Nano-modified multifunctional composite material with lattice sandwich structure as well as preparation method and application of nano-modified multifunctional composite material

Abstract

The invention provides a nano-modified multifunctional lattice sandwich structure battery composite material as well as a preparation method and application thereof, and belongs to the technical field of composite materials and energy storage. The composite material with the nano-modified multifunctional dot matrix sandwich structure comprises an upper skin layer, a lower skin layer, a dot matrix core layer arranged between the upper skin layer and the lower skin layer, and an electrochemical energy storage layer integrated in the dot matrix core layer. Through material innovation, structure optimization and multifunctional integration, the comprehensive performance of the lattice sandwich structure energy storage composite material is remarkably improved, the core advantage is that integration of structure bearing and electric energy storage is achieved, multiple functions of sensing, heat insulation, electromagnetic shielding and the like are integrated at the same time, breakthrough is made in the aspects of light weight, high efficiency and intellectualization, and the application prospect is wide. The method is especially suitable for the high-end fields of new energy automobiles, unmanned aerial vehicles, aerospace, intelligent wearing, robots and the like.

Description

Technical Field

[0001] This invention relates to the field of composite materials and energy storage technology, and in particular to a composite material with a nano-modified multifunctional lattice sandwich structure, its preparation method, and its application. Background Technology

[0002] With the increasing demand for lightweight and efficient energy utilization in industries such as new energy vehicles, drones, and aerospace, structural energy storage composite materials that combine structural materials with energy storage devices have become a research hotspot. These materials can simultaneously bear mechanical stress and store electrical energy, achieving weight reduction and efficiency improvement at the system level. For example, carbon fiber reinforced polymer composites are often used as the matrix for structural supercapacitors, where carbon fibers act as both mechanical reinforcement and electrodes and current collectors. The polymer electrolyte acts as a binder matrix, transferring loads and providing ion conduction between the carbon fibers. However, existing structural energy storage materials still have many shortcomings. First, structural electrode materials such as carbon fibers have a low specific surface area, limiting their energy storage capacity, necessitating surface treatment to increase energy density. Existing research shows that physical / chemical activation treatment of carbon fibers can increase their specific surface area by tens of times without significantly reducing mechanical properties, but the improvement is limited when combined with a structural electrolyte. Therefore, subsequent methods have developed to coat the surface of carbon fibers with nano-active materials (such as carbon nanotubes, carbon aerogels, graphene nanosheets, etc.) to increase the electrode surface area and improve energy storage performance.

[0003] Secondly, most current structural energy storage composite materials integrate only a single type of energy storage device (such as pure supercapacitors or pure batteries), making it difficult to simultaneously meet high power and high energy demands. However, scenarios such as electric vehicle startup and drone acceleration require both high power density and high energy density energy storage support. Thirdly, traditional structural energy storage composite materials often use simple honeycomb or foamed core materials, making it difficult to achieve an optimal balance between mechanical properties and energy storage unit arrangement, and the potential for topology optimization has not been fully realized. Furthermore, these materials often only possess dual functions of energy storage and load-bearing, with insufficient consideration given to the multi-functional coupling requirements of thermal insulation, electromagnetic interference resistance, and structural health monitoring.

[0004] Chinese invention patent application CN120382690A discloses a lattice sandwich composite material integrating electrical energy storage and mechanical support. By embedding a lightweight, high-strength lattice core layer within an electrochemical energy storage layer, it achieves a combination of structural support and energy storage functions. This technology uses materials such as carbon fiber or aramid fiber to form the upper and lower skin layers and the lattice core layer. The positive electrode, electrolyte, and negative electrode materials of lithium-ion or zinc-ion batteries are sequentially filled into the lattice voids and finally bonded together. This design demonstrates the feasibility of the structural battery / capacitor, but there is still room for improvement in terms of materials and structure: for example, the active materials used are mainly traditional LiFePO4 and MnO2, the conductive network relies on the carbon fiber itself, and the interface bonding and conductivity need to be strengthened; the lattice structure is limited to conventional topologies such as X-type, Kagome-type, and pyramid-type, and has not yet explored novel structures such as dual-mode, adaptive deformation, or reconfigurable structures to further optimize performance; functionally, it does not integrate other uses besides energy storage and support.

[0005] Therefore, it is very important to provide a structural energy storage composite material that has made breakthroughs in material combination, structural design, process preparation and functional integration to meet the needs of next-generation lightweight multifunctional devices. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a composite material with a nano-modified multifunctional lattice sandwich structure, its preparation method, and its application.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a composite material with a nano-modified multifunctional lattice sandwich structure, the composite material comprising an upper skin layer, a lower skin layer, a lattice core layer disposed between the upper skin layer and the lower skin layer, and an electrochemical energy storage layer integrated in the lattice core layer; The lattice core layer is a dual-modal lattice structure, a topology-optimized lattice structure, an adaptive deformation lattice structure, or a reconfigurable geometric lattice structure, used to provide support perpendicular to the upper skin layer, and the lattice core layer is a dual-phase composite structure with different moduli or different materials. The electrochemical energy storage layer comprises a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked sequentially, and includes at least two different types of energy storage units, including at least two of supercapacitor units, lithium-ion battery units, and sodium-ion battery units. The positive electrode layer and the negative electrode layer are independently composite materials modified with nanomaterials; The nanomaterials include one or more of MXene, graphene, carbon nanotubes, doped metal oxides, and conductive polymers. A conductive polymer adhesive layer or coupling agent coating is provided between the lattice core layer and the electrochemical energy storage layer.

[0008] Furthermore, the nanomaterials are bonded to the electrode substrate through grafting, covalent bonding, or surface coating; The doped metal oxide includes one or more of NiCo2O4, MnO2 and Fe2O3; the conductive polymer is PEDOT:PSS and / or polypyrrole.

[0009] Furthermore, the upper and lower skin layers are independently made of fiber-reinforced composite materials or metal plates; The fiber-reinforced composite material includes carbon fiber reinforced epoxy resin laminate, aramid fiber reinforced epoxy resin laminate, or elastic fabric layer; The metal plate includes an aluminum-lithium alloy plate and / or an aluminum alloy plate.

[0010] Furthermore, the material of the lattice core layer is a high-strength fiber-reinforced composite material, which includes one or more of carbon fiber composite materials, glass fiber, aramid fiber, basalt fiber, polylactic acid biodegradable material, bio-based nylon, and acrylonitrile-butadiene-styrene copolymer. The size of the dot matrix cells in the dot matrix core layer is 1~20mm, and the diameter of the rods is 0.1~2.0mm.

[0011] Furthermore, the inner sides of the upper and lower skin layers are provided with functional layers, which include sensor components, heat insulation layers, or electromagnetic shielding layers.

[0012] Furthermore, the conductive polymer adhesive layer is a PEDOT:PSS and / or a polypyrrole coating.

[0013] Furthermore, the positive electrode layer includes NiCo2O4 / graphene composite material, LiFePO4 / graphene composite material, and Na... x MnO2 / NiCo2O4 composite material or conductive fabric electrode; The negative electrode layer includes activated carbon / carbon nanotube composite material, graphite / graphene composite material, hard carbon / activated carbon composite material, or conductive fabric electrode. The electrolyte layer includes PVA-KOH gel, PEO-based solid electrolyte, PAN-based gel, or PVA-H3PO4 gel.

[0014] This invention provides a method for preparing the composite material with the aforementioned nano-modified multifunctional lattice sandwich structure, comprising the following steps: 1) A lattice core layer with a predetermined topology is obtained by 3D printing or modular assembly of high-strength fiber-reinforced composite materials; 2) Fix one side surface of the dot matrix core layer to the upper skin layer; 3) Nanomaterials are grown in situ on the surface of the lattice core layer using solution impregnation, electrochemical deposition or tape casting process. Then, the positive electrode layer, electrolyte layer and negative electrode layer are sequentially laid on the upper skin layer through the lattice core layer. Each layer is cured or dried after being laid. 4) After bonding the unconnected sides of the lower skin layer and the lattice core layer together, apply pressure and cure to solidify the layers into a whole, thus obtaining the composite material.

[0015] Furthermore, in step 3), the solution immersion temperature is 60~80℃, the solution immersion time is 4~6h, the electrochemical deposition temperature is 80~100℃, and the electrochemical deposition time is 2~8h. After the nanomaterial is grown in situ, a layer of PEDOT:PSS or polypyrrole conductive polymer with a thickness of 1~5μm is coated on its surface to construct a continuous conductive network.

[0016] The present invention also provides an application of the composite material of the nano-modified multifunctional lattice sandwich structure in new energy vehicle structural components, drone fuselages, aerospace vehicle cabins, smart wearable devices, or robot joints.

[0017] The beneficial effects of this invention are: 1) This invention significantly improves the performance of lattice sandwich structure energy storage composite materials by leveraging material innovation, structural optimization and multifunctional integration. By utilizing materials such as MXene and graphene to improve electrode conductivity and introducing pseudocapacitance / battery reaction, the specific capacitance and specific capacity of the electrochemical energy storage layer are increased, thereby achieving higher energy density and power density. 2) This invention uses nanomaterial surface modification and conductive polymer coating to enhance the bonding strength and load transfer efficiency of the electrode / structure interface, improve the overall mechanical properties of the composite material, and increase the bending strength and stiffness by more than 10% compared with the unmodified material. 3) The novel lattice structure design of this invention ensures the supporting strength while reducing the occupation of ineffective materials and improving the filling rate of energy storage materials, so that more energy can be stored per unit structural weight. 4) By combining multiple energy storage units, this invention enables the material to both release power quickly and store energy for a long time, thus extending the device's battery life and adapting to varying load requirements. 5) By integrating sensing and shielding functions, this invention improves the intelligence and environmental adaptability of the structure, can monitor the health status in real time, and protect the energy storage unit from external interference. In fields such as new energy vehicles and spacecraft, where there are extremely high requirements for lightweighting, the composite material provided by this invention is expected to reduce the total weight of the system by 15-30%, while providing additional electrical energy reserves while meeting structural strength requirements, and realizing the multi-functional application of the material. Detailed Implementation

[0018] This invention provides a composite material with a nano-modified multifunctional lattice sandwich structure, the composite material comprising an upper skin layer, a lower skin layer, a lattice core layer disposed between the upper skin layer and the lower skin layer, and an electrochemical energy storage layer integrated in the lattice core layer; The lattice core layer is a dual-modal lattice structure, a topology-optimized lattice structure, an adaptive deformation lattice structure, or a reconfigurable geometric lattice structure, used to provide support perpendicular to the upper skin layer, and the lattice core layer is a dual-phase composite structure with different moduli or different materials. The electrochemical energy storage layer comprises a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked sequentially, and includes at least two different types of energy storage units, including at least two of supercapacitor units, lithium-ion battery units, and sodium-ion battery units. The positive electrode layer and the negative electrode layer are independently composite materials modified with nanomaterials; The nanomaterials include one or more of MXene, graphene, carbon nanotubes, doped metal oxides, and conductive polymers. A conductive polymer adhesive layer or coupling agent coating is provided between the lattice core layer and the electrochemical energy storage layer.

[0019] In this invention, the nanomaterial is bonded to the electrode substrate by grafting, covalent bonding, or surface coating. The doped metal oxide includes one or more of NiCo2O4, MnO2 and Fe2O3; the conductive polymer is PEDOT:PSS and / or polypyrrole.

[0020] In this invention, the upper skin layer and the lower skin layer are made of fiber-reinforced composite materials or metal plates independently; The fiber-reinforced composite material includes carbon fiber reinforced epoxy resin laminate, aramid fiber reinforced epoxy resin laminate, or elastic fabric layer; The metal plate includes an aluminum-lithium alloy plate and / or an aluminum alloy plate.

[0021] In this invention, the material of the lattice core layer is a high-strength fiber-reinforced composite material, which includes one or more of carbon fiber composite materials, glass fiber, aramid fiber, basalt fiber, polylactic acid biodegradable material, bio-based nylon, and acrylonitrile-butadiene-styrene copolymer. The size of the dot matrix cells in the dot matrix core layer is 1~20mm, and the diameter of the rods is 0.1~2.0mm.

[0022] In this invention, the dual-modal lattice structure is composed of two sub-units with different equivalent stiffnesses. The first sub-unit bears the static load, and the second sub-unit participates in the force when the load exceeds the threshold. The adaptive deformation lattice structure contains shape memory polymers or shape memory alloys, and its geometric parameters can be reversibly changed under conditions of 60~120℃.

[0023] In this invention, the material of the lattice core layer contains carbon fiber or glass fiber as a reinforcing component to improve the rigidity and conductivity of the printed structure.

[0024] In this invention, the lattice core layer is used to improve the energy density and structural stiffness of the composite material.

[0025] In this invention, a functional layer is further provided on the inner side of the upper skin layer and the lower skin layer, and the functional layer includes a sensor, a heat insulation layer or an electromagnetic shielding layer.

[0026] In this invention, the purpose of the sensor, heat insulation layer, or electromagnetic shielding layer is to achieve structural health monitoring, thermal protection, or electromagnetic shielding functions; wherein the electromagnetic shielding layer is an MXene film or copper-plated fiber fabric with an electromagnetic shielding effectiveness ≥40dB in the 30MHz–10GHz frequency band.

[0027] In this invention, the energy storage unit is used to form a composite energy storage mechanism to achieve the synergy between rapid charging and discharging of the capacitor and high energy density energy storage of the battery.

[0028] In this invention, a conductive polymer adhesive layer or coupling agent coating is provided between the lattice core layer and the electrochemical energy storage layer. The conductive polymer adhesive layer is a PEDOT:PSS and / or a polypyrrole coating.

[0029] In this invention, a conductive polymer bonding layer is used to enhance the bonding force between the electrode active material and the lattice core layer and the electron transport capability.

[0030] In this invention, the positive electrode layer comprises NiCo2O4 / graphene composite material, LiFePO4 / graphene composite material, and Na... x MnO2 / NiCo2O4 composite material or conductive fabric electrode; The negative electrode layer includes activated carbon / carbon nanotube composite material, graphite / graphene composite material, hard carbon / activated carbon composite material, or conductive fabric electrode. The electrolyte layer includes PVA-KOH gel, PEO-based solid electrolyte, PAN-based gel, or PVA-H3PO4 gel.

[0031] This invention provides a method for preparing the composite material with the aforementioned nano-modified multifunctional lattice sandwich structure, comprising the following steps: 1) A lattice core layer with a predetermined topology is obtained by 3D printing or modular assembly of high-strength fiber-reinforced composite materials; 2) Fix one side surface of the dot matrix core layer to the upper skin layer; 3) Nanomaterials are grown in situ on the surface of the lattice core layer using solution impregnation, electrochemical deposition or tape casting process. Then, the positive electrode layer, electrolyte layer and negative electrode layer are sequentially laid on the upper skin layer through the lattice core layer. Each layer is cured or dried after being laid. 4) After bonding the unconnected sides of the lower skin layer and the lattice core layer together, apply pressure and cure to solidify the layers into a whole, thus obtaining the composite material.

[0032] In this invention, in step 3), the solution immersion temperature is 60~80℃, preferably 65~75℃, and more preferably 70℃; the solution immersion time is 4~6h, preferably 4.5~5.5h, and more preferably 5h; the electrochemical deposition temperature is 80~100℃, preferably 85~95℃, and more preferably 90℃; and the electrochemical deposition time is 2~8h, preferably 3~7h, and more preferably 4~6h.

[0033] In this invention, in step 3), after the nanomaterial is grown in situ, a layer of PEDOT:PSS or polypyrrole conductive polymer with a thickness of 1~5μm is coated on its surface to construct a continuous conductive network.

[0034] In this invention, the lattice core layer is manufactured layer by layer by 3D printing, printed into a Kagome-type or pyramid-type lattice basic structure, and then obtained by subsequent hot pressing and curing to obtain a core layer skeleton with high dimensional accuracy.

[0035] In this invention, nanostructured electrode materials are grown in situ on the surface of the lattice core layer by electrochemical deposition to form a composite positive electrode with a high specific surface area. Subsequently, a conductive polymer with a thickness of 1~5μm is coated on the nanowire array by in-situ polymerization to construct a continuous conductive network and enhance cycle stability.

[0036] The present invention also provides an application of the composite material of the nano-modified multifunctional lattice sandwich structure in new energy vehicle structural components, drone fuselages, aerospace vehicle cabins, smart wearable devices, or robot joints.

[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] Example 1

[0039] A 2.0 mm thick carbon fiber reinforced epoxy resin laminate was used to fabricate an upper and lower skin layer. In each layer, unidirectional carbon fiber fabric and plain weave fabric were alternately laid to balance strength and stiffness. The lattice core layer was prepared using 3D printing technology. The material consisted of PLA resin filled with 20 wt% short-cut carbon fibers. The resulting lattice was a bimodal structure combining hexagonal honeycomb and diagonal supports. Under high loads, the diagonal support units participated in the stress distribution to improve compressive stability. The lattice cell size was 10 mm, and the rod diameter was approximately 1.0 mm. mm; The lattice core layer is fixed to the inner surface of the upper skin layer with epoxy adhesive, and then the electrode materials are filled sequentially by solution impregnation method: First, NiCo2O4 / graphene composite positive electrode slurry (NiCo2O4 nanosheets account for 30wt% of the positive electrode active material, and the rest are reduced graphene oxide and conductive carbon black to improve conductivity) is prepared and coated on the upper half of the rods of the lattice structure and the inner surface of the upper skin to form the positive electrode layer; after standing and drying, a layer of PVA-KOH gel electrolyte is poured on it as the electrolyte layer, with a gel thickness of about 0.5 mm; then the activated carbon / carbon nanotube composite negative electrode slurry is filled into the lower half of the lattice space to form the negative electrode layer; after each coating, the slurry is penetrated, extended and solidified on the lattice structure under gravity by the casting method to ensure that the material is evenly distributed in the lattice cavity; the lower skin layer is covered and bonded to the lattice core layer, and then placed in a molding equipment for hot pressing and curing at 120℃ for 2 hours to obtain the composite plate.

[0040] The composite plate prepared in Example 1 was used in a new energy vehicle. Test results showed that the composite plate had a specific energy of approximately 30 Wh·kg⁻¹ under in-plane compressive load. -1 The specific power can reach 2 kW·kg -1 The composite exhibits excellent high-power characteristics; its three-point bending strength is approximately 150 MPa, and its bending stiffness is comparable to that of a pure carbon fiber sandwich panel of equal thickness. In a high-current discharge test simulating the moment of car startup, the composite panel can output peak power for driving the motor within 2 seconds and quickly recover energy during braking, demonstrating excellent performance stability. In this embodiment, NiCo2O4 / graphene is preferred as the positive electrode because NiCo2O4 has high pseudocapacitive properties, while graphene provides high-speed electron channels and mechanical reinforcement; the combination of the two can significantly improve the specific capacitance of the supercapacitor while ensuring structural strength. NiCo2O4 is grown directly on the graphene framework in the form of a nanoarray, which can obtain a higher active surface area and lower interfacial impedance.

[0041] Example 2

[0042] The upper and lower skin layers are made of Kevlar fiber / epoxy resin laminate, each 1.5 mm thick, possessing excellent impact resistance and insulation properties. They are lightweight and have a low dielectric constant to minimize impact on communication equipment. The lattice core layer employs a topology-optimized truss structure: firstly, computer simulations are used to optimize a set of member arrangements under given fuselage stress conditions and installation space, minimizing structural deformation and maximizing internal space utilization. Then, based on the optimization results, the lattice core layer is manufactured using SLA photopolymerization 3D printing technology. The material is photosensitive resin mixed with glass fiber powder, resulting in a lattice density of approximately 0.3 g·cm³. -3 The lattice structure comprises two types of members: main load-bearing diagonal braces and auxiliary stabilizing beams. Hollows are designed at key nodes to embed larger volumes of energy storage material. The electrochemical energy storage layer is a lithium-ion battery: the positive electrode layer uses LiFePO4 as the main active material, doped with a small amount of graphene nanosheets (approximately 5% by mass) to improve conductivity; the negative electrode layer uses a graphite negative electrode, with some graphite pre-exfoliated into graphene to enhance lithium-ion intercalation capacity; the electrolyte layer is a PEO-based solid electrolyte doped with 10wt% nano-SiO2 to enhance mechanical stability. A layer of elastic epoxy film about 50 μm thick was coated on one side of the lattice core layer 2 and adhered to the upper skin layer. This film served as an insulating and buffering layer. Then, an electrode layer was generated in situ within the lattice core layer framework fixed to the skin layer using an electrochemical deposition method. Specifically, conductive metal pieces were placed in the hollow nodes of the lattice as deposition guides. Then, a current was applied to the structure in the LiFePO4 precursor solution, causing LiFePO4 particles to be co-deposited in the upper half of the lattice framework to form a positive electrode layer with a thickness of about 1 mm. Subsequently, the electrolyte monomer solution was replaced, and the liquid PEO-LiTFSI precursor was filled into the voids in the middle of the lattice using vacuum infusion and cured in situ with ultraviolet light to form a solid electrolyte layer. The structure was then immersed in a graphene-modified graphite negative electrode electroplating solution, and a negative electrode layer was deposited in the lower half of the cavity by reverse electrodeposition. Finally, the lower skin layer on the other side was covered, and the adhesive was cured under molding conditions at 80°C for 2 hours to obtain the composite board.

[0043] The composite plate prepared in Example 2 was used as a solar panel for the fuselage structure of a drone. Test results showed that this solar panel structure can store approximately 250 Wh of energy per square meter (equivalent to a specific energy of approximately 70 Wh·kg). -1This material can provide drones with up to 30 minutes of battery life. The sheet material also possesses high bending stiffness (approximately 20 GPa) and impact toughness, enabling it to withstand aerodynamic loads and vibrations during flight. Because this embodiment uses an insulating aramid skin and an insulating resin lattice, the direct involvement of carbon fiber conductive materials in the circuitry is avoided, thus eliminating the risk of short circuits between battery cells. Furthermore, the LiFePO4 phosphate cathode material exhibits good thermal stability, making it suitable for harsh environments such as drones. In terms of material selection, aramid fiber composite material is preferred for the skin due to its lightweight and impact resistance. A layer of nano-ceramic coating is even more preferable, applied to the inner side of the skin to further protect the body from high temperatures during lithium battery thermal runaway. Graphene is incorporated into the LiFePO4 cathode because its excellent conductive network significantly reduces the internal resistance of the cathode. The performance improvement is most pronounced when the graphene content is 3-8 wt%, while exceeding 10 wt% results in an excessive decrease in energy density due to the excessive conductive agent.

[0044] Example 3

[0045] Both the upper and lower skin layers, each 1.0 mm thick, are made of surface-treated aluminum-lithium alloy plates to meet the airtightness and micrometeorite protection requirements of the spacecraft cabin. A 0.2 mm thick MXene / aramid paper-based electromagnetic shielding film is adhered to the inside of the aluminum plate using adhesive film. This film contains approximately 30% MXene and has an ordered layered structure. Its shielding effectiveness in the 1 MHz to 1 GHz frequency band is tested to be approximately 50%. dB, effectively shielding electromagnetic interference in the space environment; the lattice core layer adopts a two-phase composite lattice structure with two materials: the main load-bearing members use fiber-reinforced PEEK resin (to maintain mechanical properties at high temperatures) arranged in a pyramidal grid; the auxiliary support members use hollow stainless steel microtubes filled with paraffin-based phase change material to achieve thermal buffering; the two types of members are not directly connected to each other, but leave tiny gaps at the lattice nodes; under normal load at room temperature, the stainless steel auxiliary support does not participate in the load-bearing, only the PEEK truss bears the load; when subjected to impact or temperature rise causing PEEK to expand, the ends of the auxiliary support microtubes come into contact with the main members, and begin to share the load or transfer heat, thereby achieving the effect of self-adaptive load-bearing and heat conduction. This two-phase lattice design enables the structure to maintain stable support capacity in the temperature range of -80~120℃ and can buffer sudden temperature changes; the electrochemical energy storage layer adopts an energy storage system combining sodium-ion batteries and supercapacitors in parallel: the positive electrode layer is Na x MnO2 and MnO2 nanosheet composite materials, in which a portion of the MnO2 is treated with Ni 2+ and Co 2+Co-doping forms a NiCo2O4 coating to improve electronic conductivity and redox activity; the negative electrode layer is made of hard carbon material and mixed with a small amount of activated carbon to enhance high-rate performance; the electrolyte layer uses polyacrylonitrile (PAN) based gel containing 1 M NaPF6-carbonate electrolyte; the lattice core layer undergoes special surface treatment before fabrication: the PEEK main rod is plasma etched to increase roughness and coated with a layer of polypyrrole (PPy) conductive polymer to improve the adhesion to the positive electrode material; the stainless steel auxiliary support is anodized to form an oxide layer to avoid direct contact with the electrode and short circuit. Subsequently, the lattice core layer was placed inside the upper skin layer, and the pre-prepared NiCo2O4-doped MnO2 positive electrode slurry was sprayed onto the upper space of the lattice structure by spray deposition, with a thickness of about 0.8 mm; then, the PAN gel precursor liquid was injected into the middle void, and gelled to form an electrolyte layer; finally, the hard carbon / activated carbon negative electrode slurry was coated onto the lower space to form a negative electrode layer, and the lower skin layer was stacked and cured at room temperature for 48 hours to obtain the composite plate.

[0046] The sodium-ion / supercapacitor composite energy storage sandwich panel prepared in Example 3 for aerospace cabins is used in the cabin wall structure of aerospace vehicles, exhibiting both high energy density and high power density, while highlighting its thermal insulation and electromagnetic shielding performance. The sandwich panel obtained in this example contains approximately 180 Wh / m² of energy per unit area. 2 (equivalent to a specific energy of 50 Wh·kg) -1 It can be continuously charged and discharged at a 10C rate, exhibiting characteristics of both a battery and a capacitor; its in-plane tensile strength is ≥300 MPa, fully meeting the bulkhead structural requirements. Furthermore, due to the use of phase change materials and a two-phase lattice design, it can withstand rapid thermal cycling (-80℃). After the +100℃ test, the maximum internal temperature fluctuation of the composite material decreased by 35%, effectively protecting the performance stability of the energy storage unit. The key technology preferred in this embodiment lies in the combination of NiCo2O4-doped MnO2 cathode and PAN gel electrolyte: the composite of NiCo2O4 and MnO2 plays a synergistic role in the sodium storage process, one providing Faraday pseudocapacitance and the other providing ion intercalation capacity, enabling the cathode to perform well at both high and low rates; while the gel electrolyte avoids the leakage risk of liquid electrolyte in a weightless environment, and more preferably, 5wt% ZSM-5 molecular sieve powder is added to the gel, which can adsorb trace impurities of water to prevent sodium dendrite growth, thereby further improving the battery cycle life.

[0047] Example 4

[0048] The upper and lower skin layers are made of spandex fabric, which is impregnated with an epoxy resin / silicone rubber blend to impart a certain degree of hardness while maintaining good bending flexibility. The lattice core layer uses a stretchable TPU elastomer material, which is laser-cut to obtain a honeycomb mesh structure with a thickness of about 1 mm. When unfolded, it has a mesh shape and can stretch with the substrate. The electrochemical energy storage layer is designed as a symmetrical supercapacitor: both the positive and negative electrode layers are composed of conductive fabric electrodes, that is, carbon nanotube (CNT) ink and PEDOT:PSS conductive polymer are mixed and coated on polyester fabric to form a flexible electrode cloth. The active material is cellulose-derived carbon and a small amount of MnO2 nanosheets. The electrolyte layer uses PVA-H3PO4 gel and is doped with 5wt% glycerol to prevent moisture evaporation. During the fabrication process, the upper skin layer is first attached to the inside of a layer of the above-coated flexible electrode cloth as the positive electrode, and its surface-loaded specific capacitance is about 300 mF·cm. -2 Then, a PVA-H3PO4 gel of about 0.3 mm thickness is coated on it to form a solidified electrolyte layer; next, another piece of electrode cloth is used as the negative electrode to cover the gel, and an elastic TPU lattice core layer is laid on the negative electrode cloth. Finally, the lower skin layer is sewn and fixed to form a sandwich structure to obtain a composite plate.

[0049] The composite plate prepared in Example 4 was used in a flexible structure supercapacitor for smart wearable devices, combining energy storage and strain sensing functions. The TPU lattice core layer primarily acts as a spacer support, preventing short circuits in the flexible electrodes during bending, while also providing structural strength to support the fabric shape. Since all components are flexible, this energy storage structure can be sewn into clothing or used to conform to the curves of the human body. Test results show that after 1000 repeated bends with a bending radius of 5 cm, the device retains 92% of its capacitance, exhibiting good flexibility and durability; its areal density energy is approximately 0.05 Wh·m³. -2 (Corresponding specific energy of approximately 8Wh·kg) -1(Primarily limited by thickness and wearable safety considerations), but it can release stored energy in 0.1 seconds to drive low-power components such as LEDs and sensors. The flexible supercapacitor structure can also function as a strain sensor: during tensile deformation, the equivalent series resistance (ESR) and capacitance of the device change measurably due to the change in the network structure of the conductive fabric electrodes. Experimental response tests to 10% tensile strain showed a linear decrease in capacitance of approximately 5%, and the tensile amplitude can be determined by monitoring the capacitance change. This self-sensing characteristic is very useful for smart wearables, and can be used to monitor human movement or clothing fit. In this embodiment, PEDOT:PSS is preferred as the conductive additive because, compared to metal coatings, PEDOT:PSS-coated fabrics have better softness and washability, while providing sufficient conductivity to form electrodes. 1-3 wt% silica nanoparticles are added to PEDOT:PSS to improve its adhesion stability during stretching and prevent conductivity degradation after repeated bending.

[0050] Example 5

[0051] Both the upper and lower skin layers are annular aluminum alloy cover plates (each 1 mm thick), supported in the middle by a hexagonal lattice core layer. The lattice material is shape memory polymer (SMP) composite carbon fiber, with a glass transition temperature of approximately 60°C. At room temperature, the lattice is rigid, providing joint support. When heated above 60°C, the lattice softens, allowing for reconfiguration of the internal structure of the joint module or release of internal stress. The electrochemical energy storage layer is a hybrid power source: comprising eight micro lithium-ion battery units and several symmetrical supercapacitor units connected in parallel. Each lithium-ion battery unit consists of circular positive and negative electrode sheets and a separator wound together, using NCM (ternary material) positive electrodes and graphite negative electrodes, with a single unit capacity of approximately 50 mAh. The supercapacitor units consist of activated carbon electrodes and ionic liquid electrolytes, with a single unit capacitance of approximately 0.1 mAh. F. These units are uniformly embedded in the gaps of the matrix core layer, serving as both energy storage elements and part of the matrix. Specifically, a lithium-ion battery unit is placed in every other hole in the hexagonal cells of the matrix, with supercapacitor units filling the surrounding holes, forming a checkerboard pattern. To connect these dispersed units, a flexible printed circuit board (FPCB) is etched with a grid of copper foil lines and attached to the surface of the matrix structure as a current collector frame, leading out the corresponding positive and negative electrodes of each unit and connecting them in parallel. The FPCB also incorporates several strain gauges and temperature sensors, attached to key parts of the matrix to monitor the deformation and thermal condition of the joint module during movement. During manufacturing, each energy storage unit is pre-encapsulated and soldered onto the FPCB board. Then, it is embedded into the SMP dot matrix core layer (the dot matrix has localized openings to accommodate the units). After softening the SMP at 80°C, it is gently pressed to embed the FPCB and units into the dot matrix surface. Upon cooling, the SMP regains its rigidity, firmly fixing it in place. The dot matrix core layer is then bonded to the upper skin layer, and a small amount of low-viscosity epoxy resin is injected into the dot matrix cavity for in-mold curing to enhance overall integrity. After the epoxy cures, the lower skin layer is installed and sealed, forming a sealed annular module. This module has an overall annular sandwich structure, equivalent to a hollow disk with an outer diameter of 100 mm, an inner diameter of 50 mm, and a thickness of 10 mm. It can be fitted onto the outer surface of a spherical bearing.

[0052] The composite plate prepared in Example 5 was used in a structural battery module and sensing components for robot joints, combining energy storage and power supply with joint status monitoring functions. Tests showed that the module has a total energy storage of approximately 4 Wh (3.2 Wh from lithium batteries and 0.8 Wh from a supercapacitor, which can discharge at high speed). It can provide a large instantaneous current during peak joint movements and be continuously powered by lithium batteries during slow movements. The module itself has a compressive strength exceeding 100 MPa, capable of withstanding the assembly preload and working load of the robot joint. Through the placement of strain and temperature sensors, combined with data from the voltage and current of the energy storage unit, this module achieves real-time monitoring of the joint's operating status: for example, when the joint operates under high load for an extended period, causing temperature increases, the SMP lattice in the module softens to appropriately alleviate connection stiffness, while the signal collected by the temperature sensor triggers the cooling fan to start; furthermore, by monitoring the deformation trend of the module through strain gauges, it is possible to determine whether the joint is loose or abnormally worn, thus providing early warning before a failure occurs. This demonstrates the application potential of structural power modules in the field of robotics. In terms of materials, the preferred shape memory polymer in this embodiment is due to the need for joints to have a certain self-adjustment capability in the working environment of the robot. More preferably, 10wt% of carbon nanotube reinforcing agent is added to the SMP matrix to improve the thermal and electrical conductivity of the material, so as to accelerate the shape recovery speed and also be able to be heated and deformed under the action of electric field. At the same time, the flexible circuit uses a multilayer polyimide substrate, which can withstand repeated bending and a certain high temperature, ensuring the reliability of the sensing and power supply lines.

[0053] As can be seen from the above embodiments, the present invention provides a nano-modified multifunctional lattice sandwich structure battery composite material, its preparation method, and its application. The nano-modified multifunctional lattice sandwich structure composite material includes an upper skin layer, a lower skin layer, a lattice core layer disposed between the upper and lower skin layers, and an electrochemical energy storage layer integrated in the lattice core layer. The lattice core layer provides support perpendicular to the upper skin layer, and the lattice core layer is a dual-mode lattice structure, a topology-optimized lattice structure, an adaptive deformation lattice structure, or a reconfigurable geometric lattice structure. The electrochemical energy storage layer includes a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked sequentially. The positive electrode layer and the negative electrode layer of the electrochemical energy storage layer are independently composite materials modified by nanomaterials. This invention significantly improves the overall performance of lattice sandwich structure energy storage composite materials through material innovation, structural optimization, and multifunctional integration. Its core advantage lies in the integration of structural load-bearing and electrical energy storage, while also integrating multiple functions such as sensing, heat insulation, and electromagnetic shielding. It achieves breakthroughs in lightweighting, high efficiency, and intelligence, and is particularly suitable for high-end fields such as new energy vehicles, drones, aerospace, smart wearables, and robots.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite material with a nano-modified multifunctional lattice sandwich structure, characterized in that, The composite material includes an upper skin layer, a lower skin layer, a lattice core layer disposed between the upper skin layer and the lower skin layer, and an electrochemical energy storage layer integrated in the lattice core layer. The lattice core layer is a dual-modal lattice structure, a topology-optimized lattice structure, an adaptive deformation lattice structure, or a reconfigurable geometric lattice structure, used to provide support perpendicular to the upper skin layer, and the lattice core layer is a dual-phase composite structure with different moduli or different materials. The electrochemical energy storage layer comprises a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked sequentially, and includes at least two different types of energy storage units, including at least two of supercapacitor units, lithium-ion battery units, and sodium-ion battery units. The positive electrode layer and the negative electrode layer are independently composite materials modified with nanomaterials; The nanomaterials include one or more of MXene, graphene, carbon nanotubes, doped metal oxides, and conductive polymers. A conductive polymer adhesive layer or coupling agent coating is provided between the lattice core layer and the electrochemical energy storage layer.

2. The composite material with nano-modified multifunctional lattice sandwich structure according to claim 1, characterized in that, The nanomaterials are bonded to the electrode substrate through grafting, covalent bonding, or surface coating. The doped metal oxide includes one or more of NiCo2O4, MnO2 and Fe2O3; the conductive polymer is PEDOT:PSS and / or polypyrrole.

3. The composite material with a nano-modified multifunctional lattice sandwich structure according to claim 1 or 2, characterized in that, The upper and lower skin layers are made of fiber-reinforced composite materials or metal plates, respectively. The fiber-reinforced composite material includes carbon fiber reinforced epoxy resin laminate, aramid fiber reinforced epoxy resin laminate, or elastic fabric layer; The metal plate includes an aluminum-lithium alloy plate and / or an aluminum alloy plate.

4. The composite material with nano-modified multifunctional lattice sandwich structure according to claim 3, characterized in that, The material of the lattice core layer is a high-strength fiber-reinforced composite material, which includes one or more of carbon fiber composite materials, glass fiber, aramid fiber, basalt fiber, polylactic acid biodegradable material, bio-based nylon, and acrylonitrile-butadiene-styrene copolymer. The size of the dot matrix cells in the dot matrix core layer is 1~20mm, and the diameter of the rods is 0.1~2.0mm.

5. The composite material of the nano-modified multifunctional lattice sandwich structure according to claim 4, characterized in that, The inner sides of the upper and lower skin layers are also provided with functional layers, which include sensor components, heat insulation layers or electromagnetic shielding layers.

6. The composite material of the nano-modified multifunctional lattice sandwich structure according to claim 5, characterized in that, The conductive polymer adhesive layer is a PEDOT:PSS and / or a polypyrrole coating.

7. The composite material with nano-modified multifunctional lattice sandwich structure according to claim 6, characterized in that, The positive electrode layer includes NiCo2O4 / graphene composite material, LiFePO4 / graphene composite material, and Na... x MnO2 / NiCo2O4 composite material or conductive fabric electrode; The negative electrode layer includes activated carbon / carbon nanotube composite material, graphite / graphene composite material, hard carbon / activated carbon composite material, or conductive fabric electrode. The electrolyte layer includes PVA-KOH gel, PEO-based solid electrolyte, PAN-based gel, or PVA-H3PO4 gel.

8. A method for preparing a composite material with a nano-modified multifunctional lattice sandwich structure as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1) A lattice core layer with a pre-defined topology is obtained by 3D printing or modular assembly of high-strength fiber-reinforced composite materials; 2) Fix one side surface of the dot matrix core layer to the upper skin layer; 3) Nanomaterials are grown in situ on the surface of the lattice core layer using solution impregnation, electrochemical deposition or tape casting process. Then, the positive electrode layer, electrolyte layer and negative electrode layer are sequentially laid on the upper skin layer through the lattice core layer. Each layer is cured or dried after being laid. 4) After bonding the unconnected sides of the lower skin layer and the lattice core layer together, apply pressure and cure to solidify the layers into a whole, thus obtaining the composite material.

9. The method for preparing the composite material with nano-modified multifunctional lattice sandwich structure according to claim 8, characterized in that, In step 3), the solution immersion temperature is 60~80℃, the solution immersion time is 4~6h, the electrochemical deposition temperature is 80~100℃, and the electrochemical deposition time is 2~8h. After the nanomaterial is grown in situ, a layer of PEDOT:PSS or polypyrrole conductive polymer with a thickness of 1~5μm is coated on its surface to construct a continuous conductive network.

10. The application of a composite material with a nano-modified multifunctional lattice sandwich structure as described in any one of claims 1 to 7 in new energy vehicle structural components, drone fuselages, aerospace vehicle cabins, smart wearable devices, or robot joints.