WO2018134484A1

WO2018134484A1 - Method for the manufacture of anode materials for li ion batteries by utilising short-term laser pulses

Info

Publication number: WO2018134484A1
Application number: PCT/FI2018/050054
Authority: WO
Inventors: Jari Liimatainen; Ville KEKKONEN
Original assignee: Picodeon Ltd Oy
Priority date: 2017-01-23
Filing date: 2018-01-23
Publication date: 2018-07-26
Also published as: FI20175056L

Abstract

In the present invention there is introduced a method for the manufacture of anode materials (54) for lithium batteries so that a coating method based on laser ablation is utilised in the manufacture of at least one material layer. The share by volume of the active anode material used in the invention is at least 10 percent by volume of the anode material coating, and the average particle size is at most 3 μm. A so-called roll-to-roll method can be used in the method, in which the base material (15, 22, 42, 65, 75, 85, 95) to be coated is directed from one roll (41a) to the second roll (41b), and the coating occurs in the area between the rolls (41a-b). In addition, turning mirrors (31) can be used to focus laser pulses (12, 61, 71a-b, 81a-d, 91) as a pulse front (33) to the surface of the target material (13, 62, 72a-b, 82a-d, 82A-D, 92).

Description

Method for the manufacture of anode materials for Li ion batteries by util

short-term laser pulses

Field of the invention The invention relates especially to lithium batteries, their structure and the manufacture of anode materials. Further, the invention relates to the manufacture of at least one part of said lithium batteries by utilising short-term laser pulses and so- called PLD method (Pulsed Laser Deposition).

Background of the invention As the need for mobile devices, electrically operated cars and storing of energy grows, the need for the development of battery technology has increased. Li ion batteries have succeeded well in very many applications, especially due to their good energy density and recharging possibilities compared to, among others, traditional Ni-CD (nickel-cadmium) and Ni-Mn (nickel-manganese) batteries. Li ion battery technology is based on a positive cathode, in which the active material is, for example, transition metal oxide, and on a commonly used carbon-based negative anode. A microporous polymeric separator is used between the anode and cathode to prevent contact between the anode and cathode, but nevertheless allowing the ions to move through the separator film. In addition, an electrolyte is needed, which in current solutions is principally liquid.

To improve the energy density and service life of Li ion batteries, the aim has been to develop new anode materials instead of the commonly used graphite. There are several alternative materials with own advantages and limitations. With many potential materials, the use is restricted, for example, by limitations related to safety, service life and, in certain cases, manufacturing technology and costs.

With carbon-based materials, it has been attempted to develop their use in energy storing applications by modifying the microstructure, for example, by manufacturing carbon nanotubes or graphene. It is thus possible, in theory, to achieve multiple improvements in the energy storing capacity. These materials have been used to- gether with other materials as composite materials. For example, with carbon nanotubes and graphene, their use is also limited by the lack of industrial and cost-effective manufacturing methods. For example, the use of silicon would have significant advantages, because its theoretical energy storing capacity is even 10-fold compared to graphite. Further, the availability of silicon is very good, and its price is low. The limitation with silicon is the changes in volume caused by charges and discharges during use, and damages caused by these in the structure, in the contact between particles and contact with the rest of the structure. In addition, changes in the volume of silicon cause constant distortion in the reaction layer forming to its surface, preventing the formation of a stable, non-constantly renewing reaction layer. Other disadvantages with silicon are poor electron conductivity and deterioration of capacity in long-term use. There are also many other material groups which are possible to be used as anode materials or Li ion batteries with own advantages and disadvantages; for example, germanium, titanium-based oxides, such as Li₄TisOi2 and T1O2, SnO2, S1O2, iron oxides, such as Fe3O₄, cobalt oxides, such as Co₃O₄ and CoO, metal phosphides, metal sulphides and metal nitrides. Because all materials have their own strengths and weaknesses and also different manufacturing costs, it may be advantageous to use these materials as different kinds of combinations i.e. composites to support the achievement of an appropriate property profile.

Summary of the invention

The present invention introduces a method for the manufacture of anode materials and coatings to be used in the manufacture of Li ion batteries by utilising the benefits relating to the control, doping and multi-layer manufacture of microstructures achieved by ultrashort laser pulses. The method is suited for the industrial bulk manufacture of anode materials. The method makes it possible to optimize the total performance of the anode coating, for example, regarding capacity, energy and power density and cyclic strength. These methods and means are described next.

In the method of the invention ultrashort laser pulses, with a length of less than 1000 ps, are targeted at the target material to detach material from the target material as atoms, ions, particles or a combination of these. The material detached from the target is directed to the surface of the piece to be coated so that a coating of desired quality or thickness is achieved. The quality, structure, quantity, size distribution and energeticity of the materials detached from the target are controlled by parameters used in laser ablation, such as pulse energy, pulse length, used wavelength, pulse repetition frequency and superposition, coating temperature and background gas pressure. In addition, the microstructure and doping of target materials used can be adjusted together with the selected laser pulse parameters to achieve a desired process, material distribution and coating.

Depending on the anode material or combination of anode materials to be used and on the pursued property profile, the process parameters for laser ablation can be adjusted to achieve the desired microstructure and morphology. One advantage of short-pulsed laser technology is that it can be utilised for very many materials so that it is possible to produce different combinations of material and different combinations of microstructures.

The porosity of the coating layer to be prepared by ablation, the size of anode ma- terial particles and the free area of anode materials can be adjusted by using pulsed laser technology, which has numerous meanings essential for Li ion batteries and anode. The coating produced by laser ablation must be porous so that the distribution of electrolyte through the entire anode material, large contact surface of the electrolyte-anode material particles and short diffusion ranges of ions and electrons are made possible. Minimizing the particle size to less than 1 pm has been found to be a good way to improve the functionality of the anode material in porous films. Small particle size and large specific area increase the ability to store Li atoms by adding storage places for active Li atoms, which increases specific capacity. In addition, a large open area increases the area in contact with the electrolyte and thus the magnitude of the Li atom flux through the anode particle-electrolyte surface. The reduction of the particle size of anode materials shortens the diffusion range of lithium and the transfer velocity of electrons. The above-mentioned benefits by means of controlling the structure of anode materials increase the total performance of Li ion batteries. The control and reduction of the size of particles in the structure's subunits by ultrashort pulsed laser technology increases the durability of materials against breakages and tears in connections caused by volume changes induced by charge and discharge cycles of Li ion batteries. Smaller sizes of microstructural units, such as anode material particle units can better adapt the stresses linked with volume changes, whether concerning particles, fibrous materials or combinations of these. For example, when using silicon as the anode material, the reduction of its particle size to less than 150 nm decreases, in a case of crystal silicon, its tendency to crack and risks to the deterioration of the battery's operation. Using the pulsed laser technology, silicon particles can be prepared as amorphic by controlling the laser pa- rameters and coating temperature, which reduces the tendency to crack in the charge and discharge cycles of Li ion batteries and increases the crack-free particle size as high as to the range of almost 1 pm.

Further, a hollow space achieved to the structure in the manufacture (porosity) increases the possibilities to adapt to the volume changes in the structure especially during use. In addition to the total quantity of porosity it is essential to control the porosity distribution. It would be especially advantageous to improve the uniformity of the porosity distribution. For example, by manufacturing a silicon-doped anode material by slurry technology using binding agents, the pore distribution of the coating is not uniform in relation to the volume or size distribution of the pores, which may cause high local stresses and microscopic cracking. Utilizing laser ablation in the ultrashort pulsed laser technology makes possible a uniform pore distribution, which endures better the volume changes linked with charge/discharge cycles and the stresses caused by these without breaking.

In the use of Li ion batteries, a solid electrolyte interphase (SEI) is generated to the surface of the anode material. This SEI layer cracks easily by the impact of volume changes in the anode material, which reveals fresh anode material surface to react with the electrolyte. This leads to the continuous generation of a new SEI layer, its thickening and through this to the wear of the electrolyte. Further, the thickening of the SEI layer hampers the diffusion of Li ions, thus deteriorating the functionality of the Li ion battery. Cracks generating to the SEI layer may also contribute to the growth of acicular Li dendrites through the separator film and cause a short circuit in and permanent damage to the battery. Decreasing the particle size reduces risks to the cracking of the SEI layer and to the generation of an unstable SEI layer.

A restriction to the use of certain promising anode materials, such as Li₄Ti50i2, may be poor electron conductivity, which can be improved, except by reducing the particle size of Li₄Ti50i2, also by adding metal particles, such as nickel or copper to the particles during coating. This is possible in the pulsed laser technology either by adding a desired quantity of said alloy substances to the target material, by executing a so-called combinatory coating i.e. combined coating, for example so that, sim- ultaneously with the ablation of Li₄TisOi2, the coating is targeted with a material produced by an ablation process of copper or some other material improving conductivity. It is also possible to perform the coating layer by layer so that, for example, after the coating of the anode material layer, a coating layer is executed with a material improving conductivity, and after that again with anode material, and this se- quence is repeated sufficiently long to prepare the desired structure and layer strength. In addition to the particle size of the anode coating it must also be taken into account that for the specific capacity it may be necessary to optimize the particle size, and not minimize it. For example, with Li₄Ti50i2, as the particle size is <20 nm, the specific capacity may drop and it would be preferable to control the particle size within an area of 20 - 80 nm. The storage places for Li atoms may also be smaller in case of minute particles, due to the bigger area/volume relation, which emphasizes the need to optimize the structure. In traditional processes for the manufacture of Li₄Ti50i2, the particle sizes are over 1 pm i.e. not in the optimum area. In the ultrashort pulsed laser technology, by controlling the parameters of the laser pulses and the pressure of the background gas it is possible to adjust the particle size within the optimum area to enhance the performance of the battery, which is a significant advantage compared to, for example, slurry coating or other physical or chemical coating methods, such as sputtering, atomic layer deposition or chemical vapour deposition. When needed, it is possible to perform as the last coating phase, for example, a thermomechanical protective layer, a coating impacting the properties of the SEI layer or a coating enhancing the chemical endurance of the anode material layer after the coating of the so-called active anode material layer. The porosity or thickness of this coating can be adjusted in accordance with the required functionality. By manufacturing a composite structure either layer on layer by a combinatory method by means of two or several material flows produced by laser ablation, the properties of the anode material coating can be adjusted in many ways. For example, a second material ablated simultaneously or layered with silicon particles or fibres and having suitable properties, such as carbon, makes it possible to improve the mechanical flexibility and deformation ability of the structure compared to a material containing only silicon. When different materials are added in a suitable proportion and with a suitable size distribution by means of laser ablation, either in a combinatory manner or layered, it is possible to achieve an appropriate combination of electrochemical, chemical and mechanical properties. The crystallinity of the material to be manufactured by laser ablation can be adjusted, for example, by changing the coating temperature. When performing laser ablation with short pulses, an amorphic structure can be manufactured which, for example, in the case of silicon, differs from crystalline silicon from the point of lithium's diffusion. For example, the diffusion of lithium to silicon particles is more linear, which reduces the cracking of particles. Ultrashort pulsed laser ablation can be utilised to produce many above-described advantages on the basis of one process technology, with certain preconditions even in one coating process step. Alternatively, the laser ablation process can also be performed in several steps, for example, by using a coating line in which it is per- formed, for example, in the first step the manufacture of a porous layer consisting of anode material particles and in the next step the doping, for example, with a copper or silver layer or dispersion and by continuing this step-by-step coating, until a desired coating thickness has been produced.

When desired to manufacture the composite material, for example, as a combination of silicon and carbon, a simultaneous material flow can be directed from two different targets towards the piece to be coated, i.e. in accordance with what has been described earlier using the so-called combinatory method. When needed, the parameters for laser beams to be targeted at different target materials can be adjusted separately individually to optimize the ablation process of different target materials, and to achieve the desired structure and material distribution. A structure of this type could make possible, among other things, the use of silicon as the anode material without a risk of cracks caused by volume changes or to achieve completely new property combinations for anode materials.

For example, to decrease the particle size of silicon, Li₄Ti50i2 and tin and thus to achieve the above-mentioned advantages it is possible also to use methods, in which nanoparticles are first prepared, for example, chemically. After this, for example binding agents are added to the nanoparticles and other doping substances forming the anode material with the nanoparticles (for example carbon) and the said material is used for the manufacture of the anode material, for example, using slurry technologies. However, the processing of nanoparticles is extremely difficult, and this way to utilise nanoparticles requires many steps, which increases the lead time, costs and the possibility of quality defects. In the method of the present invention the manufacture and coating of nanoparticles and the adding and doping of other materials occur in one or several steps of the ultrashort pulsed laser ablation pro- cess, which increases cost efficiency and process controllability. In addition, there is no need for a separate difficult processing of nanoparticles. Because binding agents are not needed, contrary to, for example, slurry processing, the possible dissolution of a binding agent may disturb the electrochemical function of the Li ion battery. In principle, it is possible to combine one or some of the above-mentioned methods with another coating method, for example, as successive process steps so that ultrashort pulsed laser technology is used for the coating process step best suited for it and a second coating technology is used to complement the ultrashort pulsed laser ablation. This can be performed either immediately as successive process steps or as separate processes.

The coating can be executed as a roll-to-roll method or, for example, on sheets which are fed to the coating line as successive sheets.

For the productivity of large-volume products it is essential to perform the coating by making use of a wide laser pulse distribution, which is generated by means of turning mirrors. The laser pulse front detaches the material from the target material in a desired way, and the material flow is directed from the target to the surface of the piece to be coated.

The inventional idea of the invention further comprises the final product manufac- tured by the method, i.e. the Li ion battery with different material layers, in which the anode material has been prepared by pulsed laser ablation deposition using ultrashort laser pulses.

Brief description of the drawings

Figure 1 illustrates the principle of a coating transaction with different physical com- ponents in an example of the invention;

Figure 2 illustrates an exemplary structure of a coated separator film;

Figure 3 illustrates the principle for forming a fan-shaped rectilinear laser pulse front with an apparatus arrangement of the invention;

Figure 4 illustrates an example of a so-called roll-to-roll method relating to the coat- ing process;

Figure 5 illustrates a typical structure of a lithium ion battery as a cross-sectional view;

Figure 6a illustrates an example of the coating of an anode material onto a base using the PLD technology;

Figure 6b illustrates a possible porous structure produced with the principle of Figure 6a, in which one material is used;

Figure 6c illustrates a possible porous structure produced with the principle of Figure 6a, in which two materials are used to produce a composite material; Figure 6d illustrates a possible porous structure produced with the principle of Figure 6a, in which doped material is used in addition to the principal material;

Figure 7 illustrates a combinatory coating method by using two simultaneous material flows;

Figure 8a illustrates the use of successive coating stations to improve productivity when manufacturing sandwich structures;

Figure 8b illustrates the use of successive coating stations to improve productivity when manufacturing composite structures;

Figure 8c illustrates the use of successive coating stations to improve productivity when manufacturing doped material;

Figure 8d illustrates a more detailed detail of a basic material, which includes doped particles;

Figure 9 illustrates an example of the use of a composite target material in the manufacture of a composite coating; and

Figure 10 illustrates an electronic microscope view of the surface of a Si particle coating produced by pulsed laser deposition, in which the particle size is less than 500 nm; laser light wavelength is 1064 nm; duration of laser pulses ~9 ps.; laser pulse repetition frequency 500 kHz; pulse energy ~20 J; laser scanning speed on the surface of the target ~4 m/s; coating chamber pressure 5^*10^"7 mbar. Detailed description of the invention

In a method of the invention there is manufactured an anode material layer for a Li ion battery and, when needed, also other layers by using pulsed laser ablation deposition in the manufacture of suitable material layers or material layers gaining relative productivity or quality benefits from it. In pulsed laser ablation solid material is detached by short laser pulses, the length of which can vary from milliseconds to femtoseconds. In the pulsed laser (ablation) deposition based on laser ablation, laser pulses are typically used, the length of which is at most 100 000 ps. (i.e. at most 100 ns). In an embodiment it is also possible to use a so-called ultrashort pulsed laser deposition method, in which the length of laser pulses is at most 1000 ps. When needed, different process parameters are used for different materials of the anode material layer.

Pulsed laser ablation deposition is used for controlling the micro- and nanostruc- tures to gain and optimize the previously described functional benefits of a Li ion battery. Especially, the anode material should be optimized in relation to the capac- ity of the Li ion battery, ion and electron conductivity and cyclic endurance for the part of battery charges and discharges. In addition, manufacturing costs, which are impacted by raw material choices, and the operational safety of the battery must be taken into account.

The anode material can be any material suitable as the anode material of Li ion batteries, such as carbon in its different morphologies (carbon particles, carbon nanotubes, graphene), titanium-containing oxides, such as Li₄Ti50i2, T1O2, silicon, germanium, S1O2, Sn02, iron oxides, cobalt oxides, metal phosphides and metal nitrides. Other materials or composites formed of these or sandwich structures can also be used. For example, doping with small quantities of suitable material is possible by adding to the surface of the anode material nickel, silver, copper or platinum particles, for example, as dispersions. The objective of combination or composite materials or doping is to eliminate certain defects linked with anode materials, such as poor ion or electron conductivity or microscopic damages caused by a big volume change. The advantages to be pursued and the optimisation of microstructure achievable on the basis of this vary according to materials and applications, be- cause in addition to strengths, all material groups also have weaknesses, which one wants to minimize by means of the deposition technology based on laser ablation.

Detaching materials and producing material flow from the target or targets to the surface of the piece to be coated is done by adjusting the parameters of short laser pulses. Each material has parameters especially suitable for it, which are used for adjusting the ablation process and the structure of the generating coating. To detach material from the target material, the energy density (J/cm²) generated by laser pulses must be sufficient on the surface of the target material. The threshold energy density, with which the material detachment starts from the target, is called the ablation threshold, and it is a material-specific parameter, but it also depends on, among other things, the wavelength of laser light and the length of laser pulses. The material can detach from the target also as atoms, ions, molten particles, cracked particles, particles condensed from atoms and ions after having detached from the target or combinations of these. The manner of detachment of the material and its behaviour, such as, for example, tendency to condensate after detachment from the target, depends among other things on by how much the energy density of laser pulses exceeds the ablation threshold. Depending on the anode material and the demands set on its structure and the morphology of the coating, laser ablation parameters can be changed. It is essential to note that after detaching from the target, there can occur changes in the structure and size distribution of the material in the material flow before the material attaches to the base material. This change process can be controlled by process-technical means, for example, by adjusting the atmosphere of the coating chamber, i.e. the composition and pressure of background gas, and the flight range of the material (from the target to the base) in addition to the previously mentioned laser pulse parameters. Because the objective is to manufacture porous materials, their manufacture can be performed based on very different ablation processes and combinations of these. The choice of the ablation process is impacted by desired porosity, particle size and thus open area, thickness of the coating (particle sizes produced by different ablation mechanisms vary), quantity of crystallinity of the coating, productivity require- ment, and control requirements of stoichiometry. In a monoatomic material there usually are no stoichiometric problems, unless these are caused by the material reacting with the atmosphere in the coating chamber. In multiatomic compounds, the control of stoichiometry must be taken into consideration, because a change in composition may further cause changes in the structure and functionality of the ma- terial. For the strength of the porous structure, it is important to provide a structure, in which the material flow has, in addition to particles, fine-grained, atomized or ionized material to contribute to the bond between the particles and thus to the strength of the entire structure. In addition, the sufficient kinetic energy of the material flow contributes to the bonding of the particles with each other and to the base material. A coating process based on ultrashort pulsed laser ablation differs from other thin film coating methods in that it makes possible a relatively precise control of the size of particles producing a porous coating. If the intention is to produce a desired coating by initially forming an essentially atomized or ionized material, the tendency of the material to form so-called clusters depends especially on the speed and size distribution of the units composing the material flow detached by ablation and on background pressure. For example, the condensing of the material produced from the target by certain laser ablation into particles can be intensified by raising the background pressure in the coating chamber in a controlled manner. Increase in pressure probably enhances the probability of collisions with gas atoms/molecules. In collisions, the material flow units lose energy and change their direction. Deceleration and changes in direction again increase the probability of collisions with other material flow units and thus the formation of clusters.

To manufacture porous material, it is also possible to perform the ablation process so that particles are detached from the target material by breaking material, for ex- ample, from the surface of the target material manufactured from powder material. Breakage of the material and breaking limits can be adjusted, for example, by weakening certain microstructural areas and interfaces of the target material so that the material detaches more easily and as particles of a certain size. Alternatively, the laser ablation process can be controlled so that the surface of the target material melts locally, in which case molten particles detach from the target material, which are then directed to the surface of the base material. The process can then be determined as thermal ablation. The above-described alternative methods can be chosen according to what type of microstructure is wanted to the anode material and which laser ablation process is best suited for each material. Laser pulses can be brought to the target also in so-called bursts, which are formed of a certain number of laser pulses on a chosen repetition frequency. For example, the laser power of 100 W can be formed by using individual laser pulses of 100 J on a repetition frequency of 1 MHz or by using laser pulse bursts, which have 10 pulses of 10 J on a repetition frequency of 60 MHz, and these pulses are repeated on the frequency of 1 MHz. Such laser pulse packages can be used to significantly change the interaction of laser with the material and to control the properties of the detaching material and the coating process. For example, laser pulse bursts make possible the reduction of the size of particles forming in laser ablation and thus the growing of the specific area of the anode coating material, shortening of diffusion ranges (improvement in ion and electron conductivity) and, with certain materials, better resistance against microcracks caused by changes in specific volume.

The laser ablation process makes possible the production of different material and coating concepts even with one method and apparatus, due to the flexibility of the method and its suitability for very different materials by the selection of suitable pa- rameters. This reduces significantly the quantity of apparatus investments needed in different anode coating solutions, accelerates the manufacture and delivery time, and reduces the number of manufacturing and processing errors.

The method is especially suited for roll-to-roll manufacture, in which base material (for example, copper strip) is directed from a roll to coating stations as a continuous strip, after which the strip is coated with anode material on the coating stations (of which there can be one or several). Coating stations can also be positioned sequentially so that either the same anode material or anode materials are coated sequentially in several coating stations so that the coating efficiency increases or different materials can be coated in different stations to manufacture composite and multi- layer structures or by doping, for example, materials containing conductivity to the surface of anode materials. There are later own figure examples of these embodiment options. In the coating stations it is also possible to manufacture different protective layers to the surface of the anode materials in different layers or, for example, only onto the last layer, for example, to prevent the dissolution of essential doping substances or detrimental reactions with the electrolyte. Instead of successive coating stations, the coating can alternatively be prepared in the roll-to-roll method so that the band to be coated moves first through the coating station so that its surface is provided with one material layer of desired material. After this the direction of motion of the roll in question is changed and the target material is changed auto- matically in the coating station and the coating of another material, for example, an additive (i.e. doping material), a second substance of a composite material (for example, carbon) or in layered materials, the coating of the second material is performed, and this process is repeated until the desired total structure is completed.

There is not necessarily a need to use laser ablation for the coating of all material layers, and also other coating and manufacturing methods for material layers can be linked to the manufacturing chain, if it is optimal for the total solution. Such supporting methods are e.g. CVD (Chemical Vapour Deposition) technology, ALD (Atomic Layer Deposition) technology, and PVD (Physical Vapour Deposition) technology, such as sputtering. The composition of the material detached by laser ablation must remain on an appropriate area for the functionality of the coating. In principle the pulsed laser technology, especially ultrashort pulsed laser technology is a suitable method for minimizing disadvantageous composition, for example, due to the non-simultaneous evaporation of doping substances. By means of the ultrashort pulsed laser technol- ogy it is possible to minimize the melting of the material and the formation of extensive molten areas, which increase uneven material losses and impede the control of stoichiometry. With several target materials it is sufficient to restrict the length of the laser pulses to under 5 - 10 ps. to minimize the melting of the target and excessive loss of doping components in laser ablation, if the superposition of laser beams is slight. On big repetition frequencies the superposition of laser beams may cause the material to melt even with short pulse lengths. A change in stoichiometry may cause a loss of the desired structure and appropriate functionality. In industrial production, the process must stay constantly stable, due to which also changes occurring in the target composition over long time intervals are detrimental. When manufacturing composite materials, sandwich structures or by doping the principal material of the anode coating with some other material, the optimum process parameters and circumstances of different materials are not necessarily the same. This must be taken into account when planning and combining different steps in the production process. If it is desired to manufacture a composite material using a combinatory solution, the laser parameters can be tailored optimally in relation to different materials by using a different laser source for different materials, but in this case, it must be possible to ablate all materials sufficiently well in the same coating atmosphere, because it can be can be difficult to adjust the control of the coating atmosphere separately when performing combinatory ablation. If it is necessary to adjust the coating atmosphere separately for all materials, this can be most easily carried out in successive coating steps so that a coating atmosphere advantageous for different materials can be controlled separately. Several such coating steps can be built in a process solution depending on the type of material distribution one de- sires to produce.

In certain situations, it is also possible to make the desired doping to an individual target material piece, and if the ablation thresholds of the materials in relation to each other and the condensation tendency in the chosen gas atmosphere are suitable, the composite structures can be manufactured by blending the desired mate- rials to the target material in a desired proportion. This situation is separately illustrated in Figure 9.

The basic principle of the method is illustrated in the view of principle in Figure 1 , in which the structural parts and directions of motion of the material included in the coating transaction are shown at a principled level. In Figure 1 , the energy source for the ablation process is the laser light source 1 1 , from which laser light is directed in short pulses 12 towards the target material 13. The laser pulses 12 cause local detachment of material on the surface of the target material 13 as particles or other respective fragments, which have been mentioned above. Thus, the material flow 14 is generated, which extends towards the piece 15 to be coated. The piece 15 to be coated can also be called a coating base or substrate. The correct alignment can be performed by setting the direction of the plane of the target material surface 13 appropriately in relation to the piece 15 to be coated so that the direction of motion energy releasing as plasma is towards the piece 15 to be coated. The laser source 1 1 can naturally be moved in relation to the target 13, or the angle of orientation of the laser beams in relation to the surface of the target 13 can be varied. Further, a separate arrangement can be placed between the laser source 1 1 and the target 13 for unifying the front of laser pulses hitting the target 13. There is a different figure 3 of this arrangement. Other kinds of optics and, for example, mirrors can also be placed between the laser source 1 1 and the target 13.

The plasma and particle material flow 14 in Figure 1 can be fan-shaped so that a wider area can be coated on the area of the surface of the piece 15 to be coated by one angle of orientation of the laser pulses assuming that the material to be coated is not transferred laterally (seen from the figure). In a second embodiment the material to be coated is movable, and of this embodiment there is the separate figure 4. Generally, in an example of ablation used in the invention, the detachment of the target surface material, formation of particles and transfer of material from the target to the base and to the previously formed material layer are achieved with laser pulses focused on the target, in which the timely duration of an individual laser pulse can be between 0.5 - 10000 ps. In an example of the invention, laser pulses can be generated on a repetition frequency, which is between 50 kHz - 100 MHz.

The film formed by the material transferring by laser ablation and as particles from the target material to the base material must build a reliable bond to the base material or a material layer prepared previously. This can be achieved by sufficient kinetic energy of the particles, which makes possible sufficient energy to generate a bond between different materials. In addition, in a particle-intensive material flow it would be preferable to have a sufficient quantity of atomised and ionised material to support the generation of bonds between the particles.

A very essential process parameter in laser ablation when manufacturing porous coatings is the gas pressure used in the process chamber. Increasing the gas pressure promotes the formation and growth of particles during the material's flight from the target to the surface of the material to be coated. An optimal gas pressure may vary according to the type of material being coated and to the desired particle size distribution, porosity and adhesion between the particles, and the bond of the parti- cles to the rest of the battery material.

In an embodiment laser ablation and coating occur in a vacuum chamber, i.e. either in a vacuum or background gas, where a controlled pressure can be applied. An alternative is to set the pressure between 10^"8 - 1000 mbar. When pursuing porous coatings or an increase in porosity, a background pressure of 10 ⁶— 1 mbar is typically used. The relative purpose of background gas varies depending on the density and total energy of the material flow and on the distance the material travels from the ablation point to the surface of the piece to be coated. If laser ablation is per- formed with so-called thermal ablation and local melting of the target material surface, a porous coating and a particle size of less than 1 pm can also be produced in a low background pressure, because the formation of particles occurs through molten drops and not through condensation from atomised material. Further, a particle-based material flow can be achieved also by promoting the detachment of par- tides in the target material through selective energy absorption or partial cracking of target materials.

In Figure 2 there is illustrated an exemplary structural view of a separator film functioning as part of a Li ion battery after it has been coated using the PLD method. The porosity of the forming coating must be sufficient to make possible the diffusion of ions through the coating and the film. Typically, the separator film 22 used in battery applications is polymer-based, and it has a microporous 23 structure, as has been stated above. The pores 23 in the polymer film can be of varying sizes. Also a coating 21 consisting of inorganic material has a porous structure. In the separator films of Li ion batteries, the porosity of microporous polymer films is typically be- tween 30 - 50 percent by volume and the objective is that the porosity of the inorganic coating would be at least 30 percent by volume. It is essential that the porosity of inorganic material is mainly through-going and this makes possible that the electrolyte moistens the film as well as possible. A porous material is accomplished by detaching material by laser ablation and by creating conditions, in which nanoparti- cles typically of 10 - 100 nm or particle clusters are formed as detached material. As these particles and particle clusters accumulate to the surface of the polymer film, they form a porous coating. Alternatively, the detachment of material executed by laser ablation occurs entirely or partly through molten particles or particles detaching from the target material, which form a coating of inorganic material to the surface of the polymer film. The former mechanism provides a narrower particle distribution, in which case also the pore distribution becomes more even. In practice, the coating is often generated by both mechanisms, which is further supplemented by the plasma generated as the result of laser ablation. The structure and porosity of the inorganic coating is adjusted by controlling the different material detachment mechanisms. To improve homogenity and productivity, it would be preferable to produce as wide a material flow as possible from the target to the base material. In an example of the invention, this can be executed by disintegrating the laser pulses by turning mirrors to form a laser pulse front on the same plane. This arrangement has been illustrated in Figure 3. Instead of the target, the laser pulses 12 of the laser source 1 1 are thus directed to the turning mirrors 31 , which can be, for example, a hexagonal and ro- tatable mirror surface similar to the figure. The laser pulses 12 are reflected from the turning mirrors 31 to form a fan-shaped laser pulse formation (or laser beam distribution) and the reflected pulses are directed to the telecentric lens 32. By means of the telecentric lens 32, the laser pulse front can be aligned to form an essentially concurrent laser pulse front 33 so that the laser pulses hit the target material 13 at the same angle. In the example in figure 3, the said angle is 90°.

The laser pulse front can also be executed by other means, e.g. a rotating monogon mirror, which focuses the laser pulses, for example, to an annular target material, of which an annular material front is formed.

In an application example a part of the Li ion battery is well suited to be coated so that material is discharged from a roll to be coated over a desired width in the coating chamber. A view of principle is shown of this application alternative in Figure 4. Material is targeted at the desired coating width from one or several coating sources so that material is constantly discharged from a roll to coating and, after it has passed the coating zone, the material is again collected to the roll. The method can be called a roll-to-roll method, as has already been stated above. In other words, the part 42 of the Li ion battery to be coated is initially found around the roll 41 a. The ablation apparatus with laser sources 1 1 and target materials 13 is included as has been stated above. The laser pulses 12 cause the material to detach as a particle flow 14 (i.e. in the form of a material flux) towards the material 42 to be coated, and as a result of adherence, the coated part 43 of the Li ion battery is produced. The coated film 43 is allowed to rotate around the second roll 41 b, the direction of motion of the film being from left to right in the situation illustrated in Figure 4. The roll structures 41 a, 41 b can be motor-driven. Seen in the direction of depth in the figure, the Li ion battery film to be coated can be the entire area of the surface, or only part of the surface. Likewise, in the direction of motion of the film, a desired part (length) of the film can be chosen for coating, or alternatively, the entire roll can be gone through from beginning to finish so that the entire roll becomes coated. Figure 5 illustrates a typical structure of a lithium ion battery as a cross-sectional view. Of the parts, the first one from the top is the aluminium film 51 , which functions as current collector for the electric current. Moving down, the next part is the cathode material 52. Next there is the porous polymer membrane 53, which functions as separator film in the battery. It can be made, for example, of polyethylene. The fourth film is the anode material 54, which is especially discussed in this invention. The lowermost, fifth film is the copper film 55, which functions as current collector in a respective way as the uppermost aluminium film 51 .

Figure 6a is a structural view of an arrangement, in which anode material is coated onto a base by using PLD technology. The laser beam pulses 61 have here been marked with thick dashed lines underneath, and the laser pulses arrive at the picture area from bottom right. The laser pulses are focused onto the surface 62 of the target material piece, and preferably the direction of the target surface encountered by the pulses is preferably set in an inclined direction in relation to the direction of arrival of the pulses. The material flow 63 consisting of particles, atoms and/or ions is formed of this interaction. This material flow is seen as a droplet-shaped material cloud in the figure. The base material 65 to be coated is uppermost, and the actual coating 64 is formed to its lower surface, which is here shown as five circles with a uniform diameter. In other words, the material flow hits the lower surface of the base, and adheres to it.

Figure 6b illustrates a possible coating structure produced by the principle in Figure 6a, in which the coating adheres to the lower surface of the base 65. As can be seen in the figure, the coating forming of the material flow is porous, and it consists only of one material, which can here be called the principal material 66. In other words, in this example, also the target used consists of one material, and there is one target to be used. Figure 6c illustrates a second type of a coating structure produced onto the base 65 using the principle in Figure 6a. In this situation a composite material is generated, which consists of two different materials. The principal material 66 is marked with circles, and between the principal material there is the second material 67. The structure is still porous. Figure 6d illustrates a possible porous structure produced by the principle in Figure 6a, in which so-called doped material is used in addition to the principal material. The bigger circles seen here on the lower surface of the base 65 illustrate the principal material 66, and the smaller circles illustrate the so-called doping material i.e. additive 68. In this situation it can be determined, for example, that the quantity of the additive 68 is at most 10 percent by volume of the entire volume of the coating. Also this structure is porous. As can be seen in the figure, the additive 68 settles among the principal material 66, and in an advantageous embodiment this distribution of doping material into the principal material is made homogeneous, so that the entire porous coating is similar, i.e. of uniform quality. Figure 7 illustrates an example of a combinatory coating method using two coincidental material flows. Here, two separate laser beams, i.e. the first pulse string 71 a and the second pulse string 71 b enter the arrangement, and these pulse strings are directed to hit the target material pieces, i.e. the first target 72a and the second target 72b. The material of the first target is different from the material of the second target. Of these interactions, the material flows 73a and 73b are formed as the result of laser ablation. Both these material flows comprise particles, atoms and ions, but concerning different materials. The material flows hit the lower surface of the base 75 simultaneously, thus forming the composite coating 74. The compositions of the different substances in the composite coating 74 can be varied, for example, by independently adjusting either one or both of the laser sources, which generate the laser beams 71 a and 71 b. The composite coating 74 thus forms the material flows 73a and 73b on the lower surface of the base 75 principally at the same time and immediately as a finished coating.

Figure 8a illustrates the use of successive coating stations to improve productivity when manufacturing sandwich structures. In this example, there are shown four coating stations, and each incoming laser beam (or pulse string) 81 a-d is focused on the appropriate target 82a-d through a mirror (P, each beam having its own). In this situation, the roll-to-roll method can be used, and the lower surface of the base 85 first contacts the first material flow 83a, of which the first coating layer 84a is formed. This first coating layer 84a again contacts the second material flow 83b as the base 85 moves, and this way the second coating layer 84b is produced onto the first coating layer 84a. This process still continues in two coating stations, and the final result is the base material 85 which has contacted the four material flows 83a- d, and this coating has a sandwich-type structure 84a, 84b, 84c, 84d. The targets 82a-d can be of the same materials, as has been shown in this figure.

Figure 8b illustrates the use of successive coating stations to improve productivity in the manufacture of composite structures. This is otherwise similar to the situation in Figure 8a, but now there are chosen two different types of materials as the target material pieces 82A, 82B, and these are placed alternately, one target to one coat- ing station, and the next target being of the second material. In other words, seen from the left, the first and third target are of the same first material "A", and the second and fourth target, respectively, are of the same second material "B". The laser pulse strings 81a-d can still be controlled independently and focused on the targets through the mirrors P. This arrangement provides two different types of material flows 83A, 83B, which alternate. When the material flows hit the moving base 85, a new different layer is formed on top of the older layers, and the final result is the 4-layered composite structure 84A, 84B, 84A, 84B visible in the right edge. In this coating, the material layers thus alternate with each other.

Figure 8c illustrates the use of successive coating stations to improve productivity in the manufacture of doped material. This arrangement is otherwise similar to the one in Figure 8b, but here the first and third target 82C are made of the basic material, and the second and fourth target 82D, respectively, are made of the additive, i.e. doping material. The laser pulse strings 81 a-d can still be controlled independently, and they can be focused to the targets through the mirrors P. This arrangement produces two material flows 83C, 83D of different types, which alternate. With the respective principle as above, the doped basic material now forms the coating to the base 85, and the relative proportion of doped material of the entire coating can be chosen by independently adjusting the laser parameters. In the coating layers, 84C represents the basic material layer and 84D the additive layer.

Figure 8d illustrates a more exact detail of the basic material, in which doped parti- cles are included. Thus, this describes a more detailed structure of the coating generated by the arrangement in Figure 8c. The basic material 86 is seen as bigger parts in the figure, and the doped material, i.e. additive 87 is seen in the figure as smaller parts among the basic material. The additive 87 is in practice found as particles among the basic material. Figure 9 illustrates an example of the use of a composite target material in the manufacture of a composite coating. Now there only is only one physical element as the target material piece, but this element in itself has a composite structure, i.e. the target 92 consists in this example of two different materials. When laser beam pulses 91 are focused on such target 92, there is generated a material flow 93 con- sisting of atoms, ions and particles of two different materials. This material flow 93 hits the lower surface of the base material 95, and the final result is a composite coating 94 containing two materials, the composite coating adhering to the lower surface of the base material 95.

Figure 10 illustrates an example of an electronic microscope image of the surface of a Si particle coating produced by pulsed laser deposition, in which the particle size is less than 500 nm. In this example, the following laser parameters and background gas pressure have been used: laser light wavelength 1064 nm; laser pulse duration ~9 ps.; laser pulse repetition frequency 500 kHz; pulse energy ~20 J; laser scanning velocity on the surface of the target ~4 m/s; coating chamber pressure 5^*10^"7 mbar.

As has emerged in many connections above, in addition to the manufacturing method, the inventional idea of the invention further includes the manufactured product, i.e. foil or film-type anode, which is intended for a Li ion battery, and also the essential components of the entire Li ion battery, of which at least one part has been manufactured using laser ablation.

As a summary, in the invention there is produced an anode material coating for a Li ion battery so that the share by volume of at least one active anode material used in the coating is at least 10 percent by volume of the anode material coating, and the average particle size is at most 3 m. In addition, at least one material layer of the Li ion battery is manufactured based on laser ablation, i.e. at least the film-type anode is manufactured using the PLD method. Finally, the Li ion battery is assembled by utilising the manufactured material layers.

When speaking of the active anode materials of the invention, a titanium-bearing oxide can be chosen to be, for example, Li Ti50i2 or ΤΊΟ2, but it can also be some other titanium-bearing oxide. For example, Fe30₄ can be chosen as iron oxide and for example Co30₄ or CoO as cobalt oxide. However, other selections in these substance groups are also possible.

Combinatory coating arrangements and successive coating stations according to Figures 7 and 8a can be combined so that, for example, one coating arrangement of another type has been taken at the place of one or some coating stations in Figure 8a, such as a combinatory coating station comprising two or several targets in accordance with the principle of the example in Figure 7.

In the following, features of the invention are still compiled in a list-type form in the way of a summary. The invention relates to a method for manufacturing the anode materials (54) of a Li ion battery, the method comprising the steps of targeting short-term laser pulses (12, 61 , 71 a-b, 81 a-d, 91 ) to at least one target (13, 62, 72a-b, 82a-d, 82A-D, 92); detaching at least one material (14, 63, 73a-b, 83a-d, 83A-D, 93) from at least one target (13, 62, 72a-b, 82a-d, 82A-D, 92) by laser ablation;

directing at least one detached material (14, 63, 73a-b, 83a-d, 83A-D, 93) to the base material (15, 22, 42, 65, 75, 85, 95) of the coating to at least surface or part of surface.

It is characteristic of the invention that the method further comprises the step of producing the anode material coating for the Li ion battery so that the average particle size of the at least one active anode material used in the coating is at most 3 pm, the share by volume of the anode material in the anode material coating being at least 10 percent by volume, and the anode material coating being manufactured based on pulsed laser ablation deposition.

In an embodiment of the invention, a Li ion battery is further assembled in the method by using manufactured material layers, which material layers comprise an anode, cathode, and a solid or liquid electrolyte material so that at least the anode material is manufactured by using pulsed laser ablation deposition.

In an embodiment of the invention, when using pulsed laser ablation deposition, the detachment of material, formation of particles and transfer of material from the target (13, 62, 72a-b, 82a-d, 82A-D, 92) to the base material (15, 22, 42, 65, 75, 85, 95) is achieved by laser pulses (12, 61 , 71 a-b, 81 a-d, 91 ) focused on the target (13, 62, 72a-b, 82a-d, 82A-D, 92), in which the time duration of an individual laser pulse is between 0.5 - 10000 ps.

In an embodiment of the invention, laser pulses (12, 61 , 71 a-b, 81 a-d, 91 ) are generated on a repetition frequency, which can be chosen from the range of 50 kHz - 100 MHz. In an embodiment of the invention, the average particle size of at least one active anode material used in the coating is less than 1 .5 pm, the share by volume of the anode material in the anode material coating being at least 10 percent by volume.

In an embodiment of the invention, the average particle size of at least one active anode material used in the coating is less than 900 nm, the share by volume of the anode material in the anode material coating being at least 10 percent by volume. In an embodiment of the invention, at least one active anode material is one or some of the group of silicon, germanium, tin, carbon, titanium-bearing oxides, iron oxides, cobalt oxides, metal phosphides, metal sulphides and metal nitrides.

In an embodiment of the invention, the anode material coating has at least 5 percent by weight of silicon.

In an embodiment of the invention, the anode material coating has at least 12 percent by weight of silicon.

In an embodiment of the invention, the anode material coating has at least 20 percent by weight of Li₄Ti50i2. In an embodiment of the invention, the anode material coating has at least 10 percent by weight of metal oxide.

In an embodiment of the invention, the anode material coating has at least 10 percent by weight of carbon.

In an embodiment of the invention, the anode material coating has at least 15 per- cent by weight of carbon.

In an embodiment of the invention, at least two laser sources are set to operate simultaneously, forming together a combinatory continuous material flow (73a, 73b) from at least two targets (72a, 72b) to the surface of the base material (75), thus forming the anode material coating (74) consisting of at least two different materials. In an embodiment of the invention, coating is performed in at least two successive coating stations so that at least one of the coating stations operates so that the material flow generated by it does not meet the second coating station before the generation of the coating to the surface of the base material (85).

In an embodiment of the invention, a carbon-based material is coated in a combina- tory manner in at least one coating step by pulsed laser ablation deposition together with anode material particles, the quantity of which is at least 5 percent by volume and the average size of which is at most 3 pm.

In an embodiment of the invention, in the next step a carbon material is coated onto at least one anode material coating, in which the quantity of anode material particles is at least 5 percent by volume and the average size is at most 3 pm. In an embodiment of the invention, the anode material coating has at most 10 percent by volume of metal produced by laser ablation or at least 40 percent by weight of metal containing particles.

In an embodiment of the invention, the material containing at least 25 percent by weight of metal is coated in a combinatory manner or sequentially by means of coating stations.

In an embodiment of the invention, the average size of particles comprising metal is at most 500 nm.

In an embodiment of the invention, the said metal is one or several of the following group: copper, silver, gold, tin, nickel, platinum or palladium.

In an embodiment of the invention, the total thickness of the anode material coating is at most 100 pm.

In an embodiment of the invention, the coating of an active anode material occurs from a target material, which comprises, in addition to anode materials, either me- tallic materials and/or carbon, in which when using metallic materials, the metallic materials comprise at least 25 percent by weight of either copper, silver, gold, tin, nickel, platinum or palladium, or a blend of at least two of these materials.

In an embodiment of the invention, the quantity of metallic materials in the target material is at most 15 percent by weight. In an embodiment of the invention, the quantity of carbon in the target material is at most 90 percent by weight.

In an embodiment of the invention, a non-oxide based active anode material has a structure, which is amorphic by at least 80 percent by volume.

In an embodiment of the invention, the porosity of the anode material coating is at least 5 percent by volume.

In an embodiment of the invention, the porosity of the anode material coating is at least 20 percent by volume.

The inventional idea further comprises a Li ion battery, which comprises a cathode material (52) and anode material (54). It is characterized in that the Li ion battery further comprises either a solid or liquid electrolyte, and in which at least one embodiment option of the method described above has been utilised in the manufacture of the anode material (54).

The method of the invention has the following advantages: i. Porous anode materials for Li Ion batteries can be manufactured with a simple arrangement

ii. Good adherence is achieved between different material layers without special adhesion layers or binding agents

iii. Open area and porosity of the anode material can be adjusted by altering laser pulse parameters, background gas or its pressure and the distance between the target and base

iv. During the processing and installation of different material layers there is no risk for the materials becoming damaged or contaminated, if the method is performed with one apparatus

v. Sandwich structures can be manufactured to optimize the properties vi. Composite materials can be manufactured for the optimal combining of different materials

vii. It is possible to perform doping to add small quantities of doping substances; for example, to improve conductivity

viii. With anode materials with a complex composition, it is possible to retain the appropriate composition of coatings from the target to the coating

ix. It is possible to avoid the use of binding agents, which reduces the contamination of battery chemistry in long-term use

x. Several material layers essential for different functionalities can be manufac- tured with one manufacturing method and partly even in one manufacturing step

xi. The quantity of productional investments can be reduced

xii. Anode materials with a very small particle size (<1 pm) can be manufactured, which

a. Increases the quantity of active surface in contact with the electrolyte b. Shortens the diffusion range of ions and electrons

c. Decreases the cracking sensitivity of the anode material particles due to changes in volume during the discharge and charge steps

xiii. The result is a fine structure, in which the optimized pore distribution endures better the changes in volume occurring during the discharge and charge of the battery, especially with silicon without cracking xiv. It is possible to manufacture amorphic materials, which endure better the changes in volume caused by charge/discharge cycles without cracking or damages with certain materials (for example, silicon)

xv. An even pore distribution reduces the stresses generated by changes in volume caused by charge/discharge cycles

xvi. It is possible to manufacture batteries with a considerably larger energy density than the traditional anode material solutions

In the invention, it is possible to combine individual features of the invention mentioned above and in the dependent claims into new combinations, in which two or several individual features can have been included in the same embodiment.

The present invention is not limited only to the examples shown, but many variations are possible within the scope of protection defined by the enclosed claims.

Claims

1 . A method for the manufacture of anode materials (54) for a Li ion battery, the method comprising the following steps:

directing short-term laser pulses (12, 61 , 71 a-b, 81 a-d, 91 ) to at least one tar- get (13, 62, 72a-b, 82a-d, 82A-D, 92);

detaching at least one material (14, 63, 73a-b, 83a-d, 83A-D, 93) from at least one target (13, 62, 72a-b, 82a-d, 82A-D, 92) by laser ablation;

directing at least one detached material (14, 63, 73a-b, 83a-d, 83A-D, 93) to the base material (15, 22, 42, 65, 75, 85, 95) of the coating to at least one surface or part of surface, characterised in that the method further comprises the step of

producing the anode material coating for the Li ion battery so that the average particle size of at least one active anode material used in the coating is at most 3 pm, the share by volume of the anode material from the anode material coat- ing being at least 10 percent by volume, and the anode material coating being manufactured based on pulsed laser ablation deposition.

2. Method according to claim 1 , characterised in that in the method the Li ion battery is assembled by using manufactured material layers comprising an anode, cathode and a solid or liquid electrolyte material so that at least the anode material has been manufactured by using pulsed laser ablation deposition.

3. Method according to claim 1 or 2, characterised in that when using pulsed laser ablation deposition, the detachment of material, formation of particles and transfer of material from the target (13, 62, 72a-b, 82a-d, 82A-D, 92) to the base material (15, 22, 42, 65, 75, 85, 95) is achieved by laser pulses (12, 61 , 71 a-b, 81 a- d, 91 ) focused on the target (13, 62, 72a-b, 82a-d, 82A-D, 92), in which the timely duration of an individual laser pulse is between 0.5 - 10000 ps.

4. Method according to any of the preceding claims 1 - 3, characterised in that laser pulses (12, 61 , 71 a-b, 81 a-dm 91 ) are generated on a repetition frequency, which can be chosen between 50 kHz - 100 MHz. 5. Method according to any of the preceding claims 1 - 4, characterised in that the average particle size of at least one active anode material used in the coating is less than 1.

5 pm, the share by volume of the anode material in the anode material coating being at least 10 percent by volume.

6. Method according to any of the preceding claims 1 - 5, characterised in that the average particle size of at least one active anode material used in the coating is less than 900 nm, the share by volume of the anode material in the anode material coating being at least 10 percent by volume.

7. Method according to any of the preceding claims 1 - 6, characterised in that at least one active anode material is one or some of the group of silicon, germanium, tin, carbon, titanium-bearing oxides, iron oxides, cobalt oxides, metal phosphides, metal sulphides and metal nitrides.

8. Method according to any of the preceding claims 1 - 7, characterised in that the anode material coating has at least 5 percent by weight of silicon.

9. Method according to any of the preceding claims 1 - 7, characterised in that the anode material coating has at least 12 percent by weight of silicon.

10. Method according to any of the preceding claims 1 - 7, characterised in that the anode material coating has at least 20 percent by weight of Li₄Ti50i2.

1 1 . Method according to any of the preceding claims 1 - 7, characterised in that the anode material coating has at least 10 percent by weight of metal oxide.

12. Method according to any of the preceding claims 1 - 1 1 , characterised in that the anode material coating has at least 10 percent by weight of carbon.

13. Method according to any of the preceding claims 1 - 1 1 , characterised in that the anode material coating has at least 15 percent by weight of carbon.

14. Method according to any of the preceding claims 1 - 13, characterised in that at least two laser sources are set to operate simultaneously, forming together a combinatory continuous material flow (73a, 73b) from at least two different targets (72a, 72b) to the surface of the base material (75), forming an anode material coat- ing (74) consisting of at least two different materials.

15. Method according to any of the preceding claims 1 - 14, characterised in that the coating is performed in at least two successive coating stations so that at least one of the coating stations operates so that the material flow produced by it does not meet with the second coating station before the generation of the coating to the surface of the base material (85).

16. Method according to one of the preceding claims 1 - 15, characterised in that a carbon-based material is coated in a combinatory manner by pulsed laser ablation deposition in at least one coating step together with anode material particles, the quantity of which is at least 5 percent by volume and the average size of which is at most 3 pm.

17. Method according to one of the preceding claims 1 - 15, characterised in that in the next step carbon material is coated by pulsed laser ablation deposition onto at least one anode material coating, in which the quantity of anode material particles is at least 5 percent by volume and the average size at most 3 pm.

18. Method according to any of the preceding claims 1 - 17, characterised in that the anode material coating has at most 10 percent by volume of metal produced by laser ablation or at least 40 percent by weight of metal containing particles.

19. Method according to claim 18, characterised in that the material containing at least 25 percent by weight of metal is coated in a combinatory manner or by means of successive coating stations.

20. Method according to claim 18 or 19, characterised in that the average size of metal containing particles is at most 500 nm.

21 . Method according to claim 18, 19 or 20, characterised in that the said metal is one or several of the following group: copper, silver, gold, tin, nickel, platinum or palladium.

22. Method according to any of the preceding claims 1 - 21 , characterised in that the total thickness of the anode material coating is at most 100 pm.

23. Method according to any of the preceding claims 1 - 22, characterised in that the coating of an active anode material occurs from a target material which com- prises, in addition to anode materials, either metallic materials and/or carbon, in which when using metallic materials, the metallic materials comprise at least 25 percent by weight of either copper, silver, gold, tin, nickel, platinum or palladium, or a mixture of at least two of these substances.

24. Method according to claim 23, characterised in that the quantity of metallic materials in the target material is at most 15 percent by weight.

25. Method according to claim 23, characterised in that the quantity of carbon in the target material is at most 90 percent by weight.

26. Method according to any of the claims 1 - 25, characterised in that a non- oxide based active anode material has a structure, which is amorphic by at least 80 percent by volume.

27. Method according to any of the claims 1 - 26, characterised in that the silicon used as the anode material has a structure, which is amorphic by at least 80 percent by volume.

28. Method according to any of the claims 1 - 27, characterised in that the porosity of the anode material coating is at least 5 percent by volume.

29. Method according to any of the claims 1 - 27, characterised in that the po- rosity of the anode material coating is at least 20 percent by volume.

30. Li ion battery, which comprises: a. a cathode material (52), and b. an anode material (54), characterised in that the Li ion battery further comprises c. either a solid or liquid electrolyte, and in which

d. the method according to any of the claims 1 - 29 has been utilised in the manufacture of the anode material (54).