DESC:FIELD OF THE INVENTION
[0001] The present disclosure broadly relates to the field of battery. Particularly, the present disclosure relates to an electrolyte, more particularly to a solid electrolyte, and process of preparing the electrolyte.

BACKGROUND OF THE INVENTION
[0002] The rapid increase of lithium-ion batteries in daily life has raised concerns regarding safety and durability issues of lithium-ion batteries with liquid electrolytes due to volatile nature and side reactions between organic liquid electrolytes and electrodes. The replacement of organic liquid electrolytes with inorganic solid electrolytes has attracted enormous attention, because they not only offer a wide electrochemical stability window, but also make the batteries safer and more durable, with a higher energy density and simple battery design as well.
[0003] Therefore, all-solid-state lithium batteries (ASSLBs) with solid electrolytes are a promising candidate to support the demand for high energy density storage systems. In general, solid electrolytes can be classified as oxide-based electrolytes, sulphide-based electrolytes, and polymer-based electrolytes. Among them, polymer electrolyte and oxide-based electrolyte show low ionic conductivity and poor performance at room temperature.
[0004] The sulphide solid electrolytes are attracting much consideration due to the high ionic conductivity. Sulphide solid electrolytes often possess a wide electrochemical stability window, allowing them to be compatible with a broad range of electrode materials, including high-voltage cathodes and lithium metal anodes. This wide compatibility enhances the potential applications of sulphide-based solid-state batteries. Sulphide solid electrolytes can form intimate contact with electrode materials, leading to low interfacial resistance at the electrolyte-electrode interfaces. This low resistance is beneficial for promoting efficient charge/discharge processes and minimizing energy losses within the battery.
[0005] While sulphide solid electrolytes offer several advantages, they also come with some disadvantages and challenges. Sulphide-based materials can be chemically unstable in the presence of moisture and oxygen, leading to degradation of the electrolyte and reduced battery performance over time. This instability can result in the formation of sulphide species or side reactions, compromising the integrity of the electrolyte-electrode interfaces and reducing the cycle life of the battery. Many sulphide solid electrolytes exhibit poor mechanical properties, such as low fracture, toughness and brittleness. This can lead to mechanical failure or cracking of the electrolyte during battery operation, especially under mechanical stress or during cycling, compromising the overall reliability and safety of the battery. Sulphide solid electrolytes may exhibit poor compatibility with certain electrode materials, especially high-voltage cathodes or lithium metal anodes. This can lead to increased interfacial resistance, degradation of electrode performance, and poor cyclability of the battery.
[0006] The moisture sensitivity of sulphide electrolytes is a major concern in the wide commercialization of solid state batteries. The atmosphere in which sulphide solid electrolytes are handled requires special consideration because of the moisture reactivity of sulphide electrolyte and the release of toxic gas like H2S. As a result, their preparations must be conducted under protected conditions. This may increase the production cost of solid state batteries.
[0007] Generally, to reduce the moisture sensitivity and the unwanted reactions of sulphide electrolytes, various coatings on the surface of sulphide electrolytes are employed. However, most of the coatings are formed by the solvent process.
[0008] In recent years, the "dry coating" technology has garnered significant attention due to its elimination of the tedious solvent evaporation step and its alignment with environmentally friendly practices.
[0009] Therefore, there is a need in the art to develop a sulphide solid electrolyte with reduced moisture sensitivity.
[00010] The present invention discloses a sulphide solid electrolyte coated with a coating material and the coating is formed by without using the solvent.

OBJECTIVE OF THE INVENTION
[00011] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
[00012] An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
[00013] Another object of the present disclosure is to provide a sulphide solid electrolyte.
[00014] Yet another object of the present disclosure is to provide a composite sulphide electrolyte having a coating material on the surface of the sulphide electrolyte.
[00015] Still another object of the present disclosure is to provide a process to coat the coating material over the surface of the sulphide electrolyte by a solvent free process.
[00016] Yet another object of the present disclosure is to provide a surface coated composite sulphide electrolyte, which has a reduced moisture reactivity.
[00017] Still another object of the present disclosure is to provide a surface coated composite sulphide electrolyte, which has high ionic conductivity
[00018] Still another object of the present disclosure is to provide a process for the preparation of a composite sulphide electrolyte that is scalable and easy.
[00019] Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY OF THE INVENTION
[00020] In a first aspect of the present disclosure, there is provided a surface coated composite sulphide comprising a coating material is coated over the surface of the sulphide electrolyte.
[00021] In a second aspect of the present disclosure, there is provided a process for preparing the surface coated composite sulphide electrolyte, comprising: a. blending a polymer and sulphide solid electrolyte in a blade mixer at 80 degrees Celsius to get a first mixture; and b. mixing the first mixer in 800 to 1200 RPM for 2 to 8 minutes to melt and mix the polymer mix homogeneously followed by mixing at 1500 to 2500 RPM for 5 to 15 minutes to coat the polymer properly over the electrolyte surface, and further mix at 800 to 1500 RPM for 2 to 10 minutes for final homogenization of the surface coated composite sulphide electrolyte.
[00022] In a third aspect of the present disclosure, there is provided a surface coated sulphide electrolyte having a reduced moisture reactivity.
[00023] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[00024] The following drawings form a part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein. The present disclosure will now be described with the help of the accompanying drawing, in which:
[00025] Figure 1 illustrates the schematic representation of the surface coated composite sulphide electrolyte, in accordance with an embodiment of the present disclosure.
[00026] Figure 2 depicts the Field Emission Scanning Electron Microscopic (FESEM) images of 2(a) bare LPSCl and 2(b) surface coated composite LPSCl electrolyte.
[00027] Figure 3 depicts the Field Emission Scanning Electron Microscopic (FESEM) images of surface coated composite sulphide electrolyte coated with different weight percentages of polymeric coating material; 3(a) LPSCl electrolyte coated with 1.5 wt% of polymer, 3(b) LPSCl electrolyte coated with 1.75 wt% of polymer and 3(c) LPSCl electrolyte coated with 2 wt% of polymer
[00028] Figure 4 depicts the time-dependent electrochemical impedance measurement of, 4(a) bare LPSCl and 4(b) surface coated composite LPSCl electrolyte.

DETAILED DESCRIPTION OF THE INVENTION
[00029] Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing. Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well known processes, well-known apparatus structures, and well-known techniques are not described in detail. The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure.
[00030] As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise.
[00031] The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
[00032] Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
[00033] The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
[00034] The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary. While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure.
[00035] As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
[00036] The term “electrolyte” used herein refers to the sulphide-based solid electrolyte particles in the size ranges of 100nm- 20µm. The examples of electrolyte include but not limited to Li-P-S, LixMS4 (M: Ge, Sn, and As), Li6PS5X (X: Cl, Br and I), LixMPxSx (M: Sn, Si, and Al), Li2S-P2S5, Li2S-B2S3, Li2S-Si2S3, Li2S-SiS2, LiI-Li2S-B2S3, LiI-Li2S-SiS2, or combinations thereof.
[00037] The term “polymer” refers to ion-conducting or conductive polymers which 20 has a melting point in the range of 60 to 200°C. Examples of polymers include but not limited to polyethylene oxide, butadiene-styrene copolymer, poly methacrylic acid ester series, polyethylene glycol, polyvinyl chloride series, polyamide series, polyacrylonitrile series, polypropylene oxide, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl alcohol, polydimethylsiloxane, 25 polyvinylpyrrolidone, polyacrylonitrile, acrylonitrile-butadiene copolymer, polycarbonate series or combinations thereof.
[00038] The term “surface coated” refers to the surface of sulphide electrolyte is coated with the polymer.
[00039] The term “composite sulphide electrolyte” refers to the surface coated sulphide electrolyte comprising sulphide electrolyte and the polymer.
[00040] As discussed in the background, the sulphide-based solid-state electrolytes has the disadvantage of air instability. The instability in solid electrolytes can be addressed by slight modification of the interface between electrode and electrolyte or by introducing a protective coating over the particles of the electrolyte.
[00041] The present disclosure provides a solution to the atmospheric instability problem of the sulphide based solid electrolyte as well as long term stability of electrolyte. The processability of sulphide based solid electrolyte is made easier in dry room conditions. Also, the present disclosure, enhances the dry film processability for sulphide based solid electrolytes.
[00042] The present disclosure relates to the process of developing an ion conducting polymer coated sulphide based solid electrolyte for safer and long cycle-life batteries. More particularly, the present disclosure relates to a method of synthesizing thin layer coated sulphide based solid electrolyte assisted with ion-conducting polymer. This polymeric ion conduction coating layer reduces the moisture reactivity of sulphide electrolyte. Also provides a suitable lithium ion diffusion path as well as prevent the reaction between sulphide solid electrolyte and electrode. The polymer coated sulphide electrolyte can be directly used as a solid electrolyte conferring improved interfacial contact.
[00043] In an embodiment of the present invention a fast, scalable and the organic solvent free process is adopted, which is a green synthesis process, easy processing, and great commercial viability.
[00044] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte comprising: (a) an electrolyte; and (b) a polymer, wherein the electrolyte is a sulphide-based solid electrolyte, and the polymer is coated over the electrolyte.
[00045] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the electrolyte is selected from Li-P-S, LixMS4 (M: Ge, Sn, and As), Li6PS5X (X: Cl, Br, and I), LixMPxSx (M: Sn, Si, and Al), Li2S-P2S5, Li2S-B2S3, Li2S-Si2S3, Li2S-SiS2, LiI-Li2S-B2S3, LiI-Li2S-SiS2, or combinations thereof.
[00046] In an embodiment of the present disclosure, there is provided a composite as disclosed herein, wherein the polymer has a melting point in the range of 60 to 200°C.
[00047] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the polymer is in a weight range of 0.1 to 3% with respect to the total weight of the composite.
[00048] In an embodiment of the present disclosure, there is provided a sulphide electrolyte composite as disclosed herein, wherein the thickness of the polymer coating is in a range of 5 to 100 nm.
[00049] In an embodiment of the present disclosure, there is provided a sulphide electrolyte composite as disclosed herein, wherein the polymer is selected from polyethylene oxide, butadiene-styrene copolymer, poly methacrylic acid ester series, polyethylene glycol, polyvinyl chloride series, polyamide series, polyacrylonitrile series, polypropylene oxide, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl alcohol, polydimethylsiloxane, polyvinylpyrrolidone, polyacrylonitrile, acrylonitrile-butadiene copolymer, polycarbonate series, or combinations thereof. In a preferred embodiment the polymer is polyethylene oxide (PEO).
[00050] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the polymeric layer further comprises conducting additives selected from LiTFSI, LiClO4, LiFSI, LiPF6, LiBF6, LiBOB, LiPF6, or combinations thereof.
[00051] In an embodiment of the present disclosure, there is provided a sulphide electrolyte composite as disclosed herein, wherein the polymer further comprises non-volatile or non-flammable ionic liquid plasticizers selected from imidazolium-based (imidazolium), pyrrolidinium-based (pyrrolidinium), pyridinium-based (pyridinium), phosphonium-based (Phosphonium), piperidinium-based (piperidinium) plasticizers, or combinations thereof.
[00052] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the composite sulphide electrolyte has an ionic conductivity in a range of 10-4to 10-2 S/cm.
[00053] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the composite electrolyte has a reduced air sensitivity to an extend of 40-80%, prevents electrolyte-electrode reactivity.
[00054] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte as disclosed herein, wherein the composite electrolyte has an increase in resistance is in the range of 20-30 ohm in 9 hours.
[00055] In an embodiment of the present disclosure, there is provided a dry process for preparing the composite as disclosed herein, said process comprising: a. mixing one or more of a polymer with an electrolyte to obtain a first mixture; and b. processing the first mixture to obtain a composite.
[00056] In an embodiment of the present disclosure, there is provided a dry process as disclosed herein, wherein processing the first mixture is carried out by a process selected from mechanical stirring, hand milling, ball milling, roller milling, shear kneading or combinations thereof, at a temperature in the range of 60°C to 200°C.
[00057] In an embodiment of the present disclosure, there is provided a dry process as disclosed herein, wherein subjecting the first mixture to ball milling is carried out in a milling jar and weight ratio of the balls to first mixture is in a range of 5:1 to 10:1.
[00058] In an embodiment of the present disclosure, there is provided a dry process as disclosed herein, wherein the first mixture is milled at a speed in the range of 500 to 1000 rpm.
[00059] In an embodiment of the present disclosure, there is provided a dry process as disclosed herein, wherein ball milling the first mixture is carried out to attain a temperature in the range of 60 to 200°C.
[00060] In an embodiment of the present disclosure, there is provided a dry process as disclosed herein, wherein the composite is further allowed to cool to room temperature and dried to obtain the composite sulphide electrolyte comprising a polymer coating over the surface of sulphide electrolyte.
[00061] In an embodiment of the present disclosure, there is provided a dry process for preparing the composite as disclosed herein, said process comprising the steps of: a. mixing one or more of a polymer with an electrolyte to obtain a first mixture; and b. subjecting the first mixture to ball milling in a milling device at a temperature in the range of 20°C to 400°C, at a speed in the range of 500 to 1000 rpm and weight ratio of the balls to first mixture is in a range of 5:1 to 10:1, to obtain a composite; and c. allowing the composite to cool to room temperature and drying to obtain a dried composite.
[00062] In an embodiment of the present disclosure, there is provided a dry process for preparing the composite as disclosed herein, said process comprising the steps of: a. mixing one or more of a polymer with an additive selected from conducting additive, plasticizer or combinations thereof to obtain a 10 polymeric mixture; b. mixing the polymeric mixture with an electrolyte to obtain a first mixture; and c. subjecting the first mixture to ball milling in a ball mill at a temperature in the range of 20°C to 400°C, at a speed in the range of 500 to 1000 15 rpm and weight ratio of the balls to first mixture is in a range of 5:1 to 10:1, to obtain a composite; and d. allowing the composite to cool to room temperature and drying to a dried composite.
[00063] In an embodiment of the present disclosure, there is provided a dry process for preparing the composite sulphide electrolyte as disclosed herein, wherein mixing one or more of a polymer with an additive selected from conducting additive, plasticizer or combinations thereof to obtain a polymeric mixture is carried out with the weight ratio of polymer: conducting additive: plasticizer in a electrolyte; and (ii) a polymer, wherein the electrolyte is sulphide-based solid electrolyte and the polymer is coated over the electrolyte,
[00064] In an embodiment of the present disclosure, there is provided an electrochemical cell comprising: a) a cathode; b) an anode; and c) the composite sulphide electrolyte comprising: (i) a sulphide electrolyte and (ii) a polymer.
[00065] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte. The sulphide electrolyte is a Lithium Phosphorus Sulfur Chloride electrolyte (LPSCl). The particle size of LPSCl is in the range of 2 to 12 micrometer.
[00066] In an embodiment of the present disclosure, there is provided a composite sulphide electrolyte. The sulphide electrolyte is coated with a polymer.
[00067] In an embodiment of the present disclosure, the polymer is polyethylene oxide. The thickness of polymer coating over the sulphide electrolyte is in the range of 5 to 100 nm.
[00068] In an embodiment of the present disclosure, the polymer is coated in-situ during the mixing of polymer and sulphide electrolyte.
[00069] In an embodiment of the present disclosure, 97 wt% to 98.5 wt% of LPSCl electrolyte was blended with 1.5 to 3 wt% of PEO polymer in a blade mixture which was introduced to an external temperature of 80 Degree C using a hot bath. This mixture was further mixed at three different RPM for different intervals. Initially the mixture was mixed at 800 to 1500 RPM for 2 to 10 minutes to allow the polymer to mix homogeneously and melt followed by mixing at 1000 to 2500 RPM for 5 to 20 minutes for the polymer to coat properly over the electrolyte surface. For the final homogenization, the polymer coated electrolyte mixture is mixed at 800 to 1500 RPM for 2 to 10 minutes.
[00070] In a preferred embodiment, the composite sulphide electrolyte is prepared in a blade mixer.
[00071] The temperature is employed in the mixing process. Polyethylene oxide melts during the initial mixing as the melting temperature of PEO is in the range of 60°C to 67°C. The melted polymer coated homogeneously over the surface of sulphide electrolyte.
[00072] Although the subject matter has been described in considerable detail with reference to certain examples and implementations thereof, other implementations are possible.
[00073] Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.

EXAMPLES
[00074] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices, and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.
Materials and Methods
[00075] The various chemicals and solvents used in the present disclosure are as follows:
[00076] Polyethylene Oxide (PEO) and Li6PS5Cl

EXAMPLE 1
Preparation of composite sulphide electrolyte
[00077] A method of preparing the polymer coated sulphide-based solid electrolyte composite, according to an embodiment of the present invention, will now be described in more detail
[00078] 1.75 weight percentage of polyethylene oxide (PEO) was mixed homogeneously in a blade mixer with 98.23 weight percentage of LPSCl electrolyte powder for 5 minutes to obtain a first mixture. The blade mixture was introduced to an external temperature of 80-degree C using a hot water chiller. This mixture was then mixed at 3 different RPM for different intervals. The first mixture was initially mixed at 1000 RPM for 5 min to melt and mix the polymer homogeneously with the sulphide electrolyte. Then it was further mixed at 2000 RPM for 10 minutes for the polymer to coat properly over the electrolyte surface followed by mix at 1200 RPM for 5 min for final homogenization. The polymer melted during the mixing resulted a homogenous viscous medium for proper mixing as well as uniform coating of the polymer particles over the sulphide based solid electrolyte particles. The polymer coated sulphide electrolyte was further allowed to cool to room temperature to obtain the composite sulphide electrolyte.

EXAMPLE 2
Preparation of an electrochemical cell
[00079] The composite comprising a polymer coated sulphur-based solid electrolyte was prepared by the process explained above. The composite solid electrolyte was then sandwiched between a lithium metal anode and a nickel manganese cobalt oxide cathode. The whole electrochemical cell setup was then compressed by applying pressure.

EXAMPLE 3
Characterisation of the composite sulphide electrolyte
a. Field emission scanning electron microscopy (FESEM) analysis:
[00080] The morphological analysis of the composite sulphide electrolyte was analyzed using FESEM technique. Figure 1(a) depicts the FESEM image of bare LPSCL without the polymer coating. Figure 1(b) depicts the LPSCl particles coated with polymer without changing the morphology of bare LPSCl.
[00081] Figure 2 (a-c) depicts the FESEM image of different weight percentages of polymer coating over the LPSCl electrolyte particles. Figure 2(a) depicts that 1.5 wt% of PEO was not sufficient to coat all the particles of LPSCl electrolyte. Many uncoated LPSCl particles were observed. Figure 2(b) depicts that 1.75 wt% of PEO particles coated uniformly over all the particles of LPSCl. Figure 2(c) depicts that 2wt% of PEO which are in the agglomerated state. The PEO of 1.75 wt% was observed to be the optimum amount to coat the LPSCl electrolyte particles.

b. Electrochemical impedance spectral (EIS) analysis
[00082] Time-dependent Electrochemical impedance spectral (EIS) analysis of the obtained electrodes was carried out with bare LPSCl and PEO coated composite LPSCl.
[00083] Figure 3(a) depicts the impedance spectral analysis of bare LPSCL. For the bare system the increase in resistance is in the range of 100-120 ohm in 9 hours. Figure 3(b) depicts the impedance spectral analysis of PEO coated composite LPSCl. The coated system the increase in resistance is in the range of 20-30 ohm in 9 hours. This shows that the coated system has less reactivity with moisture. Hence, this seems to reduce the moisture reactivity hence enhancing utilization and processing in dry room condition.

ADVANTAGES OF THE PRESENT INVENTION
[00084] The present disclosure provides an electrolyte composite comprising (a) an electrolyte; and (b) a polymer, wherein the electrolyte is a sulphide-based solid electrolyte and the polymer is coated over the electrolyte. The composite sulphide electrolyte as disclosed in the present disclosure is stable in air and the electrochemical performance of the cell or ionic conduction is not affected even after introduction of a polymeric layer. The composite as disclosed herein, has a reduced air sensitivity and prevents electrolyte-electrode reactivity.
[00085] The process disclosed herein to obtain the composite sulphide electrolyte is a dry process wherein a solvent is not required. Hence, the process disclosed herein is a green synthesis, compatible and possess great commercial viability. The process also provides best results by avoiding the possibilities of perturbation caused by the solvents. The process disclosed is simple, economical and scalable. The present disclosure also provides an electrochemical cell comprising an anode, a cathode and the composite sulphide electrolyte as disclosed herein as the solid electrolyte wherein the electronic and ionic conduction along with the electrochemical performance of the cell is not significantly affected upon the incorporation of the polymeric coating over the solid electrolyte.
,CLAIMS:I/We Claim:
1. A solid electrolyte composite comprising:
i) a sulphide electrolyte; and
ii) a polymer;
wherein the melting point of the polymer is in the range of 60 to 200 °C and the polymer is coated over the sulphide electrolyte.
2. The electrolyte composite as claimed in claim 1, wherein the electrolyte is selected from Li-P-S, LixMS4 (M: Ge, Sn, and As), Li6PS5X (X: Cl, Br, and I), LixMPxSx (M: Sn, Si, and Al), Li2S-P2S5, Li2S-B2S3, Li2S-Si2S3, Li2S-SiS2, LiI-Li2S-B2S3, LiI-Li2S-SiS2, or combinations thereof.
3. The electrolyte composite as claimed in claim 1, wherein the polymer is in a weight range of 0.1 to 3% with respect to the total weight of the composite.
4. The electrolyte composite as claimed in claim 1, wherein the sulphide electrolyte is in a weight range of 97 % to 99.9 % with respect to the total weight of the composite.
5. The electrolyte composite as claimed in claim 1, wherein the polymer is selected from polyethylene oxide, butadiene-styrene copolymer, poly methacrylic acid ester series, polyethylene glycol, polyvinyl chloride series, polyamide series, polyacrylonitrile series, polypropylene oxide, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl alcohol, polydimethylsiloxane, polyvinylpyrrolidone, polyacrylonitrile, acrylonitrile-butadiene copolymer, polycarbonate series, or combinations thereof.
6. The electrolyte composite as claimed in claim 1, wherein the polymer coating optionally comprises ion conducting additives and ionic liquid plasticizers.
7. The electrolyte composite as claimed in claim 1, wherein the the composite has the ionic conductivity in a range of 10-4 to 10-2 10 S/cm.
8. The electrolyte composite as claimed in claim 1, wherein the the thickness of the polymer coating is in a range of 5 to 100 nm.
9. A dry process for preparing the composite as claimed in claims 1 to 8, said process comprising the steps of: process for preparing the integrated anode as claimed in claim 1, comprising:
a) mixing one or more of a polymer and an electrolyte to obtain a first mixture; and
b) processing the first mixture to obtain an electrolyte composite.
10. The process as claimed in claim 9, wherein processing the first mixture is carried out by a process selected from mechanical stirring, high shear mixing, hand milling, ball milling, roller milling, shear kneading, or combinations thereof, at a temperature in the range of 60°C to 200°C.