Dendrite-free electrode and a metal ion battery comprising the same

Abstract

The present invention relates to an electrode material comprising an electrode active material having an additive comprising 5 wt.% to 90 wt.% of nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, said nanoparticles having an average particle size ranging between 20 nm to 500 nm and are selected from Sn, (Sn6O4(OH)4), Sn(OH)2, SnO, SnO2, Si, SiO, SiO2, Ge, and Sb, 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 500 nm, and optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I; along with one or more binders, and one or more selected from an electrically conductive carbon, solvents, solvent additives, and acids.

Description

Voltrez-2024210615221TITLE OF THE INVENTION DENDRITE-FREE ELECTRODE AND A METAL ION BATTERY COMPRISING THE SAMETECHNICAL FIELD

[0001] The present invention relates to an electrode material. The present invention also relates to a method of preparing the electrode material and a metal-ion battery comprising the same.BACKGROUND OF THE INVENTION

[0002] Batteries are classified according to their rechargeability into primary and secondary batteries. Primary batteries such as alkaline batteries and Aluminium-air batteries are single use items that produce energy by an irreversible chemical reaction that consumes the electrode and / or electrolyte. Primary batteries cannot be recharged once they are depleted. Secondary batteries in comparison can be recharged due to the reversible nature of the chemical reactions they use to produce energy. Secondary batteries can be charged by supplying an external DC power source of reverse polarity to that of the battery terminals and at slightly higher voltage than that produced by the battery itself. During charging the positive active material is oxidised generating free electrons which reduce the negative active material under the influence of the external power source. Common example of secondary batteries includes lead-acid batteries, lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, etc.

[0003] Typically, in a secondary battery two electrodes and an electrolyte are commonly employed with electrochemical reactions proceeding at both electrodes. Commonly used battery types are characterized by their choice of electrolyte and electrode. For instance, lead acid batteries contain lead electrodes (pure lead or lead oxides) in an acidic electrolyte such as sulfuric acid. Metal ion batteries are a type of secondary battery currently in high demand due to their higher power density and favourable charge-discharge properties. Typical examples of metal -ion batteries reported in various studies include sodium, lithium, potassium, magnesium, calcium, and fluorine- ion batteries.

[0004] Metal ion batteries use a variety of electrode types based on the desired properties of the battery and the choice of electrolyte. Earlier lithium batteries used pure Li metal sheets or films as the negative electrode (anode) which resulted in certain problems regarding safety and reactivity of the Li metal if contacted by air or water. For this reason, lithium ion and lithium polymer batteries were developed where the modern lithium batteries use conductive carbonaceous materials in construction of the anode.Voltrez-2024210615222

[0005] In addition to carbon, other materials have been included in the construction of anodes for metal ion batteries. These include metal oxides, metal nitrides, metal sulphides, and a range of metals, metal alloys, and intermetallic compounds that can accommodate lithium atoms / ions in stoichiometric and non-stoichiometric quantities. The carbon and transition metal compounds also provide for the intercalation of Li ions in the anode material during the lifespan of the cell. As the cells charge and discharge, Li ions from the electrolyte permeate the anode and deposit along the interface between the anode and the electrolyte. This leads to the formation of a solid electrolyte interface (SEI) layer. During the first charge of a lithium-ion battery, some of the lithium ions become trapped on the anode material surface, forming a solid electrolyte interphase (SEI) layer. This SEI layer is crucial for the battery's long-term stability but results in a loss of active lithium, reducing the battery's initial capacity. This leads to an irreversible loss of capacity which leads to formulated cell having lower actual capacity than ideally required. Additionally, use of compounds such as sulphides leads to significant challenges including loss of metal ions due to formation of metal sulphides. Anodes made of metal sulphide demonstrate poor long-term stability with significant degradation observable after -200 charge-discharge cycles, along with difficulty in synthesis and binder compatibility due to the presence of sulphur in the anode material. To address these shortcomings, a stable and non-degrading material is desired for anode construction.

[0006] Pre-lithiation is a process used in the development of lithium-ion batteries to improve their performance and lifespan. It involves the intentional addition of lithium to the anode material before the battery is fully assembled and cycled. This helps to offset the initial loss of lithium that typically occurs during the first charge and discharge cycles, known as the "first cycle irreversible capacity loss." Pre-lithiation compensates for this loss by ensuring there is sufficient lithium available, which can improve the overall energy density and efficiency of the battery.

[0007] Pre-lithiation can be achieved through various methods, such as chemical, electrochemical, and mechanical techniques. Each method has its own advantages and challenges, and the choice of method depends on factors like the specific anode material used and the intended application of the battery. For instance, pre-lithiation may be performed by deposition of Li metal through chemical vapour deposition (CVD), physical vapour deposition (PVD) or by electrospinning. These steps add a further complexity to the manufacture of anodes for lithium-ion batteries.

[0008] Another problem with the standard anode construction is that over sufficient number of charge and discharge cycles, the electrolyte at the anode chamber decomposes and further causes increase in the thickness of the SEI layer. Typically, this deposition is uneven and results in the growth of Li metal in tree-like structures called dendrites. These dendrites significantly impact performance of the anode and may even grow over time to pierce the separator and contact theVoltrez-2024210615223 cathode, causing internal short-circuiting of the cell.

[0009] Several methods and techniques are employed in lithium-ion cell technologies to mitigate dendrite formation and deposition of metallic lithium on the anode surface. Commonly used approaches to reduce dendrite formation include use of electrolyte additives such as lithium salts (e.g., LiNCh, LiTFSI) or other compounds (e.g., fluoroethylene carbonate, FEC); surface coatings on the anode material (e.g., with polymers, ceramics, or conductive carbon materials); optimizing the composition and concentration of electrolyte components such as solvents and salts; use of advanced separator materials that are more resistant to puncture or degradation; controlling the operating temperature range of the battery; implementing current limiting during charging and discharging and employing optimized cycling protocols; Cell design modifications, such as altering the physical structure of the anode or separator and developing solid-state electrolytes that do not rely on liquid components can potentially eliminate the issues associated with liquid electrolytes, including dendrite formation and SEI instability.

[0010] These methods are often combined and tailored based on the specific requirements and characteristics of the battery application to achieve the best balance between performance, safety, and longevity. However, none of these are satisfactory in fully solving the problems associated with the dendrite formation. Similar issues also exist with the construction of sodium or other metal ion batteries.[Oi l] Further, the uneven adsorption of Li ions needs to be remedied by ensuring that the Li ions released from the electrolyte during the gradual breakdown of the electrolyte are deposited uniformly across the surface of the electrode instead of as dendrites. For this, homogeneous adsorption of Li ions on the surface of the anode is of primary importance.

[0012] Thus, there is a need in the art to provide an electrode material and a method for preparing the same which provides these advantageous properties.SUMMARY OF THE INVENTION

[0013] An aspect of the present invention relates to an electrode material. In an embodiment, the electrode material is a dendrite-free electrode material comprising an electrode active material having an additive comprising 5 wt.% to 90 wt.% of nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, said nanoparticles having an average particle size ranging between 20nm to 500 nm and are selected from Sn, (SneO4(OH)4), Sn(OH)2, SnO, SnCh, Si, SiO, SiCh, Ge, and Sb, 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 500 nm, and optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I, wherein wt.% is based on the total weight of the additive;Voltrez-2024210615224 along with one or more binders, and one or more selected from the following: an electrically conductive carbon, solvents, solvent additives, and acids.

[0014] In an embodiment, the carbon source is selected from carbon black, acetylene black, carbon nanotubes, and carbon nanofibers.

[0015] In another embodiment, the elements or compounds of Group I is selected from LiOH, Li2CO3, LiF, LiCl, LiBr, Lil, LiNO3, and Li2SO4.

[0016] In another embodiment, the additive is in the form of nanoparticles spaced apart within the electrode active material at a separation ranging between 200 nm to 500 nm.

[0017] In another embodiment, the additive is obtained by mixing one or more elements or compounds of Group 14 and / or Group 15 with a solvent and water to obtain a homogeneous mixture, mixing the homogeneous mixture with a chelating agent for a duration ranging between Ih to 4h, adding a pH adjusting agent to the homogeneous mixture to obtain a first suspension, centrifuging the first suspension to obtain a precipitate comprising nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, drying a mixture comprising 5 wt.% to 90 wt.% of the nanoparticles of the elements or compounds of Group 14 and / or Group 15, and 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 300 nm, at a temperature ranging between 60°C to 100°C for a duration ranging between Ih to 40h to obtain a nanocomposite comprising the nanoparticles of one or more elements or compounds of Group 14 and / or Group 15 and carbon, mixing the nanocomposite with one or more carbon source, optionally one or more auxiliaries, and optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I to obtain a second suspension, and drying the second suspension at a temperature ranging between 60°C to 100°C for a duration ranging between Ih to 40h to obtain a powder comprising the additive.

[0018] In another embodiment, the solvent is selected from deionized water, acetone, and isopropyl alcohol; and the pH adjusting agent is selected from ammonia, KOH, and NaOH.

[0019] In a further embodiment, the electrode material further comprises the step of reducing the powder in presence of a reducing agent at a temperature ranging between 600°C to 800°C to obtain nanoparticles of the additive, wherein the average particle size ranges between lOnm to 500nm.

[0020] In yet another embodiment, the electrode active material is obtained by mixing the additive with the one or more carbon source to obtain a first mixture; heating the first mixture at a temperature ranging between 600°C to 800°C to obtain a reduced first mixture, and milling a second mixture comprising a conductive carbon material and the reduced first mixture at a temperature less than 200°C to obtain the electrode active material.

[0021] In another embodiment, prior to milling the second mixture the reduced first mixture isVoltrez-2024210615225 subjected to heating in ambient air at a temperature ranging between 180°C to 250°C.

[0022] In another embodiment, the conductive carbon material is selected from natural graphite, artificial graphite, flake graphite, hard carbon, and mesocarbon microbeads (MCMB).

[0023] Another aspect of the present invention relates to a method for preparing the dendrite-free electrode material. In an embodiment, the method comprises mixing the electrode active material with the one or more binders and one or more selected from the following: electrically conductive carbon, solvents, and acids, to obtain a slurry; coating the slurry on a substrate to obtain a coated substrate, and drying the coated substrate at a temperature ranging between 80°C to 120°C; wherein the electrically conductive carbon, solvents, solvent additives, and acids are present in an amount such that the viscosity of the slurry ranges between 3000 to 8000 cPs at 25°C.

[0024] In an embodiment, the binder comprises a carbon nanotube suspension in an amount ranging between 0.04 wt.% to 0.1 wt.% based on the total weight of the electrode material.

[0025] In another embodiment, the method of preparing the dendrite-free electrode material further comprises the step of calendaring the coated substrate.

[0026] Yet another aspect of the present invention relates to a metal-ion battery comprising the dendrite-free electrode material as disclosed above or obtained from the aforesaid method, along with an electrolyte.BRIEF DESCRIPTION OF FIGURES

[0027] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.Figure 1 shows an SEM image of an additive in accordance with an embodiment.Figure 2 is an SEM image of an anode after 621 cycles at 1C-1C in accordance with an embodiment of the present invention.Figure 3 is an SEM image of an anode after 200 cycles at 3C-3C in accordance with an embodiment of the present invention.Figure 4 shows a cell formation protocol in accordance with an embodiment of the present invention.Figure 5 shows a cycle life of a pouch cell containing an anode in accordance with an embodiment of the present invention.Voltrez-2024210615226Figure 6 shows SEM images of an anode after 614 cycles at 1C-1C in accordance with an embodiment of the present invention.Figure 7 shows SEM images of an anode after 621 cycles at 1C-1C in accordance with an embodiment of the present invention.Figure 8 shows SEM images of an anode after 732 cycles at 1C-1C in accordance with an embodiment of the present invention.Figure 9 shows SEM images of an anode after 200 cycles at 3C-3C in accordance with an embodiment of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0028] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.

[0029] At the outset, it is stated that the terms "comprising", "comprises" and "comprised of' as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of' as used herein comprise the terms "consisting of', "consists" and "consists of'.

[0030] In the following passages, different aspects of the invention are defined. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0031] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the presently claimed invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of this invention, and form different embodiments, as would be understood by those skilled in the art.

[0032] As used herein, the terms “lithiate” and “lithiation” may refer to a process of adding lithium to an electrode active material. Similarly, the terms “sodiate” and “sodiation” may refer to aVoltrez-2024210615227 process of adding sodium to the electrode active material.

[0033] As used herein, the terms “charge” and “charging” may refer to a process of providing electrochemical energy to a cell or battery.

[0034] Further, the terms “discharge” and “discharging” refer to a process for removing electrochemical energy from a cell or battery, for example, when using the cell or battery to perform desired work.

[0035] Furthermore, the term “positive electrode” may refer to an electrode (often called a cathode) where electrochemical reduction occurs during a discharging process. Similarly, the term “negative electrode” may refer to an electrode (often called an anode) where electrochemical oxidation occurs during a discharging process.

[0036] An aspect of the present invention is directed towards an electrode material.

[0037] In an embodiment, the electrode material is dendrite-free (hence, dendrite-free electrode material). The term 'dendrite-free' indicates the absence or minimal presence of such dendritic growths to a degree that they do not significantly impair the performance, safety, or structural integrity of the battery or cell.

[0038] In an embodiment, the electrode material comprises an electrode active material having an additive, one or more binders, and one or more selected from an electrically conductive carbon, solvents, solvent additives, and acids.

[0039] In another embodiment, the dendrite-free electrode material comprises an electrode active material having an additive comprising 5 wt.% to 90 wt.% of nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, said nanoparticles having an average particle size ranging between 20nm to 500 nm and are selected from Sn, (SneO^OFfh), Sn(OH)2, SnO, SnCh, Si, SiO, SiCh, Ge, and Sb, 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 500 nm, and optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I, wherein wt.% is based on the total weight of the additive; along with one or more binders, and one or more selected from the following: an electrically conductive carbon, solvents, solvent additives, and acids.

[0040] Group 14 and / or Group 15 of the Periodic Table includes transition metals, particularly having electrically active properties. In an embodiment, the Group 14 and / or Group 15 elements are selected from Sn, Si, Ge, and Sb. The compounds of 14 and / or Group 15 elements include oxides, hydroxides, and sulphides. In a preferred embodiment, Group 14 and / or Group 15 elements or compounds are selected from Sn, (SneO4(OH)4), Sn(OH)2, SnO, SnO2, Si, SiO, SiO2, Ge, and Sb.

[0041] In another embodiment, the Group 14 and / or Group 15 elements or compounds possessVoltrez-2024210615228 nano-scale morphology having an average particle size ranging between 20 nm to 500 nm. In an embodiment, the average particle size ranges between 20 nm to 200 nm. In yet another embodiment, the average particle size ranges between 30 nm to 60 nm.

[0042] In another embodiment, the carbon source is selected from carbon black, acetylene black, carbon nanotubes and carbon nanofibers, and having an average particle size ranging between 20 nm to 500 nm. In an embodiment, the carbon source has an average particle size in the range of 20 nm to 300 nm. In another embodiment, the average particle size ranges between 45 nm to 100 nm. The carbon source has different morphologies including micro-scale particulates of carbon such as but not limited to carbon black, acetylene black; nano-scale spherical carbons including carbon black, acetylene black, Super P, and the likes; and non-spherical carbons such as singlewalled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanofibers.

[0043] In another embodiment, the carbon source does not include graphene, graphene composites, and / or their derivatives.

[0044] In an embodiment, the additive does not include one or more Group 1 element or compound thereof.

[0045] In another embodiment, the additive comprises one or more Group 1 element or compound thereof. The Group 1 element is selected from Li or Na. Suitable compounds include LiOH, Li2CO3, LiF, LiCl, LiBr, Lil, LiNO3, and Li2SO4.

[0046] In another embodiment, the additive further comprises up to 5 wt.% of one or more auxiliaries selected from binding agent, sugar, and organic acid.

[0047] In an embodiment, suitable binders / binding agents include, but are not limited to polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid, alginic acid, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose (HPC), regenerated cellulose, polyvinylpyrrolidone (PVP), tetrafluoroethylene (TFE), polyethylene (PE), polypropylene (PP), an ethyl ene-propylene- diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), and fluorinated rubber. Further, suitable sugars include monosaccharides and / or disaccharides such as but not limited to glucose and sucrose. Furthermore, the organic acids include, but are not limited to, oxalic acid and citric acid.

[0048] In an embodiment, the nanoparticles of one or more elements or compounds of Group 14 and / or Group 15 is present in an amount ranging between 5 wt.% to 90 wt.% based on the total weight of the additive. In another embodiment, the one or more carbon source is present in an amount ranging between 5 wt.% to 90 wt.% based on the total weight of the additive. In yet another embodiment, the one or more elements or compounds of Group I is added in an amount ranging between 5 wt.% to 90 wt.% based on the total weight of the additive. In a further embodiment, theVoltrez-2024210615229 one or more auxiliaries and / or chelating agent is added in an amount ranging up to 5 wt.% based on the total weight of the additive.

[0049] In a further embodiment, the weight ratio between the one or more elements or compounds of Group 14 and / or Group 15, the one or more carbon source, and the one or more elements or compounds of Group I is 1 : 1 : 1.

[0050] Preferably, nanoparticles of the additive are used in the electrode active material. Advantageously, the uniform distribution of the additive assists in uniform distribution of metal ions in a metal-ion battery, thereby minimizing the dendrite formation or rendering the electrode dendrite-free. In fact, it has been observed that the nanoparticles spaced apart within 200nm to 500nm result in the 20 absence of dendrite formation. The presence of additive also ensures that the metal ion adsorption is uniform and in fact, there is a reduced deposition of the free metal ions without forming a bond with the additive or the base active material. Since the deposition of metal ions reduces due to the additive, hence the conversion from metal ions to metal also reduces. These metal depositions or metal plating occur in a controlled fashion due to the spacing between the additive particles in the electrode and are distributed at a distance from each other on the surface of active material particles preventing the plated metals to agglomerate or nucleate. Thereby the uniform distribution of the additive prevents nucleation of plated metal, which results into elimination of the dendritic structures. In fact, it has been observed that the nanoparticles spaced apart within 200nm to 500nm result in the absence of dendrite formation. The presence of additive also ensures that the metal ion adsorption is uniform and in fact, there is a reduced deposition of the free metal ions without forming a bond with the additive or the base active material. When the additive of the present invention is distributed on micron size graphite particle, it gets distributed and arranged with a spacing of -200 nm range. The additive nanoparticles then act as a catalyst to adsorb lithium ions in a controlled fashion on the surface.

[0051] In another embodiment, the additive is obtained from the method as described follows: a. mixing one or more elements or compounds of Group 14 and / or Group 15 with a solvent and water to obtain a homogeneous mixture, b. mixing the homogenous mixture with a chelating agent for a duration ranging between Ih to 4h, c. adding a pH adjusting agent to the homogeneous mixture to obtain a first suspension, d. centrifuging the first suspension to obtain a precipitate comprising nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, e. mixing 5 wt.% to 90 wt.% of the nanoparticles of the elements or compounds of Group 14 and / or Group 15, and 5 wt.% to 90 wt.% of one or more carbon source having an averageVoltrez-20242106152210 particle size ranging between 20 nm to 500 nm, followed by drying at a temperature ranging between 60°C to 100°C for a duration ranging between 1 h to 40 h to obtain a nanocomposite comprising the nanoparticles of one or more elements or compounds of Group 14 and / or Group 15 and carbon, f. mixing 5 wt.% to 90 wt.% of one or more elements or compounds of Group I with the one or more carbon source, the nanocomposite, and up to 5 wt.% of one or more auxiliaries to obtain a second suspension, and g. drying the second suspension at a temperature ranging between 60°C to 100°C for a duration ranging between 1 h to 40 h to obtain the additive.

[0052] In an embodiment, the solvent is selected from deionized water, acetone, and isopropyl alcohol.

[0053] In another embodiment, the pH adjusting agent is selected from ammonia, KOH, and NaOH.

[0054] The additive also contains a chelating agent. The chelating agent functions to stabilize the nanoparticles in dispersion and prevent excessive agglutination. Suitable chelating agents include, but are not limited to, diethanolamine (DEA), triethanolamine (TEA), ethylenediaminetetraacetic acid (EDTA), citric acid, nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTP A), hydroxyethyl ethylenediaminetriacetic acid (HEDTA), glycine, malic acid, tartaric acid, phytic acid, dimercaptosuccinic acid (DMSO), and cyclohexane.

[0055] In another embodiment, the method further comprises the step of reducing the powder in presence of a reducing agent at a temperature ranging between 600°C to 800°C to obtain the nanoparticles of the additive having an average particle size ranging between lOnm to 500nm.

[0056] In an embodiment, the reduction is carried out in the presence of a reducing agent selected from hydrogen, argon, nitrogen, and combinations thereof. The reducing step involves subjecting one or more of the following: SneO OH Sn(OH)2, SnO, SnCE, SiO, and / or SiCE, to thermal reduction process in the presence of a reducing agent (e.g., hydrogen gas) at temperatures ranging from 600 °C to 800 °C. This reduction results in the conversion of metal oxides and hydroxides into their corresponding elemental (zero-valent) metallic forms, yielding highly conductive nanoparticles. For instance, tin-based compounds such as SneO OH Sn(OH)2, SnO, and / or SnO2 are reduced to form elemental tin (Sn°) nanoparticles, while silicon-based oxides such as SiO and SiO2 are reduced to form elemental silicon (Si0).

[0057] Mixing, in the present context, is carried out using suitable mixing means. For instance, the mixing means can be selected from a hydrodynamic shear mixer, a granulator, a ball mill, and the likes. As will be noted above, the present invention mitigates the use of complex methods suchVoltrez-20242106152211 as vapor deposition techniques (physical and chemical both) or electrochemical routes. In fact, the present invention provides pre-lithiation or pre-sodiation using a simple chemical synthesis route.

[0058] In an embodiment, the electrode active material comprises suitable amounts of the additive, and the one or more carbon sources. Further, the one or more elements or compounds of Group I may also be added. Other materials which are generally added to the electrode active material include binders, solvents, and surfactants. These ingredients may be added in suitable amounts to achieve the desired effect, i.e., dendrite-free structure.

[0059] In an embodiment, the electrode active material is an anode active material.

[0060] In yet another embodiment, the electrode active material is obtained by mixing the additive with the one or more carbon source to obtain a first mixture; heating the first mixture at a temperature ranging between 600°C to 800°C to obtain a reduced first mixture; and milling a second mixture comprising a conductive carbon material and the reduced first mixture at a temperature less than 200°C to obtain the electrode active material.

[0061] Suitable examples of the electrically conductive material include natural graphite, artificial graphite, flake graphite, hard carbon, mesocarbon microbeads (MCMB), and other electrode active materials. Other electrode active materials include Lithium Titanate Oxide (LTO), Niobium Titanium Oxide (NTO), and the likes. Further, suitable examples of the one or more carbon source here include natural graphite, artificial graphite, flake graphite, hard carbon, and mesocarbon microbeads (MCMB).

[0062] In an embodiment, heating is carried out in presence of a reducing agent. Suitable reducing agents include H2, Ar-Fb, and N2-H2.

[0063] In another embodiment, the method is devoid of a template agent. The template agent creates a specific structure or morphology in the electrode material. Particularly, the template agent results in the electrode material in a specific form, such as porous structures, nanowires, nanoparticles or nanotubes. Once the desired structure is formed, the template agent is usually removed, leaving behind a structured electrode material.

[0064] In another embodiment, prior to milling the second mixture the reduced first mixture is subjected to heating in ambient air at a temperature ranging between 180°C to 250°C. This step results in the formation of oxides on a surface of the electrode active material which makes it air stable and also increases the shelf life. This heating step is flexible based on the target materials, which will be evident to persons skilled in the art based on their choice of electrode material ingredients.

[0065] Typically, mixing is carried out using suitable means, such as ball mill, blenders, air mill, and jet mill. In an embodiment, milling is carried out in dry state. In another embodiment, millingVoltrez-20242106152212 is carried out in wet state, i.e., in the presence of deionized (DI) water, and solvents.

[0066] In an embodiment, ball milling in dry condition is carried out with 3-10 mm diameters balls having a weight ratio between material to ball in the range of 1 :3 to 1 : 10. The temperature prevalent during milling in dry state is room temperature.

[0067] As noted in Figure 1, the electrode active material has a uniform distribution of Group 14 and / 15 elements on its surface. This contributes to a dendrite free electrode material.

[0068] Suitable binders in the electrode material are selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyacrylic acid (PAA), and cross-linked binders. Suitable examples of cross-linked binders include, but are not limited to, PAA-divinylbenzene (DVB), CMC-citric acid, and PVA- boric acid.

[0069] Suitable solvents in the present invention are selected from N-Methyl-2-pyrrolidone (NMP), isopropyl alcohol, ethanol, and cyclohexane.

[0070] Optionally, CNT (carbon nanotube) suspension may also be added along with the binder. While suitable amounts of the binder range between 2 wt.% to 10 wt.% based on the total amount of the electrode material, the amount of CNT suspension ranges between 0.04 wt.% to 0.1 wt.% based on the total amount of the electrode material. As an alternate to CNT, MWCNT (multiwalled CNT) can also be used.

[0071] Further, the acids used in the electrode material include solvent additives selected from salicylic acid, lactic acid, and oxalic acid.

[0072] Another aspect of the present invention relates to a method for preparing the dendrite-free electrode material, as described above. Accordingly, the embodiments pertaining to the electrode material are applicable here as well.

[0073] In an embodiment, the method comprises mixing the electrode active material with the one or more binders and one or more selected from the following: electrically conductive carbon, solvents, solvent additives / acids, to obtain a slurry; coating the slurry on a substrate to obtain a coated substrate, and drying the coated substrate at a temperature ranging between 80°C to 120°C; wherein the electrically conductive carbon, solvents and acids are present in an amount such that the viscosity of the slurry ranges between 3000 to 8000 cPs at 25°C. Presence of these materials helps to reduce tortuosity of the electrode, thereby enabling faster adsorption of the metal ion while charging and discharging.

[0074] Suitable substrates for coating the slurry are selected from coated or uncoated copper foil, stainless steel foil, and nickel foil. The substrate is coated with a suitable thickness of the slurry, such as but not limited to, 4 microns to 20 microns. Further, wet thickness for coating the slurryVoltrez-20242106152213 ranges between 100 microns to 500 microns.

[0075] The drying step ensures that any solvent is removed from the slurry and that the coated substrate is dried. Subsequently, the coated substrate is subjected to calendaring whereby suitable porosity (e.g., 20% to 60%) in the electrode material is achieved.

[0076] Yet another aspect of the present invention relates to a metal ion battery comprising the electrode material, as described above. Accordingly, the embodiments pertaining to the electrode material are applicable here as well.

[0077] Suitable examples of metal-ion battery include sodium, lithium, potassium, magnesium, calcium, and fluorine-ion batteries. The electrode material of the present invention may be employed in any metal-ion battery as an anode along with the typical components thereof, such as but not limited to, cathode, current collector, electrolyte and separator. Such components are commonly used in the industry and are well known to persons skilled in the art.

[0078] Typically, the current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery. The current collector may be, for example, aluminium, nickel, titanium, copper or stainless steel, which may be optionally surface treated with carbon, nickel, titanium, silver, or the like. Alternatively, the current collector may be an alloy of these metals. In addition, fine irregularities may be formed on the surface of the current collector to enhance the binding force of the positive electrode active material to the surface, and the current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous material, foam, and a non-woven fabric.

[0079] Further, the electrolyte may include a liquid electrolyte, a gel polymer, a solid electrolyte, or a combination thereof.

[0080] The separator separates the negative electrode and the positive electrode from each other, and provides a channel for metal ions to move, and any known separator may be used for this purpose. Said otherwise, it is possible to use a separator having excellent electrolyte solution soaking ability while having low resistance to electrolyte ion movement. For example, the separator may be selected from among glass microfibers, polyester, Teflon, polyethylene, polypropylene, , polytetrafluoroethylene (PTFE), or combinations thereof, and may be in the form of nonwoven fabric or woven fabric.

[0081] The electrode material in accordance with the present invention is assembled along with other components to obtain the secondary metal-ion battery.

[0082] Advantageously, the present invention provides for an improved additive having good electrochemical performance in terms of rate capability as well as being resistant to dendrite formation over repeated charge and discharge cycles. Further, the additive of the present inventionVoltrez-20242106152214 can be pre-lithiated or pre-sodiated depending upon the intended use of the additive in lithium or sodium metal batteries. Moreover, the present invention provides a simple and cost-effective method of lithiating or sodiating the additive without the requirement of complex techniques such as vapour deposition or electrospinning. This enables the metal-ion battery useful for application in electric vehicles, EVToLs (Electric Vertical Take-Off and Landing vehicles), electric trucks, portable electronics, energy storage, and the likes.EXAMPLES

[0083] The following examples are illustrative of the invention but not limitative of the scope thereof since numerous modifications and variations within the scope of the present invention will be apparent to those skilled in the art. Unless otherwise noted, all parts, percentages and ratios reported in the following examples are on a weight basis.

[0084] Example 1 - Synthesis of Tin oxide hydroxide

[0085] Experiment 1 A - Synthesis Path 1

[0086] 80 to 120 g of SnCh.2H2O was taken in a container with 80 to 120 ml acetone and 120 to 180 ml deionized (DI) water. The ingredients were mixed for 100-150 mins at 350-450 rpm using a magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5 to 10 mins and mixed for 30 mins at 350 to 450 rpm using the stirrer. The stirrer speed was reduced to 180 to 220 rpm, 120 to 180 ml triethanolamine (TEA) and 40 to 60 ml DI water was added. The mixture was agitated by hand for 5 mins and mixed for 250 to 350 mins at 350-450 rpm using the stirrer.

[0087] Experiment IB - Synthesis Path 2

[0088] 80 to 120g of SnC12.2H2O was taken in a container with 80 to 120 ml acetone and 120-to 180 ml DI water. The ingredients were mixed for 100 to 150 mins at 350 to 450 rpm using a magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 120 to 180 ml triethanolamine (TEA) and 40 to 60 ml DI water was added. The mixture was agitated by hand for 5 to 10 mins and mixed for 100 to 150 mins at 350 to 450 rpm. The stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5 to 10 mins and mixed for 250 to 350 mins at 350 to 450 rpm using the stirrer.

[0089] Experiment 1C - Synthesis Path 3

[0090] 80 to 120g of SnC12.2H2O was taken in a container with 80 to 120 ml acetone and 120 to 180 ml DI water. The ingredients were mixed for 100 to 150 mins at 350 to 450 rpm using aVoltrez-20242106152215 magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5-10 mins and mixed for 250 to 350 mins at 350 to 450 rpm using the stirrer.

[0091] Experiment ID - Synthesis Path 4

[0092] 80 to 120g of SnC12.2H2O was taken in a container with 80 to 120 ml acetone and 120 to 180 ml DI water. The ingredients were mixed for 100 to 150 mins at 350 to 450 rpm using a magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5-10 mins and mixed for 30 mins at 350 to 450 rpm using the stirrer. The stirrer speed was reduced to 180 to 220 rpm, 120 to 180 ml diethanolamine (DEA) and 40 to 60 ml DI water was added. The mixture was agitated by hand for 5 to 10 mins and mixed for 250 to 350 mins at 350 to 450 rpm using the stirrer.

[0093] Experiment IE - Synthesis Path 5

[0094] 80 to 120g of SnC12.2H2O was taken in a container with 80 to 120 ml acetone and 120 to 180 ml DI water. The ingredients were mixed for 100 to 150 mins at 350 to 450 rpm using a magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 120 to 180 ml diethanolamine (DEA) and 40 to 60 ml DI water was added. The mixture was agitated by hand for 5 to 10 mins and mixed for 100 to 150 mins at 350 to 450 rpm. The stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5 to 10 mins and mixed for 250 to 350 mins at 350 to 450 rpm using the stirrer.

[0095] Experiment IF - Synthesis Path 6

[0096] 80 to 120g of SnC12.2H2O was taken in a container with 200 to 300 ml of DI water. The ingredients were mixed for 100 to 150 mins at 350 to 450 rpm using a magnetic stirrer, then the stirrer speed was reduced to 180 to 220 rpm and 120 to 180 ml triethanolamine (TEA) and 40 to 60 ml DI water was added. The mixture was agitated by hand for 5 to 10 mins and mixed for 100 to 150 mins at 350 to 450 rpm. The stirrer speed was reduced to 180 to 220 rpm and 60 to 80 ml ammonia and 40 to 60 ml DI water was added to the mixture. The mixture was agitated by hand for 5 to 10 mins and mixed for 250 to 350 mins at 350 to 450 rpm using the stirrer.

[0097] The tin oxide hydroxide precipitate (each starting from 100g SnCh^EEO) synthesised by the above 6 paths were dried at 60 °C and the gravimetric yield (in grams) was measured. The presence of SneO^OEfE was verified using X-Ray diffraction. The results are given in Table 1 below.

[0098] Table 1 : Gravimetric yield (in grams) of (SneO^OEfE) produced from 100g SnCh^EEO.Voltrez-20242106152216

[0099] The Group 14 and / or 15 nanoparticles produced by Path 2 was utilised for further experiments.

[0100] Example 2 - Preparation of Tin oxide hydroxide nanocarbon mixture

[0101] The mixture resulting from synthesis path 2 of Example 1 was transferred into a centrifugal tube and centrifuged for 10 to 20mins at 6000 to lOOOOrpm. The supernatant was discarded, and the precipitate was washed by dispersing it in 1 to 2% ammonia aqueous solution. The dispersion was centrifuged again for 10 to 20mins at 6000 to 10000 rpm; the supernatant was discarded. The washing step was repeated again.

[0102] The precipitate was transferred to a mixer with 150 to 600 ml of DI water and mixed for 10 to 30 mins. SC45 is added to the solution in 3 steps of 10g to 30g each, along with 250 to 750 ml of DI water. The mixture was mixed at 250 to 350 rpm with manual assistance for 60 to 240 mins and then transferred to a mortar and pestle and granulated for 10 to 45 mins. The granulated mixture was dried at 60°C for 36 hrs. The dried mixture is milled in a ball mill using stainless steel balls of diameter 16mm for 30 min at 200 to 250rpm with additional DI water such that the ratio of mixture: balls = 1 : 10.3 and ratio of mixture: water = 1 :8. The milled mixture was dried at 60°C for 18 to 36 hrs followed by grinding in a mortar and pestle to obtain a fine powder.

[0103] Example 3 - Additive preparation without pre-lithiation

[0104] 30 to 70 wt.% of Tin oxide hydroxide nanocarbon mixture produced in Example 2, 25 to 40 wt.% glucose and 1 to 5 wt.% of multi-walled carbon nanotubes (MWCNT) by weight were taken in a ball mill with SS balls of diameter 16mm and milled at 200 to 250 rpm for 30min, wherein total material to ball ratio = 1 :10. The milled material was passed through a 150 to 250 micron sieve to obtain the finished additive.

[0105] Example 4 - Additive preparation with pre-lithiation

[0106] 30 to 70 wt.% of Tin oxide hydroxide nanocarbon mixture produced in Example 2, 20 to 30 wt.% glucose, 12 to 22 wt.% lithium hydroxide and 1 to 5 wt.% of multi-walled carbonVoltrez-20242106152217 nanotubes (MWCNT) by weight were taken in a ball mill with SS balls of diameter 16mm and milled at 200 to 250 rpm for 20 to 30min, wherein total material to ball ratio = 1 : 10. The milled material was passed through a 150 to 250 micron sieve to obtain the finished additive.

[0107] Example 5 - Production of Anode using the additive of Example 3

[0108] Experiment 5A - Production of additive graphite composite

[0109] 10 to 20 wt.% of the additive produced by Example 3 along with 80 to 90 wt.% of natural graphite by weight were taken and milled in a ball mill using SS balls of diameter 16mm for 20 to 30 min at 200 to 250rpm with additional water such that the ratio of mixture: balls = 1 :4.65 and ratio of mixture: water = 1 :0.9. The milled mixture was dried for 6 to 12hrs at 60°C. The dried mixture was transferred to a mortar and pestle with 0.8 to 1 times DI water by weight. The mixture was granulated for 20 to 30 mins and dried at 60°C for 6 to 12 hrs. The granulation step was optionally repeated one or more times. The granulated mixture was milled using Zirconia balls of diameter 3mm at 280-380rpm for 120 min wherein ratio of mixture to balls was 1 :5. The milled mixture was passed through 150-250-micron sieve.

[0110] The sieved material was heated at 650-800°C under Ar-H2 atmosphere (2 to 5 hr reaching time, 3 to 7 hr holding time). Any foreign particles on the top layer were removed and the material was milled using Zirconia balls of diameter 3mm at 250-350rpm for 20 to 40 min wherein ratio of material to balls was 1 :5. The milled material was passed through 45 to 125 micron sieve to obtain the additive Graphite composite.

[0111] Experiment 5B - Slurry making for coating

[0112] Binder and active materials were stored at 60-80°C one day earlier to the coating, CNT were stored in RH chamber, consumables were cleansed and stored at 50-60°C. Mixer blade and pot are cleaned with isopropyl alcohol and dried.

[0113] 40gm of CMC was measured out. 2200ml of DI water was taken in the mixing pot and l / 4th of the binder was added with mixing at 3000(impeller) - 98(rotor) rpm under vacuum of -80 to -90 kPa. The mixture was scraped down from the sides of the pot and blade, and the above adding and mixing steps were repeated 3 more times till the entirety of binder is incorporated in the slurry. 150 - 250gm of CNT with 100ml of DI water were added and mixed for 60 min at 4000(impeller) - 98(rotor) rpm under vacuum. 1500 to 2000gm of graphite composite was measured out and half of the amount was added to the mixer pot, followed by mixing for 5 minutes at low rpm of 60(impeller)-60(rotor). The mixture was scraped down from the sides of the pot and blade, and the above adding and mixing steps were repeated with the remaining half. 250 ml DI water was added and mixed for 150 min at 1800(impeller) - 98(rotor) rpm under vacuum of -80 to -90 kPa. lOOgm (2% of total solid) of SBR with 50 ml DI water was added, followed by mixingVoltrez-20242106152218 for 60 min at lOO(impeller) - 98(rotor) rpm under vacuum. Slurry viscosity and density were measured, and the slurry was sieved through 125micron sieve.

[0114] Experiment 5C - Electrode making

[0115] The temperature of the heating chambers 1 to 4 of the coating machine were set to 70, 70, 80 and 90°C respectively. The tension of the tension rolls of the head and tail part of the coating machine were set as 9 and 3 N respectively. The roll speeds were set as lOOOmm / min for main roller and 1200mm / min for comma roller. The slurry was poured, and coating was done of thickness based on desired loading value. The coated foil was kept overnight at 60°C under vacuum of -40 to -80 kPa. The coated foil was passed through into the heating chambers of coating machine at 120°C for complete drying. The coated foil was cut into pieces at the size of 250mm using cutting machine. The cut foil was kept overnight at 100-120°C under vacuum of -40 to -80 kPa. The cut foil was calendered to achieve 20-40% porosity, followed by cutting into 116 mm by 168 mm size using a die cutter to get electrodes. The electrodes were sorted and burrs removed before calendaring again such that the thickness of the electrode is maintained at 100 to 150 microns.

[0116] Example 6 - Production of Anode using Additive of Example 4

[0117] Experiment 6A - Production of additive graphite composite

[0118] 10 to 20 wt.% of the additive obtained in Example 4 and 80 to 90 wt.% of natural graphite by weight were taken and milled in a ball mill using SS balls of diameter 16mm for 20 to 30 min at 200 to 250rpm with additional water such that the ratio of mixture: balls = 1 :4.65 and ratio of mixture: water = 1 :0.9. The milled mixture was dried for 12hrs at 60°C. The dried mixture was transferred to a mortar and pestle with 0.9 times DI water by weight. The mixture was granulated for 30 mins and dried at 60°C for 12 hrs. The above granulation step was repeated. The granulated mixture was milled using Zirconia balls of diameter 3mm at 300-350rpm for 120 min wherein ratio of mixture to balls is 1 :5. The milled mixture was passed through 200-250 micron sieve. The sieve material was heated at 700-750°C under Ar-EE atmosphere (3 hr reaching time, 4 hr holding time). Any foreign particles on the top layer were removed and the material was milled in a ball mill using Zirconia balls of diameter 3mm at 320rpm for 30 min wherein ratio of material to balls is 1 :5. The milled material was passed through 45 to 125-micron sieve to obtain the additive Graphite composite.

[0119] Experiment 6B - Slurry making for coating

[0120] Binder and active materials were stored at 60-80°C one day earlier to the coating, CNT were stored in a dry chamber at 40% relative humidity, consumables were cleansed and stored at 50-60°C. Mixer blade and pot are cleaned with isopropyl alcohol and dried.Voltrez-20242106152219

[0121] 40 gm of CMC was measured out. 2200ml of DI water was taken in the mixing pot and l / 4th of the binder was added with mixing at 3000(impeller) - 98(rotor) rpm under vacuum of -40 to -90 kPa. The mixture was scraped down from the sides of the pot and blade, and the above adding and mixing steps were repeated 3 more times till the entirety of binder is incorporated in the slurry. 150-250gm of CNT with 100ml of DI water were added and mixed for 60 min at 4000(impeller) - 98(rotor) rpm under vacuum. 1500 to 2000 gm of graphite composite was measured out and half of the amount was added to the mixer pot, followed by mixing for 5 minutes at low rpm of 60(impeller)-60(rotor). The mixture was scraped down from the sides of the pot and blade, and the above adding and mixing steps were repeated with the remaining half. 250 ml DI water was added and mixed for 150 min at 1800(impeller) - 98(rotor) rpm under vacuum of -40 to -90 kPa. lOOgm (2% of total solid) of SBR with 50 ml DI water was added, followed by mixing for 60 min at lOO(impeller) - 98(rotor) rpm under vacuum. Slurry viscosity and density were measured, and the slurry was sieved through 75 to 200 micron sieve.

[0122] Experiment 6C - Electrode making

[0123] The temperature of the heating chambers 1 to 4 of the coating machine were set to 70, 70, 80 and 90°C respectively. The tension of the tension rolls of the head and tail part of the coating machine were set as 9 and 3 N respectively. The roll speeds were set as lOOOmm / min for main roller and 1200mm / min for comma roller.

[0124] The slurry was poured, and coating was done of thickness based on desired loading value. The coated foil was kept overnight at 60 to 80°C under vacuum of -40 to -80 kPa. The coated foil was passed through into the heating chambers of coating machine at 90 to 120°C for complete drying. The coated foil was cut into pieces at the size of 250mm using cutting machine. The cut foil was kept overnight at 100-120°C under vacuum of -40 to -80 kPa. The cut foil was calendered to achieve 20-40% porosity, followed by cutting into 116 mm by 168 mm size using a die cutter to get electrodes. The electrodes were sorted and burrs removed before calendaring again such that the thickness of the electrode is maintained at 100 - 150 microns.

[0125] While evaluating lithium plating and lithium loss characteristics, a significant reduction in both lithium plating and lithium loss was observed in the sample electrodes (Experiment 6C) comprising the additive of the present invention, as compared to a control electrode (i.e., a natural graphite electrode devoid of the additive). The electrochemical performance evaluation was carried out at an areal loading of 4 mAh / cm2, which corresponds to the standard commercial electrode loading typically employed in lithium-ion battery applications.

[0126] Tables 2 and 3 provided below summarize the data for reversible lithium plating and lithium loss measured at different C-rates.Voltrez-20242106152220

[0127] Table 2: Reversible plating at different C rates0128] Table 3: Lithium loss at 4 different C rates

[0129] Example 7 - Cell making, electrolyte filling and cell testing

[0130] Stack making

[0131] The separator was loaded in the stacking machine and set in place. The anodes and cathodes were placed in the respective electrode holders. The parameters were filled according to the required capacity. Once the stack was made and comes out of the stack making machine, they were taped together using Kapton tape to temporarily hold them in place for tab welding.

[0132] Tab Welding

[0133] A slight portion of the tabs at the top of the sealant was covered using Kapton tape and stack plates were placed on top and bottom of the stack and clipped together. The tabs of the cathode (Al) and anode (Ni) were welded one by one respectively at the required frequency. The exposed metal portion near the tab area and the anode side of the stack was covered using Kapton tape to ensure there is no metal portion exposed.

[0134] Pouch Formation

[0135] The width of the stack was measured using the Vernier calliper and the pouch material was cut as per the required length (usually 23.5 cm). The depth of the pouch-forming machine was adjusted according to the width of the stacks and a cavity was made using pouch forming machine. The stack inside the cavity where it should fit exactly inside the cup, if not then the depth of the pouch-forming machine should be adjusted. One more pouch material was cut according to the length of the stack from tab to tab and placed on top of the stack. The steel plates were placed on top and bottom of the pouch and held tightly while they are clipped on both sides. Then the pouchVoltrez-20242106152221 is sealed sides using a heat sealing machine at 180°C with two seals on both sides and one seal on tab side. All the pouches are sealed on three sides and one side is left open for electrolyte filling. The tabs are covered with tape and the weight and thickness of the pouches are measured. The pouches (unfilled cells) are stored in the oven at 80°C under vacuum at -80kPa for 24 hours.

[0136] Electrolyte filling

[0137] The formed pouches were transferred to the antechamber of the glove box and the chamber and release nitrogen for at least 3 cycles. The unfilled cells and consumables in the antechamber for 2 hours then transferred into the glove box and kept for 2 hours. The desired quantity of electrolyte in a measuring cylinder and poured into the pouch of the cell. The cell was gently pressed in all directions so that the electrolyte can distribute all over the cell. Once filled, the cells were placed in a cell holder and kept inside the vacuum standing box for 2 cycles of 120 seconds. The cells are then closed by heat sealing the final side at 180°C. The final weight and thickness of the cells are measured.

[0138] Cell preconditioning

[0139] The cells were pressed using a glass plate so that the electrolyte distributes evenly and the tabs were cleaned using isopropyl alcohol. The cells were charged up to 2V and placed inside the oven at 45°C in the horizontal position for two days. The cells were then taken out from the oven and kept at room temperature for four days.

[0140] Cell Formation

[0141] Glass plates were placed exactly on the top and bottom of the stack (ensuring the stack remains fully covered) and taped to make sure the glass plates hold the pouches evenly and tightly. The cells were connected to the channels of Neware testing machine and the following protocol was run in 3 cycles:Step 1 : OCV to 3 V at C / 20, Constant Current Charge Step 2: 3V to 3.8V at C / 30, Constant Current Charge Step 3: 3.8V to 4.2V at C / 10, Constant Current Charge Step 4: till 3.8V, Constant Current Discharge Step 5: till 3 V, Constant Current DischargeStep 6: 2 cycles charge and discharge at C / 30 in the voltage range of 3 to 3.8VThe protocol graph is provided in Figure 4.

[0142] Experiment 7G - Final Sealing

[0143] The cells are removed from Neware testing machine and all the glass plates and cover tabs are removed. The cells were taped one by one to the Vacuum sealing machine and sealed. The excess pouch was cut and the spilled electrolyte wiped. The cut side was heat sealed again at 180°CVoltrez-20242106152222 and the pouches were cleaned using isopropyl alcohol. The sides of the cells are taped, and the weight and thickness of the cells are measured. Then the cells were kept at room temperature for six days for post conditioning.

[0144] Experiment 7H - Activation of Pouch cell

[0145] The cells were activated using the protocol below:Step 1 : 6 days rest on ambient conditionStep 2: 5 cycles at C / 20 in the voltage range of 3 to 3.8V at C / 20, constant current charge discharge Step 3: 5 cycles at C / 10 in the voltage range of 2.7 to 4.2V at C / 10, constant current charge dischargeStep 4: 5 cycles at C / 5 in the voltage range of 2.7 to 4.2V at C / 10, constant current charge discharge Step 5: 5 cycles at C / 3 in the voltage range of 2.7 to 4.2V at C / 10, constant current charge discharge

[0146] Example 8 - Cycle Life Test

[0147] The cell cycle life was tested using 12 to 13 Ah pouch cell as provided in Table 4:

[0148] Table 4: Cycle life test protocol for 0.5C - 0.5C testing for 2000 cycles.

[0149] The results are presented in Figure 5. The projected cell life is 1426 cycles.

[0150] Similarly, testing was done at 1C-1C after 500 cycles like 614 cycles, 621 cycles and 732 cycles. The anodes of the tested cells were observed under SEM imaging to check for dendrite formation. The SEM images are provided in Figures 2, 6, 7 and 8 respectively. No dendrite formation was observed

[0151] Similarly, testing was done at 3C-3C for 200 cycles. The anodes of the tested cells wereVoltrez-20242106152223 observed under SEM imaging to check for dendrite formation. The images are provided in Figures 3 and 9. No dendrite formation was observed.

[0152] As will be noted above, the present invention provides for a dendrite free electrode material having good electrochemical performance in terms of rate capability as well as being resistant to dendrite formation over repeated charge and discharge cycles. Further, the additive of the present invention can be pre-lithiated or pre-sodiated depending upon the intended use of the additive in lithium or sodium metal batteries. Moreover, the present invention provides a simple and cost- effective method of lithiating or sodiating the additive without the requirement of complex techniques such as vapour deposition or electrospinning.

[0153] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

Claims

Voltrez-20242106152224CLAIMS1. An electrode material comprising: an electrode active material having an additive comprising:(a) 5 wt.% to 90 wt.% of nanoparticles of one or more elements or compounds of Group 14 and / or Group 15, said nanoparticles having an average particle size ranging between 20 nm to 500 nm and are selected from Sn, (SneO4(OH)4), Sn(OH)2, SnO, SnO2, Si, SiO, SiO2, Ge, and Sb,(b) 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 500 nm, and(c) optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I, wherein wt.% is based on the total weight of the additive, one or more binders, and one or more selected from the following: an electrically conductive carbon, solvents, solvent additives, and acids.

2. The electrode material as claimed in claim 1, wherein the carbon source is selected from carbon black, acetylene black, carbon nanotubes, and carbon nanofibers.

3. The electrode material as claimed in claim 1, wherein the elements or compounds of Group I is selected from LiOH, Li2CO3, LiF, LiCl, LiBr, Lil, LiNCh, and Li2SO4.

4. The electrode material as claimed in claim 1, wherein the additive is in the form of nanoparticles spaced apart within the electrode active material at a separation ranging between 200 nm to 500 nm.

5. The electrode material as claimed in claim 1, wherein the additive is obtained as follows:(a) mixing one or more elements or compounds of Group 14 and / or Group 15 with a solvent and water to obtain a homogeneous mixture,(b) mixing the homogeneous mixture with a chelating agent for a duration ranging between Ih to 4h,(c) adding a pH adjusting agent to the homogeneous mixture to obtain a first suspension,(d) centrifuging the first suspension to obtain a precipitate comprising nanoparticles of one or more elements or compounds of Group 14 and / or Group 15,Voltrez-20242106152225(e) mixing 5 wt.% to 90 wt.% of the nanoparticles of the elements or compounds of Group 14 and / or Group 15, and 5 wt.% to 90 wt.% of one or more carbon source having an average particle size ranging between 20 nm to 500 nm, followed by drying at a temperature ranging between 60°C to 100°C for a duration ranging between 1 h to 40 h to obtain a nanocomposite comprising the nanoparticles of one or more elements or compounds of Group 14 and / or Group 15 and carbon,(f) mixing the nanocomposite with one or more carbon source, optionally one or more auxiliaries, and optionally 5 wt.% to 90 wt.% of one or more elements or compounds of Group I to obtain a second suspension, and(g) drying the second suspension at a temperature ranging between 60°C to 100°C for a duration ranging between Ih to 40h to obtain a powder comprising the additive.

6. The electrode material as claimed in claim 5, wherein the solvent is selected from deionized water, acetone, and isopropyl alcohol; and the pH adjusting agent is selected from ammonia, KOH, and NaOH.

7. The electrode material as claimed in claim 5 further comprising the step of reducing the powder in presence of a reducing agent at a temperature ranging between 600°C to 800°C to obtain nanoparticles of the additive having an average particle size ranging between lOnm to 500nm.

8. The electrode material as claimed in claim 1, wherein the electrode active material is obtained as follows:(A) mixing the additive with the one or more carbon source to obtain a first mixture;(B) heating the first mixture at a temperature ranging between 600°C to 800°C to obtain a reduced first mixture, and(C) milling a second mixture comprising a conductive carbon material and the reduced first mixture at a temperature less than 200°C to obtain the electrode active material.

9. The electrode material as claimed in claim 8, wherein prior to milling the second mixture the reduced first mixture is subjected to heating in ambient air at a temperature ranging between 180°C to 250°C.Voltrez-2024210615222610. The electrode material as claimed in claim 8, wherein the conductive carbon material is selected from natural graphite, artificial graphite, flake graphite, hard carbon, and mesocarbon microbeads (MCMB).

11. A method for preparing the electrode material as claimed in one or more of claims 1 to 10, the method comprising: mixing the electrode active material with the one or more binders and one or more selected from the following: electrically conductive carbon, solvents, and acids, to obtain a slurry; coating the slurry on a substrate to obtain a coated substrate, and drying the coated substrate at a temperature ranging between 80°C to 120°C, wherein the electrically conductive carbon, solvents, and acids are present in an amount such that the viscosity of the slurry ranges between 3000 to 8000 cPs at 25°C.

12. The method as claimed in claim 11, wherein the binder comprises a carbon nanotube suspension in an amount ranging between 0.04 wt.% to 0.1 wt.% based on the total weight of the electrode material.

13. The method as claimed in claim 11 further comprising the step of calendaring the coated substrate.

14. A metal-ion battery comprising the electrode material as claimed in one or more of claims 1 to 10 or obtained from the method as claimed in one or more of claims 11 to 13, and an electrolyte.

15. The metal -ion battery as claimed in claim 14, wherein the metal-ion battery demonstrates an order of magnitude lower lithium plating compared to a control electrode under equivalent conditions, including at higher C-rates, and wherein the lower lithium plating is indicative of a dendrite-free electrode material, thereby resulting in a dendrite-free metalion battery.

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