] It should be understood that the order of steps or order for performing certain action is immaterial so long as the invention remains operable. Moreover, two or more steps or actions may be conducted simultaneously.

[0047] The mention herein of any publication is not an admission that the publication serves as prior art with respect to any of the claims presented herein. The Background section is presented for purposes of clarity and is not meant as a description of prior art with respect to any claim.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0048] Headers are provided for the convenience of the reader - the presence and / or placement of a header is not intended to limit the scope of the subject matter described herein.

[0049] Presented herein is a porous composite cathode active material. The porous composite cathode active material includes an interconnected framework of metal sulfide particles in a conductive binder. The porous composite cathode active material contains between 50 and 75 mass % of an electroactive chalcogen conversion cathode material and between 10 and 35 mass % metal sulfide(s).

[0050] Referring to Figs. 4-7, relevant performance characteristics are plotted on ternary plots against the relative concentration of components of the cathode active material. The inventors unexpectedly discovered one or more regions on the plot corresponding to a compositional space where performance is significantly improved over the state-of-the-art and represents a significant advance toward achieving a commercially viable lithium-sulfur battery.

[0051] Without wishing to be bound by any particular theory, the porosity of the cathode active material and / or the porous structure of the cathode active material is believed to be highly relevant to the improved performance capability. In some cases, the porous composite material has an as- deposited porosity of between 60% and 78%. In some cases, the porous composite material has an as-deposited porosity of between 65% and 75%. The porosity can be measured by Hg porosimetry or He pycnometry, as understood by an analytical chemist having ordinary skill in the art.

[0052] The cathode active material is operable at an elemental chalcogen loading of 3 mg / cm2or greater. This is an important technical capability, because it is expected that most commercially valuable uses will require at least this level of elemental chalcogen loading.

[0053] The cathode active material is operable at an electrolyte to chalcogen ratio of 6 or lower. This is an important technical capability, because it is expected that most commercially valuable uses will require at least this electrolyte to chalcogen ratio.

[0054] The electroactive chalcogen conversion cathode material can be introduced in a variety of forms, so long as the electroactive chalcogen conversion cathode material can be electrochemically converted to support battery operation. In some cases, the electroactive chalcogen conversion cathode material is present or introduced as Ss. In some cases, the electroactive chalcogen conversion cathode material is present or introduced as Se$2.

[0055] In some cases, a material may be introduced that is partly an electroactive sulfur conversion cathode material and / or partly an electroactive selenium conversion cathode material. In these instances, a skilled artisan will recognize that an elemental analysis can divide the mass of theAttorney Docket No.: CONA-OOOl-WO (1340.0010) material into respective components, such that a given percentage of mass can be attributed to the electroactive sulfur conversion cathode material and / or the electroactive selenium conversion cathode material. To use SeSz as an example, the formula represents a stoichiometric relationship of 2 parts S to 1 part Se. Based on the atomic masses of sulfur (32.065 g / mol) and selenium (78.96 g / mol), a given mass unit of SeS2 will be considered to be (78.96 / 143.09) of a mass unit of electroactive selenium conversion cathode material and (64.13 / 143.09) of a mass unit of electroactive sulfur conversion cathode material.

[0056] The cathode active material can include the electroactive chalcogen conversion cathode material in a weight ratio (w / w) of at least 50%, at least 55%, at least 60%, at least 65%, or at least 70%. The cathode active material can include the electroactive chalcogen conversion cathode material in a weight ratio (w / w) of at most 75%, at most 72%, at most 70%, at most 68%, at most 65%, at most 60%, or at most 55%.

[0057] The cathode active material can include the metal sulfide(s) in a weight ratio (w / w) of at least 10%, at least 15%, at least 20%, at least 25%, or at least 30%. The cathode active material can include the metal sulfide(s) in a weight ratio (w / w) of at most 35%, at most 30%, or at most 25%, at most 20%, or at most 15%.

[0058] The cathode active material can also include a conductive binder. The conductive binder can be either: i) a conductive matrix; or ii) a non-conductive matrix having conductive particles distributed throughout. The cathode active material can include the conductive binder in a weight ratio (w / w) or between 5% and 25%. In some cases, the cathode active material includes the conductive binder in a weight ratio (w / w) or at least 5%, at least 10%, or at least 15%. In some cases, the cathode active material includes the conductive binder in a weight ratio (w / w) of at most 25%, at most 20%, or at most 15%.

[0059] In some cases, the conductive binder includes the conductive particles distributed in the non-conductive matrix. In these cases, the cathode active material layer can include the conductive particles in a weight ratio (w / w) of between 2% and 22% and the non-conductive matrix in a weight ratio (w / w) of between 3% and 23%. In some cases, the cathode active material includes the conductive particles in a weight ratio (w / w) of at least 2%, at least 5%, at least 7%, at least 10%, or at least 15%. In some cases, the cathode active material includes the conductive particles in a weight ratio (w / w) of at most 22%, at most 20%, at most 17%, at most 15%, or at most 10%. In some cases, the cathode active material includes the non-conductive matrix in a weight ratio (w / w) of at least 3%, at least 5%, at least 8%, at least 10%, or at least 15%. In some cases, the cathodeAttorney Docket No.: CONA-OOOl-WO (1340.0010) active material includes the non-conductive matrix in a weight ratio (w / w) of at most 23%, at most 20%, at most 18%, at most 15%, or at most 10%.

[0060] The conductive particles can be carbon black, among other conductive particles. The non- conductive matrix can be a polymeric binder. The polymeric binder can be selected from the group consisting of a poly (aery I ic acid), poly(vinylidene fluoride) (PVDF), a cellulose derivative (e.g., carboxymethyl cellulose), and combinations thereof. In some cases, the polymeric binder is a salt of poly(acry I ic acid), such as sodium poly(acrylic acid).

[0061] In certain embodiments, an electrically conductive material is selected from the group consisting of conductive carbon powders, such as carbon black, Super P*, C-NERGY™ Super C65, Ensaco’ black, Ketjenblack*, acetylene black, synthetic graphite such as Timrex* SFG-6, Timrex* SFG- 15, Timrex* SFG-44, Timrex* KS-6, Timrex* KS-15, Timrex* KS-44, natural flake graphite, carbon nanotubes, fullerenes, hard carbon, mesocarbon microbeads, and the like. In certain embodiments, a conductive material comprises one or more conductive polymers. For example, in certain embodiments, a conductive polymer is selected from the group consisting of polyaniline, polythiophene, polyacetylene, polypyrrole, and the like. In some embodiments, a conductive polymer is a cationic polymer. In some embodiments, a cationic polymer is a quaternary ammonium polymer. In certain embodiments, a cationic polymer is selected from the group consisting of a polydiallyldimethylammonium salt, a poly[(3-chloro-2- hydroxypropyl)methacryloxyethyldimethyl-ammonium salt, a polyfbutyl acrylatemethacryloxyethyltrimethylammonium) salt, poly(l-methyl-4-vinylpyridinium) salt, a poly(l-methyl- 2-vinylpyridinium) salt, and a poly(methyacryloxyethyltriethylammonium) salt. In certain embodiments, a cationic polymer is selected from polydiallyldimethylammonium chloride (polyDADMAC), polybrene, epichlorohydrin-dimethylamine (epi-DMA), poly[(3-chloro-2- hydroxypropyl)methacryloxyethyldimethyl-ammonium chloride), poly(acrylamide- methacryloxyethyltrimethylammonium bromide), polyfbutyl acrylatemethacryloxyethyltrimethylammonium bromide), poly(l-methyl-4-vinylpyridinium bromide), poly(l-methyl-2-vinylpyridinium bromide), and poly(methyacryloxyethyltriethylammonium bromide). In certain embodiments, a conductive material comprises one or more metal oxides or chalcogenides (e.g. metal sulfides, selenides or tellurides). For example, in certain embodiments, a conductive material comprises one or more oxides, sulfides, selenides or tellurides of a first-row transition metal such as titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, or combinations thereof. For example, in certain embodiments, a conductive material comprises oneAttorney Docket No.: CONA-OOOl-WO (1340.0010) or more oxides, sulfides, selenides or tellurides of a second-row transition metal such as zirconium, indium, tin, antimony, or combinations thereof. In certain embodiments, a single metal oxide or chalcogenide is included. In other embodiments, a provided conductive material is composed of a mixture of two or more metal oxides or chalcogenides or comprises a mixed metal oxides or chalcogenides.

[0062] While one of the particular advantages of the present disclosure is replacing the carbon "host" that is conventionally deployed, and while this does unlock the possibility of a carbon-free or extremely-low-carbon embodiment, it should also be apparent that carbon can be deployed in a "non-host" capacity without deviating from the scope of the disclosure. In particular, it should be appreciated that the inventors have discovered a system that provides excellent performance, while using much less carbon than would typically be deployed in this context. Additionally, evidence is provided that lower cost carbon materials can be deployed within the aspects described herein, so many of the concerns of using higher-cost advanced materials such as graphene, carbon nanotubes or engineered forms of carbon black may be eliminated by appropriate material selection.

[0063] In certain embodiments, a binder is included in the provided cathode compositions. Binders are generally polymeric materials that help adhere individual particles composing a cathode mixture into a stable composite. Typical binders include polyvinylidene fluoride, polyvinylidene fluoride-co- hexafluoropropene) (PVDF / HFP), polytetrafluoroethylene (PTFE), Kynar Flex® 2801, Kynar® Powerflex LBG, Kynar® HSV 900, Teflon®, carboxymethylcellulose, styrene-butadiene rubber (SBR), polyethylene oxide, polypropylene oxide, polyethylene, polypropylene, polyacrylates, polyvinyl pyrrolidone, poly(methyl methacrylate), polyethyl acrylate, polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polycaprolactam, polyethylene terephthalate, polybutadiene, polyisoprene or polyacrylic acid, or derivatives, mixtures, or copolymers of any of these. In some embodiments, a binder is water soluble binder, such as sodium alginate or carboxymethyl cellulose. Generally, binders hold the active materials together and in contact with a current collector (e.g., aluminum foil or copper foil). In certain embodiments, a binder is selected from the group consisting of poly( vi ny I acetate), polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, alkylated polyethylene oxide, crosslinked polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), polyvinylidene fluoride, a copolymer of polyhexafluoropropylene and polyvinylidene fluoride, polyethyl acrylate, polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinyl pyridine, polystyrene, and derivatives, mixtures, and copolymers thereof.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0064] In certain embodiments, the cathode active material comprises an intercalation material capable of reversibly intercalating lithium ions in operation within a voltage range roughly corresponding to the voltage of sulfur-to-lithium-sulfide conversion (e.g., from about 1.8V to about 2.6V vs. Li / Li+, e.g., from about 2.0V to about 2.4V vs. Li / Li+). Intercalation is the process by which a mobile ion or molecule is reversibly incorporated into vacant sites in a crystal lattice of a host network. Intercalation processes are generally characterized by minimal volume change and mechanical strain during repeated insertion and extraction of ions during charge and discharge. An intercalation cathode material comprises a solid host network which can reversibly store guest ions that are inserted into and removed from the host network.

[0065] In certain embodiments, in addition to the above-referenced metal sulfide(s), the cathode active material can optionally comprise one or more other chalcogenides. In certain embodiments, a chalcogenide has at least one chalcogen anion (sulfur, selenium, or tellurium) and at least one electropositive element. In certain embodiments, the other chalcogenide may be sulfide-, selenide-, or telluride-based. In certain embodiments, the chalcogenide comprises a metal sulfide (for example a sulfide of a metal other than lithium or sodium). In certain embodiments, the one or more other chalcogenides comprises a transition metal sulfide. In certain embodiments, the one or more other chalcogenides comprises one or more of the following: TiS2, LiTiSz (LTS), VS2, M0S2, MogSs, and NbSes. In certain embodiments, the one or more other chalcogenides comprise a polyanion compound. In certain embodiments, the one or more other chalcogenides comprise a metal monochalcogenide having the formula MX where M is a transition metal and X is S, Se, or Te. In certain embodiments, the one or more other chalcogenides comprise at least one transition metal dichalcogenide (TMD) of the formula MX2, where M is a transition metal (e.g., Ti, V, Co, Ni, Zr, Nb, Mo, Tc, Rh, Pd, Hf, Ta, W, Re, Ir, or Pt) and where X is S, Se, or Te. In certain embodiments, the one or more other chalcogenides comprise a material with a layered crystal structure (e.g., LiTiSz). In certain embodiments, the cathode active material can optionally include certain transition metal oxides (e.g., LiCoOz, LiNiOz, LiMnCh, LiNio.33Mno.33Coo.33O2, LiNio.sCoo.15Alo.05O2, LizMnOs, LiMn2O4 or UCO2O4) as intercalating materials.

[0066] The interconnected framework of the cathode active material can also include metal selenide particles and / or metal telluride particles. The metal selenide particles are composed of a metal selenide. The metal selenide can be selected from the group consisting of TiS z, MoS z, MoeSes, VSe2, WSez, mixed metal selenides thereof, and mixtures thereof. The metal telluride particles are composed of a metal telluride. The metal telluride can be selected from the groupAttorney Docket No.: CONA-OOOl-WO (1340.0010) consisting of TiTe2, MoTe2, MogTeg, VTe2, WTe2, mixed metal tellurides thereof, and mixtures thereof. While the present disclosure includes significant disclosure surrounding aspects relating to compositions including metal sulfides, the disclosure expressly contemplates embodiments where the metal sulfides are partially or fully substituted for metal selenides, metal tellurides, or a mixture thereof.

[0067] The interconnected framework functions as a "host" material much in the same way that carbon-based host materials functioned in conventional lithium ion cathode active materials. This is highly surprising for a few reasons. First, the metal sulfides that are utilized (optionally with metal selenides and metal tellurides) are low surface area materials. When lithium sulfide precipitates during function, the surface area of metal sulfides may be more easily occluded. Second, the metal sulfides generally have a platelet-type morphology, which usually results in dense particle packing, thus lowering porosity. A skilled artisan would have the intuition that substituting the conventional carbon "host" for the disclosed interconnected framework would be unlikely to succeed for these reasons.

[0068] Carbon-based cathodes for lithium sulfur batteries are generally designed to maximize porosity and surface area, which is why graphene and low-dimensionality materials are often selected. Typical carbons used in sulfur cathodes are high surface area (e.g., Ketjen Black™ 600 with surface area of >1000 m2 / g or Black Pearls™ 2000 with surface area of approximately 1500 m2 / g), providing both high porosity and surface area to the film, facilitating sulfur conversion by entraining large quantities of electrolyte, providing high surface area for charge transfer and maintaining open porosity as lithium sulfide precipitates and consumes porosity due to increase volume relative to elemental sulfur.

[0069] In some cases, no more than 15 mass% of the interconnected framework is composed of nanoporous materials, including but not limited to, no more than 12 mass%, no more than 10 mass%, no more than 8 mass%, no more than 5 mass%, or no more than 1 mass%. In some cases, substantially 0% of the interconnected framework is composed of nanoporous materials.

[0070] The inventors unexpectedly discovered that this replacement of carbon as the "host" material provided good results, improving lithium sulfur batter performance relative to previous benchmarks. Compared with existing lithium sulfur batteries with the best-available cathode active material, the disclosed materials are capable of operating at lower E / S ratios than their carbon counterparts, which corresponds to higher energy capability. Cells with sulfur loadings in excess of 3 mg S / cm2and E / S ratios as low as 2 were operable, which represents a tremendous improvementAttorney Docket No.: CONA-OOOl-WO (1340.0010) relative to the state of the art (see, Chung et al. "Progress on the Critical Parameters for Lithium- Sulfur Batteries to be Practically Viable", Adv. Funct. Mater. 2018, 28, 1801188, which is incorporated herein in its entirety by reference for all purposes, and which shows that reasonable capacity is presently unachievable at low E / S). Moreover, again compared with existing batteries having the best-available cathode active material, the disclosed materials have improved power efficiency relative to the carbon counterparts. As outlined above, one tendency in the field is to "game" the numbers in a laboratory environment, which makes the results achieved herein even more impressive, as they are grounded in real world conditions. In many earlier experiments, rate capability may have been shown at low sulfur loadings and / or high electrolyte ratios, which are not translatable to the real world.

[0071] In some aspects, the cathode active material has an exceptionally low carbon content. For example, the cathode active material can have a total carbon content of 20% or lower. In some cases, the cathode active material has a total carbon content of 15% or lower. In some cases, the cathode active material has a total carbon content of 10% or lower. In some cases, the cathode active material has a total carbon content of 5% or lower. Prior to the discoveries disclosed herein, it was generally thought that lithium-sulfur batteries would require a highly conductive and high dimensionality carbon as a host material. The inventors surprisingly discovered that the disclosed host material produces a cathode active material having improved performance relative to its counterparts having significantly more carbon.

[0072] The composite material has a microstructure that is advantageous for battery function. Without wishing to be bound by any particular theory, it is believed that the present disclosure provides evidence of a microstructure that enhances surface area and maintains material continuity sufficient for the flow of electrons and lithium ions, while simultaneously possessing a physical openness to elemental sulfur being repeatedly stripped and deposited. Without wishing to be bound by any particular theory, it is believed that a new microstructure exhibits unexpectedly improved behavior in a high sulfur loading environment (>3mg S / cm2) that will be required should an automobile-suitable Li-S battery ever be fully realized. Reducing sulfur loading is the approach that has traditionally been taken to dealing with the problem of precipitation of LizS and to retain a high degree of original porosity with reduced blockages and maintain access to active surface area. The inventors unexpectedly discovered a microstructure that allows high sulfur loading that retains significant porosity and access to active surface area when LizS precipitates.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0073] The inventors also discovered other unexpected performance properties downstream of this discovery. As different formulations have been investigated, certain combinations provided the highest power efficiencies, but the trend for situations where lower efficiencies were observed was not immediately apparent. Without wishing to be bound by any particular theory, a skilled artisan considering a system having a high elemental chalcogen (e.g., sulfur) mass fraction, such as those disclosed herein, may have traditionally expected the power efficiency to correlate with the chalcogen mass percentage (as a ratio of inactive-to-chalcogen). At the high end (ratio of inactive- to-chalcogen), the skilled artisan may have expected reduced power efficiency, because there is less material in the cathode to support the chalcogen reaction, and on the low end (ratio of inactive-to- chalcogen), they may have expected a higher power efficiency because of the opposite principle. The inventors unexpectedly discovered that there were unexpected ranges of compositions having superior and inferior power efficiencies. For example, a high sulfur (low TiS2) mass fraction active material in accordance with the present disclosure had low efficiencies at a moderate percent state of charge (e.g., ~70% SoC), while a low sulfur (high TiSz) mass fraction resulted in lower pulse efficiency at a lower percent state of charge. Aside from the unexpected lack of observable trend in regions showing low efficiencies, as discussed in this paragraph, the inventors unexpectedly discovered that there were wide and high plateaus for various pulse efficiencies discussed herein, suggesting that the composition can be varied to a reasonable degree while maintaining similar performance. This compositional flexibility (e.g., if the mass fraction needs to be varied for some other reason, efficiency may be reasonably maintained, so this cathode active material is particularly ready for subsequent innovation and improvement), while maintaining exceptional efficiencies, would not have been expected to a skilled artisan prior to these observations.

[0074] In certain embodiments, the provided composite material comprises an interconnected network containing carbon, metal chalcogenide and elemental sulfur wherein each of these components are present within a specific range of mass fractions. In certain such embodiments, provided composites comprise between 50 and 75% sulfur (e.g. elemental sulfur), between 18 and 40% of a transition metal chalcogenide (e.g. titanium disulfide), and between 9 and 18.5% elemental carbon (e.g. conductive carbon). Such cathodes have been found to have advantageous properties relative to comparative cathodes with compositions falling outside of these compositional ranges.

[0075] In various aspects of the present disclosure, the cathode active material is described as a cathode active material layer. The concept of a layer is intended to be interpreted broadly here,Attorney Docket No.: CONA-OOOl-WO (1340.0010) though narrower understandings of the term are fully encompassed. In some cases, the cathode active material layer as described herein can have a thickness of between 50 pm and 500 pm. In some cases, the cathode active material layer can have a thickness of at least 50 pm, at least 100 pm, or at least 250 pm. In some cases, the cathode active material layer can have a thickness of at most 500 pm, at most 300 pm, or at most 200 pm.

[0076] The cathode active material is operable at a low ratio of electrolyte to sulfur. In some cases, the cathode active material is operable at a ratio of electrolyte to sulfur (in pL / mg) of 6 or lower, 5.5 or lower, 5 or lower, 4.8 or lower, 4.6 or lower, 4.5 or lower, 4.4 or lower, 4.2 or lower, 4 or lower, 3.9 or lower, 3.8 or lower, 3.7 or lower, 3.6 or lower, or 3.5 or lower.

[0077] The cathode active material is operable at a high loading of chalcogen. In some cases, the cathode active material layer is operable at an electroactive chalcogen conversion cathode active material loading of 3 mg / cm2or greater, 3.3 mg / cm2or greater, 3.5 mg / cm2or greater, 3.7 mg / cm2or greater, 4.0 mg / cm2or greater, 4.2 mg / cm2or greater, 4.5 mg / cm2or greater, 4.7 mg / cm2or greater, 4.9 mg / cm2or greater, or 5.0 mg / cm2or greater.

[0078] In some cases, a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse average efficiency of at least 50%.

[0079] The cathode active material disclosed herein has an impressive pulse average efficiency. Unexpectedly, the pulse average efficiency is maintained through a surprising amount of variation in the elemental chalcogen and metal sulfide content. In some cases, a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse average efficiency of at least 93%, at least 94%, or at least 95%.

[0080] The cathode active material disclosed herein has an impressive pulse end of first plateau efficiency. Unexpectedly, the pulse end of first plateau efficiency is maintained through a surprising amount of variation in the elemental chalcogen and metal sulfide content. In some cases, a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse end of first plateau efficiency of at least 90% or at least 92%.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0081] The cathode active material disclosed herein has one or more other measurable properties that may be advantageous to battery function. In some cases, upon operating an electrode including the cathode active material at a current rate of 1000 ma / gS for 5 seconds, energy is delivered with at least 50% efficiency relative to the energy delivered at 100 mA / gS for 5 seconds.

[0082] In some cases, the disclosed cathode active material has one or more properties (e.g., pulse average efficiency) that is improved compared to a comparison cathode active material. The comparison cathode active material is a modification of the disclosed cathode active material to: (i) increase the metal sulfide in the composite material to an amount by weight of the composite material of greater than 40% and reduce the electroactive chalcogen conversion cathode material in the composite material to compensate for the increased metal sulfide content; (ii) reduce the metal sulfide in the composite material to an amount by weight of the composite material of less than 20% and increase the electroactive chalcogen conversion cathode material in the composite material to compensate for the reduced metal sulfide content; (iii) increase the electroactive chalcogen conversion cathode material in the porous composite material to an amount by weight of greater than 70% and reduce the metal sulfide in the composite material to compensate for the increase electroactive chalcogen conversion cathode material content; and / or (iv) reduce the electroactive chalcogen conversion cathode material content in the porous composite material to an amount by weight of less than 50% and increase the metal sulfide in the composite material to compensate for the decreased electroactive chalcogen conversion cathode material content. The comparison cathode active material is otherwise identical to or identically prepared as the cathode active material. The comparison property (and the inventive property) are measured in a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg of elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, at an electrolyte to chalcogen ratio of 6 or lower. In some cases, the comparison pulse average efficiency is 5% lower than the pulse average efficiency on the basis of 100% efficiency. In other words, 90% is 5% lower than 95% on the basis of 100% efficiency. Because of the extremely high efficiencies achieved by the disclosed cathode active material (e.g., greater than 90%), small values can reflect a significant impact. For example, an efficiency of 90% that is lowered by 10% is an efficiency of 80%, which actually reflects a doubling of the inefficiency, and an efficiency of 90% that is lowered by 20% is an efficiency of 70%, which reflects a tripling of the inefficiency. Without wishing to be bound by any particular theory, a skilled artisan will recognize that the efficiency and inefficiency can be reflected in various mathematical ways without impactingAttorney Docket No.: CONA-OOOl-WO (1340.0010) the meaning. In certain cases, the comparison pulse average efficiency is at least 5% lower than the pulse average efficiency on the basis of 100% efficiency. In certain cases, the comparison pulse average efficiency is at least 10% lower than the pulse average efficiency on the basis of 100% efficiency. In certain cases, the comparison pulse average efficiency is at least 15% lower than the pulse average efficiency on the basis of 100% efficiency. In certain cases, the comparison pulse average efficiency is at least 20% lower than the pulse average efficiency on the basis of 100% efficiency.

[0083] The cathode active material disclosed herein is particularly effective in high power environments. A high power environment is typically defined as high energy achieved at higher discharge rates. High energy is typically achieved by a combination of a high chalcogen loading (mg / cm2), a high achieved capacity (mAh / gS), a low electrolyte-to-chalcogen ratio, and a high average voltage (low resistance / impedance).

[0084] This disclosure provides evidence of advances in sulfur battery technology, including elements that contribute to progress toward a lithium sulfur battery that is operable under demanding conditions like the automotive environment.

[0085] Unless otherwise specified, comparisons are made under the conditions disclosed herein, such as an E / S of 6 or lower and an elemental chalcogen loading of greater than 3 mg chalcogen per cm2.

[0086] In some embodiments, a lithium-sulfur battery of the present disclosure comprises a lithium anode, a cathode including the cathode active material disclosed herein, and an electrolyte permitting ion transport between anode and cathode. In certain embodiments, described herein, an anodic portion of a battery comprises an anode and a portion of electrolyte with which it is in contact. Similarly, in certain embodiments, described herein, a cathodic portion of a battery comprises a cathode and a portion of electrolyte with which it is in contact. In certain embodiments, a battery comprises a lithium ion-permeable separator, which defines a boundary between an anodic portion and a cathodic portion. In certain embodiments, a battery comprises a case, which encloses both anodic and cathodic portions. In certain embodiments, a battery case comprises an electrically conductive anodic-end cover in electrical communication with an anode, and an electrically conductive cathodic-end cover in electrical communication with a cathode to facilitate charging and discharging via an external circuit.CathodeAttorney Docket No.: CONA-OOOl-WO (1340.0010)

[0087] In certain embodiments, an electrochemical cell includes a cathode. A cathode generally includes a cathode active material as described herein. Certain compositions disclosed herein can be adhered to a current collector to form cathodes for electrochemical cells, such as batteries.

[0088] Compositions of the present disclosure have utility in manufacture of electrochemical devices. The compositions disclosed may be porous or non-porous. Cathodes can be carbon-free (including relatively carbon free, e.g., no greater than 5wt.% carbon, no greater than 4 wt.% carbon, no greater than 3 wt.% carbon, no greater than 2 wt.% carbon, no greater than 1 wt.% carbon, or no greater than 0.5 wt.% carbon, for example) or can include some carbon. Provided cathode compositions may comprise one or more additives such as electrically conductive particles, binders, and other functional additives typically found in battery cathode mixtures. For example, in certain embodiments, provided cathode compositions may comprise 3D structured graphene (e.g., as described in U.S. Patent No. 11,299,397, LytEn, Inc., the text of which is incorporated herein by reference in its entirety). In certain embodiments, provided compositions have satisfactory electrical conductivity to provide a cathode with a low resistance pathway for electrons to access such manufactured cathode. In various embodiments, other additives are included in the composition to alter or otherwise enhance a cathode produced according to the principles described herein. Other cathode components include, for example, a current collector, connecting tabs, and the like.

[0089] In some cases, the cathode composition does not contain carbon, or contains a low amount of carbon (e.g., no greater than 5.0 wt.%, no greater than 3.0 wt. %, no greater than 2.0 wt.%, no greater than 1.0 wt.%, no greater than 0.5 wt.%, or no greater than 0.1 wt.%).

[0090] In certain embodiments, a cathode further comprises a coating layer. For example, in certain embodiments, a coating layer comprises a polymer, an organic material, an inorganic material, or a mixture thereof that is not an integral part of the porous composite or the current collector. In certain such embodiments, a polymer is selected from the group consisting of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, poly(vinyl acetate), poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate), poly(methyl methacrylate-co-ethyl acrylate), polyacrylonitrile, polyvinyl chloride-co-vinyl acetate, polyvinyl alcohol, poly(l-vinylpyrrolidone-co- vinyl acetate), cellulose acetate, polyvinyl pyrrolidone, polyacrylate, polymethacrylate, polyolefin, polyurethane, polyvinyl ether, acrylonitrile-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene styrene, a sulfonated styrene / ethylene-butylene / styrene triblock copolymer, polyethylene oxide, and derivatives, mixtures, and copolymers thereof. In some embodiments, a coating layer comprises a cationic polymer. In some embodiments, a coating layer comprises aAttorney Docket No.: CONA-OOOl-WO (1340.0010) quaternary ammonium polymer. In some embodiments, a coating layer comprises a cationic polymer as described above. In certain such embodiments, an inorganic material comprises, for example, colloidal silica, amorphous silica, surface-treated silica, colloidal alumina, amorphous alumina, tin oxide, titanium oxide, titanium sulfide (TiS?), vanadium oxide, zirconium oxide (ZrCh), iron oxide, iron sulfide (FeS), iron titanate (FeTiOs), barium titanate (BaTiCh), and combinations thereof. In certain embodiments, an organic material comprises conductive carbon.

[0091] Suitable materials for use in cathode mixtures are disclosed in Cathode Materials for Lithium Sulfur Batteries: Design, Synthesis, and Electrochemical Performance, Lianfeng, et al., Interchopen.com, Published June 1st 2016, and The strategies of advanced cathode composites for lithium-sulfur batteries, Zhou et al., SCIENCE CHINA Technological Sciences, Volume 60, Issue 2: 175- 185(2017), the entire disclosures of each of which are hereby incorporated by reference herein.

[0092] In certain embodiments, the cathode comprises one or more of the following features: (a) a "stack" of multi-functional materials (e.g., wherein the stack comprises, for example, particles with gradient structures that balance the transport of ions and electrons for improved power capability, energy density, and life; bi-functional cathode additives that simultaneously store Li and conduct electrons, replacing expensive and space-wasting carbons; a binding molecule that spatially constrains the electrochemical reaction storing the energy and thereby extends life; electrolyte components that improve the basic efficiency of the electrolyte, providing improved energy density; and / or a cathode design that enables greater safety and energy density); (b) a tight electrode layer;(c) a tight tertiary structure; (d) porosity control; (e) a core-shell structure; (f) a cross-linked polymer shell; (g) a self-doped polymer shell; (h) an ion conductive binder; (i) a dual layer hybrid cathode; (j) a polymer that traps polysulfide; (k) a three-dimensional structure with high surface area (e.g., to hold both carbon and lithium, e.g., to intercalate); and (I) a three-dimensional structure within which carbon is replaced with a metal disulfide (e.g., and wherein the battery comprises a polymer electrolyte for sulfur).

[0093] Compositions of the present disclosure have utility in manufacture of cathodes for electrochemical devices. They may be porous or non-porous. Certain compositions disclosed herein would be adhered to a current collector to form cathodes for secondary sulfur batteries. Provided cathode compositions may comprise one or more additives such as electrically conductive particles, binders, and other functional additives typically found in battery cathode mixtures. Generally, provided compositions include plentiful conductive particles to increase electrical conductivity of a cathode and provide a low resistance pathway for electrons to access such manufactured cathode.Attorney Docket No.: CONA-OOOl-WO (1340.0010)In various embodiments, other additives are included in the composition to alter or otherwise enhance a cathode produced according to the principles described herein. Other cathode components include, for example, a current collector, connecting tabs, and the like.Anode

[0094] In certain embodiments, a secondary sulfur battery comprises a lithium anode. A lithium anode suitable for use in lithium-sulfur cells may be used. In certain embodiments, an anode of a secondary sulfur battery comprises a negative active material selected from materials in which lithium intercalation reversibly occurs, materials that react with lithium ions to form a lithium- containing compound, metallic lithium, lithium alloys, and combinations thereof. In certain embodiments, an anode comprises metallic lithium. In certain embodiments, lithium-containing anodic compositions comprise carbon-based compounds. In certain embodiments, a carbon-based compound is selected from the group consisting of crystalline carbon, amorphous carbon, graphite, and mixtures thereof. In certain embodiments, the anode does not contain carbon, or contains a low amount of carbon (e.g., no greater than 5.0 wt.%, no greater than 3.0 wt. %, no greater than 2.0 wt.%, no greater than 1.0 wt.%, or no greater than 0.5 wt.%). In certain embodiments, a material that reacts with lithium ions to form a lithium-containing compound is selected from the group consisting of tin oxide (SnCh), titanium nitrate, and silicon. In certain embodiments, a lithium alloy comprises an alloy of lithium with another alkali metal (e.g. sodium, potassium, rubidium or cesium). In certain embodiments, a lithium alloy comprises an alloy of lithium with a transition metal. In certain embodiments, lithium alloys include alloys of lithium and a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, Sn, In, Zn, Sm, La, Si, and combinations thereof. In certain embodiments, a lithium alloy comprises an alloy of lithium with indium. In certain embodiments, a lithium alloy comprises an alloy of lithium with aluminum. In certain embodiments, a lithium alloy comprises an alloy of lithium with zinc. In certain embodiments, an anode comprises a lithium-silicon alloy. Examples of suitable lithium-silicon alloys include: LiisSi^ Li Si?, LiySis, Li Si^ and LiziSis / LizzSis. In certain embodiments, a lithium metal or lithium alloy is present as a composite with another material. In certain embodiments, such composites include materials such as graphite, graphene, metal sulfides or oxides, or conductive polymers.

[0095] In some embodiments, an anode is protected against redox shuttling reactions and hazardous runaway reactions by any of the methodologies reported in the art, for example, byAttorney Docket No.: CONA-OOOl-WO (1340.0010) creating a protective layer on a surface of an anode by chemical passivation or by deposition or polymerization. For example, in certain embodiments, an anode comprises an inorganic protective layer, an organic protective layer, or a mixture thereof, on a surface of lithium metal. In certain embodiments, an inorganic protective layer comprises Mg, Al, B, Sn, Pb, Cd, Si, In, Ga, lithium silicate, lithium borate, lithium phosphate, lithium phosphoronitride, lithium silicosulfide, lithium borosulfide, lithium aluminosulfide, lithium phosphosulfide, lithium fluoride or combinations thereof. In certain embodiments, an organic protective layer includes a conductive monomer, oligomer, or polymer. In certain embodiments, such polymer is selected from poly(p-phenylene), polyacetylene, poly(p-phenylene vinylene), polyaniline, polypyrrole, polythiophene, poly(2,5- ethylene vinylene), acetylene, poly( perinaphthalene), polyacene, and poly(naphthalene-2,6-di-yl), or combinations thereof.

[0096] Moreover, in certain embodiments, inactive sulfur material, generated from an electroactive sulfur material of a cathode, during charging and discharging of a secondary sulfur battery, attaches to an anode surface. The term "inactive sulfur", as used herein, refers to sulfur that cannot participate in an electrochemical reaction of a cathode such that it contributes no capacity upon repeated charge / discharge cycles. In certain embodiments, inactive sulfur on an anode surface acts as a protective layer on such anode. In certain embodiments, inactive sulfur is present in the form of lithium sulfide.

[0097] It is further contemplated that the concepts of the present disclosure can be adapted for use in sodium-sulfur batteries. Such sodium-sulfur batteries comprise a sodium-based anode and an intercalation or conversion material capable of intercalating or reacting with sodium ions. Such systems are encompassed within embodiments of the present disclosure.

[0098] It is further contemplated that the present disclosure can be adapted for use in batteries constructed in an anode-free configuration. In certain embodiments, a manufactured battery or battery component has an anode-free configuration and comprises an anodic current collector (e.g. copper) and one or more of the following: (a) a thin layer of garnet, (b) a structure (e.g., a complex 3D structure) with a coating deposited by atomic layer deposition (ALD) (e.g., wherein the ALD coating comprises one or more members selected from the group consisting of lithium phosphorus oxynitride (LiPON), lithium aluminum titanium phosphate (LATP), a phosphate, garnet, an oxide, perovskite, a sulphide, LisBC -LizCC (LBCO), a sodium super ionic conductor (NASICON), and alumina); (c) a polymer (e.g., polyethylene oxide (PEO) or a block copolymer); (d) lithiumAttorney Docket No.: CONA-OOOl-WO (1340.0010) phosphorus oxynitride (UPON), and (e) a solid-electrolyte interface (SEI) layer (e.g., an artificial SEI layer formed in situ).

[0099] In certain embodiments, provided electrochemical cells are characterized in that they have a specific molar ratio of anode capacity (e.g. lithium metal provided) to cathode capacity (e.g. electroactive sulfur compositions and optionally any additional intercalation or electroactive materials included in the cathode composite). At an electrochemical cell level, this ratio of anode to cathode capacity is referred to as the n / p ratio. In its broadest embodiments, the present invention does not place any specific limits on the n / p ratio of provided electrochemical cells, however it is preferred that this ratio be optimized such that there is sufficient anode material to support full utilization of the electroactive materials in the cathode. This can be ensured by providing an n / p ratio greater than 1. An excess of anode material can be provided to account for loss of anode active material (e.g. lithium metal) during repeated cycles of stripping and plating. Many lithium sulfur batteries described in publications use a large excess of anode material to maximize cycle life, however such cells are not commercially practical as excess anode material increases cost and lowers energy density. In certain embodiments, provided electrochemical cells are characterized in that they have an n / p ratio less than 2, or less than 1.8, or less than 1.6, or less than 1.5, or less than 1.4, or less than 1.3, or less than 1.25, or less than 1.2, or less than 1.15, or less than 1.1. In certain embodiments, provided electrochemical cells are characterized in that they have an n / p ratio between 1.0 and 1.2, or between 1.05 and 1.15.Preparation of electrodes

[0100] There are a variety of methods for manufacturing electrodes for use in a secondary sulfur battery. One such process, commonly referred to as a "wet process," involves adding the solid cathode materials to a liquid to prepare a slurry composition. These slurries are typically in the form of a viscous liquid that is formulated to facilitate a downstream coating operation. A thorough mixing of a slurry can be important for coating and drying operations, which affect performance and quality of an electrode. Suitable mixing devices include ball mills, magnetic stirrers, sonication, planetary mixers, high speed mixers, homogenizers, universal type mixers, and static mixers. A liquid used to make a slurry can be any capable of homogeneously dispersing an active material, a binder, a conducting material, and any additives, and that is also able to be evaporated. Suitable slurry liquids include, for example, N-methylpyrrolidone, acetonitrile, methanol, ethanol, propanol, butanol, tetra hydrofuran, water, isopropyl alcohol, dimethylpyrrolidone, propylene carbonate,Attorney Docket No.: CONA-OOOl-WO (1340.0010) gamma butyrolactone and the like. It should be appreciated that certain aspects of the present disclosure can eliminate the use of one or more of these solvents.

[0101] In some embodiments, a prepared composition is coated on a current collector and dried to form an electrode. Specifically, a slurry is used to coat an electrical conductor to form an electrode by evenly spreading a slurry on to a conductor, which is then, in certain embodiments, optionally roll-pressed (e.g. calendared) and / or heated as is known in the art. Generally, a matrix of an active material and conductive material are held together and on a conductor by a binder. In certain embodiments, a matrix comprises a polymer binder, such as polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropene) (PVDF / HFP), polytetrafluoroethylene (PTFE), Kynar Flex* 2801, Kynar* Powerflex LBG, Kynar* HSV 900, Teflon*, styrene butadiene rubber (SBR), polyethylene oxide (PEO), or polytetrafluoroethylene (PTFE). Alternatively or additionally, in certain embodiments, lithium salts are dispersed in a matrix to improve lithium conductivity.

[0102] In certain embodiments, a current collector is selected from the group consisting of: aluminum foil, copper foil, nickel foil, stainless steel foil, titanium foil, zirconium foil, molybdenum foil, nickel foam, copper foam, carbon paper or carbon fiber sheets, polymer substrates coated with conductive metal, and / or combinations thereof.

[0103] PCT Publication Nos. W02015 / 003184, W02014 / 074150, and W02013 / 040067, the entire disclosures of which are hereby incorporated by reference herein, describe various methods of fabricating electrodes and electrochemical cells.

[0104] In one particular aspect, the present disclosure provides a method of making a cathode active material including the following steps: a) forming a slurry into a film optionally in contact with a current collector, the slurry comprising insoluble metal sulfide particles, an electroactive chalcogen conversion cathode material, and a solution containing soluble conductive binder precursors; and b) drying the film under controlled conditions to produce a cathode active material comprising a porous composite cathode active material comprising an interconnected framework, wherein the electroactive chalcogen conversion cathode material is present in the porous composite cathode active material in an amount between 50 and 70 mass %, wherein the interconnected framework comprises the metal sulfide particles and the conductive binder.

[0105] In some cases, step a) includes milling. Any order of mixing may be utilized in step a).

[0106] In some cases, the method optionally includes melt diffusing a portion of the mixture with another portion of the mixture. For example, the method can include melt diffusing the electroactive chalcogen conversion cathode material onto the metal sulfide(s).Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0107] In some cases, the forming a slurry into a film of step a) includes casting the slurry atop a current collector, thereby forming the cathode active material layer in contact with the current collector. The cathode active material layer atop the current collector can be an effective cathode.

[0108] In some cases, the current collector is a coated metal foil. The coated metal foil can have a carbon coating and / or a plastic coating. The coated metal foil is composed of a metal selected from the group consisting of aluminum, nickel, copper, stainless steel, and combinations thereof.

[0109] The slurry can have a solvent composition that is more environmentally friendly than solvents that are conventionally used to form cathode active materials. In many conventional processes, the solvent includes N-methyl-2-pyrrolidone (NMP). The inventors unexpectedly discovered that the current process can be performed with a slurry that is free of NMP.

[0110] The solvent can include an alcohol. In some cases, the alcohol is selected from the group consisting of ethanol, propanol, butanol, diacetone alcohol, and combinations thereof. An example of a suitable propanol includes 1-propanol. An example of a suitable butanol includes 1-butanol.

[0111] The solvent can include a solvent mixture including water and an organic solvent. The organic solvent can be the aforementioned alcohol. The solvent mixture can include a ratio of water to organic solvent of between 1:2 and 10:1. The ratio of water to organic solvent can be at least 1:2, at least 1:1, at least 2:1, at least 3:1, at least 4:1, or at least 5:1. The ratio of water to organic solvent can be at most 10:1, at most 9:1, at most 8:1, at most 7:1, at most 6:1, at most 5:1, at most 4:1, at most 3:1, at most 2:1, or at most 1:1. The solvent mixture (and / or slurry) can be substantially free of amides (e.g., dimethylacetamide, dimethylformamide, etc.).

[0112] The slurry created in step a) is advantageously prepared within a range of liquid to solid ratios, so as to simultaneously maintain adequate flowability and rigidity for casting. If the slurry has a viscosity that is too low, then the drying of step b) fails to produce a single coherent material. If the slurry has a viscosity that is too high, then the slurry may not properly settle. Due to the thixotropic nature of the slurry, specific viscosity values are challenging to provide, and a skilled artisan will recognize that a visual assessment of viscosity during the mixing process is typically sufficient for determining an adequate viscosity.

[0113] In some cases, the drying of step b) is a two-stage drying process including a first stage and a second stage. The drying conditions are different between the first stage and the second stage. In some cases, the drying conditions of the first stage can include covering the layer of the slurry to reduce evaporation. In some cases, the drying conditions of the first stage include a first drying temperature that is lower than a second drying temperature of the second stage. In some cases, theAttorney Docket No.: CONA-OOOl-WO (1340.0010) drying conditions of the second stage include flowing a cooling fluid over a surface of the layer of the slurry to enhance and / or control evaporation. In some cases, the drying conditions of the second stage include reducing pressure to a second pressure value that is less than atmospheric pressure (i.e., less than 1 atm) and greater than 0.5 atm.Separator

[0114] In certain embodiments, a secondary sulfur battery comprises a separator, which divides the anode and cathode and prevents direct electron conduction between them. In certain embodiments, the separator has a high lithium ion permeability. In certain embodiments, a separator is relatively less permeable to polysulfide ions dissolved in electrolyte. In certain such embodiments, a separator as a whole inhibits or restricts passage of electrolyte-soluble sulfides between anodic and cathodic portions of a battery. In certain embodiments, a separator of impermeable material is configured to allow lithium ion transport between anode and cathode of a battery during charging and discharging of a cell. In some such embodiments, a separator is porous. One or more electrolyte-permeable channels bypassing, or penetrating through apertures in, an impermeable face of a separator can be provided to allow sufficient lithium ion flux between anodic and cathodic portions of a battery.

[0115] It will be appreciated by a person skilled in the art that optimal dimensions of a separator must balance competing imperatives: maximum impedance to polysulfide migration while allowing sufficient lithium ion flux. Aside from this consideration, shape and orientation of a separator is not particularly limited, and depends in part on battery configuration. For example, in some embodiments, a separator is substantially circular in a coin-type cell, and substantially rectangular in a pouch-type cell. In some embodiments, a separator is substantially flat. However, it is not excluded that curved or other non-planar configurations may be used.

[0116] A separator may be of any suitable thickness. In order to maximize energy density of a battery, it is generally preferred that a separator is as thin and light as possible. However, a separator should be thick enough to provide sufficient mechanical robustness and to ensure suitable electrical separation of the electrodes. In certain embodiments, a separator has a thickness of from about 1 pm to about 200 pm, preferably from about 5 pm to about 100 pm, more preferably from about 10 pm to about 30 pm.Attorney Docket No.: CONA-OOOl-WO (1340.0010)Electrolyte

[0117] For the provided cathode active material to function in an electrochemical cell, an electrolyte is needed to support the movement of metal ions (e.g. lithium or sodium ions) from the anode to the cathode. To accomplish this function, the electrolyte must be in intimate contact with both the anode (i.e. in contact with a lithium metal anode surface or a solid lithium protection layer on such a lithium metal anode) and with the cathode active material. As noted herein, cathodes are typically porous composites; it is desirable that electrolyte occupies most or substantially all of this porosity and thereby enables metal ions from the anode to reach the cathode active material and vice-versa. Beyond fulfilling this function, the present invention places no particular constraints on the composition or physical properties of the electrolyte. In certain embodiments, a suitable electrolyte may comprise a liquid, a solid, a gel, or a combination of two or more of these.

[0118] In certain embodiments, a secondary sulfur battery includes an electrolyte comprising one or more salts to support ion transport (e.g. lithium ion transport) such salts are referred to herein as electrolytic salts. Examples of useful electrolytic salts are lithium salts having reasonable solubility in organic solvents. Such salts include, for example, lithium halides, lithium sulfonyl imide salts, lithium organosulfonate salts, and lithium carboxylate salts. Examples of electrolytic salts include, for example, lithium trifluoromethane sulfonimide, lithium triflate, lithium perchlorate, LiPFe, UBF4, tetraalkylammonium salts (e.g. tetra butylammonium tetrafluoroborate, TBABF4), liquid state salts at room temperature (e.g. imidazolium salts, such as l-ethyl-3-methylimidazolium bis-(perfluoroethyl sulfonyl)imide, EMIBeti), and the like.

[0119] In certain embodiments, an electrolyte comprises one or more alkali metal salts. In certain embodiments, such salts comprise lithium salts selected from UOSO2CF3, I CIO4, UNO3, LiPFs, UBF4, LiBr, Lithium bis(trifluoromethanesulfonyl)imide( LiTFSI), Lithium bis(fluorosulfonyl)amide (LiFSI, lithium 4,5-dicyano-2-(trifluoromethyl)imidazole (LiTDI), LiBr, Lil, LiCC^CFs, LiOAc, lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium oxalatophosphates (e.g., lithium tetrafluoro oxalatophosphate, lithium trisoxalatophosphate, lithium difluoro bisoxalatophosphate, etc.), lithium trifluoroacetate, Lil, lithium difluorophosphate, or combinations of any two or more of these. In certain embodiments, an electrolyte comprises ionic liquids, such as l-ethyl-3-methylimidzaolium-TFSI, N-butyl-N-methyl-piperidinium-TFSI, N-methyl-n-butyl pyrrolidinium-TFSI, and N-methyl-N-propylpiperidinium-TFSI, or combinations thereof. In certain embodiments, an electrolyte comprises superionic conductors, such as sulfides, oxides, and phosphates, for example, phosphorous pentasulfide, or combinations thereof. In certainAttorney Docket No.: CONA-OOOl-WO (1340.0010) embodiments, electrolytes may include salts of cations other than lithium. These can include salts of other alkali earth metals (e.g. sodium, potassium, rubidium or cesium salts), tetraalkylammonium salts (e.g. tetrabutylammonium tetra fluoro bo rate, TBABF4), as well as ionic liquids (e.g. imidazolium salts, such as l-ethyl-3-methylimidazolium bis-(perfluoroethyl sulfonyl)imide, EMIBeti), and the like.

[0120] In certain embodiments, a total concentration of salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM. In certain embodiments, a total concentration of lithium salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM. In certain embodiments, a total concentration of primary lithium salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM. In certain embodiments, a total concentration of e lect rolytica lly active salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM. In certain embodiments, a total concentration of electrolytically active salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM. In certain embodiments, a total concentration of electrolytically active lithium salts in an electrolyte is no more than 2M, no more than 1.8M, no more than 1.6M, no more than 1.5M, no more than 1.4M, no more than 1.3M, no more than 1.2M, or no more than IM.

[0121] In certain embodiments, an electrolyte is a liquid. For example, in certain embodiments, an electrolyte comprises an organic solvent. In certain embodiments, an electrolyte comprises only one organic solvent. In some embodiments, an electrolyte comprises a mixture of two or more organic solvents. In certain embodiments, a mixture of organic solvents comprising one or more weak polar solvents, strong polar solvents, and lithium protecting solvents.

[0122] In certain embodiments, a provided electrolyte comprises a liquid composition comprising one or more organic solvents. In certain embodiments, provided electrolyte compositions comprise one or more ethers selected from the group consisting of: dimethoxyethane, dioxolane, tetrahydrofuran, methylcyclopentyl ether, methyl tetra hydrofuran, dimethyl tetrahydrofuran, dibutyl ether, 1,4-dioxane, glyme, diethoxy ethane, diglyme, triglyme, tetraglyme, or n-glymes with n > 5 (e.g., pentaglyme or hexaglyme), or a mixture thereof. In certain embodiments, an electrolyte comprises a mixture of organic solvents. For example, a mixture of two or more ethers, for exampleAttorney Docket No.: CONA-OOOl-WO (1340.0010) an electrolyte may comprise a mixture of dimethoxyethane and 1,3-dioxolane. Such mixtures may be mixed at a ratio (e.g., by weight) of dimethoxyethane to 1,3-dioxolane in a range of 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3.

[0123] In certain embodiments, electrolytes comprise blends of multiple classes of organic solvents, e.g., a mixture of a weak polar solvent and / or a strong polar solvent and / or a lithium protecting solvent. The term "weak polar solvent", as used herein, is defined as a solvent that is capable of dissolving elemental sulfur and has a dielectric coefficient of less than 15. A weak polar solvent is selected from aryl compounds, bicyclic ethers, and acyclic carbonate compounds. Examples of weak polar solvents include xylene, dimethoxyethane, 2-methyltetrahydrofuran, diethyl carbonate, dimethyl carbonate, toluene, dimethyl ether, diethyl ether, diglyme, tetraglyme, and the like. The term "strong polar solvent", as used herein, is defined as a solvent that is capable of dissolving lithium polysulfide and has a dielectric coefficient of more than 15. A strong polar solvent is selected from bicyclic carbonate compounds, sulfoxide compounds, lactone compounds, ketone compounds, ester compounds, sulfate compounds, and sulfite compounds. Examples of strong polar solvents include hexamethyl phosphoric triamide, y-butyrolactone, acetonitrile, ethylene carbonate, propylene carbonate, N-methylpyrrolidone, 3-methyl-2-oxazolidone, dimethyl formamide, sulfolane, dimethyl acetamide, dimethyl sulfoxide, dimethyl sulfate, ethylene glycol diacetate, dimethyl sulfite, ethylene glycol sulfite, and the like. The term "lithium protection solvent", as used herein, is defined as a solvent that forms a good protective layer, i.e. a stable solidelectrolyte interface (SEI) layer, on a lithium surface, and which shows a cyclic efficiency of at least 50%. A lithium protection solvent is selected from saturated ether compounds, unsaturated ether compounds, and heterocyclic compounds including one or more heteroatoms selected from the group consisting of N, O, and / or S. Examples of lithium protection solvents include tetra hydrofuran, 1,3-dioxolane, 3,5-dimethylisoxazole, 2,5-dimethyl furan, furan, 2-methyl furan, 1,4-oxane, 4- methyldioxolane, and the like.

[0124] In certain embodiments, a lithium protection solvent is selected from fluorinated hydrocarbons and fluoroethers. Examples of fluorinated solvents include bis(trifluoroethyl) ether,1.1.2.2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropylether, tris(2,2,2-trifiuoroethy I) orthoformate, methoxyperfluorobutane, hexafluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2- trifluoroethyi ether, 3-(Difluoromethoxy)-l,l,2,2-tetrafluoropropane, fluoroacetonitrile, ethyl1.1.2.2-tetrafluoroethyl ether.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0125] In certain embodiments, a mixture of a weak polar solvent and strong polar solvent is provided at a weight ratio in a range of 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3. In certain embodiments, a mixture of a weak polar solvent and a lithium-protective solvent is provided at a weight ratio in a range of 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3.

[0126] In certain embodiments, an electrolyte is a liquid (e.g., an organic solvent). In some embodiments, a liquid is selected from the group consisting of organocarbonates, ethers, sulfones, water, alcohols, fluorocarbons, or combinations of any of these. In certain embodiments, an electrolyte comprises an ethereal solvent.

[0127] In certain embodiments, an organic solvent comprises an ether. In certain embodiments, an organic solvent is selected from the group consisting of 1,3-dioxolane, dimethoxyethane, diglyme, triglyme, y-butyrolactone, y-valerolactone, and combinations thereof. In certain embodiments, an organic solvent comprises a mixture of 1,3-dioxolane and dimethoxyethane. In certain embodiments, an organic solvent comprises a 1:1 v / v mixture of 1,3-dioxolane and dimethoxyethane. In certain embodiments, an organic solvent is selected from the group consisting of: diglyme, triglyme, y-butyrolactone, y-valerolactone, and combinations thereof. In certain embodiments, an electrolyte comprises sulfolane, sulfolene, dimethyl sulfone, methyl ethyl sulfone, or a combination thereof. In some embodiments, an electrolyte comprises ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, or a combination thereof.

[0128] In certain embodiments, a provided electrolyte (or a portion of a provided electrolyte) is a solid. In certain embodiments, a solid electrolyte comprises a glass, a ceramic, an inorganic composite, or combinations thereof. In certain embodiments, a solid electrolyte comprises a polymer. In certain embodiments, a solid electrolyte comprises a polymer composite with a glass, a ceramic, an inorganic composite, or combinations thereof. In certain embodiments, such solid electrolytes comprise one or more liquid components as plasticizers or to form a "gel electrolyte". In certain embodiments, a solid electrolyte comprises superionic conductors, such as sulfides, oxides, and phosphates, for example, phosphorous pentasulfide, or combinations thereof.Secondary sulfur battery

[0129] Described herein are secondary sulfur batteries comprising cathode compositions described above. For example, in certain embodiments, such batteries include a lithium-containing anode composition coupled to the provided cathode composition by a lithium conducting electrolyte. InAttorney Docket No.: CONA-OOOl-WO (1340.0010) some embodiments, such batteries also comprise additional components such as separators between the anode and cathode, anodic and cathodic current collectors, terminals by which a cell can be coupled to an external load, and packaging such as a flexible pouch or a rigid metal container. It is further contemplated that the present disclosure regarding secondary sulfur batteries can be adapted for use in sodium-sulfur batteries, and such batteries are also considered within the scope of certain embodiments of the present disclosure.

[0130] FIG. 1 illustrates a cross section of an electrochemical cell 800 in accordance with exemplary embodiments of the disclosure. Electrochemical cell 800 includes a negative electrode 802, a positive electrode 804, a separator 806 interposed between negative electrode 802 and positive electrode 804, a container 810, and a fluid electrolyte 812 in contact with negative and positive electrodes 802, 804. Such cells optionally include additional layers of electrode and separators 802a, 802b, 804a, 804b, 806a, and 806b.

[0131] Negative electrode 802 (also sometimes referred to herein as an anode) comprises a negative electrode active material that can accept cations. Non-limiting examples of negative electrode active materials for lithium-based electrochemical cells include Li metal, Li alloys such as those of Si, Sn, Bi, In, and / or Al alloys, Li^isOn, hard carbon, graphitic carbon, metal chalcogenides, and / or amorphous carbon. In accordance with some embodiments of the disclosure, most (e.g., greater than 90 wt %) of an anode active material can be initially included in a discharged positive electrode 804 (also sometimes referred to herein as a cathode) when electrochemical cell 800 is initially made, so that an electrode active material forms part of first electrode 802 during a first charge of electrochemical cell 800.

[0132] A technique for depositing electroactive material on a portion of negative electrode 802 is described in U.S. Patent Publication Nos. 2016 / 0172660 and 2016 / 0172661, in the name of Fischer et al., the contents of each of which are hereby incorporated herein by reference, to the extent such contents do not conflict with the present disclosure.

[0133] Positive electrode 804 (also referred to herein as cathode) comprises a cathode composition as described herein. In certain embodiments, the cathode composition comprises about 30 to about 70 wt% electroactive sulfur. In certain embodiments, a cathode comprises at least about 70% of total sulfur present in an electrochemical cell. In certain embodiments, a cathode comprises at least about 80% of total sulfur present in an electrochemical cell. In certain embodiments, a cathode comprises at least about 90% of total sulfur present in an electrochemical cell. In certain embodiments, a cathode comprises at least about 95% of total sulfur present in an electrochemicalAttorney Docket No.: CONA-OOOl-WO (1340.0010) cell. In certain embodiments, a cathode comprises at least about 99% of total sulfur present in an electrochemical cell. In certain embodiments, a cathode comprises essentially all of the total sulfur present in an electrochemical cell.

[0134] Negative electrode 802 and positive electrode 804 can further include one or more electrically conductive additives as described herein. In accordance with some embodiments of the disclosure, negative electrode 802 and / or positive electrode 804 further include one or more polymer binders as described herein.

[0135] FIG. 2 illustrates an example of a battery according to various embodiments described herein. A cylindrical battery is shown here for illustration purposes, but other types of arrangements, including prismatic or pouch (laminate-type) batteries, may also be used as desired. Example Li battery 901 includes a negative anode 902, a positive cathode 904, a separator 906 interposed between the anode 902 and the cathode 904, an electrolyte (not shown) impregnating the separator 906, a battery case 905, and a sealing member 908 sealing the battery case 905. It will be appreciated that example battery 901 may simultaneously embody multiple aspects of the present disclosure in various designs.

[0136] A secondary sulfur battery of the present disclosure comprises a lithium anode, a sulfurbased cathode, and an electrolyte permitting lithium ion transport between anode and cathode. In certain embodiments, described herein, an anodic portion of a battery comprises an anode and a portion of electrolyte with which it is in contact. Similarly, in certain embodiments, described herein, a cathodic portion of a battery comprises a cathode and a portion of electrolyte with which it is in contact. In certain embodiments, a battery comprises a lithium ion-permeable separator, which defines a boundary between an anodic portion and a cathodic portion. In certain embodiments, a battery comprises a case, which encloses both anodic and cathodic portions. In certain embodiments, a battery case comprises an electrically conductive anodic-end cover in electrical communication with an anode, and an electrically conductive cathodic-end cover in electrical communication with a cathode to facilitate charging and discharging via an external circuit.

[0137] In certain embodiments, a secondary sulfur battery of the present disclosure is defined in terms of its ratio of electrolyte to electroactive sulfur. Electrolyte volume and the ratio (vol / wt) of electrolyte to sulfur in a cathode correlate to energy density of a sulfur battery. Electrolyte may be distributed among different volumes within a cell, for example electrolyte may be contained in porosity of the cathode, in the separator, and in contact with the anode or within an anodic solidAttorney Docket No.: CONA-OOOl-WO (1340.0010) electrolyte interphase. Electrolyte may also be contained in other spaces within a battery where it is not in direct contact with the anodic or cathodic active materials-for example electrolyte may be stranded in an annular volume at the edges of a coin cell. In certain embodiments, the present invention provides batteries where all or most of the electrolyte is contained within the cathode. Preferably, substantially all of the electrolyte is contained within the cathode and only a minimal amount of electrolyte that is necessary to wet the separator and the anode surface or SEI is outside of the cathode. Electrolyte contained within the cathode is referred to as "contained electrolyte" and its volume VCF can be estimated as theoretical pore volume, or porosity multiplied by the geometric volume of a cathode film:

[0138] In certain embodiments, a provided secondary sulfur battery is characterized in that at least 50% of the total electrolyte inventory (Vtot) is contained in the cathode (e.g. VcE / Vtot >0.5). In certain embodiments, a provided secondary sulfur battery is characterized in that at least 50% of the total electrolyte inventory (Vtot) is contained in the cathode (e.g. VcE / tot >0.8). In certain embodiments, a secondary sulfur battery has at least 60%, at least 65%, or at least 70% of the electrolyte contained in the cathode porosity. In certain embodiments, a secondary sulfur battery has at least 80%, at least 85%, or at least 90%, of the electrolyte contained in the cathode porosity. In certain embodiments, a secondary sulfur battery has at least 92%, at least 94%, at least 95%, at least 96%, or at least 97% of the electrolyte contained in the cathode.

[0139] The ratio of total electrolyte-to-sulfur (E / S) is another parameter that influences the energy density of a battery. The E / S ratio is calculated based on the total volume of electrolyte V^and the mass of electroactive sulfur (msu / ;Ur):

[0140] In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 6 microliters of electrolyte per milligram of electroactive sulfur. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 5 microliters of electrolyte per milligram of electroactive sulfur. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 4.5 microliters of electrolyte per milligram of electroactive sulfur. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 3.5 microliters of electrolyteAttorney Docket No.: CONA-OOOl-WO (1340.0010) per milligram of electroactive sulfur or less than about 3.0 microliters of electrolyte per milligram of electroactive sulfur. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 3.5 microliters of electrolyte per milligram of electroactive sulfur.In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio equal to or less than about 3 microliters of electrolyte per milligram of electroactive sulfur. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio between about 1.8 and about 3.5 pL / mg S. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio between about 1.8 and about 2.5 pL / mg S. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio between about 1.0 and about 2.0 pL / mg S. In certain embodiments, a secondary sulfur battery has an electrolyte-to-sulfur ratio between about 1.5 and about 2.0 pL / mg S.

[0141] The disclosed cathode active materials can be deployed in a variety of different applications for electrochemical storage.

[0142] In certain cases, the disclosed cathode active materials when deployed in a functioning battery (e.g., a test battery, a car battery, etc.) can produce an unexpectedly strong average pulse efficiency versus fraction discharge 10% and 100% discharge, between 20% and 95% discharge, and / or between 30% and 90% discharge. In some cases, the disclosed cathode active materials, when deployed in a functioning battery and / or test battery under the conditions described herein, can produce an average pulse efficiency of at least 60%, at least 65%, or at least 70% for each fraction discharge between 30% and 90% discharge or an average pulse efficiency of at least 70%, at least 75%, at least 80%, or at least 85% for each fraction discharge between 40% and 90% discharge.

[0143] In general, the disclosed cathode active materials when deployed in a functioning battery (e.g., a test battery, a car battery, etc.) can produce an average pulse efficiency above a first average pulse efficiency threshold over a predetermined fraction discharge range (i.e., across the entirety of the range). The first average pulse efficiency threshold can be at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, or at least 85%. The predetermined fraction discharge range can have a minimum value of at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, or at least 60%. The predetermined fraction discharge range can have a maximum value of at most 100%, at most 99%, at most 95%, at most 90%, at most 85%, at most 80%, at most 75%, at most 70%, at most 65%, at most 60%, at most 55%, or at most 50%.Attorney Docket No.: CONA-OOOl-WO (1340.0010)

[0144] For electrochemical measurements described herein, measurements may be made at a discharge rate that is intended to simulate specific real-world conditions. In some cases, the measurements may be made using a 3C discharge rate. In some cases, the measurements may be made with a discharge rate of 200-5000 mA / gS, including 500 mA / gS, 1000 mA / gS, 2000 mA / gS, or 3000 mA / gS.

[0145] Given the enhanced power and conversion efficiency, the disclosed cathode active materials may be useful in all solid state sulfur cells that operate within ranges that are around room temperature and under ambient conditions, i.e. from about -20 °C up to about 60 °C. These cells could use solid electrolytes known to those of ordinary skill in the art, such as sulfides (compositions of Li, phosphorus and sulfur, and in some cases halides, e.g. argyrodites), garnets, LiSiCON, thio-LiSiCONs, etc.

[0146] Additionally, it may be advantageous to use these blends in cells that operate at elevated temperatures where one or more of the electrodes may be in a molten state. These cells may also utilize a solid electrolyte separator, solid electrolyte in the cathode, or both. The solid electrolytes in each component may not be the same. The cathode compositions may optionally contain a metal sulfide and / or other additives that alter the performance and / or the mechanism of reduction of the conversion active.

[0147] In some cases, the cell may be a "hybrid" cell that utilizes a solid electrolyte protected anode, with a liquid electrolyte on the cathode side. There may be a solid electrolyte separator with liquid on both anode and cathode side. The liquid electrolytes need not be the same. The cell may operate at relatively low temperatures or elevated temperatures, as dictated by the stability of the components and interfaces.

[0148] Liquid electrolytes may be of the type that dissolve polysulfides, polyselenides, and polyselenosulfides, or may not give rise to dissolved intermediates, in other words the conversion may be effectively a solid state conversion of the active material in some electrolytes, and may go through dissolved intermediates in some electrolytes.

[0149] In some cases, the cathode active materials are capable of forming batteries having unexpectedly improved performance, particularly relating to improved cycle life at high power. In particular, the cathode active materials described herein have superior performance when compared with a comparison cathode active material that replaces all of the electroactive selenium conversion cathode with an equal mass of electroactive sulfur conversion cathode material. In these comparisons, the cathode active material having selenium has a battery life cycle that is at leastAttorney Docket No.: CONA-OOOl-WO (1340.0010)10%, at least 20%, at least 30%, at least 40%, or at least 50% greater than a comparison test cell battery cycle life for the comparison cathode active material.EXAMPLES

[0150] In order that the application may be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting in any manner.

[0151] Example la: operability and performance of cathode active materials with varying proportions of sulfur and metal sulfide

[0152] To evaluate the operability and performance advantages of the inventive cathodes, coin cells were constructed using single layer cathodes comprising electroactive sulfur and metal sulfide(s). Cathode active materials were prepared with varying proportions of electroactive sulfur from 30 mass % to 80 mass %, varying proportions of titanium disulfide from 9.5 mass % to 56 mass % to account for the varying proportions of electroactive sulfur, and varying proportions of carbon black from 2 mass % to 15 mass %. Binder was kept at a constant 9 mass % for all cathode formulations.

[0153] To produce cathodes, homogenized slurries of the cathode components suspended in a suitable solvent were cast onto a carbon-coated aluminum current collector and dried to provide cathodes with areal loadings of 4-6mg S / cm2. Demonstrative cathodes were fabricated to possess high porosity (60-78%) using environmentally friendly solvents.

[0154] Punches of the dried cathode films were assembled into 2032 coin cells using Celgard™ separators and lithium metal anodes. Each coin cell was loaded with enough liquid electrolyte (LiFSI and LiNCh in DOL / DME) to provide an E / S ratios of 4-4.5 pL / mg. Groups of five cells containing each cathode composition were cycled using a Maccor battery test system. The cycling protocols were, following an initial formation procedure, 3 cycles at a 1C discharge (lC=1000mA / g), 3 cycles at a C / 10 discharge, 3 cycles at a C / 5 discharge rate, and and then continuous cycling at a C / 3 discharge rate. All charges were performed at a C / 3 rate

[0155] Referring to Fig. 3, the pulse average efficiency, pulse end of plateau efficiency, and pulse end of discharge efficiency were measured and are plotted versus the sulfur content of the prepared cathode active materials. It was unexpectedly discovered that a sulfur content of between 50 mass % and 70 mass % (and corresponding metal sulfide content of roughly between 20 mass % and 40 mass %) showed significant performance improvements relative to counterpart cathodes where more typical carbon frameworks are utilized. The performance improvement was multi-fold.Attorney Docket No.: CONA-OOOl-WO (1340.0010)First, the inventive cathodes were operable at lower E / S than their carbon-framework counterparts, which is required for higher energy function. Cells with loadings in excess of 3 mg S / cm2and E / S ratios as low as 2 were operable. Second, the inventive cathodes show improved power efficiency relative to their carbon-framework counterparts. By contrast, studies have traditionally required low loadings and / or high electrolyte ratios in order to produce similar power efficiency results. The performance improvement was also counterintuitive to the inventors, because it may have been expected that a greater sulfur mass% in the cathode would have reduced power efficiency by virtue of having too little material in the cathode to support the sulfur reaction (as a ratio of inactive-to- sulfur).

[0156] Unexpectedly, the inventive compositions exhibit strong power efficiencies across different portions of the discharge profile. For example, a high sulfur mass fraction (low metal sulfide fraction) results in low efficiencies at moderate percent state of charge, while low sulfur mass fraction (high metal sulfide fraction) resulted in low pulse efficiency at low percent state of charge.

[0157] Referring to Figs. 4-7, ternary plots are provided showing measured performance from test batteries made with cathode active materials having the plotted material compositions. Values are provided adjacent to each point, with the exception of a point in Fig. 7 denoted by an asterisk (in that instance, cells did not discharge long enough to get values in a second plateau). Figs. 4-7 plot the energy density, pulse average efficiency, pulse end of first plateau efficiency, and pulse end of discharge efficiency, respectively. Unexpectedly, strong performance was observed across regions of the compositional space represented within the ternary plots and the inventors discovered one or more regions where several distinct measurements each showed superior performance.Example lb: alternative metal sulfides

[0158] Using processes similar to Example la, a series of cathode active materials were made with the same general composition but differences in the chosen metal sulfide. Test cells were made from the cathode active materials using the process described in Example la and subjected to a testing protocol. Referring to Fig. 8, capacity versus cycle number data are shown for test coin cells having cathode active materials made with TiS2 (solid black lines), M0S2 (solid gray lines), MoeSs (dotted gray lines), and VS2 (dashed black lines) as the metal sulfide, with measurements being made with sulfur loadings of 3-4 mg / cm2and E / S ratio of 5.

[0159] All cells achieve a high capacity of at least approx. 800mAh / g sulfur at a C / 3 discharge rate and relevant loadings and E / S for a viable Li-S battery.Attorney Docket No.: CONA-OOOl-WO (1340.0010)Example lc: sodium sulfur battery

[0160] Test coin cells were made in a similar fashion to those described in Example la, using sodium anodes, carbonate electrolytes, and glass fiber separators, with sulfur loading of 5-6 mg / cm2and E / S of 10 (higher due to the thickness of the glass fiber separator). The test cells were operable. Referring to Fig. 9, capacity versus cycle number plots shown for exemplary test cells.

[0161] The test cells were operable.EQUIVALENTS

[0162] It is contemplated that systems, devices, methods, and processes of the disclosure encompass variations and adaptations developed using information from the embodiments described herein. Adaptation and / or modification of the systems, devices, methods, and processes described herein may be performed by those of ordinary skill in the relevant art.

[0163] Certain embodiments of the present disclosure were described above. It is, however, expressly noted that the present disclosure is not limited to those embodiments, but rather the intention is that additions and modifications to what was expressly described in the present disclosure are also included within the scope of the disclosure. Moreover, it is to be understood that the features of the various embodiments described in the present disclosure were not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations were not made express, without departing from the spirit and scope of the disclosure. The disclosure has been described in detail with particular reference to certain embodiments thereof, but it will be understood that variations and modifications can be affected within the spirit and scope of the claimed invention.

[0164] It should be apparent to those skilled in the art that many additional modifications beside those already described are possible without departing from the inventive concepts. In interpreting this disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. Variations of the term "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, so the referenced elements, components, or steps may be combined with other elements, components, or steps that are not expressly referenced. Embodiments referenced as "comprising" certain elements are also contemplated as "consisting essentially of" and "consisting of" those elements. When two or more ranges for a particular value are recited, this disclosure contemplates all combinations of the upper and lower bounds of thoseAttorney Docket No.: CONA-OOOl-WO (1340.0010) ranges that are not explicitly recited. For example, recitation of a value of between 1 and 10 or between 2 and 9 also contemplates a value of between 1 and 9 or between 2 and 10.

[0165] As used herein, the terms "include" and "including" have the same meaning as the terms "comprise" and "comprising." The terms "comprise" and "comprising" should be interpreted as being "open" transitional terms that permit the inclusion of additional components further to those components recited in the claims. The terms "consist" and "consisting of" should be interpreted as being "closed" transitional terms that do not permit the inclusion of additional components other than the components recited in the claims. The term "consisting essentially of" should be interpreted to be partially closed and allowing the inclusion only of additional components that do not fundamentally alter the nature of the claimed subject matter.

[0166] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0167] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0168] Preferred aspects of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred aspects may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect a person having ordinary skill in the art to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0169] While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.Attorney Docket No.: CONA-OOOl-WO (1340.0010)For example, any of the features or functions of any of the embodiments disclosed herein may be incorporated into any of the other embodiments disclosed herein.

[0170] In addition to the foregoing disclosure and the claims that follow, the present disclosure includes the following clauses:1. A porous composite cathode active material comprising an interconnected framework of metal sulfide particles in a conductive binder, wherein the porous composite cathode active material contains between 50 and 75 mass % of an electroactive chalcogen conversion cathode material and between 10 and 35 mass % metal sulfide(s).2. A method of making a cathode active material, the method comprising: a) forming a slurry into a film optionally in contact with a current collector, the slurry comprising insoluble metal sulfide particles, an electroactive chalcogen conversion cathode material, and a solution containing soluble conductive binder precursors; b) drying the film under controlled conditions to produce a cathode active material comprising a porous composite cathode active material comprising an interconnected framework, wherein the electroactive chalcogen conversion cathode material is present in the porous composite cathode active material in an amount between 50 and 75 mass %, wherein the interconnected framework comprises the metal sulfide particles and the conductive binder.3. The method of clause 2, wherein the metal sulfide is present in dried cathode film in an amount between 10 and 35 mass %.4. The method of clause 2 or 3, wherein the solution comprises a solvent mixture including water and an organic solvent, wherein the organic solvent is not a pyrrolidone.5. The method of clause 4, wherein the organic solvent is an alcohol.6. The method of clause 4 or 5, wherein the organic solvent is selected from the group consisting of ethanol, propanol such as 1-propanol, butanol such as 1-butanol, diacetone alcohol, and combinations thereof.7. The method of any one of clauses 4 to 6, wherein the organic solvent is ethanol.8. The method of any one of clauses 4 to 7, wherein the solvent mixture comprises a ratio of water to organic solvent of between 1:2 and 10:1.9. The method of any one of clauses 5 to 8, wherein the solvent mixture comprises a ratio of water to alcohol of between 1:2 and 10:1.10. The method of any one of clauses 7 to 9, wherein the solvent mixture comprises a ratio of water to ethanol of between 1:2 and 10:1.Attorney Docket No.: CONA-OOOl-WO (1340.0010)11. The method of any one of clauses 4 to 10, wherein the solvent mixture is substantially free of amides (e.g., dimethylacetamide, dimethylformamide, etc.).12. The method of any one of clauses 2 to 11, wherein the forming of step a) including forming the slurry into the film atop the current collector.13. The method of any one of clauses 2 to 12, wherein the current collector is a coated metal foil.14. The method of clause 13, wherein the coated metal foil has a carbon coating and / or a plastic coating.15. The method of clause 13 or 14, wherein the coated metal foil is composed of a metal selected from the group consisting of aluminum, nickel, copper, and combinations thereof.16. The method of any one of clauses 2 to 15, wherein the slurry is substantially free of N- methyl-2-pyrrolidone.17. The method of any one of clauses 2 to 16, wherein the drying of step b) is a two-stage drying comprising a first stage and a second stage, wherein the drying conditions are different between the first stage and the second stage.18. The method of clause 17, wherein the drying conditions of the first stage produce less evaporation than the drying conditions of the second stage.19. The method of clause 17 or 18, wherein the drying conditions of the first stage include covering the layer of the slurry to reduce evaporation.20. The method of any one of clauses 17 to 19, wherein the drying conditions of the first stage include a first drying temperature that is lower than a second drying temperature of second stage.21. The method of any one of clauses 17 to 20, wherein the drying conditions of the second stage include flowing a cooling fluid over a surface of the layer of the slurry to enhance and / or control evaporation.22. The method of any one of clauses 17 to 21, wherein the drying conditions of the second stage include reducing pressure to a second pressure value that is less than atmospheric pressure (i.e., less than 1 atm) and greater than 0.5 atm.23. The cathode active material or the method of any one of the preceding clauses, wherein the porous composite cathode active material contains between 65 and 72 mass % of the electroactive chalcogen conversion cathode material.24. The cathode active material or the method of any one of the preceding clauses, wherein the conductive binder is a conductive matrix.Attorney Docket No.: CONA-OOOl-WO (1340.0010)25. The cathode active material or the method of any one of clauses 1 to 23, wherein the conductive binder is a non-conductive matrix having conductive particles distributed throughout.26. The cathode active material or the method of any one of the preceding clauses, wherein the porous composite material has an as-deposited porosity of between 60% and 78%, as measured by Hg porosimetry or He pycnometry.27. The cathode active material or the method of any one of the preceding clauses, wherein the as-deposited porosity is between 65% and 75%, as measured by Hg porosimetry or He pycnometry.28. The cathode active material or the method of any one of the preceding clauses, wherein the metal sulfide particles comprise TiS2, M0S2, MoeSs, VS2, WS2, mixed metal sulfides comprising any two or more of Ti, Mo, V, and W, or mixtures of any two or more of these materials.29. The cathode active material or the method of any one of the preceding clauses, wherein the metal sulfide particles comprise TiS2.30. The cathode active material or the method of any one of the preceding clauses, wherein the metal sulfide particles consist essentially of TiS2.31. The cathode active material or the method of any one of the preceding clauses, wherein the metal sulfide particles consist of TiS2.32. The cathode active material or the method of any one of the preceding clauses, wherein no more than 15 mass% of the interconnected framework is composed of nanoporous materials.33. The cathode active material or the method of any one of the preceding clauses, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with an average pulse efficiency of at least 50%.34. The cathode active material or the method of any one of the preceding clauses, wherein the electroactive chalcogen conversion cathode material includes elemental sulfur.35. The cathode active material or the method of any one of the preceding clauses, wherein the electroactive chalcogen conversion cathode material consists essentially of elemental sulfur.36. The cathode active material or the method of any one of the preceding clauses, wherein the electroactive chalcogen conversion cathode material consists of elemental sulfur.37. The cathode active material or the method of any one of the preceding clauses, wherein the composite material further comprises metal selenide particles comprising a metal selenide selectedAttorney Docket No.: CONA-OOOl-WO (1340.0010) from the group consisting of TiSe?, MoSe?, MosSes, VSe2, WSe?, mixed metal selenides thereof, and mixtures thereof.38. The cathode active material or the method of any one of the preceding clauses, wherein the composite material further comprises metal telluride particles comprising a metal telluride selected from the group consisting of TiTe2, MoTe2, MosTes, VTe2, WTe2, mixed metal tellurides thereof, and mixtures thereof.39. The cathode active material or the method of any one of the preceding clauses, wherein the conductive binder comprises the conductive particles embedded in the non-conductive matrix.40. The cathode active material or method of clause 39, wherein the conductive particles are conductive carbon particles.41. The cathode active material or method of clause 39 or 40, wherein the non-conductive matrix is or comprises polyacrylic acid.42. The cathode active material or the method of any one of the preceding clauses, wherein no more than 10%, no more than 5%, no more than 1%, or substantially 0% of the interconnected framework is composed of nanoporous materials.43. The cathode active material or the method of any one of the preceding clauses, wherein the cathode active material is operable in a voltage window of between 1.0 V and 4.0 V.44. The cathode active material or the method of clause 43, wherein the cathode active material is operable in a voltage window of between 1.0 V and 2.5 V.45. The cathode active material or the method of clause 43, wherein the cathode active material is operable in a voltage window of between 1.8 V and 2.8 V.46. The cathode active material or the method of clause 43, wherein the cathode active material is operable in a voltage window of between 1.8 V and 2.4 V.47. The cathode active material or the method of any one of the preceding clauses, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse average efficiency of at least 93%, at least 94%, or at least 95%.48. The cathode active material or the method of any one of the preceding clauses, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with aAttorney Docket No.: CONA-OOOl-WO (1340.0010) lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse end of first plateau efficiency of at least 90% or at least 92%.49. The cathode active material or the method of any one of the preceding clauses, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse end of discharge efficiency of at least 90% or at least 92%.50. The cathode active material or the method of any one of the preceding clauses, wherein upon operating an electrode including the cathode active material at a current rate of 1000 mA / gS for 5 seconds, energy is delivered with at least 50% efficiency relative to the energy delivered at 100 mA / gS for 5 seconds.51. The cathode active material or the method of any one of the preceding clauses, wherein a comparison cathode active material has a comparison pulse average efficiency that is lower than the pulse average efficiency, wherein the comparison cathode active material is a modification of the cathode active material to: (i) increase the metal sulfide in the composite material to an amount by weight of the composite material of greater than 40% and reduce the electroactive chalcogen conversion cathode material in the composite material to compensate for the increased metal sulfide content; (ii) reduce the metal sulfide in the composite material to an amount by weight of the composite material of less than 20% and increase the electroactive chalcogen conversion cathode material in the composite material to compensate for the reduced metal sulfide content; (iii) increase the electroactive chalcogen conversion cathode material in the porous composite material to an amount by weight of greater than 70% and reduce the metal sulfide in the composite material to compensate for the increase electroactive chalcogen conversion cathode material content; and / or (iv) reduce the electroactive chalcogen conversion cathode material content in the porous composite material to an amount by weight of less than 50% and increase the metal sulfide in the composite material to compensate for the decreased electroactive chalcogen conversion cathode material content, wherein the comparison cathode active material is otherwise identical to or identically prepared as the cathode active material and the comparison pulse average efficiency and the pulse average efficiency are measured in a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg of elemental chalcogen per cm2inAttorney Docket No.: CONA-OOOl-WO (1340.0010) combination with a lithium metal anode, and a liquid electrolyte, at an electrolyte to chalcogen ratio of 6 or lower.52. The cathode active material or the method of clause 51, wherein the comparison pulse average efficiency is at least 5% lower on the basis of 100% efficiency.53. The cathode active material or the method of any one of the preceding clauses, wherein the cathode active material has a total carbon content by weight of 20% or lower, 15% or lower, 10% or lower, or 5% or lower.54. A cathode comprising the cathode active material of or made by the method of any one of the preceding clauses.55. The cathode of clause 54, wherein the cathode comprises a current collector, a first layer of cathode active material atop the current collector, a second layer of cathode active material atop the first layer of cathode active material, wherein the first layer of cathode active material is a different composition than the second layer of cathode active material.56. A battery comprising a cathode, wherein the cathode is the cathode or is formed from the cathode active material of or made by the method of any one of the preceding clauses, an anode, and an electrolyte operably arranged relative to one another.57. The battery of clause 56, wherein the anode is a lithium anode.58. The battery of clause 56, wherein the anode is a sodium anode.59. The battery of any one of clauses 56 to 58, wherein the cathode active material has an elemental chalcogen loading of 3 mg of elemental chalcogen per cm2of active material or greater.60. The battery of any one of clauses 56 to 59, wherein the battery has an electrolyte to chalcogen ratio of 6 or lower.61. The battery of any one of clauses 56 to 60, wherein the battery has pulse average efficiency of at least 50%.62. A battery comprising a cathode, an anode, and an electrolyte operably arranged relative to one another, wherein the cathode is composed of a porous composite cathode active material comprising an interconnected framework of metal sulfide particles in a conductive binder, wherein the porous composite cathode active material contains between 50 and 70 mass % of an electroactive chalcogen conversion cathode material and between 20 and 40 mass % metal sulfide(s).63. The battery of any one of clauses 56 to 62, wherein the electrolyte is a substantially solid electrolyte.Attorney Docket No.: CONA-OOOl-WO (1340.0010)64. The battery of any one of clauses 56 to 62, wherein the electrolyte is a hybrid electrolyte.65. The battery of any one of clauses 56 to 64, wherein one or more of the electrodes of the battery is molten.

Claims

Attorney Docket No.: CONA-OOOl-WO (1340.0010)CLAIMSWhat is claimed is:

1. A porous composite cathode active material comprising an interconnected framework of metal sulfide particles in a conductive binder, wherein the porous composite cathode active material contains between 50 and 75 mass % of an electroactive chalcogen conversion cathode material and between 10 and 35 mass % metal sulfide(s).

2. A method of making a cathode active material, the method comprising: a) forming a slurry into a film optionally in contact with a current collector, the slurry comprising insoluble metal sulfide particles, an electroactive chalcogen conversion cathode material, and a solution containing soluble conductive binder precursors; b) drying the film under controlled conditions to produce a cathode active material comprising a porous composite cathode active material comprising an interconnected framework, wherein the electroactive chalcogen conversion cathode material is present in the porous composite cathode active material in an amount between 50 and 75 mass %, wherein the interconnected framework comprises the metal sulfide particles and the conductive binder, optionally wherein the metal sulfide is present in dried cathode film in an amount between 10 and 35 mass %, optionally wherein the slurry is substantially free of N-methyl-2-pyrrolidone, optionally wherein the cathode active material has a total carbon content by weight of 20% or lower, 15% or lower, 10% or lower, or 5% or lower.

3. The method of claim 2, wherein the solution comprises a solvent mixture including water and an organic solvent, wherein the organic solvent is not a pyrrolidone, optionally wherein the organic solvent is an alcohol, optionally wherein the organic solvent is selected from the group consisting of ethanol, propanol such as 1-propanol, butanol such as 1-butanol, diacetone alcohol, and combinations thereof, optionally wherein the organic solvent is ethanol.

4. The method of claim 3, wherein the solvent mixture comprises a ratio of water to organic solvent of between 1:2 and 10:1, optionally wherein the solvent mixture comprises a ratio of water to alcohol of between 1:2 and 10:1, optionally wherein the solvent mixture comprises a ratio of water to ethanol of between 1:2 and 10:1, optionally wherein the solvent mixture is substantially free of amides (e.g., dimethylacetamide, dimethylformamide, etc.).Attorney Docket No.: CONA-OOOl-WO (1340.0010)5. The method of any one of claims 2 to the immediately preceding claim, wherein the forming of step a) including forming the slurry into the film atop the current collector, optionally wherein the current collector is a coated metal foil, optionally wherein the coated metal foil has a carbon coating and / or a plastic coating, optionally wherein the coated metal foil is composed of a metal selected from the group consisting of aluminum, nickel, copper, and combinations thereof.

6. The method of any one of claims 2 to the immediately preceding claim, wherein the drying of step b) is a two-stage drying comprising a first stage and a second stage, wherein the drying conditions are different between the first stage and the second stage, optionally wherein the drying conditions of the first stage produce less evaporation than the drying conditions of the second stage, optionally wherein the drying conditions of the first stage include covering the layer of the slurry to reduce evaporation, optionally wherein the drying conditions of the first stage include a first drying temperature that is lower than a second drying temperature of second stage, optionally wherein the drying conditions of the second stage include flowing a cooling fluid over a surface of the layer of the slurry to enhance and / or control evaporation, optionally wherein the drying conditions of the second stage include reducing pressure to a second pressure value that is less than atmospheric pressure (i.e., less than 1 atm) and greater than 0.5 atm.

7. The cathode active material or the method of any one of the preceding claims, wherein the porous composite cathode active material contains between 65 and 72 mass % of the electroactive chalcogen conversion cathode material.

8. The cathode active material or the method of any one of the preceding claims, wherein the conductive binder is a conductive matrix.

9. The cathode active material or the method of any one of claims 1 to 7, wherein the conductive binder is a non-conductive matrix having conductive particles distributed throughout.

10. The cathode active material or the method of any one of the preceding claims, wherein the porous composite material has an as-deposited porosity of between 60% and 78%, as measured by Hg porosimetry or He pycnometry, or wherein the as-deposited porosity is between 65% and 75%, as measured by Hg porosimetry or He pycnometry.

11. The cathode active material or the method of any one of the preceding claims, wherein the metal sulfide particles comprise TiS2, M0S2, MogSs, VS2, WS2, mixed metal sulfides comprising any two or more of Ti, Mo, V, and W, or mixtures of any two or more of these materials, optionallyAttorney Docket No.: CONA-OOOl-WO (1340.0010) wherein the metal sulfide particles comprise TiS2, optionally wherein the metal sulfide particles consist essentially of TiSz, optionally wherein the metal sulfide particles consist of TiS?.

12. The cathode active material or the method of any one of the preceding claims, wherein no more than 15 mass% of the interconnected framework is composed of nanoporous materials.

13. The cathode active material or the method of any one of the preceding claims, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with an average pulse efficiency of at least 50%.

14. The cathode active material or the method of any one of the preceding claims, wherein the electroactive chalcogen conversion cathode material includes elemental sulfur, optionally wherein the electroactive chalcogen conversion cathode material consists essentially of elemental sulfur, optionally wherein the electroactive chalcogen conversion cathode material consists of elemental sulfur.

15. The cathode active material or the method of any one of the preceding claims, wherein the composite material further comprises metal selenide particles comprising a metal selenide selected from the group consisting of TiSe2, MoSe2, MogSes, VSe2, WSe2, mixed metal selenides thereof, and mixtures thereof, and / or wherein the composite material further comprises metal telluride particles comprising a metal telluride selected from the group consisting of TiTe2, MoTe2, MogTes, VTe2, WTe2, mixed metal tellurides thereof, and mixtures thereof.

16. The cathode active material or the method of any one of the preceding claims, wherein the conductive binder comprises the conductive particles embedded in the non-conductive matrix, optionally wherein the conductive particles are conductive carbon particles, optionally wherein the non-conductive matrix is or comprises polyacrylic acid.

17. The cathode active material or the method of any one of the preceding claims, wherein no more than 10%, no more than 5%, no more than 1%, or substantially 0% of the interconnected framework is composed of nanoporous materials.

18. The cathode active material or the method of any one of the preceding claims, wherein the cathode active material is operable in a voltage window of between 1.0 V and 4.0 V, and / or wherein the cathode active material is operable in a voltage window of between 1.0 V and 2.5 V, and / orAttorney Docket No.: CONA-OOOl-WO (1340.0010) wherein the cathode active material is operable in a voltage window of between 1.8 V and 2.8 V, and / or wherein the cathode active material is operable in a voltage window of between 1.8 V and 2.4 V.

19. The cathode active material or the method of any one of the preceding claims, characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse average efficiency of at least 93%, at least 94%, or at least 95%, and / or characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse end of first plateau efficiency of at least 90% or at least 92%, and / or characterized in that a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, is operable at an electrolyte to chalcogen ratio of 6 or lower with a pulse end of discharge efficiency of at least 90% or at least 92%.

20. The cathode active material or the method of any one of the preceding claims, wherein upon operating an electrode including the cathode active material at a current rate of 1000 mA / gS for 5 seconds, energy is delivered with at least 50% efficiency relative to the energy delivered at 100 mA / gS for 5 seconds.

21. The cathode active material or the method of any one of the preceding claims, wherein a comparison cathode active material has a comparison pulse average efficiency that is lower than the pulse average efficiency, wherein the comparison cathode active material is a modification of the cathode active material to: (i) increase the metal sulfide in the composite material to an amount by weight of the composite material of greater than 40% and reduce the electroactive chalcogen conversion cathode material in the composite material to compensate for the increased metal sulfide content; (ii) reduce the metal sulfide in the composite material to an amount by weight of the composite material of less than 20% and increase the electroactive chalcogen conversion cathode material in the composite material to compensate for the reduced metal sulfide content; (iii) increase the electroactive chalcogen conversion cathode material in the porous composite material to an amount by weight of greater than 70% and reduce the metal sulfide in the compositeAttorney Docket No.: CONA-OOOl-WO (1340.0010) material to compensate for the increase electroactive chalcogen conversion cathode material content; and / or (iv) reduce the electroactive chalcogen conversion cathode material content in the porous composite material to an amount by weight of less than 50% and increase the metal sulfide in the composite material to compensate for the decreased electroactive chalcogen conversion cathode material content, wherein the comparison cathode active material is otherwise identical to or identically prepared as the cathode active material and the comparison pulse average efficiency and the pulse average efficiency are measured in a battery constructed with a cathode composed of the cathode active material deposited at an areal loading of at least 3 mg of elemental chalcogen per cm2in combination with a lithium metal anode, and a liquid electrolyte, at an electrolyte to chalcogen ratio of 6 or lower, optionally wherein the comparison pulse average efficiency is at least 5% lower on the basis of 100% efficiency.

22. A cathode comprising the cathode active material of or made by the method of any one of the preceding claims, optionally wherein the cathode comprises a current collector, a first layer of cathode active material atop the current collector, a second layer of cathode active material atop the first layer of cathode active material, optionally wherein the first layer of cathode active material is a different composition than the second layer of cathode active material.

23. A battery comprising a cathode, wherein the cathode is the cathode or is formed from the cathode active material of or made by the method of any one of the preceding claims, an anode, and an electrolyte operably arranged relative to one another, optionally wherein the anode is a lithium anode, optionally wherein the anode is a sodium anode, optionally wherein the cathode active material has an elemental chalcogen loading of 3 mg of elemental chalcogen per cm2of active material or greater, optionally wherein the battery has an electrolyte to chalcogen ratio of 6 or lower, optionally wherein the battery has pulse average efficiency of at least 50%.

24. A battery comprising a cathode, an anode, and an electrolyte operably arranged relative to one another, wherein the cathode is composed of a porous composite cathode active material comprising an interconnected framework of metal sulfide particles in a conductive binder, wherein the porous composite cathode active material contains between 50 and 70 mass % of an electroactive chalcogen conversion cathode material and between 20 and 40 mass % metal sulfide(s), optionallyAttorney Docket No.: CONA-OOOl-WO (1340.0010) wherein the electrolyte is a substantially solid electrolyte, optionally wherein the electrolyte is a hybrid electrolyte, optionally wherein one or more of the electrodes of the battery is molten.

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