3D scaffolding

Abstract

The substrate includes carbon nanotubes oriented substantially parallel away from the substrate. In a plane along the surface of the substrate, the carbon nanotubes are formed within first cells of a carbon nanotube connection structure. The first cells are formed within a second structure of second cells, whereby the carbon nanotubes are patterned into the structure of the first cells and nested within the structure of the second cells. The first cells include at least one opening without carbon nanotubes to provide access to the surface of the substrate. The second cells are separated from each other by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves. The grooves provide access to the substrate. [Selection diagram] None

Description

[Technical Field]

[0001] The present invention relates to a substrate comprising predominantly vertically aligned carbon nanotubes formed as interconnect structures in a plane along the substrate, such structures being known for use, for example, as electrodes. [Background technology]

[0002] For example, U.S. Patent No. 6,277,633 discloses vertically aligned carbon nanotubes in a connection structure covering a large area of ​​a substrate. Lithium is deposited on these vertically aligned carbon nanotubes to form an electrode. The deposition of lithium causes aggregation of these nanotubes and a concomitant loss of orientation, resulting in bending, curling, cracking, and tipping of the tubes. It is an aspect of the present invention to provide a connection structure for carbon nanotubes that does not suffer from such loss of orientation.

[0003] Patent Document 2 also describes the use of vertically aligned carbon nanotube interconnect structures. The described carbon nanotube interconnect structures are used as scaffolds for the assembly of interlaced or interleaved finger-shaped electrodes for use in 3D batteries. The electrodes are described as having a length of approximately 1.44 cm and a width typically ranging from less than 100 μm to preferably 30 μm. The nanotube finger-shaped structures are grown using a physical vapor deposition (PVD) process from a substrate with a suitable catalyst pattern. Appropriate electrode materials are then deposited on the carbon nanotube structures. The document specifies that this cannot be performed on a single substrate because a different deposition process is required for each electrode material. Therefore, each electrode is individually cut from its substrate and processed separately. At a later stage, the anode and cathode must be assembled with a gap, and the gap must be filled with an appropriate electrolyte to form the 3D battery.

[0004] Known types of thin-film battery structures are disclosed, for example, in U.S. Patent No. 6,277,623, the contents of which are incorporated by reference. In U.S. Patent No. 6,277,623, for example, an all-solid-state composition is deposited on a 3D micropatterned structure. In this regard, while earlier battery structures utilized liquid electrolytes, all-solid-state compositions utilize solid-state electrolytes, which are inherently safer in use. In these structures, a wide variety of materials are and have been used for each electrode, as disclosed, for example, in U.S. Patent No. 6,277,623. In the discharge battery mode, the anode is the "negative electrode" through which positive current flows from the cathode, and the anode is the "positive electrode." During charging, these functions are reversed. Regardless of the charging mode, the electrochemical relationship can be characterized by charge exchange between the negative and positive electrode materials, with the negative electrode material having a work function or redox potential lower than the work function or redox potential of the positive electrode material.

[0005] For example, known negative electrode (anode) materials are lithium metal, Li4Ti6O12 (titanate), LiC6 (graphite), Li4.4Si (silicon), and Li4.4Ge (germanium). For example, known positive electrode (cathode) materials are LiCOO2 (LCO), LiCoPO4, (doped) LiMn2O4 (LMO), LiMnPO4, LiFePO4 (LFP), LiFePO4F (LFPF), or LiCO1 / 3Ni1 / 3Mn1 / 3O2 (LCNMO).

[0006] Known (solid) electrolytes may include lithium iodide (LiI), lithium phosphate (LiPO), and lithium phosphorus oxynitride (LiPON). Furthermore, lithium salts such as LiPF, LiBF, or LiClO in organic solvents such as ethylene carbonate, dimethyl carbonate, diethyl carbonate, or propylene carbonate are known to have a typical conductivity of about 10 mS / cm at RT. The electrolyte decomposes during initial charging, forming a solid layer called the solid electrolyte interphase (SEI).

[0007] As known in the art, solid polymer separators, such as polymers like polyethylene oxide (PEO), often have transport capabilities due to the presence of lithium salts such as LiTFSI or LiFSI disposed therein, can also be included. Additionally, gel polymers include aprotic solvents such as PC, EC, and DMC, or ionic liquids such as PyrLiTFSI and PyrLiTFSI. The present invention is not limited to a particular battery chemistry. Alternatively, sodium materials can be used. Anode materials include Na, Na-Sn, and NaTiO. Cathode materials include NaS, TiS, NaNiMnO, NaV(PO), NaFePO, and NaFePO. Solid-state electrolytes include NaPS, Na-β / β''-alumina, NaSiCON, and NaS-PS.

[0008] To maximize the power density of 3D batteries, it is generally desirable to increase the interfacial area between the cathode and anode and / or reduce the diffusion distance of ions and electrons. In the case of Patent Document 2, it is not possible to further improve these parameters by further minimizing the finger dimensions or by providing additional microstructures to the fingers, since Patent Document 2 requires cutting and physically processing the electrodes. This leads to the limitation that the carbon nanotube scaffold has a fairly large minimum dimension. While 30 μm appears to be the minimum width of the electrode, 25 μm is given as the minimum gap distance.

[0009] It is an aspect of the present invention to provide a solution to the above problem by providing interconnected structures of mostly vertically aligned carbon nanotubes that provide large surface area and high aspect ratio elements, allowing for further processing steps on a single substrate. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2017 / 011052 [Patent Document 2] US Patent Application Publication No. 2017 / 214083 [Patent Document 3] International Publication No. 2010 / 332159 [Patent Document 4] US Patent Application Publication No. 2011 / 117417 Summary of the Invention [Means for solving the problem]

[0011] The substrate contains carbon nanotubes oriented substantially parallel away from the substrate. In a plane along the surface of the substrate, the carbon nanotubes are formed in first cells formed by one or more carbon nanotube connection structures. The first cells are nested within the structure of second cells. The connection structures include at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate. The connection structures between second cells are separated from each other by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the groove. The grooves provide access to the substrate between the connected first structures of carbon nanotubes. The first gaps formed by the grooves separate nanotubes across the first gap by a distance between 200 nm and 20 μm. Capillary forces are prevented from propagating to adjacent cells. In this way, cracking of the connection structures is prevented. [Brief explanation of the drawings]

[0012] The invention will be further clarified on the basis of exemplary embodiments represented in the drawings, which are given by way of non-limiting example, and it should be noted that the drawings are schematic illustrations of embodiments of the invention, given by way of non-limiting example.

[0013] [Figure 1]1 shows a prior art structure showing uncontrolled aggregation of vertically aligned carbon nanotubes after contact with a liquid. [Figure 2] 1 shows a top view of a first exemplary embodiment of a connection structure; [Figure 3] 10A and 10B show schematic top views of a second exemplary embodiment of a connection structure; [Figure 4] 10A and 10B show schematic top views of a third exemplary embodiment of a connection structure; [Figure 5] (a) and (b) show scanning electron micrographs of the composite material on the substrate. [Figure 6] 10(a) and 10(b) schematically show top views of fourth and fifth exemplary embodiments of a connection structure. [Figure 7] 10(a), (b) and (c) schematically show top views of a fifth exemplary embodiment of a connection structure. [Figure 8] 1 shows a schematic side view of a connection structure in which a top layer covering the carbon nanotube structure is provided. [Figure 9] 1 shows a schematic side view of a connection structure with a top layer and an inlet structure. [Figure 10] 10A and 10B show schematic diagrams of connection structures in which layers provide vertical and lateral gradients. [Figure 11] 1 illustrates a schematic representation of a 3D energy storage system. [Figure 12] 10A and 10B show schematic diagrams of further embodiments of connection structures; DETAILED DESCRIPTION OF THE INVENTION

[0014] Objects of the present invention include the provision of a high-surface area scaffold structure that can be advantageously applied, particularly in applications that benefit from a high surface area. The scaffold or the present invention is formed by one or more connecting structures of carbon nanotubes on a substrate. The carbon nanotubes are oriented substantially parallel away from the substrate. The one or more connecting structures of carbon nanotubes can be used as scaffolds in various subsequent processes to manufacture various items and products. Such items and products include, but are not limited to, 3D batteries and 3D electrode structures. For example, 3D batteries can be manufactured using one or more structures of connected carbon nanotubes as scaffolds, e.g., the walls of the scaffold, for depositing various layers of active materials to be included in the battery. Such layers can include, but are not limited to, electrode materials, electrolyte materials, and / or current collecting materials. The layers can be provided on the scaffold, in the spaces / openings between the scaffolds, and / or within the pores in the connecting structures of the carbon nanotubes. Such a process is sometimes referred to as impregnation.

[0015] The scaffolds of the present invention are dimensioned to optimize the surface area of ​​the scaffold and / or the spacing between opposing connected structures of carbon nanotubes (e.g., the spacing between the walls of the scaffold), while simultaneously optimizing the manufacturability and / or stability of the scaffold itself. The surface area of ​​the scaffold is, for example, the surface area of ​​the walls formed by the connecting structures of the carbon nanotubes. The dimensions of the scaffold further ensure the processability of the scaffold during subsequent manufacturing processes. For example, they enable conformal coating along the scaffold walls during subsequent deposition steps. For battery applications, determining the dimensions of the spacing between the connecting structures of the nanotubes can be used to tailor the properties of the battery formed with the scaffold. For example, a larger separation between the opposing walls can leave more volume available to be filled with electrode material, thereby improving the overall battery capacity. At the same time, a larger separation between the opposing walls can increase the diffusion distance of active species during battery operation, correspondingly increasing internal resistance and / or reducing the achievable charge and / or discharge rates.

[0016] In other words, the scaffolding according to the present invention is dimensioned to optimize the manufacturability and stability of the scaffold, while at the same time optimizing the dimensions of the scaffold to ensure stability and processability of the scaffold during the subsequent process of manufacturing the functional item / product.

[0017] The inventors have found that the advantages associated with a scaffold of the above dimensions for carbon nanotube interconnect structures cannot be achieved with common carbon nanotube interconnect structures, such as individual pillars on a substrate, as described, for example, in Adv. Mater. 2016, 28, pp. 6705-6710 by Shahab Ahmad et al. For example, individual pillar structures result in relatively low usable vertical surface area per unit area of ​​substrate. Furthermore, the pillars are spaced relatively far apart, allowing for improved achievable energy density (charge and / or discharge rates) of batteries formed with such scaffolds. Aspects related to the dimensions of the scaffold are described in more detail herein below.

[0018] In some exemplary embodiments, a carbon nanotube structure is provided. In embodiments, the openings in the connecting structure of the carbon nanotubes in a first cell form one or more channels that provide access to the grooves separating the second cells, and a second gap formed by the channels separates the nanotubes beyond the channels by a minimum distance. Such a distance may be about 0.5 μm or more, e.g., 10 micrometers or 50 micrometers. By forming one or more channels from the openings in the first cell to provide access to the grooves separating the second cells, one or more connecting networks of channels and grooves are formed. These networks may form a perfusion network for process gases and liquids in a manufacturing process in a direction along the substrate, providing access to the substrate.

[0019] In another aspect, the carbon nanotube structure includes one or more channels providing access to the grooves separating the second cells, the channels and / or the grooves having a preferred orientation along the substrate. This preferred orientation may be, for example, along the direction of substrate movement during fabrication or processing of the carbon nanotube structure. If the substrate is flexible, the preferred orientation may also be defined according to a preferred bending direction, preventing carbon nanotubes separated by the channels and grooves from contacting each other.

[0020] Preferably, by providing a carbon nanotube structure, a constant distance is maintained between the ends of the carbon nanotubes, i.e., the top ends away from the substrate. For this purpose, a top layer can be provided to the carbon nanotube connection structure. The top layer connects the ends of the carbon nanotubes, thus aiding in the controlled aggregation or collapse of the carbon nanotubes, effectively increasing the potential space for providing additional composite layers to the connection structure. The aggregation or collapse can be described as a densification process of tightly packed nanotubes due to capillary interactions with the liquid as the liquid is extracted (dried). This will be further explained below. The top layer can be formed from a single material or can include multiple materials to form a composite top layer. Suitable materials include, but are not limited to, oxides such as aluminum oxide, titanium oxide, zinc oxide, vanadium oxide, indium oxide, or combinations thereof. Depending on the process conditions, the presence of grooves or other larger openings, and their dimensions and orientation, the top layer can also be deposited on the substrate. Suitable deposition methods include, but are not limited to, sputtering. Optionally, the portion of the top layer deposited on the substrate, i.e., between the carbon nanotube structures, can be electrically conductive. This conductive layer contributes to providing an electrically conductive connection between the substrate and the carbon nanotube structures. A suitable thickness of such a layer would be 5 μm. In another aspect, a carbon nanotube structure is provided that is further processed to form a composite material comprising the structural carbon nanotubes and at least a second material. The composite manufacturing process includes the following steps: preparing a carbon nanotube structure and depositing at least a second material using a fluid processing step, where the fluid processing step includes one or more of sputtering and chemical vapor deposition (CVD), PVD, ALD and spatial ALD (sALD), and wet liquid deposition methods. Wet liquid deposition methods include wet chemical vapor deposition methods, including methods such as hydrothermal growth, chemical bath deposition, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD).

[0021] Vertically aligned carbon nanotubes on a substrate can be obtained by a controlled growth process such as CVD using an appropriate catalyst. The carbon nanotubes can be single-walled or multi-walled carbon nanotubes, or a combination thereof. The catalyst can be provided as an integral part of the substrate or can be provided separately on the selected substrate. The substrate can be rigid or flexible.

[0022] Growing carbon nanotubes from a surface creates interconnected structures of carbon nanotubes, where the presence of nearby carbon nanotubes is believed to allow parallel growth of the nanotubes. Using the appropriate process, carbon nanotubes can be grown at 10, 25 μm, 50 μm, 75 μm, 100 μm, 200 μm, 500 μm, or values ​​in between.

[0023] Structured or patterned structures of vertically aligned carbon nanotubes on a substrate can be obtained starting from a substrate that is uniformly covered with carbon nanotube structures. These structures can be shaped, for example, by removing portions of the carbon nanotubes according to the desired pattern in a separate patterning or lithography step. Alternatively, connected structures of vertically aligned carbon nanotubes can be obtained by growing carbon nanotubes to the desired length using a substrate coated with a suitable catalyst provided in the desired pattern. In such cases, carbon nanotubes grow only in the areas of the substrate where the catalyst is provided.

[0024] Schematic diagrams providing top views of exemplary embodiments of carbon nanotube structures may be interpreted as top views of said structures of carbon nanotubes, or alternatively, these representations may be interpreted as substrates including appropriate catalyst layers in the corresponding designs.

[0025] As described herein below, the inventors have discovered that parallel growth conditions (also called linear or upright growth) can constrain the dimensions and geometry of the carbon nanotube interconnect structures, including the number and size of the scaffold holes and / or grooves, as well as the span or wall thickness of the carbon nanotube interconnect structures.

[0026] Within the interconnect structure, the carbon nanotubes are spaced a small distance from each other, for example in the range between 10 nanometers and 1 micrometer, which leaves spaces between the carbon nanotubes that can be filled with a second material, potentially resulting in the formation of a composite material.

[0027] Materials can be deposited on carbon nanotube structures using vacuum-based deposition methods such as CVD, PVD, ALD, and sALD. This results in a coating on and between the carbon nanotubes, impregnating the connected carbon nanotube structures. The amount of material deposited can be controlled by the process parameters of the corresponding method. These process parameters include, for example, the precursor source, precursor concentration or pressure, substrate temperature, and deposition time. In the case of a substrate containing carbon nanotube structures where the carbon nanotubes are patterned into a structure of cells containing openings that provide access to the substrate, materials can also be deposited at the locations of the openings on the substrate. The uniformity and / or resulting presence of a conformal coating along the sidewalls of the carbon nanotube structure containing the openings, as well as on the substrate at the bottom of the openings, also depend on the accessibility of the substrate and these sidewalls to the corresponding vapor under given process conditions. Accessibility is affected by the dimensions of the openings and the length of the carbon nanotubes, i.e., the aspect ratio. Wider openings and / or shorter carbon nanotubes result in improved conformal coverage of the material deposited along the sidewalls and at the bottom of the openings.

[0028] One aspect of the present invention is to provide connected carbon nanotube structures containing holes and / or channels that can be coated and / or impregnated with additional materials using vapor-based deposition methods. Important aspects that determine the quality of coatings provided using vapor-based methods include the uniformity and conformality of the formed coating along the sidewalls of the connected carbon nanotube structure and to the access openings in the substrate. Obtaining good conformal coatings is typically more difficult for structures containing narrow, deep openings, i.e., high aspect ratio holes, than for wide openings or elongated openings such as channels.

[0029] One aspect of the present invention is to provide a carbon nanotube structure that improves the quality of coatings applied to the provided structure on carbon nanotubes. The openings in the first cells form one or more channels that provide access to the grooves separating the second cells. By forming one or more channels from the openings in the first cells to provide access to the grooves separating the second cells, one or more connected networks of channels and grooves are formed. These networks form a perfusion network along the substrate, providing access to the substrate. This perfusion network improves the overall carbon nanotube structure and the accessibility of materials deposited to the substrate in vacuum-based deposition methods. It has been found that to achieve the desired effect, the second gaps formed by the channels separate the nanotubes by a minimum distance of 1 μm beyond the channels.

[0030] Material deposition in vapor-based methods, where the vapor perfusion contains an anisotropic component, can be improved by establishing a perfusion network within the carbon nanotube structure that is aligned along a preferred direction. Spatial ALD (sALD), in which the substrate to be processed is continuously moved under the process elements, is a typical example where anisotropic flow of process gases is an important aspect. In sALD, drag flows caused by the substrate movement affect the flow of vapor species. By orienting channels and grooves in the carbon nanotube structure on the substrate along the direction of substrate movement, coating quality is improved at the substrate level and along the walls that define the openings.

[0031] One aspect of the present invention is to provide a carbon nanotube structure, wherein the one or more openings have a preferential orientation along the substrate. It has been found that structures containing oriented channels and grooves can achieve linear growth of carbon nanotubes greater than 50 μm in length when the oriented connecting channels and grooves are designed to be less than 500 μm in length and comprise up to 10 grooves forming interconnections between adjacent parallel connecting channels and grooves.

[0032] Not all materials can be deposited using vacuum-based deposition methods. Reasons include, for example, limited precursor availability, diffusion limitations, or lack of precursor stability. Furthermore, multi-material compounds, such as many layered oxide structures (e.g., LiCoO2, LiMn1 / 3Ni1 / 3Co1 / 3O2, typically used in Li-ion batteries), pose significant challenges, especially from a cost perspective.

[0033] Therefore, solution processing or a combination of vapor and solution processing of vertically aligned carbon nanotubes is of great interest for the fabrication of, for example, 3D thin film all-solid-state lithium ion batteries.

[0034] The presence of a liquid combined with a connected structure of vertically aligned carbon nanotubes containing openings results in the generation of large capillary forces. Under the influence of capillary forces, high aspect ratio nanostructures, including those containing carbon nanotubes, are known to aggregate, bend, and / or deform as a result of these strong capillary forces. More specifically, to reduce the strong capillary forces acting on the nanostructures, the structures bend at the expense of an increase in elastic bending energy. This phenomenon is therefore referred to as "elastic capillary" action.

[0035] Both U.S. Patent No. 5,629,999 and U.S. Patent No. 5,629,999 teach the use of substrates to cover large areas with vertically aligned carbon nanotubes. After additional material is deposited on the carbon nanotubes, the carbon nanotubes aggregate in an uncontrolled manner, causing the tubes to bend, curl, crack, and tumble.

[0036] Uncontrolled aggregation of vertically aligned carbon nanotube structures on a substrate can be prevented by stabilizing the nanotube structures by connecting the ends of the tubes at a fixed distance from each other. This effect can be achieved, for example, by adding a top layer onto the vertically aligned carbon nanotube structures on the substrate. This layer can be deposited, for example, as a film of additional material disposed on the nanotube structures. Suitable deposition methods include, but are not limited to, sputtering. Suitable materials include, but are not limited to, oxides, such as aluminum oxide.

[0037] It is an aspect of the present invention to stabilize a structure of mostly vertically aligned carbon nanotubes by having the structure further comprise a top layer connecting the ends of the carbon nanotubes to maintain a constant distance between the ends of the carbon nanotubes.

[0038] Surfaces with nanostructures of appropriate length in the right pattern allow controlled aggregation and hierarchical assembly of structures. US9221684 and US20120126449A1 describe methods for forming nanostructure arrays using controlled aggregation processes. These documents demonstrate design rules for a wide range of architectures that can be achieved on surfaces, including pillars, tubes, sheets, and other structures with various upright, bent, twisted, or folded variations.

[0039] During controlled aggregation of carbon nanotubes present in interconnect structures, individual carbon nanotubes may aggregate to form dense solid bundles. This densification results in a lateral reduction in size of loose carbon nanotube structures. Thick walls are reduced to thinner, denser walls of carbon nanotubes. Densification of structures of carbon nanotubes with openings results in an increase in the dimensions of the openings. As a result of controlled aggregation, channels and gaps widen. Freestanding pillar-like structures of carbon nanotubes are densified into freestanding pillar-like structures of reduced diameter.

[0040] Controlled aggregation of carbon nanotubes by liquid processing can be used to produce large aspect ratio carbon nanotube structures with lateral dimensions that exceed the minimum lateral dimensions achievable by conventional lithographic methods.

[0041] It is an aspect of the present invention to provide a substrate comprising a structure of mostly vertically aligned carbon nanotubes designed to form high aspect ratio bundles of carbon nanotubes using controlled aggregation to avoid undesirable collapse, bending, curling, cracking, or other undesirable loss of structure due to contact with liquids.

[0042] Increasing the aspect ratio of predominantly vertically aligned carbon nanotube structures by controlled aggregation is a further aspect of the present invention.

[0043] While not wishing to be bound by any theory, it is believed that uncontrolled aggregation of carbon nanotubes is the result of lateral stresses within the interconnected structures of carbon nanotubes. For example, when large structures of carbon nanotubes are exposed to liquid, capillary forces during drying cause the carbon nanotubes to aggregate and bundle within the structure. This leads to densification, and in the case of large structures, this can lead to the random formation of cracks and therefore to a decrease in long-range order.

[0044] The effect of providing a groove separating one carbon nanotube structure from an opposing structure is to limit lateral forces within the structure and prevent the forces from propagating to adjacent cells. In one embodiment according to the invention, the structure includes a groove to provide controlled aggregation and prevent random cracking as a result of contact with a liquid. It also prevents carbon nanotubes from structures that cross the groove from contacting each other.

[0045] Carbon nanotube bundles impregnated with a desired material can be prepared by inducing aggregation through contact with a fluid, which may be a mixture or solution containing appropriate precursors. Suitable fluid processing methods by which layers can be deposited onto the scaffold include, but are not limited to, sputtering, CVD, ALD, spatial ALD, and wet deposition methods such as wet chemical deposition, including methods such as hydrothermal growth, chemical bath, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD).

[0046] It is an aspect of the present invention to provide nested structures of patterned carbon nanotubes on a surface where the patterning allows for controlled aggregation or aggregation in combination with impregnation.

[0047] The controlled aggregation of carbon nanotube structures can be carried out using pure liquids. The controlled aggregation can be combined with impregnation by using a suitable mixture of solutions containing the appropriate precursors. The controlled aggregation can also be preceded by a vacuum-based impregnation step. The controlled aggregation step can also be followed by a vacuum-based deposition step.

[0048] It is a further aspect of the present invention to provide a patterned nested structure of carbon nanotubes on a surface that, after densification and infiltration, is suitable for further processing steps, including but not limited to gas phase functionalization processes such as PVD, CVD, ALD and spatial ALD.

[0049] Composite materials are formed by impregnation using vapor-based processing methods or by a combination of impregnation and densification using liquid-wet methods. Repeated deposition of additional materials onto these composites can lead to the formation of multilayer composites.

[0050] It is a further aspect of the present invention that the provided carbon nanotube structures can be used as a scaffold for the fabrication of composite materials. These composite materials include carbon nanotube structures and at least one additional material. The additional material can be added using liquid deposition, vapor-based deposition, or a combination of processes. Materials can also be repeatedly deposited onto the carbon nanotube structures, resulting in multilayer structures on the substrate. When the carbon nanotube structures are provided with an appropriate pattern, controlled aggregation can be used to form high aspect ratio structures. Subsequent deposition of additional layers onto these high aspect ratio carbon nanotube structures results in layered structures with a nearly perpendicular orientation to the substrate.

[0051] In conventional 2D batteries, two suitable electrode materials separated by an electrolyte material are oriented parallel to the substrate. To increase the energy storage capacity of such layered 2D batteries, the thickness of the electrode layers can be increased. Increasing the thickness of the electrode layers increases the diffusion distance between electrons and ions. This increases the internal resistance of the battery and reduces its power density. By simultaneously increasing the volume and interfacial area of ​​the electrode materials within the battery while keeping the distance between the electrodes short, both the power density and energy density of the battery can be increased.

[0052] A further aspect of the present invention is that the ability to form multilayer structures with an orientation near perpendicular to the substrate is particularly beneficial for energy applications such as 3D batteries and supercapacitors.

[0053] In energy storage systems, volume expansion and contraction of electrode materials during operation under discharge and / or charge conditions is a well-recognized problem. The expansion and / or contraction of electrode materials can result in crack formation and / or other damage to the system, leading to reduced performance. Damage to the system can increase over repeated charge and discharge cycles, resulting in reduced performance over time. For 3D battery applications, these issues are particularly relevant.

[0054] In one embodiment of the present invention, a 3D energy storage system is formed that includes a scaffold structure according to the present invention. The scaffold structure provides a large aspect ratio structure onto which appropriate layers of electrode material and electrolyte can be deposited. The layers can be deposited using fluid deposition processes, such as the vacuum deposition and wet chemical deposition methods described above. It is desirable to have good control over the properties of the deposited layers, such as their thickness, conformality, and uniformity. To enable this control, good access to the large aspect ratio carbon nanotube structure during the deposition process is desirable, so that the deposited material is not only deposited on top of the structure, but also along the sidewalls of the large aspect ratio structure. The scaffold structure according to the present invention provides such access by providing a structure in which carbon nanotubes are formed in a first cell structure and nested in a second cell structure. wherein the first cells include at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate, and the second cells are separated from each other by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the groove. By providing appropriate openings in the cells and separating the cells within the scaffold structure across a gap, spaces are formed between adjacent large aspect ratio structures, allowing desired access to the large aspect ratio carbon nanotube structures during a subsequent fluid deposition step.

[0055] The layer deposited on the scaffold may also partially impregnate the spaces between the carbon nanotubes within the structure. By only partially filling the spaces between the carbon nanotubes within the structure, a porous structure may remain. Leaving porous regions within the carbon nanotube structure reduces potential damage to the energy storage system due to volumetric changes within the electrode material. In some cases, impregnation may result in the formation of a porosity gradient within the carbon nanotube structure along the carbon nanotubes. For example, using ALD, porosities of up to 90% have been achieved, but at layer thicknesses greater than 50 nm.

[0056] Deposited layers can be provided that include a gradual and / or stepwise compositional gradient along the substrate. Alternatively, or in addition, the deposited layer can include a compositional gradient away from the substrate. In this manner, electrode materials that experience large volume changes during operation can be desirably deposited in locations with higher porosity, e.g., near the interior regions of the carbon nanotube structure. Also, electrode materials that experience smaller volume expansions can be preferentially deposited near the exterior regions of the carbon nanotube structure.

[0057] As mentioned above, the inventors have found that parallel growth conditions may constrain the design (e.g., shape) and / or dimensions of the scaffold. In order to provide a connecting structure that grows sufficiently straight, the inventors have found that the connecting structure preferably has a minimum wall thickness. Wall thickness can be understood as the shortest distance from an opening or groove that provides access to the substrate to an adjacent opening or groove, in other words, the shortest distance between the two outer walls of the carbon nanotube connecting structure. For example, to achieve straight growth of carbon nanotubes with a length of more than 100 μm (i.e., to form a connecting structure with a thickness of more than 100 μm), a wall thickness (t min ) was found to be preferable. Table 1 shows the t min The experimentally derived values ​​of

[0058] [Table 1]

[0059] Regardless of the actual pattern, the inventors have experimentally found that: The carbon nanotube connection structures preferably have a minimum lateral dimension Dmin of at least 8 / 100 times the length of the carbon nanotubes within the structure (i.e., the height of the carbon nanotube connection structures). In other words, for a scaffold with a desired height of 100 μm (100 μm carbon nanotube length), the connection structures preferably have a minimum lateral dimension along the plane of the substrate of at least 8 μm. The minimum lateral dimension along the plane of the substrate can be understood as the minimum span diameter of the connected carbon nanotube structures, i.e., the dimension of the smallest first bounding box (B1—see FIG. 6(a)) of the connection structure. In the case of flower-shaped structures, as will be described later, e.g., with reference to FIG. 3, the minimum dimension can be understood as the diameter of the flower structure, i.e., the minimum distance between the two ends of the flower structure via the first cells that are continuously interconnected. Similarly, a minimum minimum diameter can be defined for other structures. Designs with minimum diameters below the experimentally derived minimum may be inadequate for growing straight carbon nanotubes within the design, such as tubes, as such structures have been found to have insufficient connections to other tubes within the structure to support vertical alignment, e.g., for carbon nanotube growth.

[0060] The inventors have determined the preferred minimum wall thickness (t min Similar to the previous study, we found that the minimum lateral dimension (Dmin) of a connected carbon nanotube structure is also proportional to the length of the carbon nanotubes. As the tubes become longer, they need to sense the presence of neighboring tubes over a longer distance (span) in order to grow straight. We further experimentally determined that the minimum lateral dimension (Dmin) also depends on the number and size of pores and channels in the structure, i.e., the coverage P within the connected structure.

[0061] Table 2 shows experimentally derived values ​​for the preferred minimum lateral dimension (Dmin) of connected carbon nanotube structures, categorized into specific ranges of carbon nanotube heights, and the coverage P, defined as the percentage of the substrate covered by the carbon nanotube connecting structures. A coverage of 0 provides complete open access to the underlying substrate surface in the area of ​​the connecting structures, while a coverage of 100 provides no access. The coverage includes the surrounding open channels / grooves (i.e., within the second bounding box (B2—see Figure 6(a)) formed by the connecting structures, including the surrounding open channels / grooves).

[0062] [Table 2]

[0063] where Dmin is the smallest lateral dimension of the smallest first bounding box (B1—see Figure 6(a)) of the connecting structure (unit cell), h is the height of the carbon nanotube connecting structure, e.g., the length of the carbon nanotube, and P is the local coverage, defined as the percentage of the substrate covered by the carbon nanotube connecting structure, in the region of the connecting structure that includes the surrounding open channels / grooves and provides open access to the underlying substrate surface (i.e., within the second bounding box (B2—see Figure 6(a)) formed by the connecting structure, including the surrounding open channels / grooves). As can be seen from the data in Table 2, for structures of a given height (i.e., tube length), the smallest lateral dimension Dmin must increase as the coverage increases.

[0064] For a graphical representation of Dmin, B1, and B2, see the connection structure shown in FIG. 6(a).

[0065] Thus, for a 100 μm tall structure of connected carbon nanotubes with a local coverage of 0.5 (50% open structure), the smallest dimension (e.g., diameter) of the connected carbon nanotube structure preferably exceeds 16 μm. Note that the exemplary structure shown in the schematic electron micrograph of Figure 5 has a diameter (i.e., smallest dimension) of approximately 65 μm, with a circular hole of approximately 6 μm (scale bars are 40 μm in Figure 5(a) and 4 μm in Figure 5(b)).

[0066] The specified dimension of Dmin ensures that scaffolds with complex designs, such as those described below, including nested designs, such as scaffold designs with lateral openings (side feed), sidewall patterning, and / or zigzag patterns, will grow at least as straight as structures formed with patterns of common geometric shapes such as squares, circles, or straight lines.

[0067] As noted above, the inventors have further found that carbon nanotubes separated from one another across a gap / groove should be separated by a distance of at least 200 nm. Separating carbon nanotubes across a gap by at least 200 nm prevents intermixing of the tubes across the gap.

[0068] Furthermore, the inventors have found that the portions of carbon nanotube connecting structures that connect larger sized carbon nanotube structures preferably have a minimum width (i.e., wall thickness) of 500 nm. For example, referring to Figure 3, interconnect 32 connecting structures 31 and 35 has a minimum width of 500 nm along the length of the interconnect.

[0069] Furthermore, the connection structure can be defined by a coverage ratio Pcs<0.2, where PCS is defined as the fraction of the underlying substrate covered by carbon nanotubes within each bounding box B1.

[0070] A further set of dimensional constraints relates to the dimensions of the grooves and channels. The inventors have found that the channels and / or grooves, which are not necessarily straight, preferably have a width ranging from about 500 nm to about 20 μm. This specified width allows materials, such as active chemicals, to be delivered throughout the scaffold (from above to the substrate) during subsequent processing steps, such as vapor deposition and / or wet chemical processing steps. For example, grooves with a width of 500 or 1000 nm may be sufficient to allow conformal coating of the scaffold sidewalls with electrode materials using known deposition procedures.

[0071] The minimum dimension of the carbon nanotube connection structure (e.g., D min and t min The above-provided constraints for the spacing contribute to proper parallel alignment of the carbon nanotubes forming the scaffold. In combination with the specification of the openings, grooves, and optional channels connecting the openings disclosed herein, a scaffold containing a percolation network may have an improved surface area onto which additional functional materials may be deposited during subsequent vapor and / or liquid deposition processes. The scaffold is further dimensioned to allow controlled aggregation of the carbon nanotubes into connected structures following contact with a liquid, all while providing accessibility for depositing materials along the height of the scaffold and / or onto the substrate.

[0072] The inventors have found that substrates with carbon nanotube interconnect structures having lateral dimensions greater than 500 micrometers adversely affect the handling, e.g., flexibility, of the substrate, and therefore it is desirable that the maximum dimension (span) of the carbon nanotube interconnect structure in a direction along the substrate, e.g., the dimension (span) of the second cell, does not exceed 500 μm.

[0073] At the same time, a further set of dimensional constraints can be defined, for example, related to the applications envisioned to be formed on the scaffold. These applications include, for example, 3D electrodes and 3D batteries. For both battery and electrode applications, the length of the carbon nanotubes (height of the scaffold) is preferably in the range of 20 μm to 500 μm.

[0074] For 3D electrodes, the coverage "P" is preferably between 50% and 80% (i.e., preferably 0.5≦P≦0.8). Furthermore, the maximum distance from the location of the carbon nanotubes within the connecting structure to the location on the wall of the structure is preferably less than 15 μm. It has been found that the combination of these constraints ensures the processability of the connecting structure (i.e., processability without uncontrolled agglomeration) in subsequent processing steps, including gas-phase and / or wet chemical vapor deposition processes. This combination further improves functionality in applications where 3D electrodes are combined with liquid electrolytes (e.g., power density in 3D batteries). By limiting the maximum distance from the location of the carbon nanotubes within the connecting structure to the location on the wall (where the electrolyte contacts the electrode), ion transport times can be reduced by minimizing diffusion distances (e.g., tortuosity).

[0075] Optimizing the surface area of ​​the scaffold can improve the properties of 3D batteries, such as capacity and energy density. Regarding 3D batteries, the inventors have found the following: A W ≧10 A S where A W is the outer region of one or more connecting structures of carbon nanotubes (i.e., the region of the scaffold wall), and A Sis the total area of ​​the substrate covered by the scaffold (i.e., the area of ​​the substrate covered by carbon nanotube interconnect structures, such as openings, gaps, and grooves). As with 3D electrodes, for 3D batteries, the maximum distance from a location within the carbon nanotube interconnect structure to a location on the wall of the structure is preferably less than 15 μm. The inventors have found that for 3D batteries, where the scaffold is completely filled with electrode material, the maximum distance is preferably less than 5 μm. For scaffolds for 3D batteries, the coverage P is preferably between 20% and 70% (i.e., 0.2≦P≦0.7). The inventors have found that this combination of constraints ensures the stability of the scaffold with the electrode layer (forming the 3D electrode) during further processing steps to cover the 3D electrode (i.e., improving processability). In particular, the constraint has been found to enable gas-phase and / or wet-chemical deposition processes to deposit electrolyte and cover the 3D electrode surface. Furthermore, the constraint limits the remaining volume of the remaining structure after such steps that needs to be filled with the top electrode material.

[0076] Detailed Description of the Drawings Figure 1 shows a prior art structure that exhibits uncontrolled aggregation and loss of orientation of a connected structure of vertically aligned carbon nanotubes arranged in a continuous array of first cells containing openings in a substrate after contact with a liquid. A scanning electron micrograph illustrating the uncontrolled aggregation 1 is depicted. In this illustrative case, the substrate is provided with a structure of vertically aligned carbon nanotubes containing numerous holes arranged in a regular hexagonal pattern. The vertically aligned carbon nanotubes surrounding the openings constitute first cells. In the absence of second cells separated by grooves, these first cells form a connected carbon nanotube structure covering a large area of ​​the substrate. Exposing the structure to a liquid causes the carbon nanotubes to aggregate. The nanotubes form bundles, and densification occurs. Without being bound by theory, it is believed that this aggregation leads to the formation of lateral stresses within the connected carbon nanotube structure. In this particular case, this leads to the formation of cracks 11, leading to a decrease in long-range order, leaving only small areas with the regular hexagonal array openings 12 intact. However, it should be noted that, as is known in the art, to grow sufficiently straight carbon nanotubes (i.e., aspect ratios >10), it is advantageous to grow carbon nanotubes close to each other. Growing carbon nanotubes close to each other can result in the formation of carbon nanotube interconnect structures that prevent the tubes from (at least partially) bending. In other words, the carbon nanotube interconnect structures facilitate vertical alignment of the carbon nanotubes within the structure.

[0077] On the other hand, connected structures with increasingly larger lateral dimensions (along the substrate), as shown in the continuous array of connected tubes shown in Figure 1, become increasingly susceptible to uncontrolled aggregation and / or the formation of random cracks in the connected carbon nanotube structures when in contact with liquid.

[0078] Without wishing to be bound by theory, the inventors have found that there is a minimum mutual distance between separated cells, i.e., a minimum distance between carbon nanotubes separated by gaps resulting from growth conditions. With respect to the scaffolds of the present invention, the inventors have found that carbon nanotubes of structures at least 200 nm apart, more preferably at least 500 nm apart, can be grown separately without intermixing with carbon nanotubes from adjacent cells. The inventors have experimentally found that the minimum separation distance (up to a distance of 3 μm) for growing carbon nanotubes of adjacent structures separately, for example, without intermixing, can be expressed by the following relationship: Separation distance=0.5μm+0.001×h where h is the height (in nanometers) of the connected carbon nanotube structure, e.g., the length of the carbon nanotube. Thus, a 100 μm-tall structure of connected carbon nanotubes can grow independently of neighboring structures if it is separated by 0.6 μm. Note that correlations have been observed for separation distances up to 3 μm. It is difficult to provide an exact value for the maximum separation. In this context, a maximum of approximately 20 μm may be preferred, given the general desire to maximize the surface area of ​​the scaffold and therefore minimize the groove area.

[0079] FIG. 2 shows a top view of a first exemplary embodiment of a connection structure of vertically aligned carbon nanotubes in a first cell structure nested within a second cell structure. The aligned carbon nanotubes surrounding an opening constitute a first cell. Each second cell includes, for example, seven first cells arranged in a hexagonal configuration with an opening for providing access to a substrate. The second cells are separated from each other by a groove. Avoiding uncontrolled collapse of the carbon nanotube structure due to contact with a liquid is an aspect of the first exemplary embodiment. The first exemplary structure includes a connection structure of vertically aligned carbon nanotubes 23, and each of the seven first cells includes a circular opening 21 for providing access to the substrate. In the first exemplary embodiment, the opening 21 is defined by the inner surface of the connected carbon nanotube structure. In the first exemplary embodiment, the first cells are arranged in a hexagonal configuration to form second cells, resulting in a honeycomb structure with two holes on each side. We found that honeycomb-shaped structures with a minimum dimension of 15 μm are sufficient to support parallel growth of carbon nanotubes with lengths exceeding 100 μm. In these second cells, openings are separated from adjacent openings by walls of connected carbon nanotubes. These second cells are separated from adjacent second cells across a first gap by grooves 22. The distance between two honeycomb-shaped structures across the first gap is at least 500 nm. For battery applications, the distance is ideally less than about 3 μm to maximize energy density. However, for other applications, or for applications on flexible substrates, the distance can be much larger, e.g., 4 μm, 5 μm, or even up to 10 μm. Other applications that benefit from scaffolds offering large surface areas include, but are not limited to, storage devices, sensing devices, and liquid (e.g., water) filtration systems. The scaffold structure of Figure 2 comprises carbon nanotubes in the form of one or more connecting structures 23 of carbon nanotubes that are oriented generally parallel in a direction away from the substrate.The connection structures 23 leave at least one region 21 free of carbon nanotubes to provide access to the surface of the substrate, and the connection structures 23 are separated from each other by grooves 22 to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure, forming a first gap, where the grooves provide access to the substrate between the carbon nanotube connection structures.

[0080] For honeycomb-shaped structures with up to three holes per side, wall dimensions ranging from 0.5 μm to 5 μm, and holes with diameters ranging from 2 μm to 10 μm, it was experimentally shown that long-range order persists even after the carbon nanotubes aggregate upon contact with liquid.

[0081] It will be understood that although the first exemplary embodiment includes circular openings arranged in hexagonal packing to form a honeycomb shape with two holes per side, the disclosure should not be construed as limiting. Other embodiments are contemplated, for example, including arrangements of honeycomb-shaped structures with different shaped openings, different numbers of openings, different numbers of openings per side, and / or non-hexagonal methods, such as square packing.

[0082] 3 shows a schematic top view of a second exemplary embodiment of a connecting structure 3 of vertically aligned carbon nanotubes in a first cell structure nested in a second cell structure, where the connecting structure of carbon nanotubes defined by the first cells includes openings for providing access to the surface of the substrate without carbon nanotubes, and the second cells are separated from each other by grooves, the openings forming channels providing access to the grooves separating the second cells, thereby forming a perfusion network for the flow of process gases and / or liquids.

[0083] FIG. 3 shows a top view of vertically aligned carbon nanotubes 35, with seven first cells connected by interconnects 32 to form a flower-shaped second cell, the diameter of which is defined by three interconnected first cells in a row. The second cells are separated from adjacent cells by first grooves with gaps 33. In the presented second exemplary embodiment, openings 34 providing access to the substrate are defined by the outer surface of the connected carbon nanotube structures. The scaffold structure of FIG. 3 includes one or more connecting structures 31, 35 of carbon nanotubes. The connecting structures leave at least one region 34 free of carbon nanotubes to provide access to the surface of the substrate, and are separated from each other by grooves 33 to prevent the carbon nanotubes of the connecting structures from contacting each other.

[0084] Avoiding uncontrolled collapse of the carbon nanotube structure due to contact with liquid is an aspect of the second exemplary embodiment. In the second exemplary embodiment, the first cell can have a diameter ranging from 2 μm to 30 μm. The interconnect can have a width ranging from 50 nm to 90% of the dimension of the first cell, and the interconnect can have a length ranging from 50 nm to 100% of the dimension of the first cell. The distance between adjacent second cells can be between 50 nm and 20% of the dimension of the second cell.

[0085] While the second exemplary embodiment includes seven interconnected circular first cells arranged in a flower-shaped second cell, it will be understood that the disclosure should not be construed as limiting. For example, other embodiments are also contemplated that include differently shaped first cells and second cells that include different numbers of interconnected first cells.

[0086] FIG. 4 schematically illustrates a top view of a third exemplary embodiment of a vertically aligned carbon nanotube connection structure in a first cell structure nested within a second cell structure. Here, the first cells include openings that do not contain carbon nanotubes to provide access to the surface of the substrate, and the second cells are separated from each other by a groove, with an additional opening defined by the outer surface of the carbon nanotube connection structure. The third exemplary structure includes a vertically aligned carbon nanotube 44 connection structure including a circular opening 41 that provides access to the substrate and forms a hollow pillar-like second cell. The second cell is separated from an adjacent cell by a first groove having a gap 42. The distance between adjacent hollow pillar-like structures across the first gap is at least 500 nm. In the presented third exemplary embodiment, the opening 41 is defined by the inner surface of the connected carbon nanotube structure. The opening 43 is defined by the outer surface of the adjacent carbon nanotube structure. Avoiding uncontrolled collapse of the carbon nanotube structure due to contact with a liquid is an aspect of the second exemplary embodiment. It has been found that hollow pillar-like structures with a minimum dimension of 15 μm are sufficient to support parallel growth of carbon nanotubes with lengths greater than 100 μm. A third exemplary embodiment includes pillar-like carbon nanotube structures having circular openings, the exterior surface of which is further patterned with additional circular openings, although it will be understood that the disclosure should not be construed as limiting. Other embodiments are also contemplated, including, for example, pillars including different numbers of openings and / or openings of different shapes, or pillars with different patterning of the exterior surface, or pillars arranged in a non-hexagonal pattern.

[0087] The scaffold structure of Figure 4 includes one or more connecting structures 44 of carbon nanotubes, which leave at least one area 41 free of carbon nanotubes to provide access to the surface of the substrate, and which are separated from each other by grooves 42 to prevent the carbon nanotubes of the connecting structures from contacting each other.

[0088] In a variation of the described embodiment, the pillar structure comprises additional openings in the form of short grooves along the periphery of the pillar. With the hollow pillar-like connecting structure shown in the third exemplary embodiment, a minimum dimension of 15 μm has been found to be sufficient to support parallel growth of carbon nanotubes with lengths exceeding 100 μm.

[0089] FIG. 5 shows a scanning electron micrograph of a composite material on a substrate, including interconnected structures of carbon nanotubes on which a thin layer of ZnO has been deposited by an atomic layer deposition (ALD) process.

[0090] Figures 5(a) and (b) show scanning electron micrographs of the composite material on a substrate. The composite material was created by using ALD to deposit a layer of ZnO onto the connecting structure of vertically aligned carbon nanotubes within the structure of a first cell, nested within the structure of a second cell. Here, the first cells contain openings (62, 63) that do not contain carbon nanotubes to provide access to the surface of the substrate, and the second cells 64 are separated from each other by a groove 61.

[0091] Figure 5(a) shows a schematic of a ZnO deposited carbon nanotube structure 5a. The honeycomb shaped structure of carbon nanotubes 64 is similar to the embodiment shown in Figure 2, with the modification that the carbon nanotube structure shown forms a hexagonal honeycomb shaped structure 64 with five holes on each side.

[0092] On the right, an electron micrograph (5b) is depicted, providing a close-up of the ZnO-coated carbon nanotube structure 65 adjacent to the groove. To facilitate documenting the area of ​​the carbon nanotube structure near the substrate, a portion of the carbon nanotube structure was removed. The location 68 where the carbon nanotube was removed remains visible. In the micrograph, bright areas 66 on the remaining carbon nanotube structure indicate the presence of ZnO along the length of the carbon nanotube down to the substrate level, while dark areas 67 indicate the absence of ZnO. In the presented structure, two classes of openings within the honeycomb-shaped structure are identified: the first type (62, 66) adjacent to the groove, and the second type (63, 67) representing at least one row of holes in a more central location, away from the groove. ZnO was found to be present on the substrate in areas corresponding to the first type of opening. ZnO was also found to be present at the bottom of the groove (not shown). For ZnO to cover the substrate, its vapor precursor species must flow all the way to the opening. In this case, no conformal ZnO coating was observed at the bottom of the second type of opening. It is believed that the flow of precursor vapor species through the high aspect ratio openings is insufficient to cover the substrate at locations away from the trench. The presence of a thin layer of ZnO observed at the bottom of openings adjacent to the trench is believed to be facilitated by the partial permeability of the wall separating the hole and the trench.

[0093] 6(a) and 6(b) are schematic top views of fourth and fifth exemplary embodiments 7A and 7B of a connection structure of vertically aligned carbon nanotubes 74 in a first cell structure nested in a second cell structure. Here, the first cells include openings 71 free of carbon nanotubes to provide access to the surface of the substrate, and the second cells are separated from each other by grooves 72, with the openings in the first cells forming one or more channels 73 and providing access to the grooves separating the second cells. The presented fourth and fifth exemplary embodiments can be interpreted as a variation of the honeycomb-shaped structure of the first embodiment. By providing channels connecting the openings in the first cells to the grooves, an open honeycomb-shaped structure is formed. This creates a network that allows lateral flow of gas and vapor species between the grooves and openings in the structure. This improves access of the vapor species to the substrate. Preferably, each opening in the first cells has direct access to the grooves. Alternatively, access to the grooves can be provided by interconnecting a series of holes in the first cell. It has been found that a width of the channels of 1 μm or more is preferred to improve the accessibility of the vapor species to the substrate.

[0094] FIG. 6(a) shows a minimum lateral dimension Dmin that is at least 8 / 100 times the length of the carbon nanotubes 74 within that structure 7A (i.e., the height of the carbon nanotube connection structure). The minimum lateral dimension Dmin is shown as the dimension of the smallest first bounding box B1 of the connection structure 7A. Additionally, a minimum wall thickness (t min ) is shown in FIG. 6(a) as the minimum distance between the two outer walls of the connected carbon nanotube structure 7A. min is also proportional to the length of the nanotube carbon nanotubes 74. A second bounding box B2 is shown formed by the perimeter of the connection structures, including the surrounding open channels / grooves. This bounding box B2 defines the coverage P as the percentage of the substrate that is covered with carbon nanotube connection structures, including the surrounding open channels / grooves 72, 73.

[0095] Figures 7(a)-7(c) show three schematic stages of a 3D battery fabrication process, in which an exemplary carbon nanotube structure is used as a scaffold for the fabrication of a multilayer composite. The process begins in Figure 7(a) with the fabrication of a suitable carbon nanotube interconnect structure 101 on a substrate. During this stage, the carbon nanotubes in the first branch 102 of the structure 101 remain closely spaced from one another. This is visualized using a patterned gray fill. In Figure 7(b), the carbon nanotube structure 111 is exposed to a liquid 113 containing a suitable precursor for forming the composite electrode material. At this stage, the carbon nanotube structure is partially impregnated with the electrode material. This is visualized using a gray fill with less patterning. Between the first (a) and second (b) stages, capillary-induced aggregation initially causes the carbon nanotube interconnect structures (101, 112) to shrink laterally, correspondingly increasing the separation between the cells. Once completely dried, an additional layer 123 containing a solid electrolyte is provided on the impregnated carbon nanotube structures (121, 122) in FIG. 7(c). This layer can be deposited using a wet-liquid method. Alternatively, due in part to the presence of a perfusion network, the electrolyte layer can also be deposited using a vacuum-based deposition method. After the electrolyte layer is deposited, a further step 12 follows, in which a layer 124 containing a suitable counterelectrode material is added to the remaining openings between the carbon nanotube structures. Alternatively, a second electrode material 124 can be provided to partially fill the remaining openings between the carbon nanotube structures. The electrolyte material can include a solid electrolyte material, and the first and / or second electrode layers can include lithium. Alternatively, the energy storage system can also be formed using a liquid electrolyte material.

[0096] FIG. 8 schematically illustrates a connected scaffold structure 9, for example, along line II in FIG. 8a, of vertically aligned carbon nanotubes 91 on a substrate 94. Here, the cells are separated from one another by grooves 93, and a top layer 92 is provided that connects the ends of the carbon nanotube structures within the cells. The top layer can be deposited, for example, as a film of additional material disposed on the nanotube structure. Connecting the top ends of the carbon nanotubes in the cells can prevent undesired collapse of the structure upon contact with liquid or uncontrolled aggregation of the carbon nanotubes. Suitable materials include, but are not limited to, oxides, such as aluminum oxide. Depending on the process conditions, the presence of grooves or other larger openings, and their dimensions and orientation, the top layer 92 can also be deposited on the substrate. Suitable deposition methods include, but are not limited to, sputtering. It will be understood that the concept of connecting the top ends of carbon nanotubes within a structure is not limited to the exemplary embodiments presented in this application. The top layer can be porous to allow permeation of process gases, or can be substantially non-porous. In some cases, the top layer may function prior to the densification process to maintain the integrity of the structure and may be partially removed after the process. In the embodiment shown in FIG. 9, the scaffold structure 10 is formed as a 3D electrode for a liquid electrolyte battery with a cathode 11. A top layer 102 is provided covering the connected carbon nanotube structure. The top layer 102 may be multi-layered. A LIPON or polymer electrolyte is deposited on an insulating layer that passivates the connected carbon nanotube structure 101 to prevent dendrite growth toward the cathode 11. The top layer 102 helps maintain a constant distance between the ends of the carbon nanotubes within the anode 10, thereby preventing further dendrite growth from the base of the 3D lithium anode 10. The connection structure 101 on the substrate is accessible to the liquid electrolyte 13 through an inlet structure 103a provided in the scaffold structure.The carbon nanotube structure in the anode can be impregnated with alternating ZnOx / TiOx / SnOx / .. coatings or coated with a Li metal coating, or a combination thereof.

[0097] The inlet structures 103a can be formed by the grooves 103 separating the cells, but can also be formed by channels of wider dimensions, for example, more than 10 times the width of the grooves 103, e.g., more than 30 micrometers. The inlet structures 103a are preferably patterned outside the overlap area of ​​the cathode 11 to provide uniform electrical conditions for the liquid electrolyte.

[0098] It will be understood that the visualized stages of the exemplary manufacturing process of energy application are not limited to the exemplary process, nor to the materials used and / or the carbon nanotube structures shown. Other manufacturing processes are also contemplated, such as starting with carbon nanotube structures other than the exemplary structures presented herein, or using other materials, or using different deposition processes, and / or including further steps for the deposition of additional layers or materials.

[0099] FIG. 10 shows a schematic side cross-section of 3D electrodes 13 and 14 including a connecting structure of vertically aligned carbon nanotubes covered with a first electrode material. Here, the electrode material partially filling the pores of the carbon nanotubes includes a density gradient of material composition, for example, of the type disclosed in WO2010032159 and specified in the background of the specification. In the exemplary 3D electrode 13, the connecting structure of carbon nanotubes 133 on a substrate 131 is covered with a first electrode material 132. During the deposition process, the electrode material 132 partially impregnates the carbon nanotube structure. Typical bulk expansion electrode materials that may be deposited using a vapor-based process are: sulfur, silicon, Li2O2, Zn. x O y , V x O y , Snx ABOUT y 、Fe x ABOUT y 、Fe x P y ABOUT z 、Mn x ABOUT y 、Zn x Ti y ABOUT z 、Sn x Ti y ABOUT z 、ZnwSn x Ti y ABOUT z 、V x Ti y ABOUT z 、V x Ni y ABOUT z 、V x Mn y ABOUT z 、V x Cu y ABOUT z 、V x Fe y ABOUT z 、V x What y ABOUT z 、V x Cr y ABOUT z 、Zn x Cr y ABOUT z 、Zn x Fe y ABOUT z 、Zn x Mn y ABOUT z 、Zn x What y ABOUT z 、Zn x V y ABOUT z 、Zn x Ni y ABOUT z 、Sn x Cr y ABOUT z 、Sn x Fe y ABOUT z 、Sn x Mn y ABOUT z 、Sn x Whaty O z , Sn x V y O z , Sn x Ni y O z , In x O y , In x Sn y O z , Al x O y , Zn x S y , Fe x S y , Ti x S y , Zn x S y O z , Fe x S y O z , Ti x S y O z , or a combination thereof, where w, x, y, z>0.

[0100] Therefore, the present application further relates to a patterned 3D electrode comprising a scaffold structure according to the present invention. In a preferred embodiment, the scaffold is provided on a current collector foil, e.g., grown on the current collector foil. In another or even more preferred embodiment, the scaffold comprises one or more of the electrode materials, e.g., is impregnated and / or coated with one or more of the electrode materials (e.g., anode materials including Li, Sn, SnO, ZnO, Si, or Li x M y O z (wherein M represents one or more transition metals), including cathode materials such as air or sulfur, as well as bulk expansion electrode materials such as those listed above.

[0101] By impregnating and / or covering the scaffold with an electrode material, electrodes can be obtained for battery applications with improved energy density per unit area compared to thin film battery and / or less porous (e.g., scaffolds with fewer openings per unit volume) 3D battery applications.

[0102] These materials can also be lithiated, for example, using a chemical bath, thereby partially filling the pores 134 between the carbon nanotubes forming the connected carbon nanotube structure. In exemplary embodiment 13, the material is deposited in a gradient along the substrate, resulting in denser packing away from the center of the carbon nanotube structure, or vice versa. Providing a gradient in the vertical direction, i.e., along the length of the carbon nanotubes, can be advantageously achieved for the open portion of the scaffold, closer to the substrate, which requires a longer diffusion distance than the portion of the scaffold closer to the (vapor) deposition tool.

[0103] Generally speaking, a layer thickness of 10-100 nm of material deposited on the CNTs has been found to be beneficial for battery performance. This may prevent internal cracking of the carbon nanotube interconnect structures, potentially affecting their integrity. Furthermore, lithium metal can be plated into the formed pore structures after partially filling the pores with electrode material 132. This leads to a hybrid anode of lithium metal and electrode material 132. Lithium deposition can also be performed at a later stage of battery fabrication, and ultimately during operation, i.e., during the first formation cycle of a complete battery including the cathode material. Additionally or alternatively, a continuous layer of electrode material can be deposited on the top and sidewalls of the carbon nanotube structures, as well as in areas adjacent to these structures, which may be formed from openings and / or grooves provided in the carbon nanotube interconnect structures. The thickness of the closing electrode layer is preferably between 50 nm and 1000 nm. The continuous layer can be a different electrode material from the first electrode material partially impregnated into the carbon nanotube structures. For example, using a material with low expansion upon lithiation as a continuous layer may improve the cycling performance of a 3D electrode, while impregnated electrode materials expand more and result in higher capacity. The inner material expands to a controlled porosity, while the outer surface of the 3D electrode material maintains minimal expansion / contraction during cycling. Providing electrode material in a gradient on the carbon nanotube interconnect structures can be advantageously used to provide a higher density of electrode material near openings, grooves, and / or channels, e.g., near pores. By providing a higher density of electrode material near pores, expansion and / or contraction of the electrode material during charge and / or discharge cycles is less likely to result in degradation, e.g., crack formation.

[0104] In some preferred embodiments, the carbon nanotube structure forming the scaffold is first coated with a wetting layer. The wetting layer may improve impregnation and / or conformal coating of the scaffold with the electrode material. When lithium metal is used as the electrode material, such a wetting layer may comprise, for example, ZnO, SnO, or doped versions thereof, which exhibit an affinity for lithium metal.

[0105] In addition to the above, the connected carbon nanotube structures can be initially capped with an electrically insulating, and optionally ionically conductive, layer. The inventors have found that such a layer can aid in uniform impregnation of the connected carbon nanotube structures with the electrode material, regardless of whether vapor-phase, wet-chemical, diffusion-based, and / or electrodeposition-based deposition methods are used. Furthermore, such a layer also prevents lithium ions from intercalating or plating onto the CNTs when the battery is in operation. Such a layer can also be deposited in small spaces, such as the bottom of grooves, channels, and / or openings, e.g., holes within or between the connected carbon nanotube structures that form the scaffold.

[0106] Such capping layers can be electrically insulating or, optionally, ionically conductive. The capping layer can prevent stress buildup during use by isolating portions of structures (e.g., pillar tops) in lithium-containing devices with a thin, resistive layer of substantial resistivity, thereby preventing stress buildup during use by axially plating lithium metal. The thin, resistive layer is formed, for example, of Al2O3, to block direct conduction paths between structures, such as pillar tops, and surface current collectors, through which lithium ions may migrate axially. Thus, 3D electrodes and / or energy storage applications are provided that include an electrode layer covering a scaffold according to the present invention. Here, the electrode is shielded from opposing conductive structures by an insulator covering a portion of the electrode layer adjacent to its end side (e.g., pillar top) to prevent conductive ion transport pathways between the electrode and counter-electrode during use. This reduces stress buildup near the end side of the covered scaffold, improving stability and cycle life between layers in devices that include the capping layer, and / or improving interfacial contact. For further details, reference is made to WO2017222378, which describes a method for manufacturing a battery with a substrate current collector, and is incorporated herein by reference.

[0107] In addition to the 3D electrodes described above, the present application also relates to 3D electrodes that are covered, preferably conformally covered, with a layer of solid electrolyte. In a preferred embodiment, the solid electrolyte comprises an inorganic electrolyte, a polymer, or a mixture thereof, e.g., a composite solid electrolyte material. Inorganic solid electrolytes include, but are not limited to, ceramics such as LiPON, oxides, and sulfides. Suitable polymeric materials include polyethers such as polyethylene oxide (PEO). Optionally, or in addition, the electrolyte may be a hybrid of multiple electrolyte layer types forming a laminate. This is beneficial for interfacial stability with various types of positive and negative electrode materials.

[0108] In addition to being advantageous for application in energy storage applications, the authors further envision the application of 3D electrodes comprising the scaffolds according to the invention in other electrochemical cells and devices, including but not limited to fuel cells, sensors, liquid (water) filtration devices, and any other application that would benefit from 3D electrodes comprising the scaffolds according to the invention.

[0109] In the exemplary embodiment 14 of FIG. 10, a similar structure is formed, including a connected structure of carbon nanotubes 143 on a substrate 141, and then covered with a first conductive material 142 using a vapor deposition process. In this embodiment, the material 142 also partially fills the pores 144 between the carbon nanotubes, forming the connected carbon nanotube structure. In addition to forming a density gradient along the substrate, a gradient of decreasing conductivity of the material is also formed away from the substrate, i.e., along the length of the carbon nanotubes. This can provide a 3D current collector structure for subsequent electroplating of electrode materials. For example, the conductivity gradient improves the conformality of lithium metal deposition on the 3D current collector and prevents dendrite formation on the 3D structure when using electroplating with a liquid electrolyte.

[0110] It will be understood that the illustrated exemplary 3D electrodes are not indented, as a limiting example. Other material layers or material combinations are also contemplated. The illustrated gradients may be formed by one or more variations in density, layer thickness, composition, or combinations thereof. The gradients may be step-wise, stepped, or a combination thereof. The layers may have gradients directed along and / or away from the substrate.

[0111] 11 schematically illustrates a 3D energy storage system 15 including a 3D electrode and additional layers of electrolyte and electrode materials. The exemplary embodiment 15 includes a 3D electrode including a layer of a first electrode material 152 deposited on a carbon nanotube structure, thereby partially impregnating the pores 154 between the carbon nanotubes 153. Further layers of a solid electrolyte material 155 and a second electrode material 156 are deposited on the 3D electrode. The remaining space between the covered carbon nanotube structures is filled with a polymer material 157. The exemplary energy storage system is covered with a conductive surface layer 158, i.e., a current collector.

[0112] 3D energy storage systems according to the present invention, for example 3D battery foils, can be stacked and electrically connected and / or packaged into battery cells to improve capacity and / or for environmental protection.

[0113] Optionally, a dual conductor can be deposited between the electrode layer and the counter electrode layer. For example, a layer of dual conductor material can be applied before applying the second electrode material. Dual conductors can be understood to be excellent ionic and electronic conductive materials. Therefore, the use of insulating electrode materials, such as sulfur or lithium peroxide, can improve the electronic and ionic conductivity of the dual conductor. Thus, in one embodiment, an energy storage structure is provided that includes a scaffold according to the present invention, in which a dual conductor is provided between the first and second electrode layers.

[0114] Optionally, or in addition, the second electrode material can be deposited as a mixture of the binder, electronic conductor, ionic conductor, and electrode material. The particle size of the active material can range from 10 nm to 5 microns, preferably from 100 nm to 500 nm.

[0115] In some embodiments, the second electrode material composite may optionally further comprise a gel or semi-solid electrolyte. The addition of a non-solid material to the second electrode may improve good ionic conductivity within the electrode.

[0116] In a preferred embodiment, the second electrode material composite may be partially porous, e.g., comprise a porous material. The material preferably has a porosity of at least 5%, preferably 10% or more, e.g., 15% to 30%, relative to the second electrode. Providing a partially porous electrode can accommodate volume expansion of the electrode material, e.g., during cycling, and thus may improve the stability and / or lifetime of the energy storage device.

[0117] Optionally or additionally, the porous material may comprise hollow beads, e.g., hollow latex beads, which may be compressed during use to accommodate the volumetric expansion of the electrodes. Reference is made to patent application EP18210849.8, which discloses a rechargeable battery cell comprising a compressible elastic composite material and is incorporated herein by reference.

[0118] It will be appreciated that the scaffolds of the present application are particularly suitable for use in 3D energy storage applications, such as batteries. In addition to improving energy density per unit area, as described above, the openings, grooves, and / or channels within and between the connected carbon nanotube structures provide space for accommodating not only electrode materials but also electrolyte and / or counterelectrode materials (i.e., a full stack of electrochemically active materials). By providing a full stack of electrochemically active materials in the openings, grooves, and channels defined by the scaffold, diffusion lengths can be shortened, resulting in energy storage applications with lower internal resistance and / or improved power density output. The scaffolds of the present invention are appropriately dimensioned to allow conformal deposition of one or more electrode and electrolyte materials. Furthermore, the connected carbon nanotube structures of the present invention can be appropriately dimensioned to tailor the dimensions of the openings, grooves, and / or channels by allowing controlled aggregation through wet processing steps. This results in a densification of the connected carbon nanotube structure with a controlled increase in volume, e.g., enlargement of the openings, grooves and / or channels of the scaffold, thus providing additional space for a layer of electrochemically active material.

[0119] As mentioned above, the scaffold structure according to the present invention can be obtained from a substrate containing an appropriately patterned layer of catalyst. It should be noted that in some preferred embodiments, a base buffer layer can be provided between the substrate and the catalyst. The buffer layer may improve the interfacial contact, stability, and cycle life of devices (e.g., 3D electrodes and / or energy storage systems containing scaffolds formed with the buffer layer). Suitable buffer layers include thin electrically insulating films such as aluminum oxide.

[0120] In a preferred embodiment, the carbon nanotube structure can be provided / coated (e.g., deposited, electroplated, impregnated) with a conductive material (e.g., metal) at its bottom (base), e.g., at the bottom 5 μm. Providing a conductive material at the bottom of the carbon nanotube structure can help bridge the base buffer layer, i.e., improve the electrical conductivity between the carbon nanotube structure and the underlying substrate. Reference is made to WO2016178571, which describes a device and method for fabricating high aspect ratio structures with a buffer layer and a conductive material grown from a substrate that helps bridge the conductive pillars to the conductive substrate. WO2016178571 is incorporated herein by reference.

[0121] In some embodiments, the aforementioned conductive materials provided at the base of a carbon nanotube structure to improve electrical conductivity between the structure and a substrate may result in a porosity gradient along or away from the carbon nanotubes of the structure. In other words, the conductive material may partially fill the (nano)space / nanoporosity between the carbon nanotubes, resulting in a vertical or lateral porosity gradient within the carbon nanotube structure. As previously mentioned, (nano)porosity in energy storage systems may advantageously improve lifetime by reducing expansion-induced damage, i.e., crack formation, of electrode materials.

[0122] FIG. 12 schematically illustrates a further embodiment of a connection structure of vertically aligned carbon nanotubes 84 in a structure of first cells nested in a structure of second cells. Here, the first cells include openings 81 that do not contain carbon nanotubes to provide access to the surface of the substrate, and the second cells are separated from each other by grooves. The openings in the first cells form channels 82 along a preferred direction, providing access to the grooves separating the second cells, thereby forming a perfusion network, with the openings in the first cells and channels oriented along the preferred direction. Note that FIG. 12 does not necessarily depict a complete unit cell. Orienting the channels and grooves 82 in the carbon nanotube structure on the substrate along the direction of substrate movement improves coating quality at the substrate level and along the walls defining the openings.

[0123] The presented sixth exemplary embodiment can be interpreted as a variation of the open honeycomb-shaped structure of the fourth embodiment. Instead of directly connecting each hole to a groove, the holes are connected to each other, forming multiple parallel channels in a preferred direction. Each channel is separated from adjacent channels by walls of connected carbon nanotubes. Each channel is connected to adjacent channels (83). For walls less than 5 μm thick, carbon nanotubes much longer than 100 μm in length grow straight, and no channel closures have been observed in structures with a maximum channel length of 500 μm and up to 10 interconnections between adjacent channels. Thus, the scaffold structure of FIG. 12 includes one or more connecting structures 84 of carbon nanotubes. The connecting structures 84 leave at least one region 81 free of carbon nanotubes to provide access to the surface of the substrate, and are separated from each other by grooves 82 to prevent the carbon nanotubes of the connecting structures from contacting each other.

[0124] In addition to its application in this embodiment, it will be understood that the concept of providing a network (a network that allows for lateral flow of gas and vapor species within a carbon nanotube structure) is not limited to the exemplary embodiment presented in this application, but can also be applied to other structures of carbon nanotubes, or structures that include holes or channels of different shapes, dimensions, or orientations.

[0125] It will be understood that the visualized 3D electrode and energy storage systems are not limited to the exemplary embodiments provided, nor to the materials and / or carbon nanotube structures shown. The present invention may be advantageously applied to carbon nanotube structures other than the exemplary structures presented herein, or to systems including other and / or additional materials. Material layers with gradients of one or more of thickness, density, composition, and combinations thereof are also contemplated.

[0126] (Addendum) (Appendix 1) A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; In a plane along the surface of the substrate, the carbon nanotubes are formed into first cells formed by one or more connecting structures of the carbon nanotubes, and the first cells are nested within second cell structures different from the first cells; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; the grooves provide access to the substrate between carbon nanotube connection structures; Scaffolding structure.

[0127] (Appendix 2) A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; In a plane along the surface of the substrate, the carbon nanotubes are formed with one or more connecting structures of the carbon nanotubes; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; the grooves provide access to the substrate between carbon nanotube connection structures; Scaffolding structure.

[0128] (Appendix 3) The nanotubes have a length of 20 to 500 micrometers. 3. The scaffold structure of claim 1 or 2.

[0129] (Appendix 4) the first gap formed by the groove separates nanotubes beyond the first gap by a distance between 500 nm and 20 micrometers; 2. The scaffold structure of claim 1.

[0130] (Appendix 5) the carbon nanotube interconnect structure has a minimum lateral dimension Dmin along the substrate, more specifically Dmin in the range of 1.6 micrometers to 85 micrometers; the minimum lateral dimension is in the range of 1.6 micrometers to 8.5 micrometers for a coverage in the range of 80% to 20% and for the connection structure to have a height in the range of 20 micrometers to 50 micrometers; the minimum lateral dimension is in the range of 4.0 micrometers to 17 micrometers for a coverage in the range of 80% to 20% and for the connection structure to have a height in the range of 50 micrometers to 100 micrometers; the minimum lateral dimension is in the range of 8.0 micrometers to 25.5 micrometers for a coverage in the range of 80% to 20% and the connection structure has a height in the range of 100 micrometers to 150 micrometers; the minimum lateral dimension is in the range of 12 micrometers to 85 micrometers for a coverage in the range of 80% to 20% and for the connection structure to have a height in the range of 150 micrometers to 500 micrometers; 5. A scaffold structure according to any one of appendices 1 to 4.

[0131] (Appendix 6) the carbon nanotube interconnect structure comprises a maximum dimension along the substrate of less than 500 micrometers; 6. A scaffold structure according to any one of appendices 1 to 5.

[0132] (Appendix 7) the one or more grooves separating the one or more connection structures are oriented along the direction of the single movement of the substrate during processing to take advantage of movement-induced drag flow; 7. A scaffold structure according to any one of appendices 1 to 6.

[0133] (Appendix 8) At least one of the openings may be defined by one or more of the following: 8. A scaffold structure according to any one of appendices 1 to 7. i) the inner surface of the connection structure ii) the outer surface of the connection structure iii) Openings defined by the exterior surfaces of adjacent structures

[0134] (Appendix 9) one or more of the openings have a preferential orientation in a direction along the substrate; 9. The scaffold structure according to any one of appendices 1 to 8.

[0135] (Appendix 10) The substrate may be a rigid or flexible substrate; 10. The scaffold structure according to any one of appendices 1 to 9.

[0136] (Appendix 11) a top layer covering the carbon nanotube connection structure to maintain a constant distance between the ends of the carbon nanotubes; 11. A scaffold structure according to any one of appendices 1 to 10.

[0137] (Appendix 12) 1. A method for producing a scaffold, preferably a scaffold according to any one of claims 1 to 11, comprising: providing a substrate; - patterning the substrate; growing substantially parallel carbon nanotubes from the patterned substrate in a direction away from the substrate; including the steps the pattern is arranged to define carbon nanotube growth in a plane along the surface of the substrate in a first cell of a carbon nanotube connection structure, the first cell being nested within a second cell structure formed from a second carbon nanotube connection structure, the second cell being different from the first cell; the carbon nanotube connection structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of one second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves, the grooves providing access to the substrate. method.

[0138] (Appendix 13) further comprising depositing at least a further material onto said scaffold structure using a fluid processing step; the fluid processing step includes one or more of sputtering, CVD, ALD, and wet deposition methods such as wet chemical vapor deposition; The wet chemical vapor deposition methods include methods such as hydrothermal growth, chemical bath, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD). 12. The method described in Appendix 12.

[0139] (Appendix 14) A scaffold structure according to any one of claims 1 to 11 and a layer of a further material deposited on and / or impregnated into said scaffold structure, preferably obtained by the method of claim 12 or 13, the additional material comprises an electrode; 3D electrode.

[0140] (Appendix 15) a top layer covering the connection structure of the connected carbon nanotube structures to allow access to a fluid, and an inlet structure formed by a channel provided in the top layer. 15. The 3D electrode of claim 14.

[0141] (Appendix 16) 12. A scaffold according to any one of claims 1 to 11, and at least a composite layer provided at least partially on a surface of the carbon nanotubes, the composite layer comprises a first electrode material; Energy storage structures.

[0142] (Appendix 17) the composite material further comprises an additional layer comprising an electrolyte material and a further additional layer comprising a second electrode material; the electrolyte material includes a solid electrolyte material, the first electrode layer and / or the second electrode layer contains lithium or sodium; 17. The energy storage structure of claim 16.

[0143] (Appendix 18) The composite layer is provided after controlled disintegration of the scaffold structure by wet deposition. 18. The energy storage structure of claim 16 or 17.

[0144] (Appendix 19) the composite layer has a gradient in a direction away from or along the substrate; 19. The energy storage structure according to any one of appendices 16 to 18.

Claims

1. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a connection structure in which a plurality of the carbon nanotubes are connected is formed on a plane along the surface of the substrate; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; the grooves provide access to the substrate between the connection structures; the distance between the nanotubes in the first gap separating them is between 500 nm and 20 micrometers; the smallest lateral dimension (Dmin) of the connection structure in a direction along the plane of the substrate is in the range of 1.6 micrometers to 85 micrometers; the largest dimension of the connection structure in a direction along the plane of the substrate is less than 500 micrometers; a coverage, defined as the percentage of the substrate covered by said connection structures, of between 50% and 80% for said 3D electrodes and between 20% and 70% for said 3D batteries; The minimum lateral dimension (Dmin) is the dimension of the smallest first bounding box (B1) of the connection structure; Scaffolding structure.

2. the nanotubes have a length of 20 to 500 micrometers; The scaffold structure of claim 1 .

3. the maximum distance from a position within the connection structure to a position on the wall surface of the structure is less than 15 micrometers; A scaffold structure according to claim 1 or 2.

4. the wall area of ​​the scaffold is at least 10 times the total area of ​​the substrate covered by the scaffold; A scaffold structure according to claim 1 or 2.

5. the minimum lateral dimension (Dmin) is in the range of 1.6 micrometers to 8.5 micrometers when the coverage is in the range of 80% to 20% and the connection structure has a height in the range of 20 micrometers to 50 micrometers; the coverage is in the range of 80% to 20% and the minimum lateral dimension is in the range of 4.0 micrometers to 17 micrometers when the connection structure has a height in the range of 50 micrometers to 100 micrometers; the coverage is in the range of 80% to 20%, and the minimum lateral dimension is in the range of 8.0 micrometers to 25.5 micrometers when the connection structure has a height in the range of 100 micrometers to 150 micrometers; the coverage is in the range of 80% to 20% and the minimum lateral dimension is in the range of 12 micrometers to 85 micrometers when the connection structure has a height in the range of 150 micrometers to 500 micrometers; A scaffold structure according to any one of claims 1 to 4.

6. the one or more grooves separating the one or more connection structures are preferentially oriented in a direction along the substrate, providing a perfusion network within the carbon nanotube structure having a preferential orientation along the substrate. A scaffold structure according to any one of claims 1 to 5.

7. The at least one region may be defined by one or more of the following: A scaffold structure according to any one of claims 1 to 6. i) the inner surface of the connection structure ii) the outer surface of the connection structure iii) an opening defined by the exterior surfaces of adjacent structures;

8. the at least one region having a preferential orientation in a direction along the substrate; A scaffold structure according to any one of claims 1 to 7.

9. The substrate may be a rigid or flexible substrate; A scaffold structure according to any one of claims 1 to 8.

10. a top layer covering the connection structure to maintain a constant distance between the ends of the carbon nanotubes; A scaffold structure according to any one of claims 1 to 9.

11. 1. A method for producing a scaffolding structure on a substrate for a 3D electrode or a 3D battery, comprising: providing the substrate; - patterning the substrate with a pattern; - growing substantially parallel carbon nanotubes from the patterned substrate in a direction away from the substrate; including the steps the pattern is arranged to define carbon nanotube growth in a plane along a surface of the substrate with a connection structure connecting a plurality of the carbon nanotubes; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; the grooves provide access to the substrate between the connection structures; the distance between the nanotubes in the first gap separating them is between 500 nm and 20 micrometers; the smallest lateral dimension (Dmin) of the connection structure in a direction along the plane of the substrate is in the range of 1.6 micrometers to 85 micrometers; the largest dimension of the connection structure in a direction along the plane of the substrate is less than 500 micrometers; a coverage, defined as the percentage of the substrate covered by said connection structures, of between 50% and 80% for said 3D electrodes and between 20% and 70% for said 3D batteries; The minimum lateral dimension (Dmin) is the dimension of the smallest first bounding box (B1) of the connection structure; method.

12. further comprising depositing at least a further material onto said scaffold structure using a fluid processing step; The fluid processing step includes one or more of sputtering, CVD, ALD, and wet deposition. The method of claim 11.

13. the wet deposition method is a wet chemical vapor deposition method selected from one or more of hydrothermal growth, chemical bath, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD); The method of claim 12.

14. A scaffold structure according to any one of claims 1 to 10, and a layer of a further material deposited on and / or impregnated into said scaffold structure. 3D electrode.

15. a top layer covering the connection structure of the connected carbon nanotube structures to allow access to a fluid, and an inlet structure formed by a channel provided in the top layer. 3D electrode according to claim 14.

16. A scaffolding according to any one of claims 1 to 10; at least a composite layer provided at least partially on a surface of the carbon nanotubes, the composite layer comprising a first electrode material; Including, Energy storage structures.

17. the composite layer further comprises an additional layer comprising an electrolyte material and a further additional layer comprising a second electrode material; the electrolyte material includes a solid electrolyte material, the first electrode material and / or the second electrode material comprises lithium or sodium; 17. The energy storage structure of claim 16.

18. the composite layer has a gradient in a direction away from or along the substrate; 18. An energy storage structure according to claim 16 or 17.

19. A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a first cell is formed by a connection structure in which a plurality of the carbon nanotubes are connected in a plane along the surface of the substrate, and the first cell is nested in a second cell structure different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; a scaffolding structure, the groove providing access to the substrate between the connection structures; a layer of a further material deposited on and / or impregnated into said scaffold structure; Including, 3D electrode.

20. A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a first cell is formed by a connection structure in which a plurality of the carbon nanotubes are connected in a plane along the surface of the substrate, and the first cell is nested in a second cell structure different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; a scaffolding structure, the groove providing access to the substrate between the connection structures; at least a composite layer provided at least partially on a surface of the carbon nanotubes, the composite layer comprising a first electrode material; Including, Energy storage structures.

21. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a first cell is formed by a connection structure in which a plurality of the carbon nanotubes are connected in a plane along the surface of the substrate, and the first cell is nested in a second cell structure different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; the grooves provide access to the substrate between the connection structures; the one or more grooves separating the one or more connection structures are preferentially oriented in a direction along the substrate, providing a perfusion network within the carbon nanotube structure having a preferential orientation along the substrate. Scaffolding structure.

22. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a first cell is formed by a connection structure in which a plurality of the carbon nanotubes are connected in a plane along the surface of the substrate, and the first cell is nested in a second cell structure different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; the grooves provide access to the substrate between the connection structures; a top layer covering the connection structure to maintain a constant distance between the ends of the carbon nanotubes; Scaffolding structure.

23. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a first cell is formed by a connection structure in which a plurality of the carbon nanotubes are connected in a plane along the surface of the substrate, and the first cell is nested in a second cell structure different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of a second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves; 1. A method of manufacturing a scaffolding structure, wherein the grooves provide access to the substrate between the connection structures, the method comprising: providing the substrate; - patterning the substrate with a pattern; - growing substantially parallel carbon nanotubes from the patterned substrate in a direction away from the substrate; including the steps the pattern is arranged to define carbon nanotube growth in a plane along the surface of the substrate in a first cell of the connection structure, the first cell being nested within a second cell structure formed from a second carbon nanotube connection structure, the second cell being different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of one second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves, the grooves providing access to the substrate; further comprising depositing at least a further material onto said scaffold structure using a fluid processing step; the fluid processing step includes one or more of sputtering, CVD, ALD, and wet deposition; the wet deposition method is a wet chemical vapor deposition method selected from one or more of hydrothermal growth, chemical bath, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD); method.

24. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a connection structure in which a plurality of the carbon nanotubes are connected is formed on a plane along the surface of the substrate; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; the grooves provide access to the substrate between the connection structures; the one or more grooves separating the one or more connection structures are preferentially oriented in a direction along the substrate, providing a perfusion network within the carbon nanotube structure having a preferential orientation along the substrate. Scaffolding structure.

25. A scaffold structure on a substrate for a 3D electrode or a 3D battery, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a connection structure in which a plurality of the carbon nanotubes are connected is formed on a plane along the surface of the substrate; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; 1. A method of manufacturing a scaffolding structure, wherein the grooves provide access to the substrate between the connection structures, the method comprising: providing the substrate; - patterning the substrate with a pattern; - growing substantially parallel carbon nanotubes from the patterned substrate in a direction away from the substrate; including the steps the pattern is arranged to define growth of carbon nanotubes in a plane along the surface of the substrate in a first cell of the connection structure, the first cell being nested within a second cell structure formed from the second connection structure and different from the first cell; the connecting structure includes at least one opening that does not contain carbon nanotubes to provide access to the surface of the substrate; the second cells are separated from one another by grooves to prevent carbon nanotubes of one second cell from contacting carbon nanotubes of another second cell across a first gap formed by the grooves, the grooves providing access to the substrate; further comprising depositing at least a further material onto said scaffold structure using a fluid processing step; the fluid processing step includes one or more of sputtering, CVD, ALD, and wet deposition; the wet deposition method is a wet chemical vapor deposition method selected from one or more of hydrothermal growth, chemical bath, sol-gel, chemical solution deposition, combustion synthesis, electrodeposition, and liquid source mist chemical vapor deposition (LSMCD); method.

26. A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a connection structure in which a plurality of the carbon nanotubes are connected is formed on a plane along the surface of the substrate; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; a scaffolding structure, the groove providing access to the substrate between the connection structures; a layer of a further material deposited on and / or impregnated into said scaffold structure; a top layer covering the connection structure of the connected carbon nanotube structures to allow access to a fluid, and an inlet structure formed by a channel provided in the top layer. 3D electrode.

27. A scaffold structure on a substrate, comprising: the scaffold comprises carbon nanotubes; the nanotubes are oriented substantially parallel in a direction away from the substrate; a connection structure in which a plurality of the carbon nanotubes are connected is formed on a plane along the surface of the substrate; the connecting structure leaving at least one area free of carbon nanotubes to provide access to the surface of the substrate; the connection structures are separated from one another by one or more grooves to prevent the carbon nanotubes of a second connection structure from contacting the carbon nanotubes of a first connection structure across a first gap formed by the grooves; a scaffolding structure, the groove providing access to the substrate between the connection structures; and at least a composite layer provided at least partially on a surface of the carbon nanotubes, the composite layer comprising a first electrode material; the composite layer further comprises an additional layer comprising an electrolyte material and a further additional layer comprising a second electrode material; the electrolyte material includes a solid electrolyte material, the first electrode material and / or the second electrode material comprises lithium or sodium; Energy storage structures.

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