Secondary battery

Abstract

A use of an iodine-containing ion-conductive additive in a sulfur positive electrode of a solid-state lithium-sulfur battery, and a positive electrode material and a preparation method therefor and a use thereof. The iodine-containing ion-conductive additive serves as a redox mediator to promote the oxidation of Li2S. During charging, I - in the iodine-containing ion-conductive additive is electrochemically oxidized to an oxidized iodine species at the interface between the iodine-containing ion-conductive additive and a conductive material in the sulfur positive electrode. The oxidized iodine species then chemically oxidizes Li2S in contact with the oxidized iodine species. The redox-mediated process on the surface of the iodine-containing ion-conductive additive enables a reaction at the two-phase interface between the iodine-containing ion-conductive additive and Li2S, thereby improving the solid-state reaction kinetics of sulfur. The iodine-containing ion-conductive additive comprises a compound containing iodine, lithium, and sulfur elements, wherein the molar amount of the iodine element in per mole of the iodine-containing ion-conductive additive satisfies 0<nI≤2. The iodine-containing ion-conductive additive enables the sulfur positive electrode of the solid-state lithium-sulfur battery and a battery prepared therefrom to have fast-charging performance and high cycle stability.

Description

A type of secondary battery

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 2024118989996, filed on December 23, 2024, entitled "Application of Iodine-Containing Ion-Conducting Additives in Sulfur Cathode of Solid Lithium-Sulfur Battery, Cathode Material and Preparation Method Thereof and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of solid-state lithium-sulfur battery technology, specifically to the application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries, cathode materials and their preparation methods and applications; more specifically, to the application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries, cathode materials for solid-state lithium-sulfur batteries and their preparation methods, solid-state lithium-sulfur batteries and electrical equipment. Background Technology

[0004] With the widespread application of renewable energy sources such as solar and wind power, lithium batteries play a crucial role as an important component of energy storage systems. They can balance the difference between power generation and demand, improving energy efficiency. With the rapid development of information technology, mobile communications, and electric vehicles, the global demand for high-energy-density, long-life batteries is constantly increasing. Lithium batteries, with their superior energy and power densities, have become the main solution to meet these demands. All-solid-state batteries are more competitive in electric vehicles and high-energy-demand applications due to their high safety and high energy density. All-solid-state batteries based on layered metal oxide cathodes have received widespread attention, but irreversible side reactions between the layered metal oxide cathode and the electrolyte under high voltage, as well as the chemimechanical degradation of nickel-rich layered metal oxides, hinder their long-term stability and rate performance. All-solid-state lithium-sulfur batteries, because their appropriate potential does not lead to further side reactions in the solid electrolyte and charging does not release reactive oxygen, have higher inherent safety. Furthermore, solid-state lithium-sulfur batteries using solid electrolytes eliminate the troublesome polysulfide shuttle phenomenon found in liquid lithium-sulfur batteries.

[0005] The sulfur cathode has a large theoretical capacity (1672 mAh·g). -1 Sulfur is a highly abundant and inexpensive material, making lithium-sulfur batteries cost-effective compared to rare metals like cobalt and nickel used in lithium-ion batteries, thus facilitating large-scale production. Furthermore, lithium-sulfur batteries do not generate heavy metal pollution during use, and their environmentally friendly disposal is relatively easy, aligning with green and sustainable development requirements. These advantages of sulfur cathodes make them a promising battery material.

[0006] However, solid-state lithium-sulfur batteries suffer from poor rate performance and cycle life due to the slow solid-solid sulfur redox reaction between elemental sulfur and lithium sulfide. Since both active materials (sulfur and lithium sulfide) are electronic insulators, the reaction can only occur at the three-phase boundary between the solid electrolyte, active materials, and carbon. The density of three-phase boundary sites is typically much lower than that of two-phase boundary sites, thus greatly limiting the reaction space and posing a challenge to efficient solid-solid charge transfer. Existing technologies have made a series of important attempts by introducing functional additives (such as Cu, LiVS2, and modified carbon) into the cathode, but the kinetic problems caused by the "all-solid three-phase boundary" have not been fully resolved. Furthermore, the large volume change of sulfur during charge and discharge and the complex solid-solid contact interface contribute to the short cycle life of current all-solid-state lithium-sulfur batteries.

[0007] Application content

[0008] One objective of this disclosure is to provide an application of an iodine-containing ion-conducting additive in the sulfur cathode of a solid-state lithium-sulfur battery. The iodine-containing ion-conducting additive contains iodine (I) element, which has redox activity and can act as a redox mediator to promote the oxidation of Li₂S. Specifically, during fast charging, the I₂ in the iodine-containing ion-conducting additive... - Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics; a rapid chemical reaction can occur even upon physical contact. Therefore, the redox reaction of iodine containing iodine-conductive additives significantly enhances the reaction kinetics of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-conductive additive allows the solid-state conversion reaction of sulfur to occur at the two-phase boundary of the iodine-conductive additive / Li₂S (which is typically inactive in other solid-state lithium-sulfur batteries), and the two-phase boundary contact range is larger compared to the three-phase boundary of the iodine-conductive additive / Li₂S / conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent specific capacity and fast-charging performance. In addition, the reversible redox reaction of the iodine-conductive additive avoids the continuous degradation of the iodine-conductive additive, resulting in excellent cycle stability of the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery. Therefore, the problems of poor rate performance and cycle life of conventional solid-state lithium-sulfur batteries have been solved.

[0009] Another objective of this disclosure is to provide a cathode material for solid-state lithium-sulfur batteries, which enables fast charging capability by introducing a specific class of iodine-containing ion-conducting additives. Specifically, the iodine-containing ion-conducting additives contain iodine (I) with redox activity, which can act as a redox mediator to promote the oxidation of Li₂S. During fast charging, the I in the iodine-containing ion-conducting additives... - Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics; a rapid chemical reaction can occur even upon physical contact. Therefore, the redox of iodine containing iodine-conductive additives significantly enhances the reaction kinetics of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-conductive additive allows the solid-state conversion reaction of sulfur to occur at the two-phase boundary of the iodine-conductive additive / Li₂S (which is typically inactive in other solid-state lithium-sulfur batteries), and the two-phase boundary contact range is larger compared to the three-phase boundary of the iodine-conductive additive / Li₂S / conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent specific capacity and fast-charging performance. Simultaneously, the introduction of iodine-conductive additives enables high cycle stability in solid-state lithium-sulfur batteries. Specifically, the reversible redox reaction of the iodine-containing ion-conducting additive avoids the continuous degradation of the iodine-containing ion-conducting additive, resulting in excellent cycle stability of the sulfur cathode of the solid lithium-sulfur battery and the battery made from it.

[0010] Another object of this disclosure is to provide a method for preparing a cathode material for solid-state lithium-sulfur batteries, wherein the cathode material prepared by the method has high rate performance, fast charging capability and excellent cycle stability.

[0011] Another object of this disclosure is to provide a solid lithium-sulfur battery that has fast charging capability, high cycle stability and high energy density.

[0012] In order to achieve the above-mentioned objectives of this disclosure, the following technical solution is adopted:

[0013] This disclosure provides the application of an iodine-containing ion-conducting additive in the sulfur cathode of a solid-state lithium-sulfur battery. The iodine-containing ion-conducting additive acts as a redox mediator to promote the oxidation of Li₂S. During charging, the I₂ in the iodine-containing ion-conducting additive... -The interface between the iodine-containing ion-conducting additive and the conductive material in the sulfur cathode is electrochemically oxidized to iodine in an oxidized state, and then the iodine in the oxidized state chemically oxidizes Li2S in contact with it. The redox-mediated process based on the surface of the iodine-containing ion-conducting additive enables the reaction at the iodine-containing ion-conducting additive|Li2S two-phase interface to proceed, thereby improving the solid-state reaction kinetics of sulfur; the iodine-containing ion-conducting additive includes a compound containing at least iodine, lithium, and sulfur elements, and the molar amount n of the iodine element in each mole of the iodine-containing ion-conducting additive I is 0 < n I ≤ 2.

[0014] Furthermore, the iodine-containing ion-conducting additive includes at least one compound selected from Formula (1), Formula (2), Formula (3), Formula (4), Formula (5), Formula (6), and Formula (7):

[0015] Formula (1): Li 2+y+z B 2x S 1+3x I y X z , where 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, and X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN.

[0016] Formula (2): Li 2+y P 2d S 1+5d I y , where 0.2 ≤ d ≤ 0.5, 0 < y ≤ 2.

[0017] Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, and 0 < y ≤ 2, and Q includes at least one of As, Sb, and Bi elements.

[0018] Formula (4): Li 2+y P 2s Z g S 1+5s+2g I y , where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, and Z includes at least one of Si, Ge, and Sn elements.

[0019] Formula (5): Li 2+y+c B 2b M 2a S​​​​​, where 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi, and A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN.

[0020] Formula (6): Li 6-h PS 5-h Cl 1+h-y I y , where 0 ≤ h ≤ 2, 0 < y ≤ 2, 1 + h - y ≥ 0.

[0021] Formula (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y , where 0 ≤ m ≤ 2, 0 ≤ n ≤ 2, 0 < y ≤ 2, 1 + m - n - y ≥ 0.

[0022] Furthermore, in the said formula (1), 0.25 ≤ x ≤ 2, 0.01 ≤ y ≤ 2, 0.01 ≤ y + z ≤ 2.

[0023] Furthermore, in the said formula (2), 0.25 ≤ d ≤ 0.5, 0.01 ≤ y ≤ 2.

[0024] Furthermore, in the said formula (3), 0.25 ≤ e ≤ 0.5, 0 < f ≤ 0.25, 0.01 < y ≤ 2.

[0025] Furthermore, in the said formula (4), 0.25 ≤ s ≤ 0.5, 0 < g ≤ 0.125, 0.01 < y ≤ 2.

[0026] Furthermore, in the said formula (5), 0.25 ≤ b ≤ 2, 0.05 ≤ a ≤ 2, 0.3 ≤ b + a ≤ 3, 0.01 ≤ y ≤ 2, 0.01 ≤ y + c ≤ 2.

[0027] Furthermore, in the said formula (5), 0.25 ≤ b ≤ 1.5, 0.05 ≤ a ≤ 1, 0.3 ≤ b + a ≤ 2.5, 0.01 ≤ y ≤ 2, 0 ≤ c ≤ 2, 0.01 ≤ y + c ≤ 2.

[0028] Furthermore, in the said formula (6), 0 ≤ h ≤ 1, 0.01 ≤ y ≤ 2, 1 + h - y > 0.

[0029] Furthermore, in the said formula (7), 0 ≤ m ≤ 1, 0 ≤ n ≤ 1, 0.01 ≤ y ≤ 2,​​Further, the sulfur cathode of the solid-state lithium-sulfur battery further includes a sulfur-containing active material, and the sulfur-containing active material includes at least one of elemental sulfur, sulfur-selenium alloy, composite material of sulfur and carbon material, composite material of sulfur and metal sulfide, Li2S, composite material of Li2S and carbon material, composite material of Li2S and LiI, and composite material of Li2S and metal sulfide.

[0031] Further, the sulfur cathode of the solid-state lithium-sulfur battery further includes a conductive carbon additive.

[0032] Further, the mass ratio of the sulfur-containing active material, the iodine-containing ionic conductive additive, and the conductive carbon additive is 30-95:5-70:0-50.

[0033] The present disclosure also provides a cathode material for a solid-state lithium-sulfur battery. The cathode material includes an iodine-containing ionic conductive additive, and the molar amount n of iodine element in each mole of the iodine-containing ionic conductive additive I is 0 < n I ≤ 2. The iodine-containing ionic conductive additive includes at least one compound of formula (1), formula (2), formula (3), formula (4), formula (5), formula (6), and formula (7):

[0034] Formula (1): Li 2+y+z B 2x S 1+3x I y X z , where 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, and X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN.

[0035] Formula (2): Li 2+y P 2d S 1+5d I y , where 0.2 ≤ d ≤ 0.5, 0 < y ≤ 2.

[0036] Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, 0 < y ≤ 2, and Q includes at least one of As, Sb, and Bi elements.

[0037] Formula (4): Li 2+y [[ID= 55]]P 2s Z g S 1+5s+2g I y, where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, and Z includes at least one of Si, Ge, and Sn elements.

[0038] Formula (5): Li 2+y+c B 2b M 2a S 1+3b+5a I y A c , where 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi, and A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN.

[0039] Formula (6): Li 6-h PS 5-h Cl 1+h-y I y , where 0 ≤ h ≤ 2, 0 < y ≤ 2, and 1 + h - y ≥ 0.

[0040] Formula (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y , where 0 ≤ m ≤ 2, 0 ≤ n ≤ 2, 0 < y ≤ 2, and 1 + m - n - y ≥ 0.

[0041] Furthermore, the positive electrode material further includes a sulfur-containing active material.

[0042] Furthermore, the sulfur-containing active material includes at least one of elemental sulfur, sulfur-selenium alloy, composite of sulfur and carbon material, composite of sulfur and metal sulfide, Li2S, composite of Li2S and carbon material, composite of Li2S and LiI, and composite of Li2S and metal sulfide.

[0043] Furthermore, the positive electrode material further includes a conductive carbon additive.

[0044] Furthermore, the mass ratio of the sulfur-containing active material, the conductive carbon additive, and the iodine-containing ion conductive additive is 30 - 95: 0 - 50: 5 - 70.

[0045] Furthermore, the conductive carbon additive includes at least one of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement, carbon nanotube, mesoporous carbon, microporous carbon, graphene, and acetylene black.

[0046] This disclosure also provides a method for preparing the cathode material for solid-state lithium-sulfur batteries, comprising the following steps: mixing an iodine-containing ion-conducting additive with a sulfur-containing active material, or mixing an iodine-containing ion-conducting additive with a sulfur-containing active material and a conductive carbon additive.

[0047] Furthermore, the mixing method includes at least one of grinding, ball milling, vibratory milling, and high-speed stirring.

[0048] This disclosure also provides a solid-state lithium-sulfur battery, including the cathode material for the solid-state lithium-sulfur battery.

[0049] Furthermore, the solid-state lithium-sulfur battery also includes a solid electrolyte membrane and a negative electrode.

[0050] Furthermore, the negative electrode comprises at least one of lithium metal, lithium alloy, graphite, silicon, silicon-carbon composite material, silicon oxide, and lithium-carbon material;

[0051] Furthermore, the solid electrolyte membrane includes at least one of sulfide electrolyte, halide electrolyte, oxide electrolyte, polymer electrolyte, sulfide-polymer composite electrolyte, halide-polymer composite electrolyte, and oxide-polymer composite electrolyte.

[0052] This disclosure also provides an electrical device including the aforementioned solid-state lithium-sulfur battery. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Example 1 of this disclosure at 25°C and 5C charge-discharge rate.

[0055] Figure 2 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 1 of this disclosure;

[0056] Figure 3 shows the specific capacity test results of the all-solid-state lithium-sulfur battery prepared in Example 2 of this disclosure at 60°C and different charging rates (fixed discharge rate of 2C).

[0057] Figure 4 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 2 of this disclosure;

[0058] Figure 5 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Example 3 of this disclosure;

[0059] Figure 6 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 3 of this disclosure;

[0060] Figure 7 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Example 4 of this disclosure;

[0061] Figure 8 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 4 of this disclosure;

[0062] Figure 9 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Example 5 of this disclosure;

[0063] Figure 10 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 5 of this disclosure;

[0064] Figure 11 shows the specific capacity test results of the all-solid-state lithium-sulfur battery prepared in Example 6 of this disclosure at 25°C under different charging rates (fixed discharge rate of 1C).

[0065] Figure 12 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Example 6 of this disclosure;

[0066] Figure 13 shows the specific capacity test results of the all-solid-state lithium-sulfur battery prepared in Comparative Example 1 provided in this disclosure at 60°C and different charging rates (fixed discharge rate of 2C).

[0067] Figure 14 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Comparative Example 1 provided in this disclosure.

[0068] Figure 15 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Comparative Example 2 provided in this disclosure.

[0069] Figure 16 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Comparative Example 2 provided in this disclosure;

[0070] Figure 17 shows the long-cycle test results of the all-solid-state lithium-sulfur battery prepared in Comparative Example 3 provided in this disclosure.

[0071] Figure 18 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Comparative Example 3 provided in this disclosure;

[0072] Figure 19 shows the specific capacity test results of the all-solid-state lithium-sulfur battery prepared in Comparative Example 4 provided in this disclosure at 25°C and different charging rates (fixed discharge rate of 1C).

[0073] Figure 20 shows the specific capacity-voltage curve of the all-solid-state lithium-sulfur battery prepared in Comparative Example 4 provided in this disclosure.

[0074] Figure 21 shows the XRD test results provided in this disclosure that demonstrate the physical reaction between I2 and Li2S.

[0075] Figure 22 shows the Raman test results provided in this disclosure demonstrating the physical reaction between I2 and Li2S. Detailed Implementation

[0076] In a first aspect, this disclosure provides the application of an iodine-containing ion-conducting additive in the sulfur cathode of a solid-state lithium-sulfur battery. The iodine-containing ion-conducting additive, while conducting ions, also acts as a redox mediator to promote the oxidation of Li₂S. During charging, the I₂ in the iodine-containing ion-conducting additive... - The iodine-containing ion-conducting additive is electrochemically oxidized to oxidized iodine at the interface between the iodine-containing ion-conducting additive and the conductive material in the sulfur cathode. Then, the oxidized iodine chemically oxidizes the Li2S in contact with it. Based on the redox-mediated process on the surface of the iodine-containing ion-conducting additive, the reaction at the interface between the iodine-containing ion-conducting additive and Li2S can be carried out, thereby improving the solid-state reaction kinetics of sulfur.

[0077] The proof of the above principle is as follows: as shown in Figures 21 and 22. By simply and quickly hand-grinding together I₂ and Li₂S solid powders, we demonstrated the rapid reaction between I₂ and Li₂S. Equimolar amounts of I₂ and Li₂S solid powders were ground in an agate mortar. After hand-grinding for five minutes, the ground product was subjected to XRD and Raman spectroscopy tests (Figures 21 and 22). The XRD results showed the formation of the crystalline phase LiI (Figure 21), and the Raman spectrum showed the generation of an S signal, accompanied by I₃. - The signal (Figure 22) indicates that I2 and Li2S react through a simple solid-solid contact to produce S and I. - and I3 - Therefore, this proves that during the charging process, after the iodine-containing ion-conducting additive generates elemental iodine, it can directly chemically oxidize the physically contacting Li2S, which provides strong evidence for the redox-mediated effect in the battery.

[0078] Among them, the oxidized iodine states mentioned above refer to I2 and / or I3. - And / or other forms of oxidized iodine.

[0079] The aforementioned conductive materials include any conductive materials commonly used in the art, such as materials containing metal elements (e.g., metal sulfides, alloys, etc.) and carbon materials (e.g., conductive graphite, carbon black, etc.). The source of the conductive materials can be sulfur-containing active materials or conductive carbon additives, but is not limited thereto.

[0080] The iodine-containing ion-conducting additive comprises a compound containing at least iodine, lithium, and sulfur, and the molar amount n of iodine in each mole of the iodine-containing ion-conducting additive is... I 0 <n I ≤2. Where n I This includes, but is not limited to, point values ​​or ranges between any two of the following: 0.001, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2. A suitable iodine content can give the iodine-containing ion-conducting additive a suitable ionic conductivity. If n I A value greater than 2 may reduce the ion-conducting ability of iodine-containing ion-conducting additives and / or cause the electrolyte to have an excessively high mass density, thereby affecting the overall specific capacity of the sulfur cathode.

[0081] This disclosure utilizes an iodine-containing ion-conducting additive to achieve fast charging capability for solid-state lithium-sulfur batteries. The iodine-containing ion-conducting additive contains iodine (I), an element with redox activity, which can act as a redox mediator to promote the oxidation of Li₂S. During fast charging, the I₂ in the iodine-containing ion-conducting additive... - Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics; a rapid chemical reaction can occur even upon physical contact. Therefore, the redox of iodine containing iodine-conductive ion-conducting additives significantly enhances the reaction kinetics of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-conductive ion-conducting additive allows the solid-state conversion reaction of sulfur to occur at the two-phase boundary of the iodine-conductive ion-conducting additive|Li₂S (which is typically inactive in other solid-state lithium-sulfur batteries), and the two-phase boundary contact range is larger compared to the three-phase boundary of the iodine-conductive ion-conducting additive|Li₂S|conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent fast-charging performance.

[0082] Furthermore, high cycle stability of solid-state lithium-sulfur batteries can be achieved by utilizing iodine-containing ion-conducting additives. The reversible redox reaction of the iodine-containing ion-conducting additives prevents their continuous degradation, resulting in excellent cycle stability for the sulfur cathode of the solid-state lithium-sulfur battery and the battery itself.

[0083] The redox mechanism discovered in this disclosure is used to prepare sulfur cathodes for solid-state lithium-sulfur batteries and solid-state lithium-sulfur batteries, exhibiting excellent rate performance and stability.

[0084] In some specific embodiments, the iodine-containing ion-conducting additive includes at least one compound of formula (1), formula (2), formula (3), formula (4), formula (5), formula (6) and formula (7):

[0085] Formula (1): Li 2+y+z B 2x S 1+3x I y X z (i.e., Li2S-xB2S3-yLiI-zLiX), where 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, and X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN, such as two, three, four, or more. Among them, x includes, but is not limited to, any point value of 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4 or the range value between any two of them. y includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them. z includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08,​​​​​​​​​​(i.e., Li2S-dP2S5-yLiI), where 0.2 ≤ d ≤ 0.5 and 0 < y ≤ 2. Here, d includes but is not limited to point values such as any one of 0.2, 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.43, 0.45, 0.47, 0.5 or range values between any two of them. y includes but is not limited to point values such as any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or range values between any two of them.

[0087] Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, 0 < y ≤ 2, Q includes at least one of the elements As, Sb, and Bi, such as two or three. Here, e includes but is not limited to point values such as any one of 0.2, 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.43, 0.45, 0.47, 0.5 or range values between any two of them. f includes but is not limited to point values such as any one of 0.01, 0.03, 0.05, 0.1, 0.13, 0.15, 0.18, 0.2, 0.23, 0.25, 0.28, 0.3 or range values between any two of them. y includes but is not limited to point values such as any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or range values between any two of them.

[0088] Formula (4): Li 2+y P 2s Z g S 1+5s+2g I y, where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, and Z includes at least one of Si, Ge, and Sn elements, for example, two or three of them. Among them, s includes, but is not limited to, the point value of any one of 0.2, 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.43, 0.45, 0.47, 0.5 or the range value between any two of them. g includes, but is not limited to, the point value of any one of 0.01, 0.03, 0.05, 0.1, 0.13, 0.15 or the range value between any two of them. y includes, but is not limited to, the point value of any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them.

[0089] Formula (5): Li 2+y+c B 2b M 2a S 1+3b+5a I y A c, where 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi, such as two, three, four, or more; A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN, such as two, three, four, or more. Among them, b includes, but is not limited to, the point values of any one of 0.15, 0.2, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3 or the range values between any two of them. a includes, but is not limited to, the point values of any one of 0.05, 0.1, 0.15, 0.2, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3 or the range values between any two of them. b + a includes, but is not limited to, the point values of any one of 0.25, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4 or the range values between any two of them. y includes, but is not limited to, the point values of any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0. fifteen, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range values between any two of them. c includes, but is not limited to, the point values of any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 70.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range values between any two of them. y + c includes, but is not limited to, the point values of any one of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, a0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range values between any two of them.

[0090] Formula (6): Li 6-h PS 5-h Cl 1+h-y I y, where \(0\leq h\leq2\), \(0 < y\leq2\), and \(1 + h - y\geq0\); where \(h\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(y\) includes, but is not limited to, the point value of any one of \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(1 + h - y\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.005\), \(0.01\), \(0.03\), \(0.05\), \(0.08\), \(0.1\), \(0.3\), \(0.5\), \(0.8\), \(1\), \(1.5\), \(2\), \(2.5\) or the range value between any two of them.

[0091] Formula (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y, where \(0\leq m\leq2\), \(0\leq n\leq2\), \(0 < y\leq2\), and \(1 + m - n - y\geq0\). Here, \(m\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(n\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(y\) includes, but is not limited to, the point value of any one of \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(1 + m - n - y\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.005\), \(0.01\), \(0.03\), \(0.05\), \(0.08\), \(0.1\), \(0.3\), \(0.5\), \(0.8\), \(1\), \(1.5\), \(2\), \(2.5\) or the range value between any two of them.

[0092] It can be understood that the \(y\) values in the above formulas (1), (2), (3), (4), (5), (6) and (7) can be the same or different.

[0093] In some specific embodiments, to further improve the fast charging ability and cycling performance of the sulfur cathode of the solid-state lithium-sulfur battery and the solid-state lithium-sulfur battery prepared therefrom, in formula (1), \(0.25\leq x\leq2\), \(0.01\leq y\leq2\), and \(0.01\leq y + z\leq2\).

[0094] In some specific embodiments, to further improve the fast charging ability and cycling performance of the sulfur cathode of the solid-state lithium-sulfur battery and the solid-state lithium-sulfur battery prepared therefrom, in formula (2), \(0.25\leq d\leq0.5\), \(0.01\leq y\leq2\).

[0095] In some specific embodiments, to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid-state lithium-sulfur battery and the resulting solid-state lithium-sulfur battery, in equation (3), 0.25≤e≤0.5, 0 <f≤0.25,0.01<y≤2。

[0096] In some specific embodiments, to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid-state lithium-sulfur battery and the resulting solid-state lithium-sulfur battery, in equation (4), 0.25≤s≤0.5, 0 <g≤0.125,0.01<y≤2。

[0097] In some specific implementations, in order to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid lithium-sulfur battery and the solid lithium-sulfur battery made therefrom, in the formula (5), 0.25≤b≤2, 0.05≤a≤2, 0.3≤b+a≤3, 0.01≤y≤2, and 0.01≤y+c≤2.

[0098] In some specific implementations, in order to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid lithium-sulfur battery and the solid lithium-sulfur battery made therefrom, in the formula (5), 0.25≤b≤1.5, 0.05≤a≤1, 0.3≤b+a≤2.5, 0.01≤y≤2, 0≤c≤2, and 0.01≤y+c≤2.

[0099] In some specific implementations, in order to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid lithium-sulfur battery and the solid lithium-sulfur battery made therefrom, in the formula (6), 0≤h≤1, 0.01≤y≤2, 1+hy>0.

[0100] In some specific implementations, in order to further improve the fast charging capability and cycle performance of the sulfur cathode of the solid lithium-sulfur battery and the solid lithium-sulfur battery made therefrom, in the formula (7), 0≤m≤1, 0≤n≤1, 0.01≤y≤2, 1+mny>0.

[0101] In some specific embodiments, the sulfur cathode of the solid lithium-sulfur battery further includes a sulfur-containing active material, which includes at least one of elemental sulfur, sulfur-selenium alloy, composite material of sulfur and carbon, composite material of sulfur and metal sulfides, Li2S, composite material of Li2S and carbon, composite material of Li2S and LiI, and composite material of Li2S and metal sulfides.

[0102] In some specific embodiments, the carbon material includes at least one of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement (VGCF), carbon nanotubes, mesoporous carbon, microporous carbon, graphene, and acetylene black, but is not limited thereto.

[0103] In some specific embodiments, the metal sulfide includes at least one of iron sulfide, ferrous sulfide, titanium sulfide, nickel sulfide, cobalt sulfide, copper sulfide, zinc sulfide, manganese sulfide, and chromium sulfide, but is not limited thereto.

[0104] In some specific embodiments, the sulfur cathode of the solid lithium-sulfur battery also includes conductive carbon additives.

[0105] In some specific embodiments, the conductive carbon additive includes, but is not limited to, one or more of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement (VGCF), carbon nanotubes, mesoporous carbon, microporous carbon, graphene, and acetylene black.

[0106] It is understood that when the sulfur-containing active material contains carbon materials or other conductive materials, the aforementioned conductive carbon additive may not be added to the sulfur cathode of the solid lithium-sulfur battery.

[0107] In some specific embodiments, to further improve the capacity of the sulfur cathode in solid-state lithium-sulfur batteries and the fast-charging capability and cycle performance of the resulting solid-state lithium-sulfur batteries, the mass ratio of the sulfur-containing active material, the iodine-containing ion-conducting additive, and the conductive carbon additive is 30–95 (e.g., 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90): 5–70 (e.g., 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65): 0–50 (e.g., 5, 10, 15, 20, 25, 30, 35, 40, or 45). A too small proportion of sulfur-containing active material will result in a too small overall specific capacity of the sulfur cathode, while a too large proportion will result in too low electronic and ionic conductivity of the electrode, thus limiting the overall capacity of the sulfur cathode. Too low a proportion of iodine-containing ion-conducting additives will result in insufficient redox mediation and / or inadequate ionic conductivity of the sulfur cathode; too high a proportion will result in insufficient sulfur-containing active material in the sulfur cathode, thus leading to an overall low specific capacity. Too high a proportion of conductive carbon additives will result in an overall low specific capacity of the sulfur cathode.

[0108] Secondly, this disclosure provides a cathode material for solid-state lithium-sulfur batteries, the cathode material comprising an iodine-containing ion-conducting additive, the iodine-containing ion-conducting additive containing at least iodine, lithium, and sulfur, wherein the molar amount n of iodine in each mole of the iodine-containing ion-conducting additive is... I 0 <n I ≤2, wherein the iodine-containing ion-conducting additive includes at least one compound from formula (1), formula (2), formula (3), formula (4), formula (5), formula (6) and formula (7).

[0109] Equation (1): Li 2+y+z B 2x S 1+3xI y X z , wherein, 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN, such as two, three, four, five, or more. Among them, x includes, but is not limited to, any point value of 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4 or the range value between any two of them. y includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them. z includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them. y + z includes, but is not limited to, any point value of 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them.

[0110] Formula (2): Li 2+y P 2d S 1+5d I y , wherein, 0.2 ≤ d ≤ 0.5, 0 < y ≤ 2. Among them, d includes, but is not limited to, any point value of 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.37, 0.4, 0.43, 0.45, 0.47, 0.5 or the range value between any two of them. y includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them.

[0111] Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, 0 < y ≤ 2, Q includes at least one of the elements As, Sb, and Bi, for example, two or three. Among them, e includes, but is not limited to, any point value of 0.2, 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.37, 0.4, 0.43, 0.45, 0.48, 0.5 or the range value between any two of them. f includes, but is not limited to, any point value of 0.01, 0.03, 0.05, 0.1, 0.13, 0.15, 0.18, 0.2, 0.23, 0.25, 0.28, 0.3 or the range value between any two of them. y includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them.

[0112] Formula (4): Li 2+y P 2s Z g S 1+5s+2g I y , where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, Z includes at least one of the elements Si, Ge, and Sn, for example, two or three. Among them, s includes, but is not limited to, any point value of 0.2, 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.47, 0.5 or the range value between any two of them. g includes, but is not limited to, any point value of 0.01, 0.03, 0.05, 0.1, 0.13, 0.15 or the range value between any two of them. y includes, but is not limited to, any point value of 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or the range value between any two of them.

[0113] Formula (5): Li 2+y+c B 2b M2a S 1+3b+5a I y A c , wherein, 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi, such as two, three, four, or more; A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN, such as two, three, four, or more. Among them, b includes, but is not limited to, any point value of, for example, 0.15, 0.2, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, or the range value between any two of them. a includes, but is not limited to, any point value of, for example, 0.05, 0.1, 0.15, 0.2, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.7, 3, or the range value between any two of them. b + a includes, but is not limited to, any point value of, for example, 0.25, 0.3, 0.5, 0.8, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, or the range value between any two of them. y includes, but is not limited to, any point value of, for example, 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.17, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or the range value between any two of them. c includes, but is not limited to, any point value of, for example, 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.15, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or the range value between any two of them. y + c includes, but is not limited to, any point value of, for example, 0.001, 0.003, 0.005, 0.01, 0.02, 0.03, 0.05, 0.06, 0.08, 0.1, 0.13, 0.16, 0.18, 0.2, 0.3, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or the range value between any two of them.

[0114] Formula (6): Li 6-h PS 5-h Cl 1+h-y I y, where \(0\leq h\leq2\), \(0 < y\leq2\), and \(1 + h - y\geq0\); where \(h\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.17\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(y\) includes, but is not limited to, the point value of any one of \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.18\), \(0.2\), \(0.4\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(1 + h - y\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.005\), \(0.01\), \(0.03\), \(0.05\), \(0.08\), \(0.1\), \(0.3\), \(0.5\), \(0.8\), \(1\), \(1.5\), \(2\), \(2.5\) or the range value between any two of them.

[0115] Formula (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y, where \(0\leq m\leq2\), \(0\leq n\leq2\), \(0 < y\leq2\), and \(1 + m - n - y\geq0\). Here, \(m\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.17\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(n\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.15\), \(0.17\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(y\) includes, but is not limited to, the point value of any one of \(0.001\), \(0.003\), \(0.005\), \(0.01\), \(0.02\), \(0.03\), \(0.05\), \(0.06\), \(0.08\), \(0.1\), \(0.13\), \(0.16\), \(0.18\), \(0.2\), \(0.3\), \(0.5\), \(0.6\), \(0.8\), \(1\), \(1.1\), \(1.2\), \(1.3\), \(1.4\), \(1.5\), \(1.6\), \(1.7\), \(1.8\), \(1.9\), \(2\) or the range value between any two of them. \(1 + m - n - y\) includes, but is not limited to, the point value of any one of \(0\), \(0.001\), \(0.005\), \(0.01\), \(0.03\), \(0.05\), \(0.08\), \(0.1\), \(0.3\), \(0.5\), \(0.8\), \(1\), \(1.5\), \(2\), \(2.5\) or the range value between any two of them.

[0116] It can be understood that the \(y\) values in the above formulas (1), (2), (3), (4), (5), (6) and (7) can be the same or different.

[0117] The positive electrode material for a solid-state lithium-sulfur battery provided by the present disclosure can achieve the fast charging ability and cycle stability of the solid-state lithium-sulfur battery by introducing a specific type of iodine-containing ion-conducting additive. Specifically, the iodine-containing ion-conducting additive contains I element with redox activity, which can act as a redox mediator to promote the oxidation of Li2S. During fast charging, I in the iodine-containing ion-conducting additive -Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics; a rapid chemical reaction can occur even upon physical contact. Therefore, the redox of iodine containing iodine-conductive ion-conducting additives significantly enhances the reaction kinetics of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-conductive ion-conducting additive allows the solid-state conversion reaction of sulfur to occur at the two-phase boundary of the iodine-conductive ion-conducting additive|Li₂S (which is typically inactive in other solid-state lithium-sulfur batteries), and the two-phase boundary contact range is larger compared to the three-phase boundary of the iodine-conductive ion-conducting additive|Li₂S|conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent fast-charging performance.

[0118] Meanwhile, the introduction of iodine-containing ion-conducting additives can achieve high cycle stability in solid-state lithium-sulfur batteries. Specifically, the reversible redox reaction of the iodine-containing ion-conducting additives avoids their continuous degradation, resulting in excellent cycle stability for the sulfur cathode of solid-state lithium-sulfur batteries and the batteries made from them.

[0119] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (1), 0.25≤x≤2, 0.01≤y≤2, and 0.01≤y+z≤2.

[0120] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (2), 0.25≤d≤0.5, 0.01≤y≤2.

[0121] In some specific embodiments, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid-state lithium-sulfur batteries and the solid-state lithium-sulfur batteries made therefrom, in the above formula (3), 0.25≤e≤0.5, 0 <f≤0.25,0.01<y≤2。

[0122] In some specific embodiments, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid-state lithium-sulfur batteries and the solid-state lithium-sulfur batteries made therefrom, in the above formula (4), 0.25≤s≤0.5, 0 <g≤0.125,0.01<y≤2。

[0123] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (5), 0.25≤b≤2, 0.05≤a≤2, 0.3≤b+a≤3, 0.01≤y≤2, and 0.01≤y+c≤2.

[0124] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (5), 0.25≤b≤1.5, 0.05≤a≤1, 0.3≤b+a≤2.5, 0.01≤y≤2, 0≤c≤2, and 0.01≤y+c≤2.

[0125] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (6), 0≤h≤1, 0.01≤y≤2, 1+hy>0.

[0126] In some specific implementations, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid lithium-sulfur batteries and the solid lithium-sulfur batteries made therefrom, in the above formula (7), 0≤m≤1, 0≤n≤1, 0.01≤y≤2, 1+mny>0.

[0127] In some specific embodiments, the cathode material also includes sulfur-containing active materials.

[0128] In some specific embodiments, the sulfur-containing active material includes at least one of elemental sulfur, sulfur-selenium alloy, composite materials of sulfur and carbon, composite materials of sulfur and metal sulfides, Li2S, composite materials of Li2S and carbon, composite materials of Li2S and LiI, and composite materials of Li2S and metal sulfides.

[0129] The carbon material includes, but is not limited to, at least one of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement (VGCF), carbon nanotubes, mesoporous carbon, microporous carbon, graphene, and acetylene black.

[0130] The metal sulfides include, but are not limited to, at least one of iron sulfide, ferrous sulfide, titanium sulfide, nickel sulfide, cobalt sulfide, copper sulfide, zinc sulfide, manganese sulfide, and chromium sulfide.

[0131] In some specific embodiments, the positive electrode material also includes conductive carbon additives.

[0132] In some specific embodiments, in order to further improve the fast charging capability and cycle stability of the cathode material used in solid-state lithium-sulfur batteries and the solid-state lithium-sulfur batteries made therefrom, the mass ratio of the sulfur-containing active material, the conductive carbon additive and the iodine-containing ion-conducting additive is 30-95 (e.g., 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90): 0-50 (e.g., 5, 10, 15, 20, 25, 30, 35, 40 or 45): 5-70 (e.g., 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65).

[0133] In some specific embodiments, the conductive carbon additive includes at least one of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement, carbon nanotubes, mesoporous carbon, microporous carbon, graphene, and acetylene black.

[0134] It is understood that when the sulfur-containing active material contains carbon materials or other conductive materials, the aforementioned conductive carbon additive may not be added to the sulfur cathode of the solid lithium-sulfur battery.

[0135] Thirdly, this disclosure provides a method for preparing the cathode material for solid-state lithium-sulfur batteries, comprising the following steps:

[0136] The iodine-containing ion-conducting additive is mixed evenly with the sulfur-containing active material to obtain the cathode material used in solid-state lithium-sulfur batteries.

[0137] Alternatively, the iodine-containing ion-conducting additive can be mixed evenly with the sulfur-containing active material and the conductive carbon additive to obtain the cathode material for solid-state lithium-sulfur batteries.

[0138] The method for preparing cathode materials for solid-state lithium-sulfur batteries disclosed herein is simple to operate, has a short process, low cost, and is suitable for mass production.

[0139] Furthermore, by adding iodine-containing ion-conducting additives, the resulting cathode material exhibits high rate performance, fast charging capability, and excellent cycle stability.

[0140] In some specific embodiments, the mixing method includes at least one of grinding, ball milling, vibratory milling, and high-speed stirring. The ball milling speed can be 50–500 rpm, and the ball milling time can be 0.1–20 h, but is not limited thereto.

[0141] In some specific embodiments, the preparation method of the sulfur-containing active material includes: mixing the raw materials and heating them, wherein the mixing method is, for example, hand milling, ball milling, vibration milling and high-speed stirring, and the heating temperature is, for example, 100-300°C and held for 10-20 hours, and the heating can be carried out in a sealed vacuum quartz tube; the atmosphere for mixing and heating can be an inert atmosphere, but is not limited thereto.

[0142] Fourthly, this disclosure provides a fast-chargeable solid-state lithium-sulfur battery, including the positive electrode material for the solid-state lithium-sulfur battery.

[0143] Solid-state lithium-sulfur batteries containing the aforementioned cathode materials for solid-state lithium-sulfur batteries exhibit fast charging capability, high cycle stability, and high energy density.

[0144] Furthermore, the fast-charging solid-state lithium-sulfur battery disclosed herein utilizes sulfur, an extremely abundant and low-cost raw material on Earth, resulting in a battery manufacturing cost far lower than that of existing commercial lithium-ion batteries.

[0145] In some specific embodiments, the solid-state lithium-sulfur battery further includes a solid electrolyte membrane and a negative electrode.

[0146] In some specific embodiments, the solid-state lithium-sulfur battery may take the form of, but is not limited to, molded batteries, button batteries, pouch batteries, prismatic batteries, and cylindrical batteries.

[0147] In some specific embodiments, the negative electrode includes at least one of lithium metal, lithium alloy, graphite, silicon, silicon-carbon composite material, silicon oxide, and lithium-carbon material (referring to a composite material of lithium metal and carbon), but is not limited thereto.

[0148] In some specific embodiments, the lithium alloy includes, but is not limited to, at least one of lithium-indium alloy, lithium-magnesium alloy, lithium-aluminum alloy, lithium-boron alloy, lithium-tin alloy, and lithium-silicon alloy.

[0149] In some specific embodiments, the solid electrolyte membrane includes, but is not limited to, at least one of sulfide electrolytes, halide electrolytes, oxide electrolytes, polymer electrolytes, sulfide-polymer composite electrolytes, halide-polymer composite electrolytes, and oxide-polymer composite electrolytes.

[0150] In some specific embodiments, the cathode material for solid-state lithium-sulfur batteries is used to form a sulfur cathode, wherein the sulfur loading of the sulfur cathode is 0.5–20 mg·cm³. -2 including but not limited to 1 mg·cm -2 2mg·cm -2 3mg·cm -2 4mg·cm -2 5mg·cm-2 6mg·cm -2 8mg·cm -2 10mg·cm -2 12mg·cm -2 15mg·cm -2 18mg·cm -2 The sulfur loading refers to the point value of any one of the values ​​or the range between any two. The sulfur loading described in this disclosure refers to the content of active sulfur substances, such as sulfur and Li₂S, in the sulfur-containing active material of the sulfur cathode. The cathode material provided in this disclosure can be used to prepare sulfur cathodes with high areal loading, which can effectively improve the overall energy density of solid-state lithium-sulfur batteries.

[0151] In some specific embodiments, the solid-state lithium-sulfur battery with iodine-containing ion-conducting additives and / or the solid-state lithium-sulfur battery containing the cathode material for solid-state lithium-sulfur batteries has a specific capacity ≥1200 mAh·g at a 10C charging rate. - 1 Specific capacity at a 20C charging rate ≥1100mAh·g -1 Specific capacity at a 50C charging rate ≥750mAh·g -1 Specific capacity ≥ 500mAh·g at 100C charging rate -1 Specific capacity ≥ 400mAh·g at 150C charging rate -1 (60℃). Specific capacity (mAh·g) in this disclosure. -1 All values ​​are calculated based on the mass of active sulfur substances in the sulfur-containing active materials of the sulfur cathode, such as sulfur and Li2S.

[0152] In some specific embodiments, the solid lithium-sulfur battery with iodine-containing ion-conducting additives and / or the solid lithium-sulfur battery containing the cathode material for solid lithium-sulfur batteries has a capacity retention of ≥75% after 25,000 cycles at 5C.

[0153] Taking LiIn alloy anode as an example, assembling an all-solid-state lithium-sulfur battery in a mold battery includes the following steps: First, 70–150 mg of solid electrolyte powder is placed in a PEEK (polyether ether ketone) cylinder, and both ends are pressed with Ti rods under a pressure of 100–150 MPa for 0.5–3 minutes to form a solid electrolyte layer (i.e., a solid electrolyte membrane). Then, the positive electrode material for the solid-state lithium-sulfur battery is evenly spread on top of the solid electrolyte layer and pressed under a pressure of 300–350 MPa for 2–5 minutes. Indium foil and lithium foil are then attached to the other side of the solid electrolyte layer. Finally, the mold battery is placed in a stainless steel casing and a pressure of 20–70 MPa is applied.

[0154] Fifthly, this disclosure provides an electrical device including the aforementioned solid-state lithium-sulfur battery.

[0155] The solid-state lithium-sulfur battery has excellent fast-charging performance and long-cycle stability, and can be used in electrical equipment, such as electric vehicles, renewable energy storage, portable electronic devices, aerospace and other fields. This disclosure does not limit its application.

[0156] The embodiments of this disclosure will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this disclosure. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0157] Example 1

[0158] The method for preparing the cathode material for solid-state lithium-sulfur batteries provided in this embodiment includes the following steps:

[0159] Li₂S, B₂S₃, LiI, and P₂S₅ were weighed in a molar ratio of 30:25:45:5, melted at 800℃ for 20 hours, removed, and quickly quenched in an ice-water mixture. The mixture was then hand-ground into powder to obtain the iodine-containing ion-conducting additive Li. 3.5 B 1.67 P 0.33 S 4.33 I 1.5 (LBPSI). This refers to the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =1.5.

[0160] Elemental sulfur (S) and Ketjen black (KB) were weighed at a mass ratio of 75:25, ground, and then placed in a quartz tube and vacuum sealed. The tube was then placed in a muffle furnace and heated to 155°C at a heating rate of 1°C / min, and held at that temperature for 10 hours to obtain sulfur-containing active material.

[0161] The sulfur-containing active material, the iodine-containing ion-conducting additive, and conductive carbon black Super P (conductive carbon additive, abbreviated as SP) were weighed at a mass ratio of 4:5:1 and placed in a zirconia ball mill jar, with a mass ratio of zirconia beads to the material being milled of 40:1. The ball mill jar was sealed under an inert atmosphere. The ball mill jar was placed in a planetary ball mill and mixed uniformly at a speed of 500 rpm for 20 hours to obtain the positive electrode material for solid-state lithium-sulfur batteries.

[0162] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment includes the following steps: under an inert atmosphere, 80 mg of Li... 3.5 B1.67 P 0.33 S 4.33 I 1.5 The electrolyte was placed into a 10mm diameter PEEK cylinder, and both ends were pressed with custom-made Ti pillars at 128MPa for 1 minute to form a solid electrolyte membrane layer (the electrolyte powder for the membrane layer was Li). 3.5 B 1.67 P 0.33 S 4.33 I 1.5 (For ease of operation). Then, according to a sulfur loading of 1.1 mg·cm³, -2 (Based on elemental sulfur) The cathode material for solid-state lithium-sulfur batteries prepared above was uniformly spread on top of the solid electrolyte layer and pressed at 320 MPa for 3 minutes. A thin indium foil (9 mm in diameter) and a thin lithium foil (7 mm in diameter) were then attached to the other side of the solid electrolyte layer. The molded battery was then placed in a custom-made stainless steel casing and subjected to a pressure of 64 MPa to obtain an all-solid-state lithium-sulfur battery.

[0163] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 1 and 2. At 25°C and a fixed charge-discharge rate of 5C, the battery exhibited a capacity of 823 mAh·g. -1 The specific capacity is high, and the capacity retention rate after 25,000 cycles is 80.2%, demonstrating extremely high stability.

[0164] This indicates that the prepared solid-state lithium-sulfur battery sulfur cathode and its battery not only have high specific capacity, but also excellent cycle stability.

[0165] Example 2

[0166] The cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is the same as that in Example 1; the preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the sulfur loading in the cathode is 1.05 mg·cm³. -2 (Based on elemental sulfur).

[0167] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the all-solid-state lithium-sulfur battery was placed in a 60°C oven and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 3 and 4. At 60°C, with a fixed discharge rate of 2C and charge rates of 10C, 20C, and 50C, the corresponding specific capacities were 1361 mAh·g. -1 1162mAh·g -1 and 815mAh·g -1Even at charging rates of 100C and 150C, the battery still has a capacity of 594mAh·g. -1 and 432mAh·g -1 Its specific capacity demonstrates super-fast charging performance.

[0168] This indicates that the iodine-containing ion-conducting additive acts as a redox mediator, promoting the oxidation of Li2S. During fast charging, the I in the iodine-containing ion-conducting additive... - The iodine-containing ion-conducting additive is electrochemically oxidized to oxidized iodine at the interface between the iodine-containing ion-conducting additive and the conductive material in the sulfur cathode. Then, the oxidized iodine chemically oxidizes the Li2S in contact with it. The redox-mediated process on the surface of the iodine-containing ion-conducting additive allows the reaction to take place at the interface between the iodine-containing ion-conducting additive and Li2S, thereby improving the solid-state reaction kinetics of sulfur.

[0169] Example 3

[0170] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the mass ratio of sulfur-containing active material, iodine-containing ion-conducting additive and conductive carbon black Super P is replaced with 6:3.5:0.5.

[0171] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the sulfur loading in the positive electrode is 1.9 mg·cm³. -2 .

[0172] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 5 and 6. At 25°C and a fixed charge-discharge rate of 0.2C, the battery exhibited a capacity of 1049 mAh·g. -1 With a high specific capacity and stable cycling performance after 200 cycles, the capacity shows almost no decay. Therefore, all-solid-state lithium-sulfur batteries with a high sulfur content cathode also have high specific capacity and cycle stability.

[0173] Example 4

[0174] The cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is the same as that in Example 1; the preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the sulfur loading in the cathode is 6.3 mg·cm³. -2 .

[0175] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 7 and 8. At 25°C and a fixed charge-discharge rate of 0.1C, the battery exhibited a capacity of 1413 mAh·g.-1 The specific capacity is high, and the capacity retention rate after 100 cycles is 85.3%. Therefore, the battery with high sulfur loading cathode still exhibits high specific capacity and cycle stability.

[0176] Example 5

[0177] The cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is the same as that in Example 1; the preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the sulfur loading in the cathode is 1.0 mg·cm³. -2 .

[0178] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in a 60°C oven and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 9 and 10. At a fixed charge-discharge rate of 15C and 60°C, the specific capacity of the battery after 1000 cycles was 1110 mAh·g. -1 It still has 979mAh·g after 10,000 cycles. -1 Due to its high specific capacity, the battery still exhibits extremely high specific capacity and cycle stability at 60°C and high rate (15C).

[0179] Example 6

[0180] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. The iodine-containing ion-conducting additive in this embodiment is Li... 2.29 P 0.66 S 2.65 I 0.29 The preparation method is as follows: Li₂S, P₂S₅, and LiI are weighed according to the molar ratio of the target chemical formula, mechanically ball-milled and mixed, sintered at 250℃, and then ground into powder to obtain the iodine-containing ion-conducting additive Li. 2.29 P 0.66 S 2.65 I 0.29 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =0.29.

[0181] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is used, and the sulfur loading in the cathode is 1.0 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0182] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 11 and 12. At 25°C, under a fixed discharge rate of 1C and charge rates of 2C and 10C, the specific capacity was 1300 mAh·g. -1 and 660mAh·g -1 .

[0183] Example 7

[0184] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. In this embodiment, the iodine-containing ion-conducting additive is Li 3.5 B 1.67 S 3.5 I 1.5 The preparation method is as follows: Li₂S, B₂S₃, and LiI are weighed in a molar ratio of 30:25:45, fully melted at 800℃ for 10 hours, removed, rapidly cooled and quenched in an ice-water mixture, and then hand-ground into powder to obtain the iodine-containing ion-conducting additive Li. 3.5 B 1.67 S 3.5 I 1.5 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =1.5.

[0185] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is used, and the sulfur loading in the cathode is 1.0 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0186] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: at 25°C, with a discharge rate of 1C and a charge rate of 10C, the battery specific capacity was 680 mAh·g. -1 .

[0187] Example 8

[0188] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. In this embodiment, the iodine-containing ion-conducting additive is Li 2.29 P 0.66 As 0.1 S 2.9I 0.29 The preparation method is as follows: Li₂S, P₂S₅, LiI, and As₂S₅ are prepared according to the target chemical formula Li 2.29 P 0.66 As 0.1 S 2.9 I 0.29 The molar ratio was determined by weighing, and the mixture was mechanically ball-milled, sintered at 250℃, and then ground into powder to obtain iodine-containing ion-conducting additive Li. 2.29 P 0.66 As 0.1 S 2.9 I 0.29 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =0.29.

[0189] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Embodiment 1, except that: the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is used, and the sulfur loading in the cathode is 1.15 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0190] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: at 25°C, with a discharge rate of 1C and a charge rate of 10C, the battery specific capacity was 625 mAh·g. -1 .

[0191] Example 9

[0192] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. In this embodiment, the iodine-containing ion-conducting additive is Li 2.29 P 0.66 Si 0.05 S 2.75 I 0.29 The preparation method is as follows: Li2S, P2S5, LiI, and SiS2 are prepared according to the target chemical formula Li 2.29 P 0.66 Si 0.05 S 2.75 I 0.29 The molar ratio was determined by weighing, and the mixture was mechanically ball-milled, sintered at 250℃, and then ground into powder to obtain iodine-containing ion-conducting additive Li. 2.29 P 0.66 Si 0.05 S 2.75 I 0.29 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n.I =0.29.

[0193] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Example 1, except that the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment has a sulfur loading of 1.2 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0194] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: at 25°C, with a discharge rate of 1C and a charge rate of 10C, the battery specific capacity was 565 mAh·g. -1 .

[0195] Example 10

[0196] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. In this embodiment, the iodine-containing ion-conducting additive is Li 5.4 PS 4.4 Cl 0.8 I 0.8 The preparation method is as follows: Li₂S, P₂S₅, LiI, and LiCl are prepared according to the target chemical formula Li 5.4 PS 4.4 Cl 0.8 I 0.8 The molar ratio was determined by weighing, followed by mechanical ball milling, sintering at 550℃, and then grinding into powder to obtain iodine-containing ion-conducting additive Li. 5.4 PS 4.4 Cl 0.8 I 0.8 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =0.8.

[0197] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Embodiment 1, except that: the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is used, and the sulfur loading in the cathode is 1.15 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0198] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: at 25°C, with a discharge rate of 1C and a charge rate of 10C, the battery specific capacity was 640 mAh·g.-1 .

[0199] Example 11

[0200] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive and its preparation method are different. In this embodiment, the iodine-containing ion-conducting additive is Li 5.8 PS 4.8 Cl 0.6 Br 0.2 I 0.4 The preparation method is as follows: Li₂S, P₂S₅, LiI, LiCl, and LiBr are prepared according to the target chemical formula Li 5.8 PS 4.8 Cl 0.6 Br 0.2 I 0.4 The molar ratio was determined by weighing, followed by mechanical ball milling, sintering at 550℃, and then grinding into powder to obtain iodine-containing ion-conducting additive Li. 5.8 PS 4.8 Cl 0.6 Br 0.2 I 0.4 That is, the molar amount of iodine in each mole of iodine-containing ion-conducting additive, n. I =0.4.

[0201] The preparation method of the all-solid-state lithium-sulfur battery provided in this embodiment is basically the same as that in Embodiment 1, except that: the cathode material for solid-state lithium-sulfur batteries prepared in this embodiment is used, and the sulfur loading in the cathode is 1.15 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0202] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: at 25°C, with a discharge rate of 1C and a charge rate of 10C, the battery specific capacity was 620 mAh·g. -1 .

[0203] Example 12

[0204] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this embodiment is basically the same as that in Example 1, except that the mass ratio of sulfur-containing active material, iodine-containing ion-conducting additive and conductive carbon black Super P is replaced with 6.7:2.3:1.

[0205] Using the cathode material obtained in this embodiment, an all-solid-state lithium-sulfur battery was prepared by referring to the preparation method of the all-solid-state lithium-sulfur battery in Example 1.

[0206] The performance of the all-solid-state lithium-sulfur battery prepared in this embodiment was tested: the battery was placed in an oven at 30°C, and at a charge / discharge rate of 0.2C, the battery specific capacity was 890 mAh·g. -1 .

[0207] Comparative Example 1

[0208] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this comparative example is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive is replaced with Li₂ which does not contain iodine. 5.5 PS 4.5 Cl 1.5 The preparation method is as follows: Li₂S, P₂S₅, and LiCl are weighed according to the target chemical formula, mechanically ball-milled and mixed, sintered at 500℃, and then ground into powder to obtain Li. 5.5 PS 4.5 Cl 1.5 .

[0209] The preparation method of the all-solid-state lithium-sulfur battery provided in this comparative example is basically the same as that in Example 1, except that the cathode material prepared in this comparative example has a sulfur loading of 1.05 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 (Easy to operate)

[0210] The performance of the all-solid-state lithium-sulfur battery prepared in this comparative example was tested: the battery was placed in a 60°C oven and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 13 and 14. At 60°C, with a fixed discharge rate of 2C and a charge rate of 50C, the specific capacity was only 123 mAh·g. -1 .

[0211] Comparative Example 2

[0212] The cathode material for solid-state lithium-sulfur batteries prepared in Comparative Example 1 is used. The preparation method of the all-solid-state lithium-sulfur battery provided in this comparative example is basically the same as that in Comparative Example 1, except that the sulfur loading in the cathode is 1.1 mg·cm³. -2 .

[0213] The performance of the all-solid-state lithium-sulfur battery prepared in this comparative example was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 15 and 16. At 25°C and a fixed charge-discharge rate of 5C, the battery specific capacity rapidly decreased to 400 mAh·g. -1After 10,000 cycles, it only has 81 mAh·g. -1 Specific capacity.

[0214] Comparative Example 3

[0215] The cathode material for solid-state lithium-sulfur batteries prepared using Comparative Example 1 is shown. The preparation method of the all-solid-state lithium-sulfur battery provided in this comparative example is basically the same as that of Comparative Example 1, the difference being that the sulfur loading in the cathode is 1 mg·cm³. -2 .

[0216] The performance of the all-solid-state lithium-sulfur battery prepared in this comparative example was tested: the battery was placed in a 60°C oven and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 17 and 18. At 60°C and a fixed charge-discharge rate of 15C, the battery's specific capacity decayed very quickly, and after only a few hundred cycles, the battery had almost no capacity, which indicates severe side reactions in the battery.

[0217] Comparative Example 4

[0218] The preparation method of the cathode material for solid-state lithium-sulfur batteries provided in this comparative example is basically the same as that in Example 1, except that the iodine-containing ion-conducting additive is replaced with Li3PS4 which does not contain iodine. The preparation method is as follows: Li2S and P2S5 are weighed according to the target chemical formula, mechanically ball-milled and mixed, sintered at 250°C, and then ground into powder to obtain Li3PS4.

[0219] The preparation method of the all-solid-state lithium-sulfur battery provided in this comparative example is basically the same as that in Example 1, except that the cathode material prepared in this comparative example has a sulfur loading of 1 mg·cm³. -2 Additionally, the solid electrolyte powder in the solid electrolyte membrane layer was replaced with Li. 5.5 PS 4.5 Cl 1.5 .

[0220] The performance of the all-solid-state lithium-sulfur battery prepared in this comparative example was tested: the battery was placed in an oven at 25°C and constant current charge-discharge tests were performed on a NEWARE battery testing system. The test results are shown in Figures 19 and 20. At 25°C, under a fixed discharge rate of 1C and charge rates of 2C and 10C, the specific capacity was 1113 mAh·g. -1 and 422mAh·g - 1 .

[0221] The key parameters of each embodiment and each comparative example, as well as the electrochemical performance test results of the all-solid-state lithium-sulfur batteries of each embodiment and each comparative example, are shown in Table 1.

[0222] Table 1 Key parameters and electrochemical performance test results for each embodiment and comparative example.

[0223] As shown in Table 1, comparing Example 1 and Comparative Example 2, it is evident that under normal temperature conditions, the sulfur cathode prepared with iodine-containing ion-conducting additive (LBPSI) not only has a high specific capacity, but its assembled battery also exhibits significantly higher cycle stability than that prepared with iodine-free ion-conducting additive Li. 5.5 PS 4.5 Cl 1.5 Solid-state lithium-sulfur batteries were prepared using sulfur cathodes.

[0224] Comparing Example 2 with Comparative Example 1, and Example 5 with Comparative Example 3, it is evident that even at a high temperature of 60°C, the fast charging capability of the sulfur cathode prepared with iodine-containing ion-conducting additive (LBPSI) is far greater than that without iodine-containing ion-conducting additive (Li). 5.5 PS 4.5 Cl 1.5 The sulfur cathode.

[0225] Comparative Examples 6-11 with Comparative Example 4 illustrate that, under normal temperature conditions, the iodine-containing ion-conducting additive (Li) 2.29 P 0.66 S 2.65 I 0.29 Li 3.5 B 1.67 S 3.5 I 1.5 Li 2.29 P 0.66 As 0.1 S 2.9 I 0.29 Li 2.29 P 0.66 Si 0.05 S 2.75 I 0.29 Li 5.4 PS 4.4 Cl 0.8 I 0.8 Li 5.8 PS 4.8 Cl 0.6 Br 0.2 I 0.4 Solid-state lithium-sulfur batteries prepared using sulfur cathodes exhibit higher specific capacity than those prepared using Li3PS4 without iodine-containing ion-conducting additives.

[0226] As can be seen from Examples 3 and 12, even when a sulfur cathode is prepared with a low mass ratio of iodine-containing ion-conducting additive LBPSI, that is, when the sulfur loading ratio is very high, the solid-state lithium-sulfur battery prepared by it still has a high specific capacity and good cycle stability.

[0227] As can be seen from Example 4, the sulfur cathode prepared by the iodine-containing ion-conducting additive LBPSI still exhibits high specific capacity and good cycle stability in the solid-state lithium-sulfur battery under high areal loading (i.e., sulfur content per square centimeter) even at room temperature.

[0228] In summary, iodine-containing ion-conducting additives act as a redox medium in sulfur cathodes, effectively enhancing the reaction kinetics of lithium sulfide. Furthermore, the reversible redox effect of these additives does not disrupt the battery interface, resulting in stable, long-cycle performance.

[0229] This disclosure provides the application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries, enabling fast charging of the batteries. The iodine-containing ion-conducting additives contain iodine (I) with redox activity, which can act as a redox mediator to promote the oxidation of Li₂S. During fast charging, the I₂ in the iodine-containing ion-conducting additives... - Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics, reacting upon slight contact, which significantly improves the utilization rate of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-containing ion-conducting additive allows the reaction to occur at the two-phase boundary of the iodine-containing ion-conducting additive / Li₂S (which is typically inactive in other solid-state lithium-sulfur batteries), and its contact range is larger compared to the three-phase boundary of the iodine-containing ion-conducting additive / Li₂S / conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent fast-charging performance.

[0230] The application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries disclosed in this disclosure achieves high cycle stability in solid-state lithium-sulfur batteries. The reversible redox reaction of the iodine-containing ion-conducting additives prevents their continuous degradation, resulting in excellent cycle stability for both the sulfur cathode and the battery fabricated from them.

[0231] The cathode material for solid-state lithium-sulfur batteries disclosed herein enables fast charging of solid-state lithium-sulfur batteries by introducing a specific type of iodine-containing ion-conducting additive. Specifically, the iodine-containing ion-conducting additive contains iodine (I) element with redox activity, which can act as a redox mediator to promote the oxidation of Li₂S. During fast charging, the I in the iodine-containing ion-conducting additive... -Iodine can be electrochemically oxidized to an oxidized state at the electrolyte / conductive material interface, and then the oxidized iodine chemically oxidizes the Li₂S it contacts. The reaction between oxidized iodine and Li₂S exhibits ultrafast reaction kinetics, reacting upon slight contact, which greatly improves the utilization rate of Li₂S in the sulfur cathode. Furthermore, this redox-mediated process based on the surface of the iodine-containing ion-conducting additive allows the reaction to occur at the two-phase boundary of the iodine-containing ion-conducting additive / Li₂S (which is usually inactive in other solid-state lithium-sulfur batteries), and its contact range is larger compared to the three-phase boundary of the iodine-containing ion-conducting additive / Li₂S / conductive material. Through this redox-mediated strategy, the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery exhibit excellent fast-charging performance. Simultaneously, the introduction of the iodine-containing ion-conducting additive enables high cycle stability in solid-state lithium-sulfur batteries. Specifically, the reversible redox reaction of the iodine-containing ion-conducting additive avoids its continuous degradation, resulting in excellent cycle stability for the sulfur cathode of the solid-state lithium-sulfur battery and the resulting battery. Industrial applicability

[0232] This disclosure provides the application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries. The iodine-containing ion-conducting additives of this disclosure enable the sulfur cathode of solid-state lithium-sulfur batteries and the batteries made from it to exhibit fast-charging performance and high cycle stability.

Claims

1. The application of iodine-containing ion-conducting additives in the sulfur cathode of solid-state lithium-sulfur batteries, characterized in that, The iodine-containing ion-conducting additive acts as a redox mediator to promote the oxidation of Li₂S, wherein, during charging, the I₂ in the iodine-containing ion-conducting additive... - The iodine-containing ion-conducting additive is electrochemically oxidized to oxidized iodine at the interface between the iodine-containing ion-conducting additive and the conductive material in the sulfur cathode. Then, the oxidized iodine chemically oxidizes the Li2S in contact with it. Based on the redox-mediated process on the surface of the iodine-containing ion-conducting additive, the reaction at the interface between the iodine-containing ion-conducting additive and Li2S can be carried out, thereby improving the solid-state reaction kinetics of sulfur. The iodine-containing ion-conducting additive comprises a compound containing at least iodine, lithium, and sulfur, and the molar amount n of iodine in each mole of the iodine-containing ion-conducting additive is... I 0 <n I ≤2.

2. The application of the iodine-containing ion-conducting additive according to claim 1 in the sulfur cathode of a solid-state lithium-sulfur battery, characterized in that, The iodine-containing ion-conducting additive includes at least one compound from formula (1), formula (2), formula (3), formula (4), formula (5), formula (6) and formula (7): Formula (1): Li 2+y+z B 2x S 1+3x I y X z , where 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, and X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN; Equation (2): Li 2+y P 2d S 1+5d I y Where 0.2≤d≤0.5, 0 <y≤2; Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, 0 < y ≤ 2, and Q includes at least one of the elements As, Sb, and Bi; Formula (4): Li 2+y P 2s Z g S 1+5s+2g I y , where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, and Z includes at least one of the elements Si, Ge, and Sn; Formula (5): Li 2+y+c B 2b M 2a S 1+3b+5a I y A c , where 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi; A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN; Equation (6): Li 6-h PS 5-h Cl 1+h-y I y Where 0 ≤ h ≤ 2, 0 <y≤2,1+h-y≥0; Equation (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y Where, 0≤m≤2, 0≤n≤2, 0 <y≤2,1+m-n-y≥0。 3. The application of the iodine-containing ion-conducting additive according to claim 2 in the sulfur cathode of a solid-state lithium-sulfur battery, characterized in that, At least one of the following conditions must be met: (1) In the above formula (1), 0.25≤x≤2, 0.01≤y≤2, 0.01≤y+z≤2; (2) In the above formula (2), 0.25≤d≤0.5, 0.01≤y≤2; (3) In the above formula (3), 0.25≤e≤0.5, 0 <f≤0.25,0.01<y≤2; (4) In the above formula (4), 0.25≤s≤0.5, 0 <g≤0.125,0.01<y≤2; (5) In the above formula (5), 0.25≤b≤2, 0.05≤a≤2, 0.3≤b+a≤3, 0.01≤y≤2, 0.01≤y+c≤2; (6) In the above formula (5), 0.25≤b≤1.5, 0.05≤a≤1, 0.3≤b+a≤2.5, 0.01≤y≤2, 0≤c≤2, 0.01≤y+c≤2; (7) In the above formula (6), 0≤h≤1, 0.01≤y≤2, 1+hy>0; (8) In the above formula (7), 0≤m≤1, 0≤n≤1, 0.01≤y≤2, 1+mny>0.

4. The application of the iodine-containing ion-conducting additive according to claim 1 in the sulfur cathode of a solid-state lithium-sulfur battery, characterized in that, The sulfur cathode of the solid lithium-sulfur battery also includes sulfur-containing active materials, which include at least one of elemental sulfur, sulfur-selenium alloy, composite materials of sulfur and carbon materials, composite materials of sulfur and metal sulfides, Li2S, composite materials of Li2S and carbon materials, composite materials of Li2S and LiI, and composite materials of Li2S and metal sulfides.

5. The application of the iodine-containing ion-conducting additive according to claim 4 in the sulfur cathode of a solid-state lithium-sulfur battery, characterized in that, The sulfur cathode of the solid lithium-sulfur battery also includes conductive carbon additives.

6. The application of the iodine-containing ion-conducting additive according to claim 5 in the sulfur cathode of a solid-state lithium-sulfur battery, characterized in that, The mass ratio of the sulfur-containing active material, the iodine-containing ion-conducting additive, and the conductive carbon additive is 30–95: 5–70: 0–50.

7. A cathode material for solid-state lithium-sulfur batteries, characterized in that, The positive electrode material includes an iodine-containing ion-conducting additive, wherein the molar amount n of iodine element per mole of the iodine-containing ion-conducting additive is... I 0 <n I ≤2, the iodine-containing ion-conducting additive includes at least one compound from formula (1), formula (2), formula (3), formula (4), formula (5), formula (6) and formula (7): Formula (1): Li 2+y+z B 2x S 1+3x I y X z , where 0.15 ≤ x ≤ 4, 0 < y ≤ 2, 0 ≤ z ≤ 2, 0.05 ≤ y + z ≤ 2, and X includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN; Equation (2): Li 2+y P 2d S 1+5d I y Where 0.2≤d≤0.5, 0 <y≤2; Formula (3): Li 2+y P 2e Q 2f S 1+5e+5f I y , where 0.2 ≤ e ≤ 0.5, 0 < f ≤ 0.3, 0 < y ≤ 2, and Q includes at least one of the elements As, Sb, and Bi; Formula (4): Li 2+y P 2s Z g S 1+5s+2g I y , where 0.2 ≤ s ≤ 0.5, 0 < g ≤ 0.15, 0 < y ≤ 2, and Z includes at least one of the elements Si, Ge, and Sn; Formula (5): Li 2+y+c B 2b M 2a S 1+3b+5a I y A c , where 0.15 ≤ b ≤ 3, 0.05 ≤ a ≤ 3, 0.25 ≤ b + a ≤ 4, 0 < y ≤ 2, 0 ≤ c ≤ 2, 0 ≤ y + c ≤ 2, M includes at least one of P, As, Sb, and Bi, and A includes at least one of F, Cl, Br, BH4, CN, OCN, and SCN; Equation (6): Li 6-h PS 5-h Cl 1+h-y I y Where 0 ≤ h ≤ 2, 0 <y≤2,1+h-y≥0; Equation (7): Li 6-m PS 5-m Cl 1+m-n-y Br n I y Where, 0≤m≤2, 0≤n≤2, 0 <y≤2,1+m-n-y≥0。 8. The cathode material for solid-state lithium-sulfur batteries according to claim 7, characterized in that, The cathode material also includes sulfur-containing active materials.

9. The cathode material for solid-state lithium-sulfur batteries according to claim 8, characterized in that, The sulfur-containing active material includes at least one of elemental sulfur, sulfur-selenium alloy, composite materials of sulfur and carbon, composite materials of sulfur and metal sulfides, Li2S, composite materials of Li2S and carbon, composite materials of Li2S and LiI, and composite materials of Li2S and metal sulfides.

10. The cathode material for solid-state lithium-sulfur batteries according to claim 8, characterized in that, The cathode material also includes conductive carbon additives.

11. The cathode material for solid-state lithium-sulfur batteries according to claim 10, characterized in that, The mass ratio of the sulfur-containing active material, the conductive carbon additive, and the iodine-containing ion-conducting additive is 30–95: 0–50: 5–70.

12. The cathode material for solid-state lithium-sulfur batteries according to claim 10, characterized in that, The conductive carbon additive includes at least one of Ketjen black, conductive carbon black, vapor-grown carbon fiber reinforcement, carbon nanotubes, mesoporous carbon, microporous carbon, graphene, and acetylene black.

13. The method for preparing the cathode material for a solid-state lithium-sulfur battery according to any one of claims 8 to 12, characterized in that, The process includes the following steps: mixing an iodine-containing ion-conducting additive with a sulfur-containing active material, or mixing an iodine-containing ion-conducting additive with a sulfur-containing active material and a conductive carbon additive.

14. The method for preparing the cathode material for solid-state lithium-sulfur batteries according to claim 13, characterized in that, The mixing method includes at least one of grinding, ball milling, vibratory milling, and high-speed stirring.

15. A solid-state lithium-sulfur battery, characterized in that, Includes the cathode material for solid-state lithium-sulfur batteries as described in any one of claims 7 to 12.

16. The solid-state lithium-sulfur battery according to claim 15, characterized in that, The solid-state lithium-sulfur battery also includes a solid electrolyte membrane and a negative electrode.

17. The solid-state lithium-sulfur battery according to claim 16, characterized in that, The negative electrode includes at least one of lithium metal, lithium alloy, graphite, silicon, silicon-carbon composite material, silicon oxide, and lithium-carbon material.

18. The solid-state lithium-sulfur battery according to claim 16, characterized in that, The solid electrolyte membrane includes at least one of sulfide electrolyte, halide electrolyte, oxide electrolyte, polymer electrolyte, sulfide-polymer composite electrolyte, halide-polymer composite electrolyte, and oxide-polymer composite electrolyte.

19. An electrical appliance, characterized in that, Including the solid-state lithium-sulfur battery as described in any one of claims 15 to 18.

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