JP7737826B2 - Positive electrode composition for all-solid-state battery and all-solid-state battery using the same - Google Patents

Description

This disclosure relates generally to the field of batteries, and more particularly to all-solid-state batteries. This disclosure particularly relates to positive electrode compositions in all-solid-state batteries.

Lithium-ion batteries (Li-ion) are the battery of choice for hybrid and electric vehicles (HEVs) due to their high energy density and long life. Among Li-ion batteries, Li-S batteries, with their high specific energy, low cost, and flexibility, have attracted considerable attention as a promising power source for future flexible and wearable electronics. Sulfur, with its high theoretical specific capacity of 1672 mAh ^g-1 , is a highly attractive candidate cathode material. Sulfur also has the advantages of being abundant, inexpensive, and environmentally friendly. Therefore, Li-S batteries will play an important role in next-generation energy storage systems. However, various challenges have limited their large-scale commercial deployment to date.

Among the major issues limiting the use of sulfur as a cathode is its insulating properties, which reduces the electrochemical utilization of sulfur and limits power output characteristics. This necessitates the use of various conductive additives that enable intimate contact between cathode particles. Significant efforts have been devoted to improving the lithium-sulfur system, and various types of conductive carbon materials and conductive polymers have been used to enhance the electronic conductivity of the cathode composite. To date, a number of interesting approaches have been successfully explored to develop sulfur cathodes with high specific capacity and good cycling characteristics.

However, the sulfur content in the sulfur composite or the sulfur loading mass on the electrode compromises the electrochemical performance enhancement of sulfur cathode materials, significantly reducing the overall energy density of lithium/sulfur batteries. Increasing the sulfur content typically leads to a significant decrease in the conductivity of the sulfur composite, while optimal sulfur loading in the porous structure composite is determined by a balance between the desire to achieve increased capacity and the allowable volume change to ensure cathode stability.

Patent Document 1 discloses metal sulfide and metal halide composites containing carbon additives to enhance electronic conductivity. Patent Document 2 discloses metal polysulfide composites containing carbon black as an additive. In addition to carbon-based additives, scientists have also used solid electrolytes to enhance ionic conductivity. Patent Document 3 discloses the use of metal sulfides and non-metal sulfides containing Li-based solid electrolytes for all-solid-state battery applications.

International Publication No. 201663877 U.S. Patent No. 6,200,704 Japanese Patent Application Laid-Open No. 2001-006674

Efforts are ongoing to identify suitable electrode modifications for practical use in all-solid-state batteries that can improve the conductivity and achieve theoretical specific capacity while using sulfur as an electrode.

In one aspect of the present disclosure, there is provided a) a conjugate of formula I,
Formula I SC-PX _n
a) a composite of formula I, wherein S is elemental sulfur; C is at least one conductive carbon; and PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5; and b) at least one additive.
A positive electrode composition for an all-solid-state battery is provided, comprising:

In another aspect of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) grinding a phosphorus halide with the first mixture to obtain a second mixture; and c) contacting the second mixture with at least one additive to obtain a positive electrode composition for an all-solid-state battery.

In yet another aspect of the present disclosure, there is provided a) a conjugate of formula I,
Formula I SC-PX _n
Provided is an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of Formula I, where S is elemental sulfur; C is at least one conductive carbon; and PX 1 _n is a phosphorus halide, where X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5, and at least one additive; b) a negative electrode; and c) at least one solid electrolyte.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This Summary is provided to introduce a selection of concepts in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

The detailed description is provided with reference to the accompanying drawings, in which the leftmost digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

FIG. 1 shows a transmission electron microscope (TEM) image of positive electrode composition 1 according to one embodiment of the present disclosure. FIG. 2 shows a transmission electron microscope (TEM) image of positive electrode composition 2, according to one embodiment of the present disclosure. FIG. 3 illustrates the fabrication of an all-solid-state battery cell according to one embodiment of the present disclosure. FIG. 4 shows the ionic resistance of a positive electrode composition according to one embodiment of the present disclosure. FIG. 5 shows the charge transfer resistance of a positive electrode composition according to one embodiment of the present disclosure. FIG. 6 shows a Nyquist plot of electrochemical impedance spectra (at 100% SOC and 0% SOC) of a positive electrode composition according to one embodiment of the present disclosure. FIG. 7 shows the first cycle of constant current charging and discharging at a rate of 1/30 C according to one embodiment of the present disclosure. FIG. 8 shows the rate performance of a positive electrode composition according to one embodiment of the present disclosure. FIG. 9 shows a broader range of rate capabilities for a positive electrode composition according to one embodiment of the present disclosure. FIG. 10 shows the capacity-voltage curves for the third cycle of a positive electrode composition at a discharge rate of 1/30C, according to one embodiment of the present disclosure. FIG. 11 shows the capacity-voltage curves of a positive electrode composition at a discharge rate of 1/10 C, according to one embodiment of the present disclosure. FIG. 12 shows the capacity-voltage curves of a positive electrode composition at a discharge rate of 1/3 C, according to one embodiment of the present disclosure. FIG. 13 shows the DC internal resistance of a battery having a positive electrode composition according to one embodiment of the present disclosure. FIG. 14 shows the DC internal resistance of a battery at various discharge rates, according to one embodiment of the present disclosure. FIG. 15 shows the DC internal resistance of batteries having various positive electrode compositions, according to one embodiment of the present disclosure.

Those skilled in the art will recognize that the present disclosure is susceptible to variations and modifications other than those specifically described. It is to be understood that the present disclosure encompasses all such variations and modifications. The present disclosure also encompasses all of the steps, features, compositions, and compounds referred to or indicated herein, individually or collectively, and any and all combinations of one or more of any such steps or features.

Definition:
For convenience, before further description of the present disclosure, specific terms and examples used herein are summarized here.These definitions should be read in light of the remaining part of the present disclosure and understood as those skilled in the art would.Terms used herein have the meanings that are recognized and well-known to those skilled in the art, but for convenience and completeness, specific terms and their meanings are described below.

The articles "a," "an," and "the" are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

The terms "comprise" and "comprising" are used in an inclusive, open-ended sense to mean that additional elements may be included. This term is not intended to be construed as "consists of only."

Throughout this specification, unless the context requires otherwise, the words "comprise" and variations such as "comprises" and "comprising" shall be understood to mean the inclusion of stated elements, steps, or groups of elements or steps, but not the exclusion of other elements or steps.

The term "including" is used to mean "including but not limited to," and "including" and "including but not limited to" are used interchangeably.

The term "solid electrolyte" refers to a solid that exhibits high ionic conductivity through the movement of cations and anions. For example, in this disclosure, solid electrolyte refers to the electrolyte used in all-solid-state battery cells/batteries. The solid electrolyte in all-solid-state battery cells/batteries allows for the movement of ions without the need for a liquid or a flexible membrane separating the electrodes.

The term "activator" refers to a catalyst capable of enhancing the reaction rate. In this disclosure, the term activator refers to a phosphorus halide that mediates the conduction of Li ions by catalyzing the reaction rate of the conversion of lithium polysulfide to lithium sulfide.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. All publications mentioned herein are incorporated by reference.

Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range format is used for convenience and brevity only and should be interpreted flexibly to include each individual numerical value or subrange, as if each and every individual numerical value or subrange contained within the range were expressly stated, rather than just the numerical values stated as the range endpoints. For example, a weight range of about 50% to about 75% should be understood to include not only the stated endpoints of about 50% to about 75%, but also subranges such as 50% to 70%, 55% to 65%, etc., and to similarly include individual amounts within the specified range, including fractions such as 50.5%, 58.2%, and 74.5%.

The specific embodiments described herein are intended for illustrative purposes only, and the present disclosure is not limited in scope by those specific embodiments. Products, compositions, and methods that are functionally equivalent to those described herein are clearly within the scope of the present disclosure.

To address the issues discussed in the background section, it is necessary to incorporate conductive carbon materials and activator components into sulfur-based positive electrodes to enhance their electronic and ionic conductivity. A major problem associated with the electrochemical process of Li/S battery operation is the easy dissolution of lithium polysulfides in most organic electrolytes when elemental sulfur reacts with lithium ions to form Li ₂ S. These intermediate products may participate in a "sulfur shuttle mechanism," whereby dissolved polysulfides migrate to the Li negative electrode and form an electrochemically inactive layer composed of lithium polysulfides on the surface of the Li negative electrode. These problems result in reduced active material utilization, shorter cycle life, and reduced system efficiency, as well as adversely affecting the operation of the negative electrode. To avoid these problems, an activator component is needed that can either prevent the formation of lithium polysulfides or convert them to eliminate the formation of the electrochemically inactive layer. The activator has strong adsorption and activation sites for polar polysulfides, which can catalyze the redox reaction of polysulfides to lithium sulfide. The activator also enhances Li-ion conduction in some ways. The present disclosure discloses a sulfur-based composite for use in a cathode of an all-solid-state battery, which contains a carbon additive and a phosphorus halide activator component. The activator component serves two roles in catalyzing the conversion of polysulfides to lithium sulfide, thereby avoiding the formation of an electrochemically inactive layer and mediating Li-ion conduction. The cathode composite of the present disclosure can achieve exceptional electrochemical performance with improved electronic and ionic conductivity.

In one embodiment of the present disclosure, there is provided a positive electrode composition for an all-solid-state battery, comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one type of conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and b) at least one additive.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition comprising: a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is Br and n is an integer selected from 3 to 5; and at least one additive. In another embodiment of the present disclosure, there is provided an all-solid-state battery positive electrode composition disclosed herein, where X is Cl and n is an integer selected from 3 to 5. In yet another embodiment of the present disclosure, there is provided an all-solid-state battery positive electrode composition disclosed herein, where X is I and n is an integer selected from 3 to 5.

In one embodiment of the present disclosure, there is provided a positive electrode composition for an all-solid-state battery, comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one type of conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and at least one additive, wherein the composite of formula I has a weight percentage in the range of 50% to 75% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for an all-solid-state battery disclosed herein, wherein the composite of Formula I has a weight percentage in the range of 50% to 75% relative to the positive electrode composition. In another embodiment of the present disclosure, the composite of Formula I has a weight percentage in the range of 55% to 70% relative to the positive electrode composition. In yet another embodiment of the present disclosure, the composite of Formula I has a weight percentage in the range of 58% to 65% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and b) at least one additive, wherein S of the composite of formula I has a weight percentage in the range of 35% to 45% of the composite; C of the composite of formula I has a weight percentage in the range of 10% to 25% of the composite; and PX _n of the composite of formula I has a weight percentage in the range of 1% to 5% of the composite.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery, comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and b) at least one additive, wherein S of the composite of formula I has a weight percentage in the range of 35% to 45% relative to the positive electrode composition; C of the composite of formula I has a weight percentage in the range of 10% to 25% relative to the positive electrode composition; and PX _n of the composite of formula I has a weight percentage in the range of 1% to 5% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition disclosed herein, wherein S of the composite of Formula I has a weight percentage ranging from 38% to 45% of the composite; C of the composite of Formula I has a weight percentage ranging from 11% to 22% of the composite; and PX _n of the composite of Formula I has a weight percentage ranging from 1% to 5% of the composite. In another embodiment of the present disclosure, S of the composite of Formula I has a weight percentage ranging from 40% to 44% of the composite; C of the composite of Formula I has a weight percentage ranging from 13% to 20% of the composite; and PX _n of the composite of Formula I has a weight percentage ranging from 1% to 5% of the composite. In yet another embodiment of the present disclosure, S in the conjugate of Formula I has a weight percentage of 42% relative to the complex; C in the conjugate of Formula I has a weight percentage in the range of 13% to 17% relative to the complex; and PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to 5% relative to the complex. Preferably, PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to less than 5% relative to the complex. More preferably, PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to 4% relative to the complex. Even more preferably, PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to 3% relative to the complex. Particularly preferably, PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to 2% relative to the complex. Most preferably, PX _n in the conjugate of Formula I has a weight percentage in the range of 1% to less than 2% relative to the complex.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition disclosed herein, wherein S of the composite of Formula I has a weight percentage in the range of 38% to 45% relative to the positive electrode composition; C of the composite of Formula I has a weight percentage in the range of 11% to 22% relative to the positive electrode composition; and PX _n of the composite of Formula I has a weight percentage in the range of 1% to 5% relative to the positive electrode composition. In another embodiment of the present disclosure, S of the composite of Formula I has a weight percentage in the range of 40% to 44% relative to the positive electrode composition; C of the composite of Formula I has a weight percentage in the range of 13% to 20% relative to the positive electrode composition; and PX _n of the composite of Formula I has a weight percentage in the range of 1% to 5% relative to the positive electrode composition. In yet another embodiment of the present disclosure, S of the composite of Formula I has a weight percentage of 42% relative to the positive electrode composition; C of the composite of Formula I has a weight percentage in the range of 13% to 17% relative to the positive electrode composition; and PX _n of the composite of Formula I has a weight percentage in the range of 1% to 5% relative to the positive electrode composition. Preferably, PX _n of the composite of Formula I has a weight percentage in the range of 1% to less than 5% relative to the positive electrode composition. More preferably, PX _n of the composite of Formula I has a weight percentage in the range of 1% to 4% relative to the positive electrode composition. Even more preferably, PX _n of the composite of Formula I has a weight percentage in the range of 1% to 3% relative to the positive electrode composition. Particularly preferably, PX _n of the composite of Formula I has a weight percentage in the range of 1% to 2% relative to the positive electrode composition. Most preferably, PX _n of the composite of Formula I has a weight percentage in the range of 1% to less than 2% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery, comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur, C is at least one type of conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and b) at least one additive, wherein the at least one type of conductive carbon is selected from the group consisting of Ketjen black, acetylene black, Vulcan XC-72, multi-walled carbon nanotubes, single-walled carbon nanotubes, graphene, and combinations thereof.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition as disclosed herein, wherein the at least one conductive carbon is selected from the group consisting of ketjen black, acetylene black, Vulcan XC-72, multi-walled carbon nanotubes, single-walled carbon nanotubes, graphene, and combinations thereof. In another embodiment of the present disclosure, there is provided a battery positive electrode composition as disclosed herein, wherein the at least one conductive carbon is selected from the group consisting of ketjen black, acetylene black, and combinations thereof. In yet another embodiment of the present disclosure, the at least one conductive carbon is ketjen black.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising a composite of formula I S-C-PX _n and at least one additive, wherein S is elemental sulfur, C is at least one conductive carbon, PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5, and the at least one additive is selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery, comprising: a) a composite of Formula I S-C-PX _n and at least one solid electrolyte, wherein S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; and b) at least one additive, wherein the at least one additive has a weight percentage in the range of 25% to 50% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a) a composite of formula I S-C-PX _n ; and b) at least one additive, wherein S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; the composite of Formula I has a weight percentage in the range of 50% to 75% relative to the positive electrode composition; and the at least one additive has a weight percentage in the range of 25% to 50% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a) a composite of formula I S-C-PX _n ; and b) at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, wherein S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; the composite of formula I has a weight percentage in the range of 50% to 75% of the positive electrode composition; and the at least one additive has a weight percentage in the range of 25% to 50% of the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising a composite of formula I S-C-PX _n and at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof; wherein S is elemental sulfur having a weight percentage of the composite ranging from 35% to 45%, C is at least one conductive carbon having a weight percentage of the composite ranging from 10% to 25%, and PX _n is a phosphorus halide having a weight percentage of the composite ranging from 1% to 5%, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; the composite of formula I has a weight percentage of the positive electrode composition ranging from 50% to 75%; and the at least one additive has a weight percentage of the positive electrode composition ranging from 25% to 50%.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery, comprising: a) a composite of formula I S-C-PX _n and at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof; wherein S is elemental sulfur having a weight percentage ranging from 35% to 45% relative to the composite; C is at least one conductive carbon selected from the group consisting of Ketjen black, acetylene black, Vulcan XC-72, multi-walled carbon nanotubes, single-walled carbon nanotubes, graphene, and combinations thereof, having a weight percentage ranging from 10% to 25% relative to the composite; and PX A positive electrode composition for a battery is provided, wherein _n is a phosphorus halide having a weight percentage of the composite ranging from 1% to 5%, where X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage of the positive electrode composition ranging from 50% to 75%, and the at least one additive having a weight percentage of the positive electrode composition ranging from 25% to 50%.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a) a composite of Formula I S-C-PX _n , where S is elemental sulfur having a weight percentage of 42% of the composite; C is at least one conductive carbon that is Ketjen black having a weight percentage in the range of 13% to 17% of the composite; PX _n is a phosphorus halide having a weight percentage in the range of 1% to 5% of the composite, where X is Br; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage in the range of 50% to 65% of the positive electrode composition; and b) at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a composite of Formula I S-C-PX _n , where S is elemental sulfur having a weight percentage of 42% of the composite; C is at least one conductive carbon that is Ketjen black having a weight percentage of 13% to 17% of the composite; PX _n is a phosphorus halide having a weight percentage ranging from 1% to 5% of the composite, where X is Cl; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage ranging from 50% to 65% of the positive electrode composition; and b) at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a) a composite of formula I S-C-PX _n , where S is elemental sulfur having a weight percentage of 42% of the composite; C is at least one conductive carbon that is Ketjen black having a weight percentage of 13% to 17% of the composite; and PX _n is a phosphorus halide having a weight percentage ranging from 1% to 5% of the composite, where X is I; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage ranging from 50% to 65% of the positive electrode composition; and b) at least one additive selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof.

In one embodiment of the present disclosure, there is provided a battery positive electrode composition comprising a composite of formula I S-C-PX _n , where S is elemental sulfur having a weight percentage of 42% relative to the composite; C is at least one conductive carbon which is Ketjen black having a weight percentage of 13% to 17% relative to the composite; and PX _n is a phosphorus halide having a weight percentage ranging from 1% to 5% relative to the composite, where X is Br; and n is an integer selected from 3 to 5, wherein the composite of Formula I has a weight percentage ranging from 50% to 65% relative to the positive electrode composition; and the all-solid-state battery positive electrode further comprises at least one additive which is Li ₃ PS ₄ having a weight percentage ranging from 38% to 42% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a composite of formula I S-C-PX _n , where S is elemental sulfur having a weight percentage of 42% of the composite; C is at least one conductive carbon that is Ketjen black having a weight percentage of 13% to 17% of the composite; PX _n is a phosphorus halide having a weight percentage in the range of 1% to 5% of the composite, where X is Cl; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage in the range of 50% to 65% of the positive electrode composition; and b) at least one additive that is Li ₃ PS ₄ having a weight percentage in the range of 38% to 42% of the positive electrode composition.

In one embodiment of the present disclosure, there is provided a positive electrode composition for a battery comprising: a) a composite of formula I S-C-PX _n , wherein S is elemental sulfur having a weight percentage of 42% relative to the composite; C is at least one conductive carbon that is Ketjen black having a weight percentage in the range of 13% to 17% relative to the composite; and PX _n is a phosphorus halide having a weight percentage in the range of 1% to 5% relative to the composite, wherein X is I; and n is an integer selected from 3 to 5, the composite of Formula I having a weight percentage in the range of 50% to 65% relative to the positive electrode composition; and b) at least one additive that is Li ₃ PS ₄ having a weight percentage in the range of 38% to 42% relative to the positive electrode composition.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, the method comprising: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) grinding a phosphorus halide together with the first mixture to obtain a second mixture; and c) contacting the second mixture with at least one additive to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising the steps of: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) milling a phosphorus halide together with the first mixture at a temperature in the range of 180°C to 190°C for a time in the range of 8 to 10 hours to obtain a second mixture; and c) contacting the second mixture with at least one additive to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) milling a phosphorus halide together with the first mixture by hand milling, ball milling, vibratory milling, high-energy milling, or a combination thereof to obtain a second mixture; and c) contacting the second mixture with at least one additive to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising the steps of: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) grinding a phosphorus halide together with the first mixture to obtain a second mixture; and c) contacting the second mixture with at least one additive for a period of 7 to 9 hours to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) milling a phosphorus halide together with the first mixture by hand milling, ball milling, vibratory milling, high-energy milling, or a combination thereof at a temperature ranging from 180°C to 190°C for a time ranging from 8 to 10 hours to obtain a second mixture; and c) contacting the second mixture with at least one additive for a time ranging from 7 to 9 hours to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising: a) contacting sulfur powder with at least one type of conductive carbon to obtain a first mixture; b) grinding a phosphorus halide together with the first mixture by hand milling at a temperature of 180°C for a period of 9 hours to obtain a second mixture; and c) contacting the second mixture with at least one additive for a period of 8 hours at a speed in the range of 250 to 300 rpm to obtain a positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided a method for preparing a positive electrode composition for an all-solid-state battery, comprising a composite of Formula I S-C-PX _n , where S is elemental sulfur, C is at least one type of conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5, and at least one solid electrolyte, the method comprising: a) contacting sulfur powder with the at least one type of conductive carbon to obtain a first mixture; b) grinding the phosphorus halide with the first mixture to obtain a second mixture; and c) contacting the second mixture with at least one additive to obtain the positive electrode composition for an all-solid-state battery.

In one embodiment of the present disclosure, a method for preparing a positive electrode composition for an all-solid-state battery, comprising a composite of formula I S-C-PX _n and at least one additive, wherein S is elemental sulfur; C is at least one conductive carbon; PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5, and at least one additive, comprises: a) contacting sulfur powder with at least one conductive carbon selected from the group consisting of Ketjen black, acetylene black, Vulcan XC-72, multi-walled carbon nanotubes, single-walled carbon nanotubes, graphene, and combinations thereof to obtain a first mixture; b) grinding the phosphorus halide with the first mixture to obtain a second mixture; and c) grinding the second mixture into a mixture of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ and contacting the composition with at least one additive selected from the group consisting of:

In one embodiment of the present disclosure, a composite of formula I SC-PX _n and at least one additive, wherein S is elemental sulfur, C is at least one conductive carbon, and PX The present invention provides a method for preparing a cathode composition for an all-solid-state battery, comprising a composite of Formula I, wherein _n is a phosphorus halide, and X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5, and at least one additive, the method comprising: a) contacting sulfur powder having a weight percentage in the range of 35% to 45% of the composite with at least one conductive carbon having a weight percentage in the range of 10% to 25% of the composite to obtain a first mixture; b) grinding the phosphorus halide having a weight percentage in the range of 1% to 5% of the composite with the first mixture to obtain a second mixture; and c) contacting the second mixture having a weight percentage in the range of 50% to 75% with at least one additive having a weight percentage in the range of 25% to 50% to obtain the cathode composition for an all-solid-state battery.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur; C is at least one conductive carbon; and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5; b) a negative electrode; and c) at least one solid electrolyte.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode selected from the group consisting of lithium, lithium-indium, lithium-aluminum, lithium-tin, and combinations thereof; and c) at least one solid electrolyte.

In one embodiment of the present disclosure, there is provided an all-solid- _state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from the group consisting of Li 3 PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode selected from the group consisting of lithium, lithium-indium, lithium-aluminum, lithium-tin, and combinations thereof; and c) at least one solid electrolyte selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, wherein S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, wherein X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode; and c) at least one solid electrolyte, wherein the all-solid-state battery has a discharge capacity in the range of 1700 to 2200 mAh/g at a discharge rate of 1/30 C.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode; and c) at least one solid electrolyte, wherein the positive electrode composition has an electronic conductivity in the range of 10e ^-8 S/cm to 10e ^-9 S/cm.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode; and c) at least one solid electrolyte, wherein the positive electrode composition has a diffusion resistance in the range of 300 Ω to 430 Ω.

In one embodiment of the present disclosure, there is provided an all-solid-state battery comprising: a) a positive electrode composition comprising a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) a negative electrode; and c) at least one solid electrolyte, wherein the positive electrode composition has a reaction resistance in the range of 220 Ω to 370 Ω.

In one embodiment of the present disclosure, there is provided a cathode composition comprising: a) a composite of formula I S-C-PX _n and at least one additive selected from Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof, where S is elemental sulfur, C is at least one conductive carbon, and PX _n is a phosphorus halide, where X is selected from Cl, Br, or I, and n is an integer selected from 3 to 5; b) an anode selected from the group consisting of lithium, lithium-indium, lithium-aluminum, lithium-tin, and combinations thereof; and c) a cathode composition comprising Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ and at ^least one solid electrolyte selected from the group consisting of ^:

In one embodiment of the present disclosure, there is provided an all-solid-state battery as disclosed herein for use in an electric vehicle.

Although the subject matter of the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible.

The present disclosure is described below using examples. However, the examples are intended to illustrate the practice of the present disclosure and are not intended to be limiting and should not be construed as implying any limitations on the scope of the disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, exemplary methods, devices, and materials are described below. It should be understood that the present disclosure is not limited to the specific methods and experimental conditions described, such that such methods and conditions may be applied.

As noted in the Background section, there is a need for a positive electrode composition containing an activator component capable of inhibiting electrochemically inactive layers. The present disclosure provides a positive electrode composite comprising sulfur, conductive carbon, and a phosphorus halide activator component. The present disclosure also discloses a positive electrode composition for an all-solid-state battery, comprising a composite of formula I S-C-PX _n , where S is elemental sulfur, C is conductive carbon, and PX _n is a phosphorus halide where X is selected from Cl, Br, or I, and n is an integer ranging from 3 to 5, and at least one additive selected from Li ₃ PS ₄ and Li ₁₀ GeP ₂ S _12. The positive electrode composition of the present disclosure exhibited improved discharge capacity and electronic conductivity. The diffusion resistance and reaction resistance values of the positive electrode indicated improved electrochemical performance.

[Example 1]
Preparation of the Cathode Composition of the Present Disclosure The cathode composition of the present disclosure included a composite of the formula S-C- _PXn , where _PXn is a phosphorus halide, and an additive, _Li3PS4 ( _LPS ). In the actual preparation method, the precursors, sulfur powder and Ketjen black, were first mixed to obtain a first mixture. The phosphorus halide was added to the first mixture in various weight ratios. The mixture containing all three components was hand-ground and heated at 185°C for 9 hours to obtain a second mixture. The second mixture was then mixed with the additive and ground at 280 rpm for approximately 8 hours. Thus, the cathode composition of the present disclosure was obtained. Various cathode compositions of the present disclosure prepared from the starting components, along with the weight ratios of the starting components, are listed in Table 1 below.

Table 1 shows various positive electrode compositions obtained using various phosphorus halides at different weight ratios. For example, positive electrode composition 1 was obtained from a mixture containing 42% sulfur powder, 18% Ketjen black, and 40% LPS. Positive electrode composition 1 was prepared by the method described above, resulting in a composition of formula S-LPS-C.

Similarly, positive electrode compositions 2, 3, 4, 5, _and 6, corresponding to the formulas S-C-PBr ₅ -LPS(1), S-C-PBr ₅ -LPS(2), S-C-PBr ₅ -LPS(5), S-C-PCl 5 -LPS(1), and S-C-PI ₃ -LPS(1), respectively, were prepared using the relative weights and methods described above in Table 1. The resulting positive electrode compositions were subjected to further testing of their electrochemical performance.

Transmission Electron Microscopy Investigation of Positive Electrode Compositions The positive electrode composition S-C-PBr ₅ -LPS (1) prepared by the method described herein was investigated under a transmission electron microscope (TEM). TEM images of the composition were obtained for characterization and component identification. Figure 1 shows a TEM image of positive electrode composition 1, S-LPS-C, which clearly shows the presence of only carbon. Meanwhile, the TEM image of positive electrode composition 2 also showed the presence of phosphorus bromide (Figure 2). These images indicated the inclusion of phosphorus halide within the positive electrode composition.

[Example 2]
Fabrication of All-Solid-State Battery Cells of the Present Disclosure The method for preparing a positive electrode composition of the present disclosure was implemented for use in an all-solid-state battery, which is an assembly of all-solid-state battery cells. To analyze the positive electrode composition, an all-solid-state battery cell was fabricated. In one example of the present disclosure described herein, the all-solid-state battery cell was composed of the positive electrode composition of Example 1, a lithium-indium alloy anode, and LGPS (Li ₁₀ GeP ₂ S ₁₂ ) solid electrolyte.

The fabrication procedure for the all-solid-state battery cell is described below. 80 mg of the solid electrolyte LGPS was pressed at a pressure of 400 MPa for approximately 3 minutes to obtain a solid electrolyte pellet. Approximately 7.5 mg of the positive electrode composition from Example 1 was pressed onto one side of the solid electrolyte pellet at a pressure of 200 MPa for 3 minutes to produce a positive electrode-solid electrolyte pellet. A 50 μm-thick lithium foil and a 200 μm-thick indium foil with a Li/In molar ratio of 0.79 were placed on the other side of the solid electrolyte pellet, resulting in the solid electrolyte being bonded to both the negative electrode and the positive electrode. Figure 3 shows the fabrication of an all-solid-state battery cell of the present disclosure, including the positive electrode, negative electrode, and solid electrolyte of the present disclosure. The fabricated all-solid-state battery cell, including the positive electrode composition of the present disclosure, was then subjected to electrochemical testing.

[Example 3]
Electrochemical Impedance Spectroscopy [0049] To investigate the electrode resistance of the positive electrode compositions of the present disclosure, the all-solid-state battery cells were analyzed using electrochemical impedance spectroscopy. The all-solid-state battery cells of the present disclosure from Example 2 were subjected to electrochemical impedance investigations in the frequency range of 100 MHz to 10 Hz at 100% state of charge (SOC) with an amplitude of 10 mV. Figure 4 shows the ionic resistance curves of all-solid-state battery cells containing positive electrode compositions 1 and ₂ (i.e., S-C-LPS and S-C-PBr5-LPS) as the positive electrode.

Figure 5 shows the charge transfer resistance of all-solid-state battery cells fabricated using compositions 1 and 2 (i.e., S-C-LPS and S-C-PBr ₅ -LPS) in the cathode. Figures 4 and 5 clearly demonstrate that the cathode compositions of the present disclosure exhibit lower ionic resistance and lower charge transfer resistance. The cathode compositions of the present disclosure were calculated to have diffusion resistances in the range of 300 Ω to 430 Ω and reaction resistances in the range of 220 Ω to 370 Ω.

FIG. 6 shows the Nyquist plots of the electrochemical impedance spectra (at 100% SOC and 0% SOC) of cathode compositions 1 and 2 of the present disclosure. From the Nyquist plots, it can be observed that the all-solid-state battery cell having cathode composition 1 (S-C-LPS) had a higher resistance value, while the Nyquist plot of the all-solid-state battery cell having cathode composition 2 (S-C-PBr ₅ -LPS) had a lower resistance value. There was no significant change in the semicircular curve of cathode composition 2 at 100% SOC and 0% SOC, which revealed the stability of the interface between the cathode and the electrolyte. The lower resistance value also indicated a higher electronic conductivity of the cathode, ranging from 10e ^-8 S/cm to 10e ^-9 S/cm.

[Example 4]
Constant Current Charge-Discharge Cycles of the All-Solid-State Battery of the Present Disclosure The all-solid-state battery cells prepared in Example 2 were subjected to constant current charge-discharge cycles at various rates and various charge-discharge cycles. FIG. 7 shows the first cycle of constant current charge-discharge at a rate of 1/30 C for all-solid-state battery cells having positive electrode compositions 1, 2, 3, and 4. The charge-discharge capacities of the all-solid-state battery cells were obtained in the voltage range of 0.5 to 2.5 V. Table 2 shows the capacity values for each positive electrode composition in mAh/g. These values clearly show that the positive electrode compositions containing phosphorus halide had higher capacities compared to positive electrode compositions not containing phosphorus halide.

Figure 8 shows the performance of the positive electrode compositions at various charge/discharge rates when the rate was changed in the range of 0.01 to 0.1 and the corresponding output characteristics were measured. From Figure 8, it can be seen that the rate performance of the positive electrodes tended to be S-C-PBr ₅ -LPS(2) > S-C-PBr ₅ -LPS(1) > S-LPS-C > S-C-PBr ₅ -LPS(5). A clear increase in the rate performance of the positive electrode composition of the present disclosure was demonstrated.

Figure 9 shows the rate performance over a wider range of positive electrode compositions 1, 2, and 3 when the charge/discharge rate was changed from 0.01 to 0.3. It was revealed that the positive electrode performance over a wider rate range maintained the following trend: S-C-PBr ₅ -LPS(2) > S-C-PBr ₅ -LPS(1) > S-LPS-C. The positive electrode composition S-C-PBr ₅ -LPS(2) showed 90% retention of discharge capacity at a rate of 1/10C, while the retention of discharge capacity at a rate of 1/3C was 44%.

Figure 10 shows the capacity-voltage curves for the third cycle of positive electrode compositions 1, 2, 3, and 4 at a charge-discharge rate of 1/30C. Table 3 shows the corresponding capacity measurements at a charge-discharge rate of 1/30C.

Table 3 clearly shows that the positive electrode composition of the present disclosure has higher capacity when compared to a standalone S-C-LPS positive electrode.

Figure 11 shows the capacity-voltage curves for positive electrode compositions 1, 2, 3, and 4 at a charge rate of 1/30C and a discharge rate of 1/10C. Table 4 shows the corresponding capacity measurements at a discharge rate of 1/10C.

Table 4 shows that the positive electrode composition of the present disclosure has improved capacity when compared to a single positive electrode.

Figure 12 shows the capacity-voltage curves for positive electrode compositions 1, 2, 3, and 4 at a charge rate of 1/30C and a discharge rate of 1/3C. Table 5 shows the corresponding capacity measurements at a discharge rate of 1/3C, demonstrating the improved capacity values of the positive electrodes of the present disclosure.

From the capacity measurements described herein, it can be noted that as the amount of _PXn in the positive electrode composition increases from 0 to 5%, the capacity also tends to increase. When _PXn was introduced into the positive electrode composite, i.e., in the case of positive electrode composition 2, the capacity increased compared to positive electrode composition 1, and further increased as the weight percentage of _PXn increased. On the other hand, in positive electrode composition 4, which had 5% _PXn , the capacity decreased. This demonstrated that when _PXn exceeded 5%, the positive electrode composite did not produce the desired characteristics of the positive electrode. Therefore, the positive electrode composite has an optimal weight percentage of _PXn in the range of 1 to 5% relative to the positive electrode composition. This decrease in capacity was believed to be the result of _PXn primarily replacing conductive carbon in the positive electrode composite by its respective weight percentage, resulting in a corresponding decrease in conductive carbon in the positive electrode composite.

[Example 5]
Positive Electrode Resistance DC Internal Resistance Method The direct current internal resistance (DCIR) of a battery is the resistance to current flowing through the battery, and changes in DCIR have a significant impact on the battery's discharge performance. Generally, the more improved the battery, the lower the internal resistance. Therefore, the DCIR method can be used as an important indicator for evaluating battery quality. The DCIR measurement method involves injecting a high current into the negative and positive electrodes of the battery for a short period of time, and then recording the changes in the battery's voltage and charge/discharge current.

In the present disclosure, DCIR tests were conducted on positive electrode compositions 1 and 2 using Al as the negative electrode. Figure 13 shows the DCIR curves of positive electrode compositions 1 and 2, which are graphs of current-time flowing through an all-solid-state battery cell including the corresponding positive electrodes. The measured electrical resistance of the positive electrode S-C-PBr ₅ -LPS was found to be 3.06 x ¹⁰ Ω, and the measured electrical resistance of S-C-LPS was found to be 6.09 x ¹⁰ Ω. This demonstrates the reduced electrical resistance and increased electrical conductivity of positive electrode composition 2 of the present disclosure.

Figure 14 shows the reaction resistance of positive electrode compositions 1 and 2 for 30 seconds at various charge rates of 0.03C, 0.05C, 0.1C, and 0.3C, respectively, and the values are summarized in Table 6. The initial state was maintained at 50% SOC and allowed to stand for 1 hour. Discharge at various rates was then performed for the remaining 4 hours. From Figure 14, it can be seen that positive electrode composition 2 of the present disclosure had a lower reaction resistance compared to positive electrode composition 1 alone. Therefore, the DCIR method demonstrated that the positive electrode of the present disclosure has improved conductivity and quality.

Similar DCIR tests were performed on cathode compositions 5 and 6, S-C-PCl ₅ -LPS, and S-C-PI ₃ -LPS, and compared with cathode compositions 1 and 2. FIG. 15 shows the electron-reaction resistances of cathode compositions 1, 2, 5, and 6 for 30 seconds at 50% SOC and a 0.1 C discharge rate, and Table 7 shows the reaction resistance values of the aforementioned cathode compositions. For convenience, the all-solid-state battery cells fabricated for this test had the cathode composition of the present disclosure and a lithium-indium anode. The stand-alone cathode had a higher resistance when compared to cathode compositions 4 and 5. Therefore, these results demonstrated that the cathode of the present disclosure had a lower reaction resistance and improved the electrochemical quality of the corresponding batteries.

From all of the above examples, positive electrode compositions 2, 3, 4, 5, and 6 exhibited lower resistance and higher conductivity. Positive electrode composition 1, which did not contain a phosphorus halide, exhibited higher resistance and lower conductivity. Positive electrode compositions 2 to 6, which contained a phosphorus halide as an activator component, were found to be electrochemically improved over the positive electrodes alone without a phosphorus halide.

Although the subject matter of the present invention has been described in considerable detail with reference to specific examples and embodiments thereof, other embodiments are possible.

Advantages of the Present Disclosure The present disclosure provides a positive electrode composition represented by the formula I S-C-PX _n , comprising elemental sulfur, conductive carbon, and a phosphorus halide, wherein X is a halogen selected from Cl, Br, or I, and n is an integer between 3 and 5, and at least one additive. The positive electrode composition for an all-solid-state battery disclosed herein has an activator component that can prevent or reduce the formation of an electrochemically inactive layer at the interface between an electrolyte electrode and an electrolyte electrode. The phosphorus halide acts as an activator that catalyzes the conversion of polysulfides to lithium sulfide at the interface and mediates Li-ion conduction. The positive electrode composition of the present disclosure has an electronic conductivity in the range of 10e ^-8 S/cm to 10e ^-9 S/cm. The positive electrode composition exhibits a lower reaction resistance in the range of 220 Ω to 370 Ω. The positive electrode composition of the present disclosure has a diffusion resistance in the range of 300 Ω to 430 Ω. An all-solid-state battery including the positive electrode composition has a discharge capacity in the range of 1700 to 2200 mAh/g at a discharge rate of 1/30C.

This application is based on Indian Patent Application No. 202041032190, filed on July 27, 2020, the disclosure of which is hereby incorporated by reference in its entirety.

Claims (13)

a) a conjugate of formula I,
Formula I SC-PX _n
wherein S is elemental sulfur;
C is at least one conductive carbon;
a complex wherein PX _n is a phosphorus halide, where X is selected from Cl, Br, or I; and n is an integer selected from 3 to 5;
b) at least one additive; and
Including,
The positive electrode composition for an all-solid-state battery, wherein the at least one additive is selected from the group consisting of Li ₃ PS ₄ , Li ₁₀ GeP ₂ S ₁₂ , and combinations thereof. The positive electrode composition for an all-solid-state battery according to claim 1, wherein the composite of Formula I has a weight percentage in the range of 50% to 75% relative to the positive electrode composition, and the at least one additive has a weight percentage in the range of 25% to 50% relative to the positive electrode composition. 3. The positive electrode composition for an all-solid-state battery according to claim 1 or 2, wherein S of the composite of Formula I has a weight percentage in the range of 35% to 45% relative to the composite; C of the composite of Formula I has a weight percentage in the range of 10% to 25% relative to the composite; and PX _n of the composite of Formula I has a weight percentage in the range of 1% to 5% relative to the composite. The positive electrode composition for an all-solid-state battery according to any one of claims 1 to 3, wherein the at least one type of conductive carbon is selected from the group consisting of acetylene black, multi-walled carbon nanotubes, single-walled carbon nanotubes, graphene, and combinations thereof. a) contacting sulfur powder with the at least one conductive carbon to obtain a first mixture;
b) grinding a phosphorus halide with the first mixture to obtain a second mixture;
c) contacting the second mixture with at least one additive to obtain the all-solid-state battery positive electrode composition;
The method for preparing the positive electrode composition for an all-solid-state battery according to any one of claims 1 to 4 , comprising: 6. The method of claim 5 , wherein the step of grinding the phosphorus halide with the first mixture is carried out at a temperature in the range of 180°C to 190°C for a period of 8 to 10 hours. 7. The method of claim 5 or 6 , wherein the step of milling a phosphorus halide with the first mixture is carried out by hand milling, ball milling, vibratory milling, high energy milling, and combinations thereof. 8. The method of claim 5 , wherein the step of contacting the second mixture with the at least one additive is carried out for a period of 7 to 9 hours. i. The positive electrode composition according to any one of claims 1 to 4 ;
ii. a negative electrode;
iii. at least one solid electrolyte;
Including solid-state batteries. 10. The all-solid-state battery of claim 9 , wherein the negative electrode is selected from the group consisting of lithium, lithium-indium, lithium-aluminum, lithium-tin, and combinations thereof. _11. The all-solid-state battery according to claim 9 or 10 , wherein the at least one solid electrolyte is selected from the group consisting _{of Li3PS4} , _Li10GeP2S12 , and combinations thereof _. 12. The all-solid-state battery according to claim 9 , wherein the discharge capacity obtained in a voltage range of 0.5 to 2.5 V in an initial cycle of constant-current charge and discharge at a rate of 1/30 C is 1700 to 2200 mAh/g, and the electronic conductivity of the positive electrode composition is in the range of 10e ^- 8 S/cm to 10e ^-9 S/cm. The all-solid-state battery according to any one of claims 9 to 12 , wherein the positive electrode composition has a diffusion resistance in the range of 300Ω to 430Ω and a reaction resistance in the range of 220Ω to 370Ω.