High-rate-capability cement carbon supercapacitor, and method for synthesizing high-rate-capability cement carbon supercapacitor

Abstract

A structural supercapacitor made of a conductive composite material and a method for manufacturing the same are described herein. Embodiments of the composite material have controllable transport porosity, enabling the transport of charges to a conductive network distributed within the composite material through an electrolyte solution. The distributed conductive network has controllable storage porosity that enables the storage of charges. The conductive composite material can be used in a variety of different fields of use, for example, as a structural supercapacitor as an energy solution for autonomous homes and other buildings, a heating cement for de-icing pavements or basement insulation of homes against capillary rise, protection of concrete against freeze-thaw (FT) or alkali-silica reaction (ASR) or other crystallization degradation processes, and in conductive cables, wires, or concrete traces, etc.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Application No. 63 / 370,618, filed on August 5, 2022. The entire disclosure of the above - mentioned application is incorporated herein by reference.

Background Art

[0002] There is currently no material that can replace cement in the short term to meet society's needs for housing, shelters, and infrastructure. Nevertheless, cement faces an uncertain future due to its non - negligible ecological footprint, which accounts for 5 - 10% of the world's CO2 production. However, thanks to the leaps and bounds in science and engineering, there are new possibilities for cement to contribute to sustainable development, including economic growth and social progress while minimizing its ecological footprint. The potential for cement to contribute to sustainable development lies in its ability to serve both as a building material and an energy storage device.

Summary of the Invention

[0003] In particular, if cement (or equivalent) composite materials can also function as capacitors, they can fulfill their traditional role as building materials while also being able to store and distribute energy. There is a need for high - rate - capable cement - carbon composite materials that can store a sufficient amount of electrical energy and discharge the stored energy at a significant rate. Such composite materials would, in effect, provide a scalable materials solution for storing energy within supercapacitors constructed from locally available and easily accessible material precursors, namely cement, water, and carbon black.

[0004] Embodiments of the present invention include a method for synthesizing a high-rate-capability cement-carbon supercapacitor made possible by synergistically leveraging the dual-porosity characteristics in a fabricated cement-carbon composite electrode (also referred to herein as a cementitious material). The dual-porosity system consists of the following: (1) the porosity of the cement that functions as a reservoir / transport pathway for the electrolyte (referred to herein as "transport porosity"), and (2) the porosity of the carbon that functions as active porosity for energy storage either within or in the vicinity of the porosity due to the electronic conductivity property of the carbon (referred to herein as "storage porosity"). The transport porosity optimizes the diffusion of the electrolyte into the storage porosity and can be finely tuned by designing the hydration process of the cementitious material. Further, the storage porosity is preferably finely tuned by the selection of a carbon material having a high specific surface area and the distribution of the carbon material in the composite material. The synergistic effect of these two elements is the core of the method disclosed herein for synthesizing a high-rate-capability cement-carbon composite material supercapacitor with a controllable capacitance and charge / discharge rate.

[0005] Embodiments of the present invention are structural supercapacitors comprising a composite material consisting of i) an electrically conductive percolation network that accepts porosity for charge storage and ii) a non-electrically conductive structural matrix, wherein the non-electrically conductive structural matrix may comprise a composite material having a controlled transport porosity configured to accept an electrolyte solution.

[0006] In some embodiments, the composite material is the product of a chemical reaction of a chemically reactive mixture, and the controlled transport porosity is a function of the amount of fluid in the chemically reactive mixture. The fluid may be an aqueous solution. Further, in the fluid, the chemically reactive mixture may exceed the level of fluid required for the formation of the non-electrically conductive structural matrix.

[0007] The composite material may further contain an electrolyte solution at a saturation level within a controlled transport porosity. The composite material may be an electrically conductive cement composite material. In some embodiments, the structural supercapacitor further includes at least one of sand, gravel, stone, or other conductive or non-conductive aggregates mixed with the composite material. The structural supercapacitor may be fabricated by additive manufacturing.

[0008] The electrically conductive percolation network that accepts porosity may include porous electrically conductive particles. In such embodiments, the porous electrically conductive particles can be selected from the group having an accessible specific surface, including carbon black nanoparticles, activated carbon, carbon nanotubes, mXene, metal organic frameworks, or a mixture of electrically conductive particles.

[0009] The structural supercapacitor may also include a non-conductive separator that separates the first electrode structure and the second electrode structure, where the first and second electrode structures are defined by the composite material, and the first and second electrode structures are configured to enable energy storage and recovery with the structural supercapacitor. In such embodiments, the first and second electrode structures may be oriented in an arrangement configured to charge / discharge energy with structural and / or non-structural elements in buildings, roads and transportation infrastructure, foundations, and other subterranean structures.

[0010] Embodiments of the present invention may include a method of manufacturing a structural supercapacitor. An example of the method includes creating a chemically reactive mixture including a non-conductive binder, porous electrically conductive particles, and a fluid, and creating a composite material including an electrically conductive percolation network that accepts porosity for charge storage and a non-electrically conductive structural matrix having a controlled transport porosity configured to accept an electrolyte solution by a chemical reaction of the chemically reactive mixture.

[0011] Fabricating the composite material may include controlling the amount of fluid applied to the chemically reactive mixture to create a controlled transport porosity. In such embodiments, controlling the amount of fluid in the chemically reactive mixture may include adding an amount that exceeds the level required for the formation of the non-electrically conductive structural matrix. Alternatively, in such embodiments, the charge / discharge rate of the composite material may depend on the controlled transport porosity.

[0012] In some embodiments of the method, the method may further include saturating the controlled transport porosity with an electrolyte solution to create a saturated electrolyte transport porosity. In such embodiments, the saturated electrolyte solution can be in contact with the electrically conductive percolation network.

[0013] The fluid may be an aqueous solution. The non-conductive binder can be a hydraulic cement. The non-conductive binder can also be selected from the group consisting of fly ash, silica fume, slag, and other soluble siliceous, aluminosiliceous, or calcium aluminosiliceous powders used as partial replacements for clinker in cement or as partial replacements for Portland cement in concrete mixtures, and a superplasticizer. The porous electrically conductive particles may be selected from the group having an available specific surface area, namely, carbon black nanoparticles, activated carbon, carbon nanotubes, mXene, metal organic frameworks, or a mixture of electrically conductive particles.

[0014] In some embodiments of the method, the porous electrically conductive particles are selected from the group having an available specific surface area, namely, carbon black nanoparticles, activated carbon, carbon nanotubes, mXene, metal organic frameworks, or a mixture of electrically conductive particles. Further, the non-electrically conductive structural matrix can be configured to support a mechanical load.

[0015] The method may further include forming a supercapacitor having a first electrode structure and a second electrode structure, the first and second electrode structures including a composite material, separated by a non-conductive separator, and the supercapacitor may be configured to provide means for storing and recovering energy via the first and second electrode structures.

[0016] Embodiments of the present invention also include a chemically reactive mixture. The mixture includes a non-conductive binder and porous electrically conductive particles and is configured to produce a composite material including an electrically conductive percolation network that accepts porosity for charge storage and a non-electrically conductive structural matrix via a chemical reaction induced by the addition of a fluid, the non-electrically conductive structural matrix having a controlled transport porosity configured to accept an electrolyte solution.

[0017] Embodiments of the present invention further include a method of storing charge using a structural supercapacitor. The method includes receiving charge from an external source outside the composite material by an electrolyte solution, the electrolyte solution being received within the controlled transport porosity of the non-electrically conductive structural matrix of the composite material. The method continues by transferring the received charge from the electrolyte solution to an electrically conductive percolation network that accepts porosity for charge storage within the composite material and storing the charge within the porosity for charge storage.

[0018] Embodiments of the present invention further include a method of discharging charge using a structural supercapacitor. The method includes transferring charge stored within or in the vicinity of a porosity for charge storage accepted by an electrically conductive percolation network within the composite material. The method continues by receiving the transferred charge by an electrolyte solution received within the controlled transport porosity of the non-electrically conductive structural matrix of the composite material and discharging the charge from the electrolyte solution to a receiving portion outside the composite material.

[0019] The patent or application documents include at least one drawing made in color. Copies of this patent or patent application publication that include color drawings are provided by the Patent Office upon request and payment of the required fee.

[0020] The foregoing will be apparent from the following more detailed description of exemplary embodiments shown in the accompanying drawings. In the accompanying drawings, the same reference numerals indicate the same parts in all the drawings. The drawings are not necessarily to scale; rather, emphasis is placed on showing embodiments.

Brief Description of the Drawings

[0021]

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Best Mode for Carrying Out the Invention

[0022] The following shows an exemplary embodiment.

[0023] Embodiments of the present invention include a method for manufacturing a cement composite material (“composite material”), a structural building material (e.g., hydraulic cement), and a composite material capable of performing both functions of a conductive material capable of storing and distributing energy. This composite material can provide an alternative energy storage solution to prior art battery technologies using inexpensive and readily available material precursors that can be procured on a global scale. This composite material can form a high-rate-capacity supercapacitor used to store and distribute energy, in contrast to the chemical energy conversion used for energy storage by batteries.

[0024] A high-rate-capacity supercapacitor depends on three elements. (i) An electronic conductive network for charging the electrodes, (ii) a storage porosity of high specific surface area to which oppositely charged surface layers adsorb, (iii) a reservoir porosity for charge transport by ion diffusion towards or away from the surface layer through a saturated electrolyte.

[0025] This composite material results from a chemically reactive mixture that produces a non-electrically conductive porous material that functions as a structural support matrix and an insulator that includes an electrically conductive network within its pores, thereby providing in element (iii) a reservoir porosity for charge transport by ion diffusion to and from the surface layer through a saturated electrolyte, necessary for fabricating a supercapacitor. The porosity of the non-electrically conductive porous material is defined as the "transport porosity" of the composite material. The electrically conductive network is distributed throughout the non-electrically conductive porous material and includes particles having porosity that enables charge storage. The porosity of the electrically conductive network is defined as the "storage porosity" of the composite material. Thereby, in element (ii), a high specific surface area storage porosity is provided to which oppositely charged surface layers necessary for fabricating a supercapacitor adsorb. Finally, the non-electrically conductive porous material also accepts an electrolyte solution within its pores and connects to the electrically conductive network to enable charge deposition and / or extraction. Thereby, in element (i), an electronically conductive network for charging the electrodes, necessary for fabricating a supercapacitor, is provided.

[0026] As used herein and in the appended claims, "electrically conductive percolation network" means a network formed by a continuous connection of conductive particles that penetrate the capillary pore network of a composite material to an extent sufficient to render the composite material electrically conductive. In the claims, "the electrically conductive percolation network of conductive particles can substantially or completely fill the porosity of the capillary pore network of the composite material, but this is not essential. The capillary pore network within a composite material (e.g., a cement composite material) can include pores sized, for example, from about 5 nanometers to about 1 micron.

[0027] As used in this specification and the appended claims, "non-electrically conductive structural matrix" means a solid formed by a chemical reaction, such as a solid formed by the hydration reaction of hydraulic cement and water, that functions as a non-conductive insulator and can support structural loads. Further, the non-electrically conductive structural matrix can have porosity (transport porosity) that includes an electrically conductive percolation network and an electrolyte solution.

[0028] Embodiments of the present invention include superconductors and electrical conductors that include at least one electrode formed of the disclosed composite material in various devices. Additionally, this composite material can be used in a variety of different fields of use, such as structural supercapacitors as energy solutions for autonomous homes and other buildings, heating cement for basement insulation of homes for de-icing of pavements or capillary rise, protection of concrete against freeze-thaw (FT) or alkali-silica reaction (ASR) or other crystallization degradation processes, and in conductive cables, wires, or concrete traces, etc.

[0029] The transport porosity of the composite material may be large enough to allow for sufficient distribution of the electrically conductive network and connection of that network to the stored electrolyte solution, providing both sufficient means for storing charge and sufficient means for accessing the stored charge. However, the transport porosity cannot be increased so much that the non-electrically conductive porous material loses strength and cannot hold any load as a safe structural and non-structural material. The resulting transport porosity of the composite material is controllable based on the ratio of the components of the chemically reactive mixture from which the composite material is made. Thus, embodiments of the present invention can ensure that the composite material has the properties necessary to form a supercapacitor and is a functional building material.

[0030] Embodiments of the present invention are based on the discovery that a supercapacitor can be constructed from a conductive carbon cement composite material formed by the hydration process of a mixture containing a mineral precursor (e.g., hydraulic cement) that can react with water to form a cement hydrate (an insulator as a solid) and carbon particles that form a network capable of storing and releasing electrical energy within the insulator. The network is formed by a continuous connection of carbon particles that penetrate throughout the capillary pore network of the hydrated cement or other porous insulator to an extent sufficient to make the composite material electrically conductive. The network of carbon particles can substantially or completely fill the porosity of the capillary pore network of the cement, but this is not essential. The capillary pore network of the cement composite material can include pores sized, for example, from about 5 nanometers to about 1 micron. Embodiments presented herein disclose the use of a cement mineral precursor, but as will be apparent to those skilled in the art, other mineral precursors that undergo a hydration process and thereby leave a substantial amount of porosity and function as a non-conductive binder (e.g., in swelling clay) can be used in alternative embodiments of the present invention, provided that an electronic conductive network of conductive particles can be established through the insulating hydrated phase.

[0031] Similarly, embodiments presented herein disclose the use of water or an aqueous solution as the hydration fluid, but as will be apparent to those skilled in the art, other fluids can also be utilized.

[0032] In some non-limiting embodiments, the resulting carbon cement composite material can contain from about 2 wt% to about 15 wt% carbon particles relative to the hydraulic cement in the total initial mixture containing the hydraulic cement, water, and carbon particles. The composite material can utilize a water-cement ratio of from about 0.5 to about 1.4. The carbon particles are sp 2A carbon material can be used that includes a dominant population of carbon atoms involved in hybridization (triple hybridization). The carbon particles may be nanoparticles and can define a pore size of less than about 10 nanometers. In other embodiments, the carbon particles may be nanoparticles and can define a pore size of less than about 1 nanometer. The carbon particles may include at least one of vulcan carbon black, ketjen carbon black, PBX carbon black, and activated porous carbon, such as AX-21 or sucrose coke, and can define a pore size of less than about 1 nanometer. The PBX carbon black can be, for example, PBX® 55 carbon black (sold by Cabot Corporation of Boston, Massachusetts, U.S.A.).

[0033] As used herein, "hydraulic cement" is a cement that solidifies in the presence of water to form a water-resistant product. Examples include Portland cement, Portland cement blends, and calcium sulfoaluminate cement. However, the resulting insulator cement has transport porosity that allows fluid transport through the solid insulator. In other words, the cement hydrates formed have voids that allow for the movement or storage of fluids.

[0034] As used herein, "Portland cement" is defined according to ASTM standard C150. The entire teachings of this document are incorporated herein by reference. More specifically, "Portland cement," as used herein, refers to a hydraulic cement (i.e., a cement that not only hardens by reaction with water but also forms a water-resistant product). This is typically made by grinding a "clinker" that consists essentially of hydraulic calcium silicate containing one or more forms of calcium sulfate.

[0035] The mineral precursors utilized by embodiments of the present invention may be hydraulic cements, can include Portland cement, and the resulting composite material can include, with respect to the total initial mixture including hydraulic cement, optional dispersant, water, and carbon particles, from about 50 wt% to about 70 wt% Portland cement (e.g., about 60 wt% Portland cement). The network of carbon particles can substantially fill the capillary pore network of the cement composite material. The capillary pore network can include pores sized from about 5 nanometers to about 1 micron. The electrically conductive cement composite material can include a greater than 90% connected percolation pore network that accepts carbon particles that form a continuous percolation network of carbon particles capable of storing, receiving, and discharging charge. The carbon particles can have a specific surface area of less than about 3000 m 2 / g, and in some embodiments, the specific surface area can be less than about 300 m 2 / g.

[0036] Furthermore, an electrically conductive mortar can be made that includes fine aggregate and any of the electrically conductive cement composite materials taught or contemplated herein. An electrically conductive concrete can also be made that includes sand, gravel aggregate, or other conductive or non-conductive aggregate and any of the electrically conductive composite materials taught or contemplated herein. When adding aggregate, it can be of any shape or size. Also, in other embodiments, it may include adding supplementary cementitious materials (SCMs), such as fly ash, silica fume, slag, agents that control the setting of cement (e.g., superplasticizers) to the mineral precursor, and other soluble silicate, aluminosilicate, or calcium aluminosilicate powders that are used as partial replacements for clinker in cement or as partial replacements for Portland cement in a concrete mixture, and adding superplasticizers.

[0037] According to some embodiments of the present invention, a high-rate-capability cement-carbon supercapacitor has, as a target transport porosity, (1) a size large enough to accommodate an electrolyte solution, and (2) a target transport porosity that is fully connected such that the electrolyte can reach carbon particles distributed in the material and form an electron conductive network (often referred to as a “volume line” or “electrically conductive network”).

[0038] In a normal Portland cement material (i.e., one without carbon particles), the porosity is created, for example, by adjusting the hydration process by means of the water-cement mass ratio. More specifically, a specific amount of water is required for complete hydration of the cement clinker, which is a so-called stoichiometric limit defined by the stoichiometry (mass balance) of the chemical reactants (clinker and water) and the chemical products (hydration products). In the case of normal Portland cement-based materials, this stoichiometric limit corresponds to a water-cement mass ratio (“W / C”) = 0.42. Thus, a cement-based material prepared with a W / C ratio greater than 0.42 is accompanied by a residual moisture content at the end of the hydration process, i.e., the moisture that was not consumed during the hydration process. In embodiments of the present invention, this stoichiometric limit is similarly applicable to the carbon-cement composite material. The residual cement porosity created by water in excess of the stoichiometric limit serves as the transport porosity in the electrodes of the supercapacitor. This transport porosity is further connected by the so-called gel porosity of the hydration products. The gel porosity is much smaller in size compared to the micrometer-sized porosity that dominates the transport porosity and is typically in the tens of nanometers.

[0039] In exemplary embodiments of the present invention, water-cement (mass) ratios “W / C” of 0.42, 0.6, and 0.8 are utilized. According to classical means in cement science, these W / C ratios correspond to residual porosities of approximately 0%, 19%, and 34 vol% of the cement hydration products determined from the Powers-Brownyard hydration model. The capacitances for the three exemplary W / C ratios will be compared later in this disclosure.

[0040] Electrical energy (transported through the electrolyte) is stored on the large surface area of carbon particles that form an electrically conductive network. In particular, it is most likely to be stored in the double layer at the interface between the surface of the conductive carbon particles and the electrolyte that saturates the transport porosity. Therefore, the energy storage capacity depends on the surface area of the carbon particles. This is well known, for example, in typical carbon-based (only) supercapacitors having a hierarchical porous structure. In embodiments of the present invention, however, this principle is utilized in a novel way for the fabricated carbon cement composite material, where the porosity of the cement functions as transport porosity, while the combination of the porosity of the carbon and its surface functions as storage porosity. In other words, in embodiments of the present invention, a combination of the storage porosity of the particles constituting the electrically conductive network and the designed controllable transport porosity of the non-electrically conductive porous material (e.g., cement hydration matrix) is used to provide a means for generating a supercapacitor for high-rate capacity structures.

[0041] In exemplary embodiments of the present invention, three types of carbon black particles with different surface areas are utilized, namely, PBX, Vulcan, and Ketjen black. These exhibit three different surface areas, namely, 50 m 2 / g, 240 m 2 / g, and 1,300 m 2 / g (determined from Brunauer-Emmett-Teller, BET measurements). The specific surface area (determining the specific surface area using the BET or non-local density functional theory (NLDFT) method) mainly shows the pore size, volume, and surface measurements of the three different carbon black particles in Table 1 below. The results were obtained based on argon adsorption at 87 K (for BET) and argon adsorption at 87 K and CO2 adsorption at 273 K using the dual fit method.

[0042]

Table 1

[0043] To convert the specific surface area of the carbon black powder to the actual specific surface area available for energy storage in the cement-carbon composite material, the theoretical specific surface area was determined by multiplying the BET specific surface area by the actual weight of the carbon black in the sample. In this calculation, it is assumed that the entire surface of the carbon available in the composite material is available for energy storage. This assumed available surface area is hereinafter referred to as the theoretical carbon surface area (m 2 represented by).

[0044] To store charge within a sample of the composite material, a voltage source is applied to the outer surface of the sample. Due to the voltage difference between the voltage source and the electrically conductive network, charge flows from the voltage source to the electrically conductive network. The electrolyte solution enables the charge to be transported from the voltage source, through the non-electrically conductive porous material, to the electrically conductive network distributed therein. The electrically conductive network can store the transported charge using the surface porosity. Similarly, by connecting a negative voltage source to the composite material, charge is released from the sample, and due to the voltage difference, the charge stored within the electrically conductive network flows through the non-electrically conductive porous material via the electrolyte solution to the negative voltage source. As is well known to those skilled in the art, various methods, means, and systems can be used to control the charging, storage, and discharging of charge on a capacitor. Embodiments of the present invention can utilize any existing technology for the charging, storage, and / or discharging of charge in a conductive material. In some embodiments, a processor, or other computing device, can be utilized to control the connection of the voltage source (positive and negative) to the composite material and the resulting charging, storage, and / or discharging of charge. Additionally, any type of conductive material can be utilized to connect the voltage source to the sample composite material and improve / control the flow of charge therebetween.

[0045] A supercapacitor can be constructed from a sample including an electrically conductive composite material separated by a dielectric porous medium permeable to electrolyte species. The constructed supercapacitor can serve both as a medium for charge storage and distribution and as a structural or non-structural (e.g., mortar layer) element in a building or other structure. The dielectric porous medium may include a separator membrane having at least one of paper and Portland cement. Each of the conductive samples may include a sheet having an electrically conductive composite material, and the sheet has a thickness of less than about 100 cm, for example, less than about 10 cm. The structural supercapacitor may be electrically connected to an energy source (e.g., at least one of a solar energy source, a wind power source, a biofuel energy source, a biomass energy source, a geothermal power source, a hydroelectric power source, a tidal power source, and a wave power source). The structural supercapacitor may be electrically connected to a battery.

[0046] [Sample Preparation Example] In an exemplary embodiment of a method for fabricating a structural supercapacitor, a method for fabricating an electronically conductive cement carbon is used. This method is described in detail in U.S. Application No. 16 / 245,752 (currently U.S. Patent No. 10,875,809). The entire teaching of this document is incorporated herein by reference. However, in some embodiments, it is not necessary to add a dispersant to the chemical reactive mixture. There are two reasons for not using a dispersant. (i) To provide a baseline of the reference electron conductivity achieved by different nanocarbon black materials, and (ii) this reference enables a direct comparison of different formulation designs by excluding the plus or minus effects of the dispersant in the material. Alternatively, in other embodiments of the present invention, a dispersant is included, and the present invention functions regardless of the presence or absence of the dispersant. In such embodiments, the "dispersant" is an agent that disperses a carbon phase containing carbon particles in water. In non-limiting examples, carboxymethyl cellulose or a cellulose-based polymer can be used.

[0047] In one non-limiting example, first, cement powder and carbon powder are mixed using an overhead stirrer to produce a dry mix. Then, water is added while continuously stirring to obtain the target W / C ratio and produce a cement / carbon paste. Alternatively, cement, carbon powder, water, and any other desired additives or aggregates may be added simultaneously. Next, the cement / carbon paste is cast into a 2.2 cm diameter polycarbonate mold. This defines the geometric area (3.8 cm 2 ) of the electrode made of the composite material produced by the chemical reaction (e.g., hydration) of the produced cement / carbon paste. According to an alternative embodiment of the present invention, electrodes of any desired shape or size can be produced. The samples are sealed at both ends with parafilm and immersed in a lime / water solution during the hydration process. During the hydration process, a non-electrically conductive structural matrix (hardened cement) is formed by a chemical reaction. The non-electrically conductive structural matrix includes an electrically conductive network capable of storing charges and carbon particles distributed throughout the structural matrix. Further, due to the porous nature of the non-electrically conductive structural matrix, transport porosity is created that connects to and provides access to the distributed electrically conductive network.

[0048] The hardened samples are removed from the mold after at least 28 days in accordance with the conventions of concrete engineering. Thereafter, the electrodes are cut to a specific thickness from the hardened samples using a low-speed rotary saw, and the surfaces of the electrodes are polished using a series of SiC papers with low abrasiveness. Thereafter, the electrodes are placed in an electrolyte solution that saturates the transport porosity of the non-electrically conductive structural matrix. In this particular non-limiting example of an embodiment, the electrolyte solution is a 1 molar solution of potassium chloride solution (KCl 1M). By saturating the transport porosity with the electrolyte solution, it enables connection to the electrically conductive percolation network and the flow of charge between the electrically conductive percolation network. As used herein, "saturate" means filling most of the transport porosity, but it is not necessary to fill all of the transport porosity. Thereafter, a measuring device can be used to record the charge storage capacity and the dispersion rate of the energy stored in the electrodes.

[0049] Other manufacturing methods can be utilized to fabricate the conductive composite material, the electrodes, and the supercapacitor composed of them. In some embodiments, these methods may be, but are not limited to, additive manufacturing, for example, 3D printing.

[0050] [Electrode Arrangement and Capacitance Measurement] The capacitance of an exemplary supercapacitor device composed of a cement composite material is examined by applying galvanostatic charge-discharge (GCD) cycles based on conventional electrochemical cyclic voltammetry (CV). The maximum storage capacity can be experimentally evaluated by combining the CV test results with the GDC test results.

[0051] Figure 1A shows a sample 100 in which two electrodes 101a and 101b made of a cement composite material produced according to an embodiment of the present invention are symmetrically arranged. Figure 1A shows only one possible geometric arrangement of electrodes 101a and 101b, but alternative embodiments of the present invention may arrange the electrodes in any desired numerical, geometric, and distributive arrangement (in non-limiting examples, in series or in parallel) that enables charging, storing, and discharging of electric charges. The measurement of the sample was performed using two symmetric porous electrodes 101a and 101b (collectively 101) with a thickness d formed of a hardened carbon cement composite material. These electrodes are separated by a glass fiber separator 102 and arranged to form an electric double layer capacitor (EDLC) system. The separator 102 was also immersed in the same electrolyte solution (1M KCl) as the electrodes 101. The electrodes 101 were covered with conductive graphite papers 103a and 103b (collectively 103) that functioned as current collectors. The sample 100 was sealed using an O-ring 105 in a closed cell 107 as shown in Figure 1B to avoid loss of the electrolyte solution due to evaporation during actual measurement. Figure 1B is a photograph of the sample 100 in which two electrodes enclosed by the O-ring 105 are symmetrically arranged.

[0052] Figure 1C is a photograph of a device 106 configured to apply pressure to a sample 100 in which two electrodes symmetrically arranged are enclosed in a closed cell 107 by an O-ring 105. A spring 106 and its support were used to pre-apply pressure to the entire sample 100 in the closed cell 105 with a force of 1,200 N to ensure good contact between different elements, thereby minimizing the generation of system resistance. With the experimental setup shown in Figure 1C, the pressure on the sample 100 can be controlled and used for electrochemical measurements. Since the resistance is limited, the charge can freely flow within the electrodes 101 between the electrolyte solution in the transport porosity and the electrical conductivity network within the electrodes 101.

[0053] Figure 2A is a set of graphs 201, 203 of cyclic voltammetry (CV) curves 202a - 202e and 204a - 204e recorded at different predetermined scan rates for sample 100 with two electrodes 101 symmetrically arranged. Graph 201 is for a sample made of a composite material with a water - cement ratio of 0.8 according to an embodiment of the present invention, showing CV curves 202a - 202e for a sample using PBX 22.4 carbon black particles and electrodes 101 with a thickness of 0.18 cm. Graph 203 is for a sample made of a composite material with a water - cement ratio of 1.4 according to an embodiment of the present invention, showing CV curves 204a - e for a sample using Ketjen black 12.8 carbon black particles and electrodes 101 with a thickness of 0.60 cm. The electrode 101 is connected to an external potential difference, and while charging one electrode with a positive charge and the other electrode with a negative charge, the current I is measured. While a force is applied, the electrode 101 is charged and discharged at a constant scan rate (u = U0 / t0) that varies from 20 mV / s to 500 mV / s on a voltage window of 0 to a maximum voltage (U0) of 1 V. Thus, the corresponding charge - discharge time ranges from 50 s to 2 s. Capacitance is the ratio of the change in charge of the system to the corresponding change in its potential. When testing the prepared sample, the capacitance is measured from the discharge curve in the cyclic voltammetry (CV) curve divided by the scan rate and a sweep potential window of 1 V, considering the symmetric arrangement of the electrodes 101 in sample 100.

[0054] Figure 2B is graph 205 of the determination of the areal capacitance as a function of the discharge rate for the cyclic voltammetry (CV) curves 202a - 202e of the sample shown in Figure 2A for a sample made of a composite material with a water - cement ratio of 0.8 according to an embodiment of the present invention. Graph 205 shows the measured capacitance results in the form of a plot of areal capacitance versus scan rate. Areal capacitance is equal to the capacitance divided by the area of the geometric electrode 101 of the test sample 100.

[0055] Figure 2C shows the results of a galvanostatic charge-discharge (GCD) test on a sample in which two electrodes are symmetrically arranged and made of a cement composite material with a water-cement ratio of 0.8 produced according to an embodiment of the present invention. As disclosed below, a second determination of capacitance becomes possible by the discharge current over the discharge time Δt on the sweep potential window (Roldan, S., Barreda, D., Granda, M., Menendez, R., Santamaria, R., & Blanco, C. (2015), An approach to classification and capacitance expressions in electrochemical capacitors technology. Physical Chemistry Chemical Physics, 17(2), 1084-1092). This second determination of capacitance is used to verify the capacitance determination from the cyclic voltammetry (CV) curves 201a - 201e shown in graph 202 of Figure 2B. More specifically, in the GCD test, a current I0 is applied and kept constant until the target voltage U(t = t0) = 1V is reached, and in that state, the current is reversed until the potential difference becomes zero, i.e., U(t = t0 + t d ) = 0. Graph 206 shows the resulting curve 207 with respect to the applied current I0 / A per unit area of electrode 101, where 0.5 - 50 are identified by the colors in legend 208. Graph 209 is a graph of the values 211 of the fractional exponent α for each value of I0 / A shown in legend 208 used in the GCD test. Error bars 210a, 210b indicate one standard deviation for 500 cycles.

[0056] Finally, cycle GCD measurements were performed. Here, the supercapacitor of sample 100 was charged and discharged for N cycles, and the capacitance was measured after each cycle. FIG. 2D is a graph 204 of the capacitance retention rate 206 and the Coulomb efficiency 205 during the charge and discharge cycles of sample 100 in which two electrodes are symmetrically arranged and which is made of a cement composite material with a water-cement ratio of 0.8 according to an embodiment of the present invention. From the results shown in the graph 204 of the cycle GCD measurement, the capacitance retention rate can be determined, and it is shown that there is almost no loss of capacitance over 100,000 cycles during the periodic loading of electrode 101 of sample 100, and thus almost no loss of energy storage capacity.

[0057] At the same time, FIGS. 2A-2D show that the electrically conductive sample 100 shown in FIG. 1A and fabricated using embodiments of the present invention has the properties necessary to perform both the functions of a structural support material and an energy storage and distribution system.

[0058] Furthermore, as will be described in more detail below, using the measurements taken in the CV and GCD tests, the capacitance as a material property of the cement composite material that makes up the measured sample can be extracted. Detailed calculations are required to correct for both the rate effect in the CV test or the effect of the magnitude of the current in the GCD test. Both of these phenomena result from diffusion control of the change storage in the double-layer capacitor configuration shown in FIG. 1A and the ionic conductivity at the electrode scale and its effect on the scales of ion diffusion, dissociation, solvation, and charge storage. To address this, an approach is taken based on the consideration that if capacitance exists as an independent electrical property that characterizes an EDLC, this capacitance should not depend on the experimental conditions for obtaining it. When capacitance measurements that do not depend on such tests become available, it becomes possible to scale the rate capability of the electrodes composed of the cement composite material fabricated according to embodiments of the present invention.

[0059] With this in mind, a resistor R representing all the resistances present within system 100 shown in FIG. 1A can be considered to be in series with a capacitor C in an equivalent R-C circuit. This problem is formulated in the context of Boltzmann's integrodifferential equation. Following this approach, the current I can be related to the potential difference by the following convolution integral.

Number

[0060] Here, the kernel R(t - t') is a time-dependent resistance function and can be used in the GCD test performed at a constant current I(t) = I0. Using the generality of this linear input-output response theory, the steady-state solutions of the repeated tests can be derived for both the CV curve and the integral representation region of the CV hysteresis loop.

Number

Number

[0061] Here,

Number

Number

[0062] The same calculation can be applied to the results of the GCD test shown in graph 207 of FIG. 2C to extract the capacitance from the recorded voltage history. However, there is one subtle difference. Instead of the integer rate equation, fractional differentiation is employed to capture the visible effect of high applied current on the model response. That is, instead of Equation 1, the following fractional integration is applied.

Number

[0063] Here, Γ x = Γ(x) is the complete gamma function. Here, U + represents the voltage after instantaneous charge and discharge, and the second term represents the non-instantaneous part of the potential difference stored in the tested electrode defined by the fractional exponent α ∈ [0, 1]. For a constant applied current I(t) = I0, integrating the fractional differentiation gives the following.

Number

[0064] U + = U(t = 0 + ) = RI0 is for charging (λ = +1), and

Number

Number

Number

Number

[0065] FIG. 2E is a set of graphs 215a, 215b showing the results of capacitance per mass of carbon black particles for two sets of electrodes made of a cement composite material produced according to an embodiment of the present invention. Graph 215a shows the results of a sample with a water-cement ratio of 0.8, using PBX22.4 carbon black particles and an electrode 101 with a thickness of 0.18 cm, and the respective CV test results are shown in graph 201 of FIG. 2A. Graph 215b shows the CV curves 204a - 204e for a sample made of a composite material with a water-cement ratio of 1.4 produced according to an embodiment of the present invention, using Ketjen black 12.8 carbon black particles and an electrode 101 with a thickness of 0.60 cm, and the respective CV test results are shown in graph 203 of FIG. 2A. The results shown in FIG. 2E show that the model-based approach disclosed herein can convert the measured CV curves of the samples into capacitance values specified by lines 216a and 216b. Similarly, lines 217a and 217b show the capacitance values obtained from the GCD tests of the respective samples. The capacitance measurement ranges per mass of each sample are represented at different values specified by lines 218a and 218b. This difference is a characteristic of the versatility of the cement composite material produced according to an embodiment of the present invention.

[0066] Thus, two series of capacitance measurement values (one from CV measurements 216a and 216b and the other from GCD measurements 217a and 217b) converge to a single value C0 at low scan rates (u → 0) in the CV test and low current values (I0 → 0) in the GCD test, respectively. This is important because the total power of the supercapacitor P = IU and the estimated energy

Equation

Equation

[0067] That is, the capacitance C0 is a rate-independent electrode property that does not depend on test conditions, ionic conductivity, and other factors. This scaling of the capacitance C0 with respect to the maximum energy storage amount enables the evaluation of the high-rate capability of the cement composite material fabricated according to the embodiments of the present invention for high-speed energy storage. Specifically, an electrode made of a composite material with a high water-cement (W / C) ratio showing large hydration porosity approaches a rate-independent capacitance even at a high scan rate and realizes a value close to the maximum energy storage amount in the shortest time. In contrast, as the thickness of the electrode increases, the rate capability decreases, and a longer exchange time is required to realize the maximum energy storage capacity of the electrode and its constituent cement composite material.

[0068] Furthermore, the normalized capacitance C(u) / C0 can be used to identify the possibility of forming a structural electrode of the fabricated cement composite material. Specifically, it is for applications that emphasize the dual functions of high-rate capacity energy storage when a power source is applied and strength capacity to safely withstand mechanical loads. The high-rate capacity is achieved by electrodes with a high W / C ratio, resulting in a decrease in the cohesive force of the material determined by hardness measurement. However, using the flexibility of the process disclosed herein for fabricating cement composite materials, a structural electrode having a desired trade-off between capacitance, rate capacity, and structural strength can be fabricated. In the present invention, by enabling the use of different types and amounts of carbon black particles and water-cement ratios, a plurality of levers are obtained for controlling both the electrical and structural properties of the resulting material.

[0069] FIG. 2F is a graph 220 showing the relationship between hardness and capacitance for an electrode made of a cement composite material fabricated according to an embodiment of the present invention. Graph 220 shows samples made of composite materials in the range of water-cement ratios 222a to 222c and their normalized capacitance for scan rates in the range 221a to 221e. Graph 220 shows the trade-off between high-rate capacity and material strength.

[0070] [Influence of Transport Porosity during Cement Hydration Process] One important element of the present invention is that the capacitance of the fabricated composite material can be controlled based on the composition of the reactive mixture that produces it. More specifically, by varying the water-cement (or other non-conductive binder) ratio in the mixture, the transport porosity (and thus the capacitance) of the resulting composite material can be adjusted. To demonstrate the concept that capacitance can be adjusted by cement hydration porosity, the CV curves of three samples prepared at different W / C ratios of 0.42, 0.6, and 0.8 (corresponding to approximately 0%, 19%, and 34 vol% of three different estimated values of the transport porosity of the cement hydration product) were compared.

[0071] Figure 3A is a graph 301a of cyclic voltammetry (CV) curves 302a, 303a, and 303a at a scan rate of 20 mV / s for three cement composite materials with water-cement ratios of 0.42, 0.6, and 0.8, fabricated according to an embodiment of the present invention. Figure 3B is a graph 301b of cyclic voltammetry (CV) curves 302b, 303b, and 303b at a scan rate of 500 mV / s for three composite materials with water-cement ratios of 0.42, 0.6, and 0.8, fabricated according to an embodiment of the present invention. The area enclosed by the cyclic voltammetry (CV) curve increases as the water-cement ratio (and thus the resulting transport porosity) increases.

[0072] Figure 3C is a graph 305a of capacitance values 306a, 307a, and 308a derived as a function of scan rate for three composite materials with water-cement ratios of 0.42, 0.6, and 0.8, fabricated according to an embodiment of the present invention. The capacitance values 306a, 307a, and 308a were divided by the geometric area 3.8 cm 2 of the sample to obtain the surface capacitance of the composite material.

[0073] Figure 3D is a graph 305b of carbon weight specific capacitance 306b, 307b, and 308c as a function of scan rate for three composite materials with water-cement ratios of 0.42, 0.6, and 0.8, fabricated according to an embodiment of the present invention. The carbon weight specific capacitance 306b, 307b represents the carbon mass specific capacitance (capacitance divided by the mass of activated carbon in the composite material). The carbon mass specific capacitance can indicate the level of efficiency of the activated carbon in the composite electrode, and the influence due to the difference in the carbon-cement mass ratio in the sample is corrected. The proportion of the total mass of the composite material consisting of conductive carbon particles varies from 10.1 mass% for the material with W / C = 0.42, to 16.8 mass% for the material with W / C = 0.6, and to 22.4 mass% for the material with W / C = 0.8. Alternative embodiments can have different mass percentages of carbon depending on the water-cement ratio used.

[0074] The results shown in FIGS. 3C and 3D provide clear evidence that means can be obtained to increase the capacitance of the cement-carbon composite material regardless of the scan rate by finely adjusting the transport porosity using means of cement engineering (i.e., mix design with a selected water-cement ratio). This confirms that the residual porosity remaining due to the hydration of the mineral precursor (cement) ("cement porosity" or "transport porosity") provides the necessary path for transporting the electrolyte to the active porosity of the carbon material ("storage porosity") in a more efficient way, and thus provides means to optimize the rate capability of the cement / carbon supercapacitor.

[0075] [Effect of Carbon Black Storage Porosity] The second embodiment of the present invention used to control the properties of the composite material produced is the specific surface area of carbon black, along which charge is stored at the interface between the electrolyte and the carbon surface. This surface can be increased by the porosity of the carbon particles used ("storage porosity"). To show the effect, the capacitances of three samples are compared. The samples are prepared with different types of carbon black, PBX55, Vulcan, and Ketjenblack. Their properties are listed in Table 1 above. However, embodiments of the present invention can utilize any type of carbon or other conductive particles that can form an electrically conductive network and store charge.

[0076] Figure 4 is a graph 401 of capacitance as a function of the carbon surface area of three sample cement composites made according to embodiments of the present invention using different carbon particles. The capacitance measurement values were obtained from the CV curve at a scan rate of 20 mV / s. The first sample 402a was made using PBX55 as the carbon particles. The second sample 402b was made using Vulcan 55 as the carbon particles. The third sample 402c was made using Ketjenblack as the carbon particles. The first and second samples 402a, 402b utilized a water-cement ratio of 0.8. The third sample utilized a water-cement ratio of 1.4. The carbon surface area in this specification was determined from the BET specific surface area (listed in Table 1) multiplied by the mass of carbon black in the sample electrode. Since there is a positive correlation indicated by the trend line 403 between the two quantities, the active porosity (storage porosity) within the carbon phase in the carbon-cement composite not only increases the capacitance with an increase in the specific surface, but this active porosity also serves as strong evidence that it is fully available to the electrolyte saturating the porosity (transport porosity) of the cement.

[0077] Detailed experimental analysis and quantification of the porosity and spatial correlation of samples prepared using embodiments of the present invention using Raman spectroscopy data are described in the following reference. N. Chanut, D. Stefaniuk, J.C. Weaver, Y. Zhu, Y. Shao-Horn, A. Masic, and F.-J. Ulm, “Carbon-cement supercapacitors as a scalable bulk energy storage solution”, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, Vol. 120, No. 32, August 8, 2023. This reference is hereby incorporated by reference in its entirety into this specification.

[0078] [Scaling of Energy Storage Capacity] Using embodiments of the present invention, large-scale energy storage in a structural carbon cement supercapacitor system may be fabricated and / or manufactured. To scale up such large-scale systems, scalability of the electrode system made of the fabricated cement composite material is required. Such scaling is possible when (1) the capacitance independent of speed can be reduced to a teaching amount independent of the size of the system, and at the same time (2) a measure for high-rate capability can be provided as a function of electrode dimensions and component characteristics. The first problem is addressed by Equation 6, which provides a means of dimensional analysis of the asymptotic state of maximum energy storage. In this asymptotic state, the surface of the carbon black particles can be considered to be completely surrounded by an oppositely charged surface layer of ions. From dimensional analysis, capacitance values independent of speed are obtained for eight samples made of the cement composite material fabricated using embodiments of the present invention.

[0079] FIG. 5 is a graph 500 of the capacitance independent of speed of eight different electrodes made of a cement material fabricated using embodiments of the present invention, showing the concentrated nature of the energy storage capacity of the fabricated electrode system. The legend 501 identifies the characteristics of the cement material and includes, in order, the type of carbon black particles, the water-cement ratio, and the thickness of the electrode. The x-axis of graph 500 shows the specific surface area S BET of the carbon black particles, which ranged from 52,241 to 1307 m 2 / g. The materials were also prepared using different carbon concentrations φ 3 ranging from 0.71 to 0.179 g / cm cρc . As shown by the trend line 502, these characteristics can be reduced to a linear scaling of the specific capacitance independent of speed.

Equation

[0080] ε nCB = 1.68×10 -2 F / m 2(Including the 95% confidence interval) is the fitted air capacitance of the carbon black. This scaling supports the intensive nature of the energy storage capacity of the electrode system made of the cement material fabricated using the embodiments of the present invention.

[0081] Similar calculations can be performed for the rate capability considering the scaling of the scan rate u = ξu0, and a single dimensionless relationship C(u) / C0 = F(ξ) can be obtained. From the asymptotic solution shown in Equation 7, it is maintained that the energy storage capacity is the process of absorbing charged ions, and ξ can be adopted for the classical dimensionless diffusion variable ξ = d 2 / (Dt0). For the diffusion rate D, using texture analysis, it is recognized that the tortuosity of the ion diffusion path through the hydrated porosity is mediated by the chord length ratio of the texture

Number

Number

[0082] Figure 6 is a graph 600 of the velocity-dependent capacitance of eight different electrodes made of the cement material fabricated using the embodiments of the present invention, scaled along the horizontal axis by the classical dimensionless diffusion variable. The characteristics of the materials used to fabricate the electrodes are described in the legend 601. As shown by Equation 8, all the electrodes gather around a single curve 602. The curve is approximated by the complementary error function of the form C(u) / C0 = a + (1 - a)erfc(ξ). γD0 = 6.654×10 -4 m 2 / s (including the 95% confidence interval) is the fitted diffusion coefficient, and a = 0.234 is the asymptotic value for ξ ≫ 1. The self-similarity of the scaling relationship is very interesting in evaluating the high-rate capability of carbon cement electrodes. For example, when ξ < 0.1, the electrode shows a high-rate capacitance C(u) / C0 > 0.91 ± 0.05, while when ξ > 1, the capacitance drops to C(u) / C0 < 0.35 ± 0.05. Therefore, the scaling relationships shown in Eqs. 7 and 8 and Figs. 5 and 6 provide a means to finely tune the material design of carbon cement composites for specific applications.

[0083] The material design of the fabricated porous carbon cement composite provides a scalable material solution for energy storage to assist the transition from fossil fuels to renewable energy. The key to scalability is the intensive nature of the volumetric capacitance arising from the unique texture of the space-filling carbon network. This intensive nature enables mass scaling of the

Number

[0084] Embodiments of the disclosed invention synthesize high-rate-capable supercapacitors using the properties of composite materials of cement-carbon materials. This is made possible by the combination of (1) the porosity of the cement (transport porosity) as a result of the hydration process of the mineral precursor and (2) the high specific surface area of the carbon phase that forms an electronically conductive network. As a proof of concept, a method is disclosed for synergistically synthesizing high-rate-capable supercapacitors by utilizing the water-cement mass ratio in combination with a high specific surface area carbon black phase. Further, a method is disclosed for controlling the capacitance and charge / discharge rate of the supercapacitors synthesized during the fabrication of the composite material by controlling its transport porosity by varying the water-cement ratio and its storage porosity by varying the carbon surface area. In alternative embodiments, other means for generating such porosity in cementitious materials can be used (e.g., the use of air-entraining agents).

[0085] The teachings of all patents, published applications, and references cited herein are incorporated by reference in their entirety.

[0086] Although the exemplary embodiments have been particularly shown and described, various modifications in form and detail may be made without departing from the scope of the embodiments encompassed by the appended claims, as will be apparent to those skilled in the art.

Claims

1. A structural supercapacitor comprising: i) an electrically conductive percolation network that accepts porosity for charge storage; and ii) a non-electrically conductive structural matrix, wherein the non-electrically conductive structural matrix comprises a composite material having a controlled transport porosity configured to accept an electrolyte solution.

2. The structural supercapacitor according to claim 1, wherein the composite material is a product of a chemical reaction of a reactive mixture, and the controlled transport porosity is a function of the amount of fluid in the reactive mixture.

3. The structural supercapacitor according to claim 2, wherein the fluid is an aqueous solution.

4. The structural supercapacitor according to claim 2, wherein the amount of fluid in the reactive mixture exceeds the level of fluid required for the formation of the non-electrically conductive structural matrix.

5. The structural supercapacitor according to claim 1, wherein the composite material further contains an electrolyte solution at a saturation level within the controlled transport porosity.

6. The structural supercapacitor according to claim 1, wherein the composite material is an electrically conductive cement composite material.

7. The structural supercapacitor according to claim 1, further comprising at least one of sand, gravel, stone, or other conductive or non-conductive aggregates mixed with the composite material.

8. The structural supercapacitor according to claim 1, fabricated by additive manufacturing.

9. The structural supercapacitor according to claim 1, wherein the electrically conductive percolation network that accepts porosity comprises porous electrically conductive particles.

10. The structural supercapacitor according to claim 9, wherein the porous electrically conductive particles are selected from the group having a usable specific surface area, including carbon black nanoparticles, activated carbon, carbon nanotubes, mXene, metal organic frameworks, or a mixture of electrically conductive particles.

11. The structural supercapacitor according to claim 1, further comprising a non-conductive separator separating a first electrode structure and a second electrode structure, wherein the first and second electrode structures are defined by the composite material and enable energy storage and recovery with the structural supercapacitor.

12. The first and second electrode structures of claim 11 are oriented in an arrangement configured to be used to charge / discharge energy between structural and / or non-structural elements in buildings, roads and transport infrastructure, foundations and other underground structures.

13. A method of manufacturing a structural supercapacitor, comprising: creating a chemically reactive mixture comprising a non-conductive binder, porous electrically conductive particles, and a fluid; creating a composite material by a chemical reaction of the chemically reactive mixture, the composite material comprising an electrically conductive percolation network that accepts porosity for charge storage and a non-electrically conductive structural matrix having a controlled transport porosity configured to accept an electrolyte solution. Method.

14. The method of claim 13, wherein creating the composite material comprises controlling the amount of fluid applied to the chemically reactive mixture to create the controlled transport porosity.

15. The method of claim 14, wherein controlling the amount of fluid in the chemically reactive mixture comprises adding an amount in excess of the level required for formation of the non-electrically conductive structural matrix.

16. The method of claim 14, wherein the charge / discharge rate of the composite material depends on the controlled transport porosity.

17. The method of claim 13, further comprising saturating the controlled transport porosity with the electrolyte solution to create a saturated electrolyte solution.

18. The method of claim 17, wherein the saturated electrolyte solution is in contact with the electrically conductive percolation network.

19. The method of claim 13, wherein the fluid is an aqueous solution.

20. The method of claim 13, wherein the non-conductive binder is a hydraulic cement.

21. The method of claim 13, wherein the non-conductive binder comprises an auxiliary cementitious material (SCM) selected from the group consisting of fly ash, silica fume, slag, and other soluble siliceous, aluminosiliceous, or calcium aluminosiliceous powders used as a partial replacement for clinker in cement or as a partial replacement for Portland cement in a concrete mixture, and a superplasticizer.

22. The method according to claim 13, wherein the porous electrically conductive particles are selected from the group having an available specific surface area, namely, carbon black nanoparticles, activated carbon, carbon nanotubes, mXene, metal organic frameworks, or a mixture of electrically conductive particles.

23. The method according to claim 13, further comprising forming a dry mix of the non-conductive binder and the conductive particles and mixing the dry mix with an amount of fluid that controls the transport porosity.

24. The method according to claim 13, wherein the non-electrically conductive structural matrix is configured to support a mechanical load.

25. The method according to claim 13, further comprising forming a supercapacitor having a first electrode structure and a second electrode structure, wherein the first and second electrode structures include the composite material, are separated by a non-conductive separator, and the supercapacitor is configured to provide means for storing and recovering energy via the first and second electrode structures.

26. Comprising a non-conductive binder and porous electrically conductive particles, A chemically reactive mixture configured to produce a composite material including an electrically conductive percolation network that accepts porosity for charge storage and a non-electrically conductive structural matrix by a chemical reaction induced by the addition of a fluid, The non-electrically conductive structural matrix has a controlled transport porosity configured to accept an electrolyte solution, the chemically reactive mixture.

27. A method of storing charge using a structural supercapacitor, the method comprising: Receiving charge from an external source of the composite material by an electrolyte solution received within the controlled transport porosity of the non-electrically conductive structural matrix of the composite material; Transferring the received charge from the electrolyte solution to an electrically conductive percolation network that accepts porosity for charge storage within the composite material; Storing the charge within the porosity for charge storage; Method.

28. A method of discharging charge using a structural supercapacitor, the method comprising: Transferring the charge stored within the porosity for charge storage received by the electrically conductive percolation network within the composite material; receiving the transferred charge by an electrolyte solution that is received within a controlled transport porosity of a non-electrically conductive structural matrix of a composite material; discharging the charge from the electrolyte solution to a receiving portion external to the composite material; A method comprising the above.

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