Artificial graphite electrode materials and methods of producing the same

Abstract

The present invention relates to a method for producing artificial graphite electrode material. The method comprises mixing a carbonaceous material with a carbon precursor to form a precursor mixture; subjecting the precursor mixture to stepwise heating, including an intermediate soaking step at about 300°C to about 900°C to obtain a treated mixture; and heating the treated mixture at about 2400°C to about 3000°C to obtain the electrode material. The electrode material obtained from the method of present invention exhibits a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size of about 10 µm to about 20 µm. The particles are shaped before mixing to reduce edges and increase circularity. The electrode material is optionally coated with amorphous carbon at about 900°C to about 1300°C.

Description

[0001] ARTIFICIAL GRAPHITE ELECTRODE MATERIALS AND METHODS OF PRODUCING THE SAME

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to carbon-based electrode materials and methods of manufacturing the same. More particularly, the present invention relates to artificial graphite materials having controlled crystal orientation and particle characteristics, and processes for producing such materials for electrochemical applications.

[0004] BACKGROUND OF THE INVENTION

[0005] Various methods of making electrode materials are known in the art. Chinese patent application CN110921659A describes a method of producing a high-capacity artificial graphite- based electrode material. Chinese patent application CN115784225 A discloses a preparation method for a modified artificial graphite negative electrode material, which includes calcining the material, adding a modifying agent, and subsequently heating the mixture to obtain the modified artificial graphite material. U.S. Patent No. US7008526B2 describes a process for preparing coke, artificial graphite, and a negative electrode material, including a method of polymerizing condensed polycyclic hydrocarbons in the presence of hydrogen fluoride and boron trifluoride to produce a pitch composition suitable for use in a battery electrode. PCT publication WO2017206544A1 describes the production of secondary particles derived from needle coke for battery electrode applications.

[0006] These references illustrate different approaches for producing graphite-based materials suitable for lithium-ion battery applications. As battery performance continues to evolve, particularly with respect to fast-charging capability, cycle stability, and safety, there is increasing interest in electrode materials that exhibit not only high capacity but also improved lithium-ion diffusion kinetics, reduced structural anisotropy, and controlled volume change during cycling.004 In this context, industry performance benchmarks, including fast-charging standards promoted by organizations such as the United States Advanced Battery Consortium (USABC), have highlighted the importance of electrode materials that combine favorable isotropy, low expansion behavior, and efficient lithium-ion transport characteristics. Achieving such performance is increasingly associated with tailoring microstructural properties of the electrode material, including crystal orientation, particle morphology, and the balance between structural order and disorder.

[0007] 005 While existing methods provide a variety of routes for producing artificial graphite and related carbon materials, continued development is directed toward processes that enable more precise control over these microstructural features. Such control is regarded as desirable for achieving rapid lithium-ion intercalation, reduced expansion behavior, and consistent electrochemical performance under high current densities.

[0008] 006 Accordingly, there remains an ongoing technical interest in improved manufacturing approaches that integrate precursor selection, particle conditioning, and thermal treatment strategies to obtain electrode materials having tailored structural characteristics suitable for advanced lithium-ion battery applications.

[0009] SUMMARY OF THE INVENTION

[0010] 007 This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description section. 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 determine the scope of the claimed subject matter. The difficulties and drawbacks of previous approaches are addressed in the present invention.

[0011] 008 In one aspect, the present invention provides a method of producing an artificial graphite electrode material comprising: mixing a carbonaceous material with a carbon precursor to form a precursor mixture, subjecting the precursor mixture to a first heat treatment at an intermediate temperature to obtain a treated mixture, and subsequently subjecting the treated mixture to a high-temperature graphitization treatment. The thermal treatment conditions are selected to obtain an artificial graphite electrode material exhibiting areduced degree of anisotropy of crystal grain alignment and a controlled average particle size.

[0012] 009 In another aspect, the present invention provides an artificial graphite electrode material obtained by the method, wherein the material exhibits a degree of anisotropy of crystal grain alignment below a defined threshold, a powder orientation index within a specified range, and a degree of granulation greater than about 75%, thereby enabling improved packing density and electrochemical performance.

[0013] 010 In certain embodiments, the method further includes a particle conditioning step, such as shaping or dispersion, performed before or after the intermediate heat treatment to reduce sharp edges, improve circularity, and enhance granulation without adversely affecting the crystallographic properties.

[0014] Oil In certain embodiments, the artificial graphite electrode material is further subjected to a post-treatment carbon coating step to form an amorphous carbon-coated electrode material, providing improved electrode wetting characteristics and surface stability.

[0015] 012 The artificial graphite electrode material, electrodes comprising the same, and electrochemical cells incorporating such electrodes demonstrate improved lithium-ion transport, reduced preferred orientation, enhanced electrode density, and stable electrochemical performance under high current density conditions.

[0016] 013 The foregoing and other aspects, features, and advantages of the present invention will be apparent from the following detailed description of exemplary embodiments when read in conjunction with the accompanying drawings. The embodiments described herein are illustrative in nature and are not intended to limit the scope of the present invention, which is defined by the appended claims and their equivalents.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 014 The advantages and features of the present invention will become better understood with reference to the following detailed description taken in conjunction with the accompanying drawings:

[0018] 015 Figure 1 is a flowchart depicting a method of making electrode material according to an embodiment of the present invention.

[0019] 016 Figure 2 is a flowchart depicting a method of making an electrode material according to another embodiment of the present invention.

[0020] 017 Figure 3 is a scanning electron microscope image of an electrode material prepared by a method in accordance with an embodiment of the present invention.

[0021] 018 Figure 4 is a flowchart depicting a method of making electrode material according to an embodiment of the present invention (Shaping).

[0022] 019 Figure 5 is a flowchart depicting a method of making electrode material according to another embodiment of the present invention (shaping and dispersion).

[0023] 020 Figure 6 is a flowchart depicting a method of making electrode material according to yet another embodiment of the present invention (Shaping and carbon coating).

[0024] 021 Figure 7 is an image showing the scanning electron micrographs of an electrode material prepared by a method in accordance with an embodiment of the present invention.

[0025] 022 Figure 8 is a graph showing the Raman spectrum of an electrode material prepared by a method in accordance with an embodiment of the present invention.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] 023 The exemplary embodiments described herein detail for illustrative purposes, are subjected to many variations. It should be emphasized, however, that the present invention is not limited to a negative material electrode and its method of preparation as disclosed. It is understood that various omissions and substitutions of equivalents are contemplated ascircumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

[0028] 024 Unless otherwise specified, the terms used in the specification and claims have the meanings commonly used in the field of negative electrode material and method of preparation involved therein. Specifically, the following terms have the meanings indicated below.

[0029] 025 Embodiments are provided thoroughly and fully convey the scope of the present disclosure to a 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, known processes, well-known apparatus or structures, and well-known techniques are not described in detail.

[0030] 026 The singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. “Substantially” means a range of values that is known in the art to refer to a range of values that are close to, but not necessarily equal to, a certain value.

[0031] 027 Other than in the examples or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as modified in all instances by the term “about.”

[0032] 028 As used herein, the term “substantially” and its variations are defined as being largely but not necessarily wholly what is specified as understood by one of ordinary skill in the art.Various numerical ranges are disclosed herein. Because these ranges are continuous, they include every value between the minimum and maximum values. The endpoints of all ranges reciting the same characteristic or component are independently combinable and inclusive of the recited endpoint. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations. The endpoints of all ranges directed to the same component or property are inclusive of the endpoint and independently combinable.

[0033] As used herein, “combinations thereof’ is inclusive of one or more of the recited elements, optionally together with a like element not recited, e.g., inclusive of a combination of one or more of the named components, optionally with one or more other components not specifically named that have essentially the same function. As used herein, the term “combination” is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0034] As used herein, the qualification of steps as "first" and "second" is for the sake of convenience. Unless specified, use of those terms should not be construed as excluding other steps. The use of such terms should not be construed as suggesting that any particular sequence of processing steps need be employed, unless specified.

[0035] As used herein, the term “graphitization” is defined as a heat treatment process that converts a carbon precursor into a three-dimensionally ordered graphite structure. Graphitization methods typically involve heating the carbon material at a high temperature, typically around 2500 °C, so that the precursor atoms are ordered into the graphite structure.

[0036] As used herein, “Powder Orientation Index (POI)” refers to an orientation index of the powder material measured by X-ray diffraction (XRD) based on the relative intensity associated with planes parallel and perpendicular to the graphite (002) / (004) direction, as per a defined test method described herein.034 As used herein, “Degree of anisotropy of crystal grain alignment” refers to a quantitative measure of preferred orientation of crystallites in the electrode material, determined by XRD-based texture analysis under a defined measurement method described herein. In embodiments, a lower value indicates reduced preferred orientation and improved isotropy.

[0037] 035 As used herein, “Electrode Orientation Index (EOI)”, also written as 1004 / 1110, refers to the ratio of XRD peak intensity of the (004) plane to that of the (110) plane measured on a calendared electrode.

[0038] 036 As used herein, the term “degree of disorder”, also denoted as (ID / IG), represents the inplane structural defects such as dangling bonds in the hexagonal networks of the graphite materials.

[0039] 037 Degree of Circularity (also referred to as circularity) is defined as: Circularity = 4n A / P2, where A is the projected area of the particle, and P is the perimeter (circumference) of the particle, as measured from a 2D image of the particle.

[0040] Measurement Methods

[0041] 038 Unless otherwise specified, measurements referenced in this specification were conducted as follows.

[0042] 039 Powder orientation index (POI) was determined by X-ray diffraction (XRD) analysis performed on powdered samples using Cu-Ka radiation, wherein the relative intensities of diffraction peaks corresponding to planes parallel and perpendicular to the graphite (002) / (004) direction were evaluated.

[0043] 040 Electrode orientation index (EOI), also expressed as 1004 / 1110, was determined by XRD analysis performed on calendared electrodes mounted on copper current collectors.

[0044] 041 The degree of anisotropy of crystal grain alignment was evaluated using XRD-based texture analysis by comparing relative orientation intensities under identical measurement conditions.Degree of granulation was determined by image analysis of scanning electron microscope (SEM) images, wherein secondary particles were identified and quantified relative to total particle population.

[0045] Degree of disorder (ID / IG) was determined by Raman spectroscopy using integrated peak intensities of the D-band and G-band measured over a defined spectral window.

[0046] In one embodiment, the present invention provides a method of manufacturing electrode material. The method comprises mixing a carbonaceous material with a carbon precursor to form a precursor mixture. The precursor mixture is heated at a temperature in the range of about 300 °C to about 1000 °C, preferably about 400 °C to about 900 °C, and more preferably about 450 °C to about 650 °C, for a duration of about 1 hour to about 7 hours, preferably about 3 hours to about 6 hours, using stepwise heating to obtain a treated mixture. Stepwise heating, optionally with one or more intermediate soaking stages, may reduce an orientation index and increase the degree of granulation. The method further comprises heating the treated mixture at a temperature in the range of about 2400 °C to about 3000 °C, preferably at least about 2800 °C, for a duration of about 3 hours to about 5 hours, to obtain the electrode material. The electrode material exhibits a degree of anisotropy of crystal grain alignment of less than about 3.5, preferably less than about 2.7. It has an average particle size in the range of about 10 pm to about 20 pm, preferably about 13 pm to about 17 pm, and more preferably about 14 pm to about 16 pm.

[0047] In another embodiment, the present invention provides a method of producing an artificial graphite electrode material, comprising:

[0048] (a) mixing a carbonaceous material with a carbon precursor to form a precursor mixture; subjecting the precursor mixture to a first heat treatment at a temperature in a range of about 300 °C to about 900 °C to obtain a treated mixture; and

[0049] (b) subjecting the treated mixture to a second heat treatment at a temperature in a range of about 2400 °C to about 3000 °C to obtain the artificial graphite electrode material,wherein the artificial graphite electrode material exhibits a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size in a range of about 10 pm to about 20 pm

[0050] 046 Referring to Figure 1, a method (100) of manufacturing an electrode material according to an embodiment is illustrated. In one embodiment, the method (100) comprises mixing (102) a carbonaceous material with a carbon precursor to form a precursor mixture; heating (104) the precursor mixture to obtain a treated mixture; and heating (106) the treated mixture to obtain the electrode material. In one embodiment, the heating (104) and heating (106) are performed within the respective temperature and time ranges described in paragraph 037 and paragraphs 051-057. The electrode material may exhibit a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size in a range of about 10 pm to about 20 pm.

[0051] 047 Referring to Figure 2, a method (200) of manufacturing an electrode material according to an embodiment is illustrated. In one embodiment, the method (200) comprises mixing (202) a carbonaceous material with a carbon precursor to form a precursor mixture; heating (204) the precursor mixture to obtain a treated mixture; dispersing (206) the treated mixture; and heating (208) the treated mixture to obtain the electrode material. In one embodiment, the heating (204) and heating (208) are performed within the respective temperature and time ranges described in paragraph 037 and paragraphs 051-057. The electrode material may exhibit a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size in a range of about 10 pm to about 20 pm.

[0052] 048 In an embodiment of the present invention, the coal tar pitch may have a softening point in a range from about 70 °C to about 240 °C.

[0053] 049 In another embodiment of the present invention, the coal tar pitch may have a softening point in a range from about 80 °C to about 100 °C.050 In an embodiment of the present invention, the carbonaceous material comprises at least one of native graphite, coke, bulk mesophase coke powder, calcined needle coke, green coke, or mesophase fine powder.

[0054] 051 In another embodiment of the present invention, the carbonaceous material has volatile matter in a range from about 1 wt.% to about 9 wt.% and a moisture content of not more than about 1 wt.%.

[0055] 052 In another embodiment of the present invention, the carbonaceous material has a tap density of more than about 0.5 g / cm3.

[0056] 053 In another embodiment of the present invention, the carbonaceous material is bulk meso coke powder.

[0057] 054 In an embodiment, the bulk mesophase coke comprises ash in an amount of about 0.01 wt.% to about 1 wt.%, based on a total mass of the bulk mesophase coke. In another embodiment, the bulk mesophase coke comprises ash in an amount of less than about 0.5 wt.%.

[0058] 055 In an embodiment, the bulk mesophase coke comprises moisture in less than about 1 wt.%, based on a total mass of the bulk mesophase coke. In another embodiment, the bulk mesophase coke comprises moisture in an amount of about 0.1 wt.% to about 0.5 wt.%.

[0059] 056 In an embodiment, the bulk mesophase coke comprises fixed carbon in an amount of about 80 wt.% to about 95 wt.%, based on a total mass of the bulk mesophase coke. In another embodiment, the bulk mesophase coke comprises fixed carbon in an amount greater than about 92 wt.%.

[0060] 057 In an embodiment, the bulk mesophase coke has a tap density in the range of about 0.5 g / cm3to about 0.9 g / cm3, preferably about 0.55 g / cm3to about 0.7 g / cm3, and more preferably about 0.6 g / cm3to about 0.7 g / cm3.In an embodiment, the bulk mesophase coke has a particle size in the range of about 3 pm to about 10 pm, preferably about 5 pm to about 9 pm.

[0061] In an embodiment, the bulk mesophase coke has a volatile-matter content in the range of about 1 wt.% to about 9 wt.%, preferably about 3 wt.% to about 6 wt.%, and more preferably about 3.8 wt.% to about 5 wt.%.

[0062] In an embodiment, the weight ratio of the carbon precursor to the carbonaceous material is in the range of about 3 wt.% to about 25 wt.%, preferably about 12 wt.% to about 20 wt.%. In an embodiment, a residual carbon weight ratio is about 1 wt.% to about 10 wt.%, preferably about 2 wt.% to about 8 wt.%, and more preferably about 3 wt.% to about 7 wt.%.

[0063] In an embodiment of the present invention, the step of heating (104) the precursor mixture at a temperature in a range from about 300 °C to about 1000 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, may be carried out in a nonoxidizing atmosphere.

[0064] In another embodiment of the present invention, the step of heating (104) the precursor mixture at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, may be carried out in an inert atmosphere. In an embodiment of the present invention, the inert gas may be nitrogen.

[0065] In an embodiment of the present invention, the step of heating (104) the precursor mixture at a temperature in a range from about 300 °C to about 1000 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, may be carried out at a heating rate in a range from about 30 °C per hour to about 60 °C per hour.

[0066] In an embodiment of the present invention, the step of heating (106) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range fromabout 3 hours to about 5 hours to obtain the electrode material may be carried out in a nonoxidizing atmosphere.

[0067] In another embodiment of the present invention, the step of heating (106) the treated mixture at a temperature in a range from 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material may be carried out in an inert atmosphere. In an embodiment of the present invention, the inert gas may be nitrogen.

[0068] In an embodiment of the present invention, the treated mixture is heated at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material. In an embodiment of the present invention, the heating may be carried out at a heating rate in a range from about 30 °C per hour to about 60 °C per hour.

[0069] In another embodiment of the present invention, the heating may be carried out at a heating rate of about 50 °C per hour.

[0070] In an embodiment of the present invention, the method of making an electrode material further includes a step of dispersing the treated mixture with above 75% degree of granulation or a secondary particle.

[0071] In an embodiment of the present invention, the step of dispersing the treated mixture may be a ball-milling step.

[0072] In an embodiment of the present invention, the method of making electrode material further includes a step of sieving the electrode material.

[0073] In an embodiment of the present invention, the electrode material may have a particle size in a range from about 12 pm to about 18 pm. In an embodiment of the present invention, the electrode material may have a tapping density in a range from about 0.9 g / cm3to about1.20 g / cm3. In an embodiment of the present invention, the electrode material may have a surface area less than about 1.3 m2 / gm.

[0074] In an embodiment of the present invention, the electrode material may have an orientation index in a range from about 2 to about 3.

[0075] In an embodiment of the present invention, the electrode material may have a first discharge capacity in a range from about 340 milliampere-hours per gram to about 358 milliampere-hours per gram, preferably 350 to 355 milliampere-hours per gram.

[0076] In an embodiment of the present invention, the electrode material may have a first cycle efficiency greater than about 95%.

[0077] In an embodiment of the present invention, the step of dispersing the treated mixture may be a ball-milling step. In another embodiment of the present invention, the ball milling step may be carried out in a hammer mill.

[0078] Referring to Figure 4, a method (300) of manufacturing an electrode material according to an embodiment is illustrated. In one embodiment, the method (300) comprises obtaining (302) a particulate carbonaceous material; shaping (304) particles of the particulate carbonaceous material to reduce jagged edges and thereby obtain shaped carbonaceous material; mixing (306) the shaped carbonaceous material with a carbon precursor to form a precursor mixture; heating (308) the precursor mixture to obtain a treated mixture; and heating (310) the treated mixture to obtain the electrode material. In one embodiment, the heating (308) and heating (310) are performed within the respective temperature and time ranges described in paragraph 037 and paragraphs 051-057, and the electrode material exhibits a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size in a range of about 10 pm to about 20 pm.077 In an embodiment, the carbon precursor comprises at least one of low softening coal tar pitch, petroleum pitch, high-softening pitch, zero-quinoline-insoluble (ZQI) pitch, or any combination thereof.

[0079] 078 In an embodiment, the carbon precursor comprises ash in an amount of about 0 wt.% to about 0.05 wt.%, based on a total mass of the carbon precursor.

[0080] 079 In an embodiment, wash oil comprises ash in an amount of about 0 wt.% to about 0.05 wt.%, based on the total mass of the wash oil.

[0081] 080 In an embodiment, the wash oil has a coking value in the range of about 0.2 wt.% to about 10 wt.%. In another embodiment, the wash oil has a coking value in the range of about 0.3 wt.% to about 3 wt.%.

[0082] 081 In an embodiment of the present invention, the wash oil may have a viscosity in a range from about 1 centipoise to about 10 centipoise in a temperature range from about 70 °C to about 100 °C.

[0083] 082 In an embodiment of the present invention, the carbonaceous precursor is coal tar pitch.

[0084] 083 In an embodiment, the coal tar pitch comprises ash in an amount of about 0 wt.% to about 0.5 wt.%, preferably about 0.03 wt.% to about 0.08 wt.%, based on a total mass of the coal tar pitch.

[0085] 084 In an embodiment, the coal tar pitch has a coking value in the range of about 20 wt.% to about 90 wt.%. In another embodiment, the coal tar pitch has a coking value in the range of about 35 wt.% to about 50 wt.%.

[0086] 085 In an embodiment of the present invention, the coal tar pitch may have a viscosity in a range from about 200 centipoise to about 12000 centipoise in a temperature range from about 70 °C to about 100 °C.086 In another embodiment of the present invention, the coal tar pitch may have a coking value in a range of about 450 centipoise to about 12,000 centipoise at a temperature range of about 100 °C to about 200 °C.

[0087] 087 In an embodiment, a bulk mesophase coke has a tap density of greater than about 0.6 g / cm3, preferably greater than about 0.62 g / cm3.

[0088] 088 In an embodiment, the weight ratio of the carbon precursor to the carbonaceous material is in the range of about 5 wt.% to about 20 wt.%, preferably about 10 wt.% to about 12 wt.%.

[0089] 089 In an embodiment of the present invention, the step of shaping the carbonaceous material may be carried out by at least one technique selected from ball milling, hammer milling, jet milling, attrition milling, fluidized-bed jet milling, planetary milling, vibratory milling, and roll milling.

[0090] 090 In an embodiment of the present invention, the time for which the step of shaping the carbonaceous material is carried out may affect the degree of circularity and the tapping density.

[0091] 091 In an embodiment of the present invention, the shaped carbonaceous material may have a degree of circularity in a range from about 0.7 to about 0.85, preferably in a range from about 0.8 or above.

[0092] 092 In another embodiment of the present application, the shaped carbonaceous material has (i) a degree of circularity greater than 0.75, (ii) a degree of disorder (ID / IG) less than 0.07, (iii) a tap density in a range from about 0.85 g / cm3to about 1.0 g / cm3and (iv) a powder orientation index in a range from about 2 to about 3.

[0093] 093 In an embodiment of the present invention, the step of heating (308) the precursor mix at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture may be carried out in a non-oxidizing atmosphere. In another embodiment of the present invention, the step of heating (304) theprecursor mix at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, may be carried out in an inert gas atmosphere. In an embodiment of the present invention, the inert gas may be nitrogen.

[0094] 094 In an embodiment of the present invention, the step of heating (308) the precursor mix at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, may be carried out at a heating rate from about 30 °C per hour to about 60 °C per hour.

[0095] 095 In an embodiment of the present invention, the step of heating (310) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material, may be carried out in a nonoxidizing atmosphere. In another embodiment of the present invention, the step of heating (306) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material may be carried out in an inert gas atmosphere. In an embodiment of the present invention, the inert gas may be nitrogen.

[0096] 096 In an embodiment of the present invention, the step of heating (306) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material, may be carried out at a heating rate of about 50 °C per hour.

[0097] 097 In an embodiment of the present invention, the method of making electrode material may further include a step of dispersing the treated mixture.

[0098] 098 In an embodiment of the present invention, the step of dispersing the treated mixture may be a hammer milling step.

[0099] 099 In an embodiment of the present invention, the electrode material may have a particle size in a range from about 10 pm to about 18 pm, preferably in a range from about 13 pm to about 17 pm.In an embodiment of the present invention, the electrode material may have a tapping density in a range from about 0.9 g / cm3to about 1.25 g / cm3, preferably in a range from about 1.0 g / cm3to about 1.15 g / cm3.

[0100] In an embodiment of the present invention, the electrode material may have a surface area less than about 1.3 m2 / gm.

[0101] In an embodiment of the present invention, the electrode material may have an orientation index in a range from about 2 to about 3.

[0102] In an embodiment of the present invention, the electrode material may have a first discharge capacity in a range from about 350 milliampere-hours per gram to about 360 milliampere-hours per gram.

[0103] In an embodiment of the present invention, the electrode material may have a first cycle efficiency greater than about 94 %.

[0104] Referring now to Figure 5, a method (400) of making electrode material according to an embodiment of the present invention is described. The method includes the steps of obtaining (402) a particulate carbonaceous material, shaping (404) particles of the particulate carbonaceous material to reduce jagged edges of the particulate carbonaceous material to obtain a shaped carbonaceous material, mixing (406) carbonaceous material with a carbon precursor to obtain a precursor mix, heating (408) the precursor mix at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, dispersing (410) the treated mixture, and heating (412) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material, wherein, the electrode material has a degree of anisotropy of crystal grain alignment less than about 3.5, and has an average particle size in a range from about 10 pm to about 20 pm.In an embodiment of the present invention, the step of dispersing the treated mixture may be a hammer milling step.

[0105] Another embodiment of the present invention is a method of making electrode material. As depicted in figure 6, the method (500) includes the steps of obtaining (502) a particulate carbonaceous material, shaping (504) particles of the particulate carbonaceous material to reduce jagged edges of the particulate carbonaceous material to obtain a shaped carbonaceous material, mixing (506) carbonaceous material with a carbon precursor to obtain a precursor mix, heating (508) the precursor mix at a temperature in a range from about 400 °C to about 900 °C for a time in a range from about 3 hours to about 5 hours to obtain a treated mixture, heating (510) the treated mixture at a temperature in a range from about 2400 °C to about 3000 °C for a time in a range from about 3 hours to about 5 hours to obtain the electrode material, and, coating (512) the electrode material with amorphous carbon to obtain the amorphous carbon-coated electrode material wherein, the amorphous carbon-coated electrode material has a degree of anisotropy of crystal grain alignment less than about 3.5, and has an average particle size in a range from about 10 pm to about 20 pm.

[0106] In an embodiment of the present invention, the step of coating the electrode material with amorphous carbon may be carried out at a temperature in a range between 900 °C and about 1300 degrees Celsius.

[0107] In another embodiment of the present invention, the step of coating the electrode material with amorphous carbon may be carried out at a temperature in a range between 1000 °C and about 1200 °C.

[0108] In an embodiment of the present invention, the amount of amorphous carbon in the amorphous carbon-coated electrode material may be in a range from about 1 % to about 10111 In another embodiment of the present invention, the amount of amorphous carbon in the amorphous carbon-coated electrode material may be in a range from about 1 % to about 7.5 %.

[0109] 112 In an embodiment of the present invention, the amorphous carbon-coated electrode material has a degree of disorder (ID / IG) less than 0.5.

[0110] 113 In an embodiment of the present invention, the amorphous carbon-coated electrode material has a powder orientation index of about 10 to 11.

[0111] 114 In an embodiment of the present invention, the amorphous carbon-coated electrode material is coated onto a copper foil current collector to provide a coated electrode having an orientation index in the range of 10 to 15.

[0112] 115 In an embodiment of the present invention, the amorphous carbon-coated electrode material may have an electrode density in the range of about 1.2 g / cm3 to 1.9 g / cm3.

[0113] 116 In an embodiment of the present invention, the amorphous carbon-coated electrode material may have a wetting time in the range of about 1 minute to 15 minutes.

[0114] 117 In an embodiment of the present invention, the amorphous carbon-coated electrode material may have an orientation index (1004 / 1110) in the range of about 5 to 55.

[0115] 118 In another embodiment of the present invention, the amorphous carbon-coated electrode material has (i) a degree of disorder (ID / IG) of less than 0.5, (ii) an electrode orientation index (1004 / 1110) in the range of about 5 to 55, and (iii) a powder orientation index of about 10 to 15

[0116] 119 In another embodiment, the present invention provides an artificial graphite electrode material comprising an agglomeration of particles of an electrode material, wherein the artificial graphite electrode material has a degree of granulation above 75%; a powder orientation index (OI) less than or equal to 2.7; and a degree of disorder (ID / IG) less than 0.1.EXAMPLES

[0117] The present invention is further explained in the form of the following examples. However, it is to be understood that the following examples are merely illustrative and are not to be taken as limitations upon the scope of the invention.

[0118] Example 1: An electrode material was synthesized using a method of making an electrode material according to an embodiment of the present invention. The method comprised the following steps:

[0119] 1. Mixing 10 percent of a coal tar pitch with 90 percent of bulk meso-phase coke to obtain a precursor mixture;

[0120] 2. Heating the precursor mixture at 600 degrees Celsius for 4 hours to obtain a treated mixture;

[0121] 3. Heating the treated mixture at a temperature of 2800 degrees Celsius for 4 hours to obtain the electrode material.

[0122] The electrode material was studied. The orientation index of the electrode material was measured to be 2.3. The degree of disorder (ID / IG) or integrated intensity of D and G of the electrode material was measured to be 0.07. The compaction density of the electrode material was measured to be 1.8 g / cc.

[0123] Referring now to Figure 3, a scanning electron micrograph of 300 of the particles of the electrode material is shown. It can be observed from the micrograph that a degree of granulation of greater than 75 % is achieved by the method of making an electrode material according to an embodiment of the present invention. It is also observed that the particles have a round and granulated morphology. This morphology results in lower orientation index values, which in turn enhances the battery performance.

[0124] Example 2: An electrode material was synthesized using a method of making an electrode material according to an embodiment of the present invention. The method comprised the following steps:1. Shaping the particles of bulk mesophase coke by the hammer milling process.

[0125] 2. Mixing 10 percent of a coal tar pitch with 90 percent of bulk mesophase coke to obtain a precursor mix;

[0126] 3. Heating the precursor mix at 600 degrees Celsius for 4 hours to obtain a treated mixture; 4. Heating the treated mixture at a temperature of 2800 degrees Celsius for 4 hours to obtain the electrode material.

[0127] 125 The electrode material was studied. It was observed that varying the time for the step of shaping the particles of bulk mesophase coke affected the degree of circularity and the tapping density. Increasing the time for which the shaping step was carried out increased the degree of circularity and the tapping density, as shown in Table 1 below:

[0128] Table 1: Effect of the variation in time for which the shaping step is carried out on the degree of circularity and tapping density

[0129]

[0130] > > 126 The orientation index of the electrode material was measured to be 10 to 15.

[0131] 127 Electrodes with varying electrode density were made from the electrode material that was prepared by the method described in Example 2. The wetting time with water and the orientation index were measured, and the results are shown in Table 2 below:

[0132] 128 The negative electrode fabrication began with pre-treating materials: sieving the negative electrode active material through a 53 pm mesh and grinding carbon black for uniformity. For the initial slurry, the sieved active material, ground carbon black, and a first portion of about 70% of Carboxymethyl cellulose (CMC) were mixed with deionized water using a Thinky mixer at 2000 rpm for 5 minutes, followed by vacuum drying for 1 minute. Graphite was then added to the mixture and mixed at 1000 rpm for 1 minute, after which a second portion of about 15% of Carboxymethyl cellulose (CMC) was incorporated and mixed at1000 rpm for 15 minutes, with another vacuum drying step. A third Carboxymethyl cellulose (CMC) portion of about 15% was added, mixed at 1000 rpm for 5 minutes, and vacuum-dried again. Styrene butadiene rubber (SBR) binder was introduced next, mixed at 500 rpm for 5 minutes, and vacuum-dried, followed by a final homogenization step at 500 rpm for 1 minute. The slurry was coated onto copper foil current collector, dried at 110°C for 2 hours under vacuum, calendered to achieve target density, and cut into 15 mm discs. These discs underwent final drying at 130°C for 8 hours under vacuum, followed by spring-back analysis. The dried electrodes were transferred to an argon glove box and assembled into coin cells with a separator, electrolyte, and lithium counter electrode. Table 2: Variation of Wetting time and orientation index with electrode density

[0133] <

[0134]

[0135] > Example 3: An electrode material was synthesized using a method of making an electrode material according to an embodiment of the present invention, similar to that described in Example 1, except that an additional step of coating the electrode material with amorphous carbon was carried out in accordance with an embodiment of the present invention, to obtain an amorphous carbon-coated electrode material.

[0136] Electrodes with varying electrode density were made from the electrode material that was prepared by the method described in Example 2. The wetting time with water and the orientation index were measured, and the results are shown in Table 3 below:

[0137] Table 3: Variation of Wetting time and orientation index with electrode density

[0138] <

[0139]

[0140] 131 Various electrode materials were synthesized by varying the percentage weight of amorphous carbon coating on the electrode material, and the temperature at which the amorphous carbon coating is carried out. The effect of the variation in the percentage of amorphous carbon coating on the electrode material, and the temperature at which the amorphous carbon coating is carried out, is shown in Table 4 below:

[0141] Table 4: Effect of percentage of amorphous carbon coating and temperature disorder

[0142] <

[0143]

[0144] 132 Comparative Example 2: An electrode material was synthesized using a method of making electrode material according to a method described in patent application no.

[0145] 202521010850 filed on 7th February 2025 and assigned to Epsilon Advanced Materials Pvt. Ltd. The method comprised the following steps:

[0146] 1. Mixing 10 percent of a coal tar pitch with 90 percent of bulk mesophase coke to obtain a precursor mix;

[0147] 2. Heating the precursor mix at 600 degrees Celsius for 4 hours to obtain a treated mixture; 3. Heating the treated mixture at a temperature of 2800 degrees Celsius for 4 hours to obtain the electrode material.

[0148] 133 No shaping step was used in the process described above.

[0149] 134 The electrode material obtained using the processes described in Example 2 and Comparative Example 2 was studied using scanning electron microscopy to observe their particle shape and particle size distributionReferring now to Figure 7, scanning electron micrographs 600 of the particles of the electrode material obtained using the processes described in Example 2 and Comparative Example 2 are shown. Image 602 is a micrograph showing the particles produced by the process of Example 2, and 604 shows a micrograph showing the particles produced by the process of Comparative Example 2. It is observed that the morphology of particles of the electrode material in 602 is more rounded and has fewer edges as compared to the morphology of particles shown in 604. It can be observed from the micrograph that a degree of granulation of greater than 75 percent is achieved by the method of making an electrode material according to an embodiment of the present invention. It is also observed that the particles have a round and granulated morphology. This morphology results in lower orientation index values, which in turn enhances the battery performance.

[0150] Referring now to Figure 8, a Raman spectrum of the electrode material prepared by the method of Example 2 is shown. It can be observed that the degree of disorder is (ID / IG). The electrode material obtained was studied, and the properties were compared with those of the electrode material obtained in Example 2. A comparison of the properties of the electrode material obtained in Example 2 and those of the electrode material obtained in Comparative Example 2 is shown below in Table 5:

[0151] Table 5: Comparison of the properties of the electrode material obtained in Example 2, and those of the electrode material obtained in Comparative Example 2

[0152]

[0153] It can be observed from Table 5 that the electrode material made by the process described in Example 2 has a lower surface area and a higher tapping density. This results in improved electrode density and lower defect concentrations, thereby improving battery performance.

[0154] ADVANTAGES OF THE INVENTION

[0155] The technical advantages brought in by the present invention are as follows:

[0156] A lesser amount of carbon precursor, which serves as a binder, is used. This results in lower surface area and higher tapping density, thus resulting in improved electrode density, lower defect concentrations, and better battery performance.

[0157] The electrode material has a first cycle efficiency greater than about 93 percent.

[0158] The electrode material has a first discharge capacity in a range from about 350 milliampere-hour per gram to about 358 milliampere-hour per gram.

[0159] The electrode material requires a lesser amount of binder, thereby improving the electrode density, lower defect concentration, and better electrode performance.

[0160] The electrode material is resistant to oxidation up to about 700 degrees Celsius, with the onset of oxidation occurring above 750 degrees Celsius in ambient air.

[0161] The electrode material is particularly suitable for quick charge and long-life cycle.

[0162] The electrode material has a lower powder and electrode orientation index.

Claims

We Claim:

1. A method of producing an artificial graphite electrode material, comprising:(a) mixing a carbonaceous material with a carbon precursor to form a precursor mixture; subjecting the precursor mixture to a first heat treatment at a temperature in a range of about 300 °C to about 900 °C to obtain a treated mixture; and(b) subjecting the treated mixture to a second heat treatment at a temperature in a range of about 2400 °C to about 3000 °C to obtain the artificial graphite electrode material,wherein the artificial graphite electrode material exhibits a degree of anisotropy of crystal grain alignment of less than about 3.5 and an average particle size in a range of about 10 pm to about 20 pm.

2. The method of claim 1, wherein the carbonaceous material has volatile matter in a range from about 1 wt.% to about 9 wt.% and a moisture content of not more than about 1 wt.%.

3. The method of claim 1, wherein the carbonaceous material has a tap density of more than about 0.5 g / cm3.

4. The method of claim 1, wherein the carbonaceous material comprises at least one of native graphite, coke, bulk mesophase coke powder, calcined needle coke, green coke, or mesophase fine powder.

5. The method of claim 1 , wherein the carbon precursor comprises at least one of low softening coal tar pitch, petroleum pitch, high softening pitch, zero quinoline insoluble pitch or any combination thereof.

6. The method of claim 1, wherein a weight ratio of the carbon precursor to the carbonaceous material is in a range from about 3 wt.% to about 25 wt.%.

7. The method of claim 1, wherein heating is carried out at a heating rate in a range from about 30°C per hour to about 60°C per hour.

8. An artificial graphite electrode material comprising an agglomeration of particles of an electrode material, wherein the artificial graphite electrode material has a degree of granulation above 75%; a powder orientation index (01) less than or equal to 2.7; and a degree of disorder (ID / IG) less than 0.1.

9. The method of claim 1, further comprising, before mixing, shaping particles of the carbonaceous material to reduce jagged edges and obtain shaped carbonaceous material.

10. The method of claim 9, wherein the shaping is carried out by at least one technique selected from ball milling, hammer milling et milling, attrition milling, fluidized-bed jet milling, planetary milling, vibratory milling, and roll milling.

11. The method of claim 9, wherein the shaped carbonaceous material has(i) a degree of circularity greater than 0.75,(ii) a degree of disorder (ID / IG) less than 0.07,(iii) a tap density in a range from about 0.85 g / cm3to about 1.0 g / cm3, and(iv) a powder orientation index in a range from about 2 to about 3.

12. The method of claim 1, further comprising coating the artificial graphite electrode material with amorphous carbon to obtain an amorphous carbon-coated electrode material.

13. The method of claim 12, wherein an amount of amorphous carbon in the amorphous carbon-coated electrode material is in a range from about 1 wt.% to about 10 wt.%.

14. The method of claim 12, wherein the amorphous carbon-coated electrode material has (i) a degree of disorder (ID / IG) of less than 0.5, (ii) an electrode orientation index (1004 / 1110) in the range of about 5 to 55, and (iii) a powder orientation index of about 10 to 15.

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