Method for producing carbon materials from agglomerated lignin

Abstract

The present invention relates to a method for producing an agglomerated lignin-thermoset resin material, the method comprising the steps of providing lignin, providing at least one thermosetting resin, forming the agglomerated lignin-thermoset resin material, and curing the agglomerated lignin-thermoset resin material. The present invention also relates to a method for producing a carbon material, the method comprising heat-treating the agglomerated lignin-thermoset resin material to obtain the carbon material. The resulting carbon material is suitable for use as an active material in the negative electrode of a secondary battery.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an agglomerated lignin-thermosetting resin material and the agglomerated lignin-thermosetting resin material. The present invention also relates to a method for producing a carbon material from the agglomerated lignin-thermosetting resin material and a carbon material obtainable by the method. The present invention further relates to a negative electrode for a secondary battery containing the carbon material as an active material. The present invention further relates to the use of the carbon material as an active material in a negative electrode for a secondary battery. [Background technology]

[0002] Secondary batteries, such as lithium-ion batteries, are batteries that can be charged and discharged multiple times, i.e., rechargeable batteries. In lithium-ion batteries, lithium ions flow from the negative electrode through an electrolyte to the positive electrode during discharge and back during charging. Typically, lithium compounds, particularly lithium metal oxides, such as lithium nickel manganese cobalt oxide (NMC) or alternatively lithium iron phosphate (LFP), are used as the positive electrode material, and carbon-rich materials are used as the negative electrode material.

[0003] Graphite (natural or synthetic) is currently utilized as the negative electrode material in most lithium-ion batteries. Alternatives to graphite are amorphous carbon materials, such as hard carbon (non-graphitizable amorphous carbon) and soft carbon (easily graphitizable amorphous carbon), which lack long-range graphitic order. Amorphous carbon can be used as the sole active electrode material or mixed with graphite (and / or other active materials).

[0004] Amorphous carbon can be derived from lignin, an aromatic polymer that is the major component in, for example, wood and is one of the most abundant carbon sources on Earth. In recent years, with the development and commercialization of techniques to extract lignin in a highly purified, solid, particulate form from the pulp manufacturing process, lignin has attracted significant attention as a potential renewable alternative to the primarily aromatic chemical precursors currently supplied by the petrochemical industry. Amorphous carbon derived from lignin is typically non-graphitizable, i.e., hard carbon.

[0005] Lignin has a complex chemical structure that depends greatly on its origin, e.g., the type of plant or tree from which it is obtained. Lignin's properties, such as its glass transition temperature, vary greatly depending on the chemical structure, the composition of the lignin, and any impurities present. In particular, lignin obtained from hardwoods, such as eucalyptus, has a relatively lower glass transition temperature than lignin obtained from softwoods.

[0006] Today, the most commercially relevant source of lignin is kraft lignin, obtained from hardwood or softwood trees through the kraft process. Lignin can be separated from alkaline black liquor using, for example, membrane filtration or ultrafiltration. One common separation process is described in WO2006031175A1. In this process, lignin is precipitated from alkaline black liquor, usually by adding carbon dioxide to lower the pH level of the black liquor, and then filtered. The lignin filter cake is then reslurried and washed under acidic conditions, usually using sulfuric acid. The precipitated, washed lignin can be used as is or further dried.

[0007] One problem with using lignin as a precursor to carbon-rich materials is that the direct use of lignin in the form of a fine powder is unsuitable due to its undesirable thermoplastic behavior as well as its strong tendency to form dust. During the thermal conversion of lignin powder to carbon-rich materials, lignin undergoes plastic deformation / melting, severe expansion, and foaming. This severely limits the processability of lignin on an industrially relevant scale in terms of equipment dimensions, process throughput, and the need for intermediate processing. Additionally, dust formation increases the risk of dust explosions during processing.

[0008] The above-mentioned problems with undesirable thermoplastic behavior are particularly pronounced when processing lignins with low glass transition temperatures, such as those obtained from hardwoods, where problems associated with melting, softening, and decomposition begin at relatively low temperatures.

[0009] WO2021250604A1 describes a method for forming agglomerated lignin from lignin powder. The agglomerated lignin is further stabilized by thermal oxidation before heat treatment and conversion to carbon material. The problems of deformation / melting and dust formation are further alleviated by using agglomerated lignin that has subsequently been heat-stabilized. However, if a lignin with a low melting point is used, melting and dissolution may occur before the temperature required for heat stabilization is reached.

[0010] Therefore, regardless of the source of lignin, there is still room for improvement in the method for producing agglomerated lignin materials and the method for producing carbon-rich materials from lignin. The method should avoid plastic deformation / melting, severe expansion, and foaming of the lignin during the heating process and when converting the lignin to the carbon-rich material. The method should also avoid dust formation during processing of the lignin. In addition, the method should be amenable to large-scale production. Summary of the Invention

[0011] It is an object of the present invention to provide an improved method for producing carbon-rich materials that allows for the use of renewable carbon sources and eliminates or mitigates at least some of the drawbacks of prior art methods.

[0012] It is a further object of the present invention to provide a method for obtaining, starting from lignin, an improved carbon-rich material suitable for use as the active material of the negative electrode of a secondary battery, such as a lithium-ion battery.

[0013] A further object of the present invention is to provide a method for obtaining agglomerated lignin that can be subjected to a subsequent heat treatment without melting / fusion or foaming.

[0014] It is a further object of the present invention to provide a method for producing carbon-rich materials from lignin that allows for heat treatment of the lignin while retaining its shape, regardless of the origin of the lignin.

[0015] A further object of the present invention is to provide a method for avoiding dust formation during processing of powdered lignin.

[0016] It is a further object of the present invention to provide a method for producing carbon-rich materials from lignin that is scalable and therefore suitable for large-scale production.

[0017] The above objectives, as well as other objectives that will be recognized by those skilled in the art in light of this disclosure, are achieved by various aspects of the present disclosure.

[0018] According to a first aspect, the present invention provides a method for producing an agglomerated lignin-thermoset resin material, comprising: - providing lignin; - providing at least one thermosetting resin; - forming an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have particle sizes within the range of 0.2 mm to 5.0 mm, the forming comprising contacting the lignin with at least one thermoset resin; and - A process for hardening agglomerated lignin-thermosetting resin materials The present invention relates to a method, comprising:

[0019] It has been surprisingly found that forming an agglomerated lignin-thermoset resin material results in a lignin material that can be heat treated after curing while retaining its shape, avoiding melting / expansion and deformation. The method of the present invention also reduces dust formation during lignin processing. Surprisingly, the method of the present invention also facilitates the heat treatment of lignins with low glass transition temperatures, such as lignins obtained from hardwoods.

[0020] According to a second aspect, the present invention relates to an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size in the range of 0.2 mm to 5.0 mm. The agglomerated lignin-thermoset resin material according to the second aspect is obtainable by the method according to the first aspect.

[0021] According to a third aspect, the present invention provides a method for producing a carbon material, comprising the steps of: - providing an agglomerated lignin-thermoset resin material obtainable by the method according to the first aspect or an agglomerated lignin-thermoset resin material according to the second aspect; and - subjecting the agglomerated lignin-thermoset material to a heat treatment at one or more temperatures in the range of from 300°C to 3000°C to obtain a carbon material, wherein the heat treatment is carried out for a total time in the range of from 30 minutes to 10 hours. - subjecting the agglomerated lignin-thermoset material to a heat treatment at one or more temperatures in the range of from 300°C to 3000°C to obtain a carbon material, wherein the heat treatment is carried out for a total time in the range of from 30 minutes to 10 hours. The present invention relates to a method, including:

[0022] It has surprisingly been found that by providing lignin in the form of an agglomerated lignin-thermoset resin material, the lignin material can be heat treated while retaining its shape, avoiding melting / expansion and deformation. The resulting carbon material is suitable for use in energy storage applications, such as the active material for the anode of a secondary battery.

[0023] According to a fourth aspect, the present invention relates to a carbon material obtainable by the method according to the third aspect.

[0024] According to a fifth aspect, the present invention relates to an anode for a secondary battery comprising, as active material, a carbon material obtainable by the method according to the third aspect.

[0025] According to a sixth aspect, the present invention relates to the use of a carbon material obtainable by the method according to the third aspect as active material in the negative electrode of a secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0026] One step of the method according to the first aspect includes providing lignin. Throughout this disclosure, the term "lignin" refers to any type of lignin that can be used as a carbon source to produce carbon-rich materials. Examples of lignin include, but are not limited to, lignin obtained from plant materials such as wood, e.g., softwood lignin, hardwood lignin, and lignin derived from cyclic plants. Lignin can also be chemically modified.

[0027] Preferably, the lignin has been purified or separated before use in the process of the present invention. The lignin can be separated from the black liquor and optionally further purified before use in the process of the present invention. Purification is typically performed so that the lignin has a purity of at least 90%, preferably at least 95%, and more preferably at least 98%, based on the dry weight of the lignin material. Thus, the lignin material used in accordance with the process of the present invention preferably contains less than 10%, preferably less than 5%, and more preferably less than 2%, of impurities such as cellulose, carbohydrates, inorganic compounds, etc., based on the dry weight of the lignin material.

[0028] Lignin can be obtained by various extraction processes, such as organosolv or kraft processes. Preferably, the lignin used in the process of the present invention is kraft lignin, i.e., lignin obtained by the kraft process. Kraft lignin can be obtained from hardwood or softwood trees.

[0029] Kraft lignin is readily available as a by-product of kraft pulp production. Utilizing kraft lignin, which is typically discarded, is beneficial from a sustainability perspective. Therefore, utilizing kraft lignin allows for more sustainable methods. Kraft lignin can be extracted on an industrial scale by well-known and established processes that result in consistent lignin quality. Kraft lignin is therefore suitable for use in large-scale processing, where process reproducibility is crucial. Extracted kraft lignin can be easily chemically modified or crosslinked, facilitating further processing.

[0030] Lignin can be obtained by the process disclosed in WO2006031175A1, commonly referred to as the LignoBoost process. Typically, this process includes the steps of precipitating lignin from alkaline black liquor by acidification, separating the precipitated lignin, and reslurrying the lignin at least once under acidic conditions. The resulting lignin can be dried and ground to provide solid particles.

[0031] The method of the first aspect also includes providing at least one thermosetting resin. As used herein, the term "thermosetting resin" refers to a resin that is irreversibly hardened by curing. The term "thermosetting resin" is not intended to encompass precursors of thermosetting resins, but rather to encompass only resins obtained by the reaction of one or more precursors. The type of thermosetting resin is not particularly limited, and any suitable thermosetting resin can be used in the method of the present invention. In some embodiments, the at least one thermosetting resin is selected from the group consisting of furan resins such as polyfurfuryl alcohol, epoxy-based resins, phenolic resins such as Bakelite, vinyl esters, melamine resins, and polyimides. Preferably, the thermosetting resin is a furan resin such as polyfurfuryl alcohol.

[0032] The at least one thermosetting resin may be provided in a liquid form or in a solid form, such as in a powder form. The thermosetting resin may be diluted using any suitable solvent. The thermosetting resin may also include at least one additive. The at least one additive may, for example, affect the properties of the thermosetting resin or may affect the aggregated lignin-thermosetting resin material.

[0033] In some embodiments, one thermosetting resin is provided. In some embodiments, more than one thermosetting resin is provided, for example, two different types of thermosetting resins or three different types of thermosetting resins. The different types of thermosetting resins may also be in different forms, such as at least one in liquid form and at least one in solid form.

[0034] The method of the first aspect also includes forming an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have particle sizes within the range of 0.2 mm to 5.0 mm. The forming step includes contacting lignin with at least one thermosetting resin. As used herein, the term "lignin thermosetting resin material" refers to a material containing both lignin and at least one thermosetting resin. The lignin thermosetting resin material may optionally contain at least one additive. The lignin thermosetting resin material of the present invention is a composite material containing lignin and at least one thermosetting resin. The lignin is contacted with a thermosetting resin, not a precursor of the thermosetting resin. Therefore, the lignin thermosetting resin material of the present invention is not a lignin-based thermosetting resin. Such a lignin-based thermosetting resin would be obtained, for example, by reacting lignin with a precursor of the thermosetting resin. In the present invention, the lignin is not modified by contacting with the thermosetting resin, and the primary polymer structure of the lignin is not changed.

[0035] As used herein, the term "forming" refers to the process of forming an agglomerated lignin-thermoset resin material by contacting lignin and at least one thermosetting resin to obtain an agglomerated lignin-thermosetting resin material. As used herein, the term "contacting" refers to the process of bringing the lignin and at least one thermosetting resin into close proximity with one another. In some embodiments, no or substantially no chemical reaction occurs between the lignin and the at least one thermosetting resin during the contacting step. In other embodiments, some chemical reaction may occur between the thermosetting resin and reactive sites on the lignin during the contacting step.

[0036] In preferred embodiments of the present invention, the agglomerated lignin-thermoset resin material comprises 80 to 99 wt. %, or 90 to 99 wt. %, or 95 to 99 wt. % lignin, based on the total weight of the agglomerated lignin-thermoset resin material. In such embodiments, the amount of lignin is always significantly greater than the amount of thermoset resin in the contacting step. Thus, if any chemical reaction occurs between the thermoset resin and the lignin, only a small portion of the lignin in the agglomerated lignin-thermoset resin material reacts, while the majority of the lignin remains unchanged by the contacting step.

[0037] The term "agglomerate" as used herein in terms such as "agglomerated lignin" and "agglomerated lignin-thermoset resin material" refers to macroparticles that in turn comprise clustered small particles of lignin or lignin and thermoset resin.

[0038] Depending on the lignin provided, the forming step may or may not include an agglomeration step. The forming step may include coating the agglomerated lignin with at least one thermosetting resin, or may include mixing lignin powder with at least one thermosetting resin powder and subsequently forming the mixture into an agglomerate. In some embodiments, the total amount of thermosetting resin in the agglomerated lignin-thermoset resin material ranges from 1 wt. % to 70 wt. %, e.g., 1 wt. % to 50 wt. %, or 1 wt. % to 20 wt. %, or 1 wt. % to 10 wt. %, based on the total dry weight of the agglomerated lignin-thermoset resin material. By "total amount of thermosetting resin" is meant the total amount of all thermosetting resins present in the lignin thermoset resin material.

[0039] In preferred embodiments, the total amount of thermosetting resin in the agglomerated lignin-thermoset resin material ranges from 1 wt. % to 20 wt. %, or 1 wt. % to 10 wt. %, or 1 wt. % to 5 wt. %, based on the total weight of the agglomerated lignin-thermoset resin material. Forming an agglomerated lignin-thermoset resin material with a small amount of thermosetting resin is advantageous because the material is then composed primarily of materials from renewable resources, allowing for a more sustainable process. The cost of lignin is also typically lower than the cost of thermosetting resin. A small amount of thermosetting resin, such as 1 wt. % to 5 wt. %, based on the total weight of the agglomerated lignin-thermoset resin material, improves the thermal properties of the agglomerated material sufficiently to avoid melting of the lignin during heat treatment.

[0040] In some embodiments, the thermoset resin may be obtained from renewable resources. In such embodiments, the lignin-thermoset resin material may be completely renewable.

[0041] The agglomerated lignin-thermoset resin material comprises 30 to 99 wt%, or 50 to 99 wt%, or 80 to 99 wt%, or 90 to 99 wt%, of lignin, based on the total weight of the agglomerated lignin-thermoset resin material. Preferably, the agglomerated lignin-thermoset resin material comprises 80 to 99 wt%, or 90 to 99 wt%, or 95 to 99 wt%, of lignin, based on the total weight of the agglomerated lignin-thermoset resin material.

[0042] The agglomerated lignin-thermoset resin material may include only lignin and thermoset resin, or may include lignin, thermoset resin, and at least one additive, the amount of the at least one additive being typically small, such as less than 5% by weight, or less than 2% by weight, based on the total weight of the agglomerated lignin-thermoset resin material.

[0043] The method of the first aspect also includes curing the agglomerated lignin-thermoset resin material. Curing can be carried out at room temperature and / or at elevated temperatures. Increasing the temperature results in faster curing. The temperature used during curing also depends on the type of thermoset resin.

[0044] In some embodiments, curing is carried out at one or more temperatures ranging from 20°C to 250°C, and the curing is carried out for a total time of at least 30 minutes, i.e., the residence time of the agglomerated lignin-thermoset resin material in the equipment used for curing is at least 30 minutes. The total curing time is preferably less than 24 hours. During curing, irreversible curing of the at least one thermoset resin occurs. After curing, an agglomerated lignin-thermoset resin material is obtained that does not change its shape during subsequent heat treatment. Additionally, the addition of a thermoset resin material to the agglomerated lignin further reduces the melting / swelling behavior of the lignin during heating.

[0045] In some embodiments, curing is carried out for a total time of at least 30 minutes at one or more temperatures ranging from 20° C. to 250° C., e.g., 20° C. to 200° C., or 20° C. to 150° C., or 50° C. to 150° C. Preferably, curing is carried out for a total time of at least 30 minutes at one or more temperatures ranging from 20° C. to 150° C., or 50° C. to 150° C. In such embodiments, the lignin exhibits no or negligible melting / swelling behavior.

[0046] In embodiments in which the agglomerated lignin is coated with at least one thermosetting resin, the inventors believe that, after curing, the cured thermosetting resin holds the lignin within the agglomerated lignin-thermosetting resin material, preventing the lignin from melting / swelling during subsequent heat treatment at temperatures at which lignin normally exhibits melting / swelling behavior.

[0047] In embodiments where lignin is mixed with at least one thermosetting resin prior to forming the aggregate material, it is believed that after curing a matrix of thermosetting resin is formed and the lignin is contained within the matrix, thereby preventing the lignin from melting / swelling during subsequent heat treatment at temperatures at which lignin normally exhibits melting / swelling behavior.

[0048] In some embodiments, lignin may react with the thermosetting resin during curing. In other embodiments, reactions occurring during curing are limited to within the thermosetting resin. In some embodiments, reactions between lignin polymer chains occur during curing. Thus, cross-linking reactions may occur within the thermosetting resin during curing, and may occur between the thermosetting resin and lignin, and / or between different lignin polymer chains. Cross-linking reactions between the lignin and the thermosetting resin, as well as between different lignin polymer chains, reduce the melting / swelling behavior of the lignin during a subsequent heating step at temperatures where lignin normally exhibits melting / swelling behavior. Cross-linking within the thermosetting resin may create physical constraints that prevent the lignin from melting / swelling.

[0049] What reactions occur during curing, other than crosslinking of the thermosetting resin, depends, for example, on the temperature and the type of thermosetting resin used.

[0050] In some embodiments, curing is carried out using the same temperature throughout the curing process, hi some embodiments, curing is carried out at room temperature for a total time of at least 30 minutes.

[0051] In some embodiments, curing is carried out at various temperatures, such as using a stepwise temperature increase or a temperature gradient. In some embodiments, curing is carried out in several steps at different temperatures. The temperature can be increased from one step to the next using a temperature ramp or gradient. For example, curing can be carried out by heating the agglomerated lignin-thermoset resin material to a first temperature ranging from 20° C. to 250° C., such as from 20° C. to 200° C., or from 20° C. to 150° C., or from 0° C. to 150° C., followed by heating to a second temperature ranging from 20° C. to 250° C., such as from 20° C. to 200° C., or from 20° C. to 150° C., or from 50° C. to 150° C., and holding at each selected temperature for a predetermined time, such as from 10 minutes to 3 hours. By carrying out curing in several steps at different temperatures, improved crosslinking of the cured agglomerated lignin-thermoset resin material can be achieved. The properties of the carbon material obtained by heat treatment of the agglomerated lignin-thermoset material are improved in terms of microporosity by improving cross-linking during the curing of the agglomerated lignin-thermoset material. In addition, the curing process can be carried out in a more controlled manner, reducing the risk of cracking of the agglomerated lignin-thermoset material during curing.

[0052] In some embodiments, an acid catalyst is added to at least one thermosetting resin material, and the curing of the agglomerated lignin-thermosetting resin material is catalyzed by the acid catalyst. In one embodiment, the acid catalyst is selected from sulfuric acid, maleic anhydride, or p-toluenesulfonic acid. The curing using the catalyst can be carried out at room temperature and / or at an elevated temperature. Curing is faster at elevated temperatures.

[0053] Curing can be achieved using both a catalyst and elevated temperature, or by catalyst alone, or elevated temperature alone.

[0054] After formation and curing, an agglomerated lignin-thermoset resin material is obtained having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm. Preferably, the particle size distribution is such that at least 90%, more preferably at least 95%, by weight of the particles have a particle size within the range of 0.2 mm to 5.0 mm. More preferably, at least 90%, more preferably at least 95%, by weight of the particles have a particle size within the range of 0.5 mm to 2 mm.

[0055] The agglomerated lignin-thermoset resin material preferably has a density of 0.5 g / cm 3 to 0.7 g / cm 3 , more preferably 0.5 g / cm 3 to 0.6 g / cm 3 It has a bulk density in the range of

[0056] In one embodiment of the invention, the lignin in the process according to the first aspect is provided in the form of agglomerated lignin having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size in the range of 0.2 mm to 5.0 mm. The agglomerated lignin preferably comprises: a) providing a powdered lignin, wherein the particle size distribution of the powdered lignin is such that at least 80% by weight of the particles have a particle size less than 0.2 mm and a moisture content less than 45% by weight; b) compacting the lignin powder of step a); c) crushing the densified lignin obtained in step b) to obtain agglomerated lignin; and d) optionally sieving the agglomerated lignin obtained in step c) to remove particles having a particle size of less than 100 μm, thereby obtaining an agglomerated lignin having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm. The compound is obtained by a method comprising:

[0057] Preferably, the powdered lignin is dried before compaction. Drying of the lignin is carried out by methods and apparatus known in the art. The powdered lignin used in step a) has a moisture content of less than 45% by weight. Preferably, the moisture content of the lignin before compaction according to the invention is less than 25% by weight, preferably less than 10% by weight, more preferably less than 8% by weight. In one embodiment, the moisture content of the lignin before compaction according to the invention is at least 1% by weight, for example at least 5% by weight. The temperature during drying is preferably in the range of 80°C to 160°C, more preferably in the range of 100°C to 120°C.

[0058] The lignin powder obtained after drying has a wide particle size distribution ranging from 1 μm to 2 mm, which is significantly biased towards the micrometer range, meaning that a significant proportion of the particles have a particle size in the range of 1 to 200 micrometers.

[0059] Lignin compaction is preferably carried out by roll compaction. Roll compaction of lignin can be achieved using a roller compactor, which aggregates lignin particles. The compaction process produces an intermediate product. Here, fine lignin powder is typically fed through a hopper and conveyed to the compaction zone by a horizontal or vertical feed screw. There, the material is compacted into flakes by compaction rollers with a specified gap. By controlling the feed screw speed and pressure generation in the compaction zone, flakes of uniform density can be obtained. Pressure generation in the compaction zone is preferably monitored and controlled by the rotation speed of the compaction rolls. As the powder is drawn between the rollers, it enters a region called the nip region, where the density of the material increases, converting the powder into flakes or ribbons. The rolls used contain cavities. The depth of each cavity used in roll compaction is 0.1 mm to 10 mm, preferably 1 mm to 8 mm, more preferably 1 mm to 5 mm or 1 mm to 3 mm. The specific pressure applied during compaction may vary depending on the equipment used for compaction, but may range from 1 kN / cm to 100 kN / cm. Suitable equipment for carrying out compaction is known in the art.

[0060] After compaction, crushing is preferably carried out, in which the intermediate product from the compaction step is subjected to crushing or grinding, such as by a rotary granulator, cage mill, beater mill, hammer mill, or crusher mill, and / or combinations thereof, during which further intermediate products are produced.

[0061] After crushing, the crushed material is preferably subjected to a sieving step to remove fine materials. Additionally, larger materials, such as agglomerates with a particle size greater than 5.0 mm, can be removed and / or recycled to the crushing step. In the sieving step, the intermediate product from the crushing step is screened by physical separation, such as sieving, also known as screening, to obtain a product that is an agglomerated lignin with a defined particle size distribution set by the porosity of the sieve or screen used in this step. The sieve or screen is selected so that most particles with a particle size less than 100 (or 500) μm are rejected through the screen and preferably returned to the consolidation step, while most particles with a particle size greater than 100 (or 500) μm are retained and subjected to the subsequent heating step of the method according to the present invention. Sieving may be carried out in more than one step, i.e., sieving may be carried out such that the crushed material from the crushing step passes successively through more than one screen or sieve.

[0062] In one embodiment of roll compaction, the roll configuration is such that the first roll has an annular rim configured such that the powder in the nip region is sealed axially along the roller surface.

[0063] In one embodiment, the roll configuration is such that the nip region is sealed axially along the roller surface by a static plate. By ensuring that the nip region is sealed, powder loss at the axial ends of the roller is minimized compared to a fully cylindrical nip roller.

[0064] During the preparation of agglomerated lignin, lignin powder is compacted, so that the bulk density of the lignin increases when pressure is applied to the lignin powder. This means that the agglomerated lignin will have a higher bulk density than the lignin powder. More compacted lignin particles can be beneficial during subsequent processing into carbon-rich materials, as the compacted lignin particles have been found to maintain their shape without melting or expanding. The agglomerated lignin particles also have a relatively high hardness after compaction. Hard particles are advantageous for subsequent processing because they can withstand physical impacts during processing. Furthermore, the use of hard compacted particles avoids processing problems that may arise due to the presence of lignin dust on the particle surface. This is particularly important in large-scale processes, as the dust can form explosive mixtures with air and cause blockages in processing equipment.

[0065] The agglomerated lignin is preferably 0.5 g / cm 3 to 0.7 g / cm 3 , more preferably 0.5 g / cm 3 to 0.6 g / cm 3 The lignin powder before agglomeration preferably has a bulk density in the range of 0.3 g / cm 3 to 0.4 g / cm 3 It has a bulk density in the range of

[0066] The agglomerated lignin has a particle size distribution such that at least 80% by weight of the particles have a particle size in the range of 0.2 mm to 5.0 mm. Preferably, the particle size distribution is such that at least 90%, more preferably at least 95% by weight of the particles have a particle size in the range of 0.2 mm to 5.0 mm. More preferably, at least 90%, more preferably at least 95% by weight of the particles have a particle size in the range of 0.5 mm to 2 mm.

[0067] In some embodiments, the powdered lignin is mixed with at least one additive prior to compaction. Mixing is performed by methods and equipment known in the art. One suitable method is a vertical mixer, such as a paddle, screw, or ribbon screw mixer, in batch or continuous mode. The mixing process can be performed in low, medium, or high shear impact mode. Any suitable additives, such as binders or lubricants, can be added to facilitate the subsequent compaction process and to improve the density and mechanical properties of the resulting agglomerated lignin. Additionally, additives that affect the properties of the final material, such as functionality-enhancing additives, may be added. The total amount of additives is preferably less than 5 wt. %, e.g., less than 2 wt. %, based on the total dry weight of the mixture of lignin powder and additives. The compaction, crushing, and optional sieving steps for producing agglomerated lignin from lignin powder mixed with additives are performed as described above for the case of using only lignin powder without additives.

[0068] In embodiments in which the lignin is provided in the form of an agglomerated lignin, the at least one thermosetting resin is preferably provided in liquid form, and the step of forming the agglomerated lignin-thermosetting resin material comprises coating the agglomerated lignin with at least one thermosetting resin to obtain the agglomerated lignin-thermosetting resin material. Any suitable coating method known to those skilled in the art can be used, such as spray coating or dip coating. Coating the agglomerated lignin with a thermosetting resin provides an outer layer of thermosetting resin on the agglomerated lignin-thermosetting resin material. After curing, the agglomerated lignin-thermosetting resin material is provided with a hard, protective layer, which reduces dust formation and also reduces the tendency of the agglomerated lignin-thermosetting resin material to stick together due to surface melting / softening during subsequent heat treatment. The bulk density of the agglomerated lignin is not significantly affected by coating with a thermosetting resin.

[0069] In embodiments in which the at least one thermosetting resin is liquid, the at least one thermosetting resin may be diluted with a solvent. If the thermosetting resin has a high viscosity, dilution of the thermosetting resin is preferred to facilitate the subsequent coating process. Any solvent suitable for the at least one thermosetting resin may be used, such as water, tetrahydrofuran, or dichloromethane.

[0070] The agglomerated lignin-thermoset resin material can be dried after coating. Drying can be carried out at room temperature or at an elevated temperature. Drying can be carried out using any suitable means known to those skilled in the art. Drying can be carried out under atmospheric pressure, reduced pressure, or vacuum. In some embodiments, drying is carried out at room temperature for at least 10 hours. In some embodiments, drying is carried out at one or more temperatures below 60°C, such as in the range of 30°C to 60°C, for a time period ranging from 5 minutes to 10 hours. After drying, the agglomerated lignin-thermoset resin material has a dry content of at least 50% by weight, e.g., at least 70% by weight, or at least 80% by weight. The drying step is particularly important in embodiments where the thermoset resin is diluted with a solvent to remove the solvent.

[0071] If the agglomerated lignin-thermoset resin material is not dried prior to curing at elevated temperatures, drying occurs simultaneously with curing.

[0072] In one embodiment of the invention, the lignin provided by the method according to the first aspect is in powder form, and the particle size distribution of the powdered lignin is such that at least 80% by weight of the particles have a particle size less than 0.2 mm and a moisture content less than 45% by weight. Preferably, the powdered lignin is dried before further processing into agglomerated lignin. Drying of the lignin powder is carried out by methods and apparatus known in the art. The powdered lignin has a moisture content less than 45% by weight. Preferably, the moisture content of the lignin powder is less than 25% by weight, preferably less than 10% by weight, more preferably less than 8% by weight. In one embodiment, the moisture content of the lignin powder is at least 1% by weight, such as at least 5% by weight. The temperature during drying is preferably in the range of 80°C to 160°C, more preferably in the range of 100°C to 120°C.

[0073] The lignin powder obtained after drying has a wide particle size distribution ranging from 1 μm to 2 mm, which is heavily biased towards the micrometer range, meaning that a significant proportion of the particles have a particle size in the range of 1 to 200 micrometers.

[0074] In embodiments of the method according to the first aspect in which the lignin is provided in powder form, the at least one thermosetting resin is preferably provided in powder form. The thermosetting resin powder can be obtained by freezing a liquid thermosetting resin and subsequently crushing it. The moisture content of the powdered thermosetting resin is preferably less than 1% by weight.

[0075] In embodiments where the lignin and at least one thermoset resin are both provided in powder form, the step of forming the agglomerated lignin-thermoset resin material preferably comprises the following steps: i) mixing lignin powder, at least one thermosetting resin powder, and optionally at least one additive to obtain a lignin-thermosetting resin mixture; ii) consolidating the lignin-thermosetting resin mixture obtained in step i) to obtain a lignin-thermosetting resin material; iii) crushing the lignin-thermosetting resin material obtained in step ii) to obtain an agglomerated lignin-thermosetting resin material; and iv) optionally sieving the agglomerated lignin-thermoset resin material obtained in step iii) to remove particles having a particle size less than 100 μm, thereby obtaining an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm. Includes.

[0076] The mixing of the lignin powder, thermosetting resin powder, and optional at least one additive is carried out by methods and equipment known in the art. One suitable method is a vertical mixer, such as a paddle, screw, or ribbon screw mixer, in batch or continuous mode. The mixing process can be carried out in low, medium, or high shear impact mode. By ensuring sufficient mixing, good dispersion of the lignin powder and the powdered at least one thermosetting resin is achieved. Good dispersion then facilitates further processing and provides uniform properties to the resulting lignin-thermosetting resin material.

[0077] Optionally, at least one additive may be added during mixing. Any suitable additive, such as a binder or lubricant, may be added to facilitate the subsequent consolidation process and to improve the density and mechanical properties of the resulting agglomerated lignin-thermoset resin material. In addition, additives that affect the properties of the final material, such as functionality-enhancing additives, may be added. The total amount of additives is preferably less than 5% by weight, e.g., less than 2% by weight, based on the total dry weight of the mixture of lignin powder, thermoset resin, and additives.

[0078] The consolidation of the lignin-thermosetting resin mixture in step ii) is preferably carried out by roll compaction. Roll compaction of the lignin-thermosetting resin mixture can be achieved by a roller compactor that aggregates the materials. The consolidation process produces an intermediate product. Here, fine powders of lignin and thermosetting resin are typically fed through a hopper and conveyed by a horizontal or vertical feed screw to the consolidation zone, where the material is consolidated into flakes by compaction rollers with a defined gap. By controlling the speed of the feed screw and the pressure generated in the consolidation zone, flakes of uniform density can be obtained. The pressure generated in the consolidation zone is preferably monitored and can be controlled by the rotation speed of the compaction rolls. As the powder is drawn between the rollers, it enters a region called the nip region, where the density of the material increases and the powder is converted into flakes or ribbons. The rolls used have cavities. The depth of each cavity used in roll compaction is 0.1 mm to 10 mm, preferably 1 mm to 8 mm, more preferably 1 mm to 5 mm or 1 mm to 3 mm. The specific pressure applied during compaction may vary depending on the equipment used for compaction, but may range from 1 kN / cm to 100 kN / cm. Equipment suitable for carrying out compaction is known in the art.

[0079] After compaction, crushing is preferably carried out, in which the intermediate product from the compaction step is subjected to crushing or grinding, such as by a rotary granulator, cage mill, beater mill, hammer mill, or crusher mill, and / or combinations thereof, during which further intermediate products are produced.

[0080] After crushing, the crushed material is preferably subjected to a sieving step to remove fine materials. Additionally, larger materials, such as agglomerates with a particle size greater than 5.0 mm, can be removed and / or recycled to the crushing step. In the sieving step, the intermediate product from the crushing step is screened by physical separation, such as sieving, also known as screening, to obtain a product that is an agglomerated lignin with a defined particle size distribution set by the porosity of the sieve or screen used in this step. The sieve or screen is selected so that most particles with a particle size less than 100 (or 500) μm are rejected through the screen and preferably returned to the consolidation step, while most particles with a particle size greater than 100 (or 500) μm are retained and subjected to the subsequent heating step of the method according to the present invention. Sieving may be carried out in more than one step, i.e., sieving may be carried out such that the crushed material from the crushing step passes successively through more than one screen or sieve.

[0081] In one embodiment of roll compaction, the roll configuration is such that the first roll has an annular rim configured such that the powder in the nip region is sealed axially along the roller surface.

[0082] In one embodiment, the roll configuration is such that the nip region is sealed axially along the roller surface by a static plate. By ensuring that the nip region is sealed, powder loss at the axial ends of the roller is minimized compared to a fully cylindrical nip roller.

[0083] During the preparation of the agglomerated lignin-thermoset resin material, the lignin powder and thermosetting resin powder are compacted, resulting in an increase in the bulk density of the material when pressure is applied to the powders. This means that the agglomerated lignin-thermoset resin material will have a higher bulk density than the lignin powder and thermosetting resin powder. More compacted lignin particles can be beneficial during subsequent processing into a carbon-rich material, as the compacted lignin particles have been found to retain their shape without melting or expanding. The presence of a thermosetting resin in the agglomerate further improves the processability of the lignin. Thus, the presence of a thermosetting resin in the agglomerate together with the lignin, combined with the agglomeration process itself, results in a lignin material that maintains its shape and can be heat-treated without melting or expanding.

[0084] The agglomerated lignin-thermoset material particles also have a relatively high hardness after compaction. Hard particles are advantageous for subsequent processing because they can withstand physical impacts during processing. Furthermore, the use of hard compacted particles avoids processing problems that may arise due to the presence of lignin dust on the surface of the particles. This is especially important in large-scale processes because the dust can form explosive mixtures with air and cause blockages in processing equipment.

[0085] In a preferred embodiment, the lignin provided in step a) of the method of the present invention is provided in a dry state, such as in the form of an agglomerated lignin or in the form of a lignin powder. In such embodiments, the lignin preferably remains dry when contacted with the thermosetting resin in step c). Preferably, the lignin does not dissolve during any step of the method of the present invention.

[0086] According to a second aspect, the present invention relates to an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm. The agglomerated lignin-thermoset resin material comprises lignin and at least one thermosetting resin. The agglomerated lignin-thermoset resin material may optionally comprise at least one additive. The agglomerated lignin-thermoset resin material according to the second aspect is obtainable by the method according to the first aspect.

[0087] Preferably, the lignin in the agglomerated lignin-thermoset resin material is kraft lignin, i.e., lignin obtained by the kraft process. Preferably, the kraft lignin is obtained from softwood or hardwood.

[0088] The type of thermosetting resin in the agglomerated lignin-thermosetting resin material is not particularly limited, and any suitable thermosetting resin can be used. In some embodiments, the thermosetting resin in the agglomerated lignin-thermosetting resin material is selected from the group consisting of furan resins such as polyfurfuryl alcohol, epoxy-based resins, phenolic resins such as Bakelite, vinyl esters, melamine resins, and polyimides. Preferably, the thermosetting resin is a furan resin such as polyfurfuryl alcohol. In some embodiments, more than one thermosetting resin is selected.

[0089] In some embodiments, the total amount of thermoset resin in the agglomerated lignin-thermoset resin material ranges from 1 wt % to 70 wt %, e.g., 1 wt % to 50 wt %, or 1 wt % to 20 wt %, or 1 wt % to 10 wt %, based on the total dry weight of the agglomerated lignin-thermoset resin material.

[0090] The agglomerated lignin-thermoset resin material according to the second aspect may be further defined as described above with reference to the first aspect.

[0091] According to a third aspect, the present invention relates to a method for producing a carbon material, the method according to the third aspect comprising providing an agglomerated lignin-thermoset resin material obtainable by the method according to the first aspect, or an agglomerated lignin-thermoset resin material according to the second aspect, the agglomerated lignin-thermoset resin material and the method for producing the same being further defined as described above with reference to the first aspect.

[0092] Thus, the method according to the third aspect may comprise carrying out the method according to the first aspect.

[0093] The method of the third aspect also includes subjecting the agglomerated lignin-thermoset resin material to a heat treatment at one or more temperatures ranging from 300°C to 3000°C. The heat treatment is carried out for a total time ranging from 30 minutes to 10 hours, i.e., the residence time of the lignin-thermoset resin material in the equipment used for the heat treatment ranges from 30 minutes to 10 hours, so as to obtain a carbon material. The resulting carbon retains the shape of the agglomerated lignin-thermoset resin starting material, i.e., the agglomerated lignin-thermoset resin material does not change dimensions, expand, or melt during the heat treatment. The resulting carbon material is suitable for use in energy storage applications, such as, for example, as an active material in the negative electrode of a secondary battery.

[0094] As used herein, the term "heat treatment" refers to a process in which the agglomerated lignin-thermoset resin material is heated at one or more temperatures for a sufficient time to increase the carbon content of the agglomerated lignin-thermoset resin material and convert it into a carbon material. Depending on the temperature during heat treatment, different types of carbon materials, such as charcoal or hard carbon, can be obtained from the agglomerated lignin-thermoset resin material.

[0095] The terms "carbon material" and "carbon-rich material" are both used herein to denote a material that consists primarily of carbon, such as at least 80% by weight, or at least 90% by weight, or at least 95% by weight, and that is obtained by carbonization of an organic compound.

[0096] The heat treatment may be carried out at the same temperature throughout the heat treatment, or at varying temperatures, such as by increasing the temperature stepwise or using a temperature gradient. The heat treatment may include a temperature ramp from a starting temperature to a target temperature. The heating rate may be 1 to 100°C / min. For example, the heat treatment may include several intermediate temperatures with temperature ramps between them before reaching the target temperature required for carbonization of the lignin-thermoset resin material. The heat treatment may be carried out as a batch or continuous process. Any suitable reactor may be used, such as a rotary kiln, a moving bed furnace, a pusher furnace, or a rotary hearth furnace. The heat treatment is preferably carried out under an inert atmosphere, preferably a nitrogen atmosphere.

[0097] In some embodiments, heat treatment is performed immediately after curing the agglomerated lignin-thermoset resin material provided according to the method of the first aspect of the present invention. For example, curing of the agglomerated lignin-thermoset resin material can be initially performed at one or more temperatures in the range of 20° C. to 250° C., e.g., 20° C. to 200° C., or 20° C. to 150° C., or 50° C. to 150° C., and the temperature can then be increased to the temperature used during the heat treatment. The temperature increase can be stepwise or can include a temperature ramp. Thus, in some embodiments, curing can be performed in the same reactor as the subsequent heat treatment.

[0098] Preferably, the heat treatment includes a preheating step, preferably followed by a final heating step. The preheating step is preferably carried out at one or more temperatures in the range of 300°C to 800°C, for example in the range of 500°C to 700°C. The preheating step is preferably carried out under an inert atmosphere, preferably a nitrogen atmosphere. The duration of the preheating step is at least 30 minutes, preferably less than 10 hours. The surface area of ​​the carbon material obtained after the preheating step is typically between 300 and 700 m, measured as BET using nitrogen gas. 2 / g range.

[0099] The final heating step is preferably carried out at one or more temperatures in the range of 800°C to 3000°C. The final heating step is preferably carried out under an inert atmosphere, preferably a nitrogen atmosphere. The duration of the final heating step is at least 30 minutes, preferably less than 10 hours. After a final heating step carried out at 1000°C or above, the surface area of ​​the resulting carbon material is typically 50 m 2 / g or less.

[0100] The preliminary and final heating steps can be performed as separate steps or directly in succession as a single step. The preliminary and final heating steps can include heating at one or more temperatures, as discussed above for heat treatment. For example, preliminary heating can begin at about 300°C, and the temperature can then be increased to about 500°C. The final heating step is preferably performed at a temperature between 900°C and 1300°C, e.g., about 1000°C.

[0101] The preheating and final heating steps can be carried out as a batch process or a continuous process. Any suitable reactor can be used. The preheating and final heating steps can be carried out in the same reactor or in separate reactors.

[0102] In some embodiments, the method of the third aspect further comprises a step of grinding the agglomerated lignin-thermoset resin material or the resulting carbon material. Grinding can be performed before, during, or after the heat treatment, and can be performed on the (cured) agglomerated lignin-thermoset resin material or the resulting carbon material. Alternatively, if the heat treatment includes a pre-heating step and a final heating step, grinding can be performed after the pre-heating step or after the final heating step. Multiple grinding steps may also be performed. Grinding is performed to reduce the average particle size. Grinding can be performed by methods such as impact grinding, hammer grinding, ball grinding, and jet grinding. Optionally, fine / coarse particle separation by classification and / or sieving may be performed after grinding.

[0103] After heat treatment and optional grinding, the resulting carbon material may be subjected to further processing, such as carbon coating by, for example, chemical vapor deposition (CVD), pitch coating, thermal and / or chemical refining, further heat treatment, particle size adjustment, and blending with other electrode materials, for example, to further improve its electrochemical performance.

[0104] The carbonaceous material obtainable by the method according to the third aspect is preferably used as an active material in the negative electrode of a non-aqueous secondary battery, such as a lithium-ion battery. When used to manufacture such a negative electrode, any suitable method for forming such a negative electrode can be utilized. In forming the negative electrode, the carbon-rich material can be processed with additional components. Such additional components can include, for example, one or more binders for forming the carbon-rich material into an electrode, a conductive material, such as carbon black, carbon nanotubes, or a metal powder, and / or an additional Li-storage material, such as graphite or lithium. For example, the binder can be selected from, but is not limited to, poly(vinylidene fluoride), poly(tetrafluoroethylene), carboxymethyl cellulose, natural butadiene rubber, synthetic butadiene rubber, polyacrylate, poly(acrylic acid), alginate, etc., or a combination thereof. Optionally, a solvent, such as 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, water, or acetone, is utilized during processing.

[0105] According to a fourth aspect, the present invention relates to a carbon material obtainable by the method according to the third aspect. The carbon material obtainable by the method according to the third aspect is suitable for use in energy storage applications, for example as an active material in the negative electrode of a secondary battery. The carbon material according to the fourth aspect may be further defined as described above with reference to the third aspect.

[0106] According to a fifth aspect, the present invention relates to an anode of a secondary battery comprising as active material a carbon material obtainable by the method according to the third aspect, wherein the carbon material of the anode according to the fifth aspect may be further defined as described above with reference to the third aspect.

[0107] According to a sixth aspect, the present invention relates to the use of a carbon material obtainable by the method according to the third aspect as an active material in the negative electrode of a secondary battery. The carbon material of the sixth aspect may be further defined as described above with reference to the third aspect. [Example]

[0108] Example 1 Lignin powder from the LignoBoost process was agglomerated by roller compaction. The resulting agglomerated lignin had an average particle size ranging from 0.2 to 2.0 mm. The agglomerated lignin was coated with a liquid thermosetting resin, and the total amount of thermosetting resin in the resulting agglomerated lignin-thermosetting resin material was 5 wt%. The material was dried at room temperature for 12 hours. The coated and dried agglomerated lignin was thermally cured using a stepwise sequence that included heating at 50°C for 1 hour, 70°C for 1 hour, 90°C for 1 hour, and 150°C for 1 hour. The material gradually darkened during processing. After curing, the agglomerated lignin-thermosetting resin material was carbonized at 500°C to 1400°C under an inert atmosphere. The shape was maintained during carbonization, and no melting was observed.

[0109] Example 2 - Comparative Example Lignin powder from the LignoBoost process was agglomerated by roller compaction. The resulting agglomerated lignin had an average particle size ranging from 0.2 to 2.0 mm. The agglomerated lignin was carbonized at temperatures between 500 and 1400 °C under an inert atmosphere. The agglomerated lignin melted during carbonization, resulting in excessive foaming.

[0110] It should be apparent that other modifications and variations will be apparent to those skilled in the art in view of the above detailed description of the invention, and that such other modifications and variations can be made without departing from the spirit and scope of the invention.

Claims

1. 1. A method for producing an agglomerated lignin-thermoset resin material, comprising: providing lignin; - providing at least one thermosetting resin; - forming an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have particle sizes within the range of 0.2 mm to 5.0 mm, the forming comprising contacting the lignin with at least one thermoset resin; and - curing the agglomerated lignin-thermosetting resin material A method comprising:

2. 10. The method of claim 1, wherein the lignin is provided in the form of an agglomerated lignin having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm.

3. The agglomerated lignin provided is a) providing a powdered lignin, wherein the powdered lignin has a particle size distribution such that at least 80% by weight of the particles have a particle size less than 0.2 mm and a moisture content less than 45% by weight; b) compacting the lignin powder of step a); c) crushing the compacted lignin obtained in step b) to obtain agglomerated lignin; d) optionally sieving the agglomerated lignin obtained in step c) to remove particles having a particle size of less than 100 μm to obtain agglomerated lignin having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size in the range of 0.2 mm to 5.0 mm.

3. The method of claim 2, wherein the polymer is produced by a process comprising:

4. 4. The method of claim 3, wherein the powdered lignin is mixed with at least one additive before compaction.

5. 5. The method of any one of claims 2 to 4, wherein the at least one thermosetting resin is provided in liquid form, and the step of forming the agglomerated lignin-thermoset resin material comprises coating the agglomerated lignin with the at least one thermosetting resin to obtain the agglomerated lignin-thermoset resin material.

6. The method of claim 5 wherein the at least one thermosetting resin is diluted with a solvent.

7. 7. The method of claim 5 or 6, wherein the agglomerated lignin-thermoset resin material is dried after coating.

8. 10. The method of claim 1, wherein the lignin is provided in powder form, and the powdered lignin has a particle size distribution such that at least 80% by weight of the particles have a particle size less than 0.2 mm and a moisture content less than 45% by weight.

9. 10. The method of claim 8, wherein the at least one thermosetting resin is provided in powder form.

10. forming an agglomerated lignin thermoset material; i) mixing lignin powder, at least one thermosetting resin powder, and optionally at least one additive to obtain a lignin-thermosetting resin mixture; ii) consolidating the lignin-thermosetting resin mixture obtained in step i) to obtain a lignin-thermosetting resin material; iii) crushing the lignin-thermosetting resin material obtained in step ii) to obtain an agglomerated lignin-thermosetting resin material; iv) optionally sieving the agglomerated lignin-thermoset resin material obtained in step iii) to remove particles having a particle size of less than 100 μm to obtain an agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have a particle size within the range of 0.2 mm to 5.0 mm.

10. The method of claim 9, comprising:

11. 11. The method of claim 1, wherein the lignin is kraft lignin.

12. 12. The method according to claim 1, wherein the at least one thermosetting resin is selected from the group consisting of furan resins such as polyfurfuryl alcohol, epoxy-based resins, phenolic resins such as bakelite, vinyl esters, melamine resins, and polyimides.

13. 13. The method of any one of claims 1 to 12, wherein the total amount of thermosetting resin in the agglomerated lignin-thermosetting resin material is in the range of 1 to 70 wt%, based on the total dry weight of the agglomerated lignin-thermosetting resin material.

14. 14. The method of any one of claims 1 to 13, wherein curing is carried out at one or more temperatures in the range of 20°C to 250°C for a total time of at least 30 minutes.

15. 15. The method of any one of claims 1 to 14, wherein an acid catalyst is added to the thermosetting resin and the curing of the agglomerated lignin-thermosetting resin material is catalyzed by the acid catalyst.

16. An agglomerated lignin-thermoset resin material having a particle size distribution in which at least 80% by weight of the agglomerates have particle sizes within the range of 0.2 mm to 5.0 mm.

17. 17. The agglomerated lignin-thermoset resin material of claim 16, wherein the lignin in the agglomerated lignin-thermoset resin material is kraft lignin.

18. 18. The agglomerated lignin-thermosetting resin material according to claim 16 or 17, wherein the thermosetting resin in the agglomerated lignin-thermosetting resin material is selected from the group consisting of furan resins such as polyfurfuryl alcohol, epoxy-based resins, phenolic resins such as bakelite, vinyl esters, melamine resins, and polyimides.

19. 19. The agglomerated lignin-thermoset resin material of any one of claims 16 to 18, wherein the total amount of thermosetting resin in the agglomerated lignin-thermoset resin material is in the range of 1 to 70 wt%, based on the total dry weight of the agglomerated lignin-thermoset resin material.

20. 1. A method for producing a carbon material, comprising: - providing an agglomerated lignin-thermoset resin material obtainable by a method according to any one of claims 1 to 15 or an agglomerated lignin-thermoset resin material according to any one of claims 16 to 19; - subjecting the agglomerated lignin-thermoset resin material to a heat treatment at one or more temperatures in the range of from 300°C to 3000°C to obtain a carbon material, wherein the heat treatment is carried out for a total time in the range of from 30 minutes to 10 hours. A method comprising:

21. 21. The method of claim 20, wherein the heat treatment comprises a preheating step followed by a final heating step.

22. 22. The method of claim 21, wherein the preheating step is carried out at one or more temperatures in the range of 400°C to 800°C for at least 30 minutes.

23. 23. The method of claim 21 or 22, wherein the preheating step is carried out under an inert atmosphere.

24. 24. The method of any one of claims 21 to 23, wherein the final heating step is carried out at one or more temperatures in the range of 800°C to 3000°C for at least 30 minutes.

25. 25. The method of any one of claims 21 to 24, wherein the final heating step is carried out under an inert atmosphere.

26. 26. The method of any one of claims 20 to 25, comprising the additional step of comminuting the agglomerated lignin-thermoset resin material or the resulting carbon material.

27. 27. A carbon material obtainable by the method according to any one of claims 20 to 26.

28. 27. A negative electrode for a secondary battery comprising, as an active material, a carbon material obtainable by the method according to any one of claims 20 to 26.

29. 27. Use of a carbon material obtainable by the method according to any one of claims 20 to 26 as active material in the negative electrode of a secondary battery.

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