3D printed nano-microbattery composite electrode material and preparation method thereof

Abstract

The present invention discloses a 3D-printed nano-microbattery composite electrode material and a preparation method thereof, which belongs to the field of battery technology. A new type of 3D-printed V2O5-Ti3C2-Au nano-composite electrode material is constructed for high-performance lithium-ion energy storage. The nano-composite material has a layered heterogeneous structure, in which V2O5 is connected to Ti3C2MXene through a defect-rich TiO2 intermediate layer, and the Ti3C2 intermediate layer can anchor the oxide, minimize the lattice mismatch, and introduce oxygen vacancies, which is beneficial to enhance the transmission of electrons and lithium ions. Gold nanoparticles are anchored on the Ti sites on the MXene surface to form conductive interface bonds, thereby improving the interface conductivity and mechanical integrity. The 3D-printed nano-composite cathode is manufactured by an ink direct writing 3D printing technology molding method, which can precisely control the structure and spatial distribution of the active material, thereby shortening the ion / electron pathway and improving the electrochemical kinetics.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a 3D printed nano-micro battery composite electrode material and a preparation method thereof. Background Art

[0002] Against the backdrop of global energy transformation and the rapid development of portable electronic devices, high-performance energy storage systems have become one of the core technologies supporting modern science and technology. Due to its high theoretical capacity, rich oxidation states, and excellent electrochemical activity, V2O5 has been widely studied as a cathode material for energy storage devices such as lithium-ion batteries and sodium-ion batteries. It is suitable for applications ranging from portable electronic devices to electric vehicles and renewable energy storage systems. However, its practical application is limited by three key bottlenecks: extremely low intrinsic conductivity, structural collapse caused by phase transitions during cycling, and long ion diffusion paths, which lead to rapid battery capacity decay, short cycle life, and poor rate performance.

[0003] Existing research has improved the conductivity of V2O5 by introducing carbon-based conductive additives (such as graphene and carbon nanotubes). Although a conductive network can be formed, there are two major problems: the synthesis process is complex, requiring high-temperature carbonization, chemical vapor deposition and other steps, which is costly and difficult to control the uniform dispersion of the nanostructure; the synergistic effect is insufficient, and the carbon material only physically coats the V2O5 particles, which cannot inhibit their structural phase transformation during the charge and discharge process, and the improvement in ion transmission efficiency is limited.

[0004] MXenes, due to their high conductivity, lyophilicity, and interlayer ion channel properties, have been explored in composites with V2O5. However, current research has used MXenes solely as conductive fillers, failing to fully exploit the chemical coupling between their surface functional groups and V2O5. This results in insufficient interfacial stability in the composites, and the layered stacking easily blocks ion transport pathways, resulting in less-than-optimal structural stability.

[0005] Au nanoparticles (AuNPs) can accelerate electrode reaction kinetics due to their surface plasmon effect and catalytic activity, but there are key gaps in their application in V2O5-based cathodes: traditional preparation methods (such as liquid-phase blending) make it difficult to achieve uniform dispersion of AuNPs in the V2O5 / MXenes system and lack precise control over the electrode microstructure; it is not yet clear how AuNPs and MXenes in the V2O5 matrix can synergistically optimize conductivity, ion diffusion and structural stability through interfacial effects, and related research is still in its preliminary stages.

[0006] Moreover, traditional electrode preparation relies on coating, pressing and other methods, which makes it difficult to construct a three-dimensional structure with controllable porosity and conductive network, resulting in low utilization of active materials and poor rate performance. In addition, the process is complex and the cost is high, making it unsuitable for large-scale production.

[0007] Therefore, it is a problem that needs to be solved at present to propose a 3D printed nano-microbattery composite electrode material and its preparation method that can improve conductivity, structural integrity and electrochemical performance. Summary of the Invention

[0008] The purpose of the present invention is to provide a 3D printed nano-microbattery composite electrode material and a preparation method thereof to solve the current problems of low conductivity of electrode materials, structural instability during circulation and slow ion diffusion rate.

[0009] To achieve the above objectives, the present invention provides a 3D printed nano-microbattery composite electrode material, wherein the composite electrode material comprises V2O5, Ti3C2MXene material and gold nanoparticles (AuNPs), wherein:

[0010] V2O5 is the matrix material, acting as an active substance and providing lithium ion storage sites;

[0011] Ti3C2MXene acts as a conductive enhancer and structural support, uniformly dispersed in a two-dimensional lamellar structure within a V2O5 matrix material. The two are connected by a defect-rich TiO2 interlayer, which anchors the oxide, reduces lattice mismatch, and introduces oxygen vacancies.

[0012] Gold nanoparticles act as catalytic active sites and ion transport accelerators, anchored on the Ti sites on the Ti3C2MXene surface, forming conductive interface bonds (AuTi3, Au2Ti), and are evenly loaded on the V2O5 surface and in the gaps between MXene sheets.

[0013] The composite electrode material is printed and formed by ink direct writing technology to form a layered stacking structure, construct a through-going electronic conductive network and lithium ion transmission channel, accurately control the structure and spatial distribution of the active material, and shorten the ion / electron transmission path.

[0014] Preferably, in the above-mentioned 3D printed nano-microbattery composite electrode material, the layered stacking structure formed has a single layer thickness of 10-20 μm and a total number of layers of 2-8 layers. The TiO2 intermediate layer and the MXene sheet form a heterojunction interface between the layers, so that the composite electrode material has a layered heterogeneous structure.

[0015] Preferably, in the above-mentioned 3D printed nano-microbattery composite electrode material, the pore structure of the composite electrode material is regulated by adjusting the solid phase content of the printing ink and the printing parameters.

[0016] The preparation method of 3D printing nano-micro battery composite electrode material comprises the following steps:

[0017] S1. Prepare a precursor ink by mixing V2O5 nanoparticles, Ti3C2MXene material, and AuNPs in a mass ratio of 5:1-3:0.1-1, add a binder (polyvinylidene fluoride or sodium carboxymethyl cellulose) containing a TiO2 precursor (such as tetrabutyl titanate) and a solvent (N-methylpyrrolidone or deionized water), and ultrasonically disperse for 1-3 hours to form a uniform ink. The TiO2 precursor is converted into a defect-rich TiO2 intermediate layer in subsequent treatment;

[0018] S2, 3D printing, using ink direct writing technology, prints the precursor ink layer by layer on the aluminum substrate through a precision nozzle. The thickness of a single layer is 10-20 μm, the interlayer drying time is 5-15 minutes, and a total of 2-8 layers are printed to form a wet electrode blank;

[0019] S3, post-treatment, vacuum drying the wet electrode blank at 60-80°C for 12-24 hours, and then heat treating it at 300-400°C in an argon atmosphere for 1-2 hours to remove the binder and strengthen the interface bonding to obtain the 3D printed composite material. During the heat treatment, the TiO2 precursor is converted into a TiO2 intermediate layer containing oxygen vacancies, and the gold nanoparticles form a conductive interface bond with the Ti sites on the MXene surface.

[0020] The nano-microbattery prepared by the above-mentioned 3D printed nano-microbattery composite electrode material, the nano-microbattery structure includes:

[0021] The anode is made of lithium cobalt oxide and is made by 3D printing. It is arranged on a substrate, and a positive electrode shell is arranged on the top of the substrate;

[0022] A cathode, which is a 3D printed composite material and is disposed on a substrate, with a negative electrode housing disposed at the bottom of the substrate;

[0023] The diaphragm is a porous polyolefin membrane or a ceramic coating diaphragm, which is arranged between the anode and the cathode;

[0024] The electrolyte is an organic electrolyte containing lithium ions. The lithium ions are transferred from the anode to the cathode and embedded in the interlayer structure of the cathode material to realize the charging process; the lithium ions are released from the cathode and returned to the anode to realize the discharging process.

[0025] Preferably, the nano-microbattery is used in wearable devices, medical implantable devices or Internet of Things sensors.

[0026] Therefore, the 3D printed nano-micro battery composite electrode material and its preparation method of the present invention have the following beneficial effects:

[0027] (1) MXenes, as conductive fillers in the V2O5 matrix, are characterized by high conductivity. This integration reduces resistance and improves overall efficiency. The unique layered structure and large specific surface area of ​​MXenes provide an optimal pathway for lithium ion transport, significantly accelerating the insertion and extraction processes. MXenes contribute to the mechanical stability of V2O5, alleviate the risk of structural collapse during cycling, and improve long-term cycling performance. The introduction of AuNPs improves the electronic conductivity of the composite material, which is beneficial to efficient electron transfer during battery operation. AuNPs can accelerate charge transfer at the electrode interface, thereby improving the kinetics of lithium insertion and extraction, leading to faster battery response time. The presence of AuNPs provides additional nucleation sites, promotes uniform and efficient lithium ion insertion, and enhances the overall cycling stability.

[0028] AuNPs also catalyze the reaction of MXenes with V2O5, promoting the formation of TiO2 at the interfacial layer. The combination of V2O5, MXenes, and AuNPs produces a synergistic effect, in which each component enhances the overall performance. V2O5 serves as the active species, while MXenes and AuNPs simultaneously improve electronic and ionic conductivity. With improved electron and lithium-ion transport pathways, the kinetics of the intercalation and deintercalation processes are significantly enhanced, leading to faster charge and discharge rates. The structural reinforcement of MXenes, combined with the conductive advantages of AuNPs, leads to improved cycling stability and significantly reduced capacity fade over long-term use. The designed V2O5-Ti2C3 heterostructure is interconnected by the interfacial TiO2 layer, promoting the formation of oxygen vacancies, generating localized stress, and enhancing lithium ion intercalation through synergistic redox and electronic interactions. Titanium atoms further anchor the gold nanoparticles, forming gold-titanium bonds (AuTi3, Au2Ti), further improving interfacial conductivity and structural integrity. The interfacial TiO2 layer formed between V2O5 and Ti2C3 can anchor the oxides, reduce lattice mismatch, introduce oxygen vacancies, and promote electron / ion transport, thereby improving electrochemical performance. 3DP-VTA composites provide ideas for higher-performance energy storage systems.

[0029] (2) The layered stacking structure constructed by direct ink writing (DIW) technology forms a continuous ion transmission channel and electronic conductive network, enhancing ion transmission and overall energy density. 3D printing technology enables precise control of electrode thickness, porosity, and geometry, meeting the customized requirements of different micro-devices for battery volume and performance, supporting rapid iterative optimization, optimizing material use, and reducing waste.

[0030] (3) The two-dimensional conductive layer of MXenes and the catalytic sites of AuNPs are synergistically integrated into the V2O5 matrix to form a multifunctional composite system of "conductivity-catalysis-structural support". This solves the problem that single carbon-based materials (such as graphene) only physically enhance conductivity but cannot inhibit structural phase transitions. 3D printing technology based on DIW combines nanoscale material dispersion with macroscopic structural control. Compared with traditional coating processes, it avoids the problems of active material agglomeration and uneven distribution of conductive additives. It also does not require high-temperature sintering, reduces energy consumption, and is suitable for large-scale production.

[0031] (4) The electrode thickness can be controlled, and combined with the 3D-printed multi-layer stacked battery structure, it meets the "small size and long battery life" requirements of wearable devices such as smart watches and implantable sensors. The structural stability ensures that the battery maintains stable performance under complex working conditions such as bending and vibration, making it suitable for outdoor operation of IoT terminal devices such as wireless sensor nodes.

[0032] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the SEM image of vanadium pentoxide;

[0034] Figure 2 SEM image of MXene;

[0035] Figure 3 is the SEM image of gold nanoparticles;

[0036] Figure 4 SEM images of gold nanoparticles and MXene integrated with vanadium pentoxide;

[0037] Figure 5 This is the SEM image of the 3D printed sample;

[0038] Figure 6 This is a close-up SEM image of the 3D printed sample;

[0039] Figure 7 Optical image of the 3D printed sample on an aluminum substrate;

[0040] Figure 8 Schematic diagram of nano-micro battery;

[0041] Figure 9 This is a cyclic voltammetry test diagram for the nano-micro battery;

[0042] Figure 10 This is a test diagram of the nano-micro battery at different current densities;

[0043] Figure 11 A diagram showing the long-term electrochemical cycling test of nano-microbatteries.

[0044] Figure numerals: 1. anode; 2. substrate; 3. positive electrode housing; 4. cathode; 5. negative electrode housing; 6. separator; 7. electrolyte. DETAILED DESCRIPTION

[0045] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0047] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0048] The present invention provides a 3D-printed nano-microbattery composite electrode material, which includes V2O5, Ti3C2MXene material and gold nanoparticles (AuNPs), wherein: V2O5 is a matrix material, serving as an active material and providing lithium ion storage sites; Ti3C2MXene serves as a conductive enhancer and structural support, and is uniformly dispersed in the V2O5 matrix material in a two-dimensional layered form, and the two are connected by a defect-rich TiO2 intermediate layer, which is used to anchor the oxide, reduce lattice mismatch, and introduce oxygen vacancies to promote electron / ion transport, thereby improving electrochemical performance; the gold nanoparticles serve as catalytic active sites and ion transport accelerators, and are anchored on the Ti sites on the Ti3C2MXene surface to form conductive interface bonds (AuTi3, Au2Ti), which are uniformly loaded on the V2O5 surface and in the gaps between the MXene layers; the composite electrode material is printed and formed using an ink direct writing technology to form a layered stacking structure, construct a through-hole electronic conductive network and lithium ion transport channels, precisely control the structure and spatial distribution of the active material, and shorten the ion / electron transport path.

[0049] The resulting layered stacked structure has a single layer thickness of 10-20 μm and a total of 2-8 layers. TiO2 interlayers form heterojunction interfaces with MXene sheets between the layers, resulting in a layered heterostructure for the composite electrode material. The pore structure of the composite electrode material can be controlled by adjusting the solid phase content of the printing ink and the printing parameters. V2O5, as both the matrix material and active material, possesses a high theoretical capacity and can provide a large number of lithium ion storage sites, making it a key component in achieving battery energy storage. MXene, uniformly dispersed in the V2O5 matrix as a two-dimensional sheet, acts as a conductivity enhancer. Its high conductivity significantly reduces the electrode's resistance and improves electron transfer efficiency. It also serves as a structural support, enhancing the electrode's mechanical stability and mitigating performance degradation caused by structural changes during charge and discharge. AuNPs are uniformly loaded on the V2O5 surface and in the interstices between the MXene sheets, acting as catalytic active sites. They accelerate charge transfer reactions at the electrode interface and optimize the kinetics of lithium insertion and removal. They also act as ion transport accelerators, providing additional ion transport pathways and promoting the rapid migration of lithium ions.

[0050] The composite electrode material is printed using direct ink writing (DIW) technology, forming a layered stacked structure with a single layer thickness of 10-20μm and a total of 2-8 layers. This layered structure creates a continuous electronic conductive network, enabling rapid electron transport within the electrode. Simultaneously, the gaps between the layers form lithium-ion transport channels, providing a convenient path for lithium ion insertion and extraction during charge and discharge, thereby improving the battery's charge and discharge efficiency and overall performance.

[0051] MXene materials, with their unique two-dimensional structure and surface functional groups, can form a stable interface with the V2O5 matrix through chemical bonds or physical interactions, further enhancing the conductivity and structural stability of the composite material. Furthermore, different types of MXene materials have distinct performance characteristics, and through rational selection and combination, the overall performance of composite electrode materials can be optimized.

[0052] The pore structure of the composite electrode material can be controlled by adjusting the solid phase content of the printing ink and the printing parameters. A suitable pore structure can increase the specific surface area of ​​the electrode, providing more active sites, which is conducive to the adsorption and embedding of lithium ions. At the same time, an optimized pore distribution can shorten the diffusion path of lithium ions and increase the ion diffusion rate, thereby improving the battery's charge and discharge performance and cycle stability.

[0053] The preparation method of 3D printing nano-micro battery composite electrode material comprises the following steps:

[0054] S1. Prepare precursor ink, mix V2O5 nanoparticles, Ti3C2MXene material, and AuNPs in a mass ratio of 5:1-3:0.1-1, add a binder (polyvinylidene fluoride or sodium carboxymethyl cellulose) containing a TiO2 precursor (such as tetrabutyl titanate) and a solvent (N-methylpyrrolidone or deionized water), and ultrasonically disperse for 1-3 hours to form a uniform ink. The TiO2 precursor is converted into a defect-rich TiO2 intermediate layer in subsequent treatment; ultrasonic dispersion is used to fully mix the components. The binder helps maintain the stability and formability of the ink, and the solvent ensures that the various substances can be evenly dispersed in the system, providing a good foundation for subsequent printing and molding.

[0055] S2, 3D printing molding, uses ink direct writing technology to print the precursor ink layer by layer on the aluminum substrate through a precision nozzle. The single layer printing thickness is 10-20μm, the interlayer drying time is 5-15 minutes, and a total of 2-8 layers are printed to form a wet electrode blank; ink direct writing technology can accurately control the shape and structure of the electrode to achieve customized design; layer-by-layer printing and interlayer drying ensure the layered structure and interlayer bonding strength of the electrode, laying the foundation for the formation of a through electronic conductive network and lithium ion transmission channel.

[0056] S3, post-treatment: vacuum drying the wet electrode body at 60-80°C for 12-24 hours, followed by heat treatment at 300-400°C in an argon atmosphere for 1-2 hours to remove the binder and strengthen interfacial bonding, thereby producing the 3D printed composite material. During the heat treatment, the TiO2 precursor is converted into a TiO2 interlayer containing oxygen vacancies, and the gold nanoparticles form conductive interfacial bonds with the Ti sites on the MXene surface. Vacuum drying removes the solvent and initially solidifies the electrode body. Heat treatment in an argon atmosphere removes the binder, preventing its impact on electrode performance, while promoting interfacial bonding between V2O5, MXene, and AuNPs, enhancing the stability and conductivity of the composite material.

[0057] The nano-microbattery prepared by the above-mentioned 3D printed nano-microbattery composite electrode material has a nano-microbattery structure including:

[0058] Anode 1: Made of lithium cobalt oxide (LCO), produced via 3D printing, it is mounted on a substrate 2, topped by a cathode housing 3. LCO has a high voltage platform and energy density, enabling it to provide a high output voltage as an anode material. The 3D-printed anode can be customized in shape and structure to meet specific needs, improving space utilization. The cathode housing provides structural support and protection for the anode, while also facilitating electrical connections.

[0059] Cathode 4: The cathode is a 3D-printed composite material, mounted on substrate 2. A negative electrode housing 5 is located at the bottom of substrate 2. This 3D-printed composite electrode material, used as a cathode, combines the advantages of V2O5, MXene, and AuNPs. It boasts high conductivity, excellent structural stability, and rapid ion transport, enabling efficient storage and release of lithium ions during charge and discharge. The negative electrode housing provides protection and structural support for the cathode, ensuring battery stability and safety.

[0060] Separator 6: A porous polyolefin membrane or ceramic-coated membrane, positioned between anode 1 and cathode 4. The primary function of separator 6 is to prevent direct contact between anode 1 and cathode 4, which could cause a short circuit, while allowing lithium ions to pass through. The porous polyolefin membrane or ceramic-coated separator has appropriate porosity and ionic conductivity, facilitating smooth lithium ion transport while ensuring battery safety.

[0061] Electrolyte 7: This is an organic electrolyte containing lithium ions. The lithium ions transfer from the anode 1 to the cathode 4 and become embedded in the interlayer structure of the cathode material, enabling the charging process. The lithium ions are released from the cathode and return to the anode, enabling the discharge process. The electrolyte acts as a transport medium for lithium ions. During charging, lithium ions are released from the anode, migrate through the electrolyte to the cathode, and become embedded in the interlayer structure of the cathode material, storing electrical energy. During discharge, lithium ions are released from the cathode and return to the anode through the electrolyte, releasing electrical energy to power the device.

[0062] Nano-micro batteries are used in wearable devices, medical implants, and IoT sensors. Due to their high performance and miniaturization, they can meet the requirements of these devices for small size, high energy density, and good cycle stability. They provide long-lasting power support for wearable devices, ensure the reliable operation of medical implants, and provide a stable energy supply for IoT sensors, promoting the development of related fields.

[0063] Example 1

[0064] Preparation of 3D printed nano-microbattery composite electrode materials:

[0065] To prepare the precursor ink, 60 g of V2O5, 30 g of Ti3C2MXene material and 10 g of AuNPs were mixed, 5 g of polyvinylidene fluoride binder and 100 g of N-methylpyrrolidone solvent were added, and ultrasonic dispersion was performed for 2 h to form a uniform ink.

[0066] 3D printing molding uses ink direct writing technology to print the precursor ink layer by layer on the aluminum substrate through a 100μm nozzle. The single layer printing thickness is 15μm, the interlayer drying time is 10 minutes, and a total of 6 layers are printed to form a wet electrode blank.

[0067] For post-treatment, the wet electrode body was vacuum dried at 70 °C for 18 h, and then heat treated at 350 °C in an argon atmosphere for 1.5 h to obtain a 3D printed nano-microbattery composite electrode material.

[0068] Example 2

[0069] Assembly of nano-micro batteries:

[0070] For anode preparation, lithium cobalt oxide powder is mixed with a binder and a conductive agent in a certain proportion to form a slurry, which is then 3D printed on a substrate to form an anode. A positive electrode shell is installed on top of the substrate.

[0071] The cathode was prepared by using the 3D printed nano-microbattery composite electrode material prepared in Example 1 as the cathode and installing it on a substrate, and a negative electrode shell was installed at the bottom of the substrate.

[0072] The separator and electrolyte are placed between the anode and the cathode, and an organic electrolyte containing LiPF6 is injected to assemble a nano-micro battery.

[0073] The performance of the V2O5, MXene and AuNPs used in Examples 1-2, the prepared composite electrode material, and the prepared nano-microbattery were tested.

[0074] like Figure 1 Figure 2 shows a scanning electron microscope (SEM) image of a two-dimensional layered V2O5 (vanadium pentoxide) material. The SEM image depicts the structural features of the V2O5 material, particularly highlighting its two-dimensional layered morphology. This structure is crucial for improving electrochemical performance because the layered structure facilitates efficient lithium ion insertion, contributing to the material's high capacity and cycling stability.

[0075] like Figure 2 As shown, a 2D layered MXene material, MXene (Ti2C3Ti x ) SEM image. MXenes are a class of transition metal carbides, nitrides, or carbonitrides known for their excellent conductivity, large surface area, and outstanding electrochemical properties. These properties make MXenes highly suitable for use in lithium-ion batteries, particularly for improving the performance of the positive and negative electrodes, thereby increasing the battery's overall energy storage capacity and cycle life.

[0076] like Figure 3The figure below shows an SEM image of gold nanoparticles. Integrating gold nanoparticles (AuNPs) into battery materials can improve the electrochemical properties and performance of lithium-ion batteries. Gold nanoparticles exhibit unique electronic properties and a high surface area, which help enhance the conductivity, stability, and capacity retention of battery systems. These nanoparticles are strategically incorporated into battery electrodes to optimize charge and discharge cycles and enhance the durability of the materials.

[0077] like Figure 4 As shown, the SEM image of the hybrid nanocomposite material integrating V2O5, MXene and gold nanoparticles is shown, which combines the unique properties of each material to enhance the performance of lithium-ion batteries, optimize conductivity, capacity and cycle stability, and improve energy storage.

[0078] like Figure 5 Shown is the SEM image of the 3D printed sample, showing the scanning electron microscope image (SEM) of the 3D printed cathode material prepared by direct ink writing technology (DIW), showing the detailed morphology and structural characteristics of the printed layer.

[0079] like Figure 6 Shown is a close-up SEM image of the 3D printed sample, showing an optical image of a complete cathode structure consisting of 6 layers mounted on an aluminum substrate. The multi-layer design enhances the performance of lithium-ion batteries.

[0080] like Figure 7 The figure shows an optical image of a 3D-printed sample on an aluminum substrate, illustrating a 3D-printed cathode developed using vanadium pentoxide (V2O5) as the substrate material. MXene and gold (Au) nanoparticles in varying proportions were integrated to enhance the cathode's electrochemical performance. The white portion in the image represents the aluminum substrate, the black portion represents the cathode material, the entire structure represents the processed cathode, and the white frame represents the aluminum foil used to attach the cathode material. This black cathode material and white aluminum foil constitute the cathode portion of the battery. The cathode material is a line with a thickness of 10 to 20 μm. Each cathode layer is designed to have a thickness of approximately 10 μm. Typically, two to eight layers are used in construction, which contributes to overall structural integrity and performance. Stereolithography and ink direct writing techniques enable precise control of material deposition and structural configuration. Optimizing the surface area facilitates greater interaction between lithium ions and the active material, significantly improving the overall performance of the negative electrode in energy storage applications.

[0081] Figure 8 Schematic diagram of nano-micro battery; Figure 9The cyclic voltammetry plots for this cell show both anodic and cathodic scans, highlighting the characteristic electrochemical behavior of the hybrid material composed of VO, MXene, and Au (gold) nanoparticles. Multiple curves correspond to cyclic voltammetric scans of a VO-TiC-Au cathode in a lithium-ion battery over multiple cycles, particularly the first, second, and third cycles. These curves demonstrate the electrochemical reversibility and stability of this composite electrode material during lithium ion insertion / deinsertion. The nearly overlapping redox peaks indicate highly reversible and stable charge-discharge behavior. During the anodic scan, lithium ions exit the electrode, initiating oxidation reactions, while during the cathodic scan, lithium ions reenter the electrode, initiating reduction reactions. Distinct characteristic peaks corresponding to VO, MXene, and Au reflect the redox activity of each component in the composite. These peaks demonstrate the successful integration of each material, each contributing to the overall electrochemical profile. Multiple sharp redox peaks are observed in the range of approximately 1.5 V to 3.0 V, indicating the gradual insertion / deinsertion of lithium into the VO layer. These redox characteristics confirm the material's pseudocapacitive and Faradaic properties. The introduction of Ti3C2MXene enhances electronic conductivity, while the gold nanoparticles promote charge transfer kinetics and activate more active sites for electrochemical reactions. This characteristic behavior highlights the potential of this hybrid material for enhanced reversibility, stability, and performance in lithium-ion battery applications.

[0082] Figure 10 The battery is tested at different current densities (0.1A, 0.2A, 0.4A, 0.8A, and back to 0.1A) to evaluate performance under different load conditions. Testing at multiple current densities understands the material's rate performance, stability, and adaptability to real-world scenarios, ensuring the battery maintains high efficiency and capacity under different usage scenarios.

[0083] Figure 11 Results from long-term electrochemical cycling, a process that involves repeatedly charging and discharging a battery over an extended period of time, are presented. This testing evaluates the durability, stability, and capacity retention of battery materials under realistic operating conditions, which are important indicators of lithium-ion battery performance. The results show that the battery exhibited a high specific capacity of 455.87 mAh / g at a current density of 0.1 A, which highlights its ability to store large amounts of energy. In addition, the cycle efficiency (CE) of 99.89% highlights excellent stability and minimal capacity decay over long periods of cycling, indicating that the material is a promising candidate for high-performance and long-life lithium-ion batteries. These findings reflect the potential of innovative materials to meet the needs of commercial applications that require high-capacity and stable energy storage solutions.

[0084] Therefore, the 3D printed nano-microbattery composite electrode material and its preparation method of the present invention use MXenes as conductive fillers in the V2O5 matrix, which has the characteristics of high conductivity. This integration reduces resistance and improves overall efficiency. The unique layered structure and large specific surface area of ​​MXenes provide an optimal pathway for lithium ion transport, significantly accelerating the insertion and extraction process. MXenes contribute to the mechanical stability of V2O5, alleviate the risk of structural collapse during the cycle, and improve long-term cycle performance. The introduction of AuNPs improves the electronic conductivity of the composite material, which is beneficial to effective electron transfer during battery operation. AuNPs can accelerate charge transfer at the electrode interface, thereby improving the kinetics of lithium insertion and extraction, resulting in faster battery response time. The presence of AuNPs provides additional nucleation sites, promotes uniform and efficient lithium ion insertion, and enhances overall cycle stability.

[0085] AuNPs also catalyze the reaction of MXenes with V2O5, promoting the formation of TiO2 at the interfacial layer. The combination of V2O5, MXenes, and AuNPs produces a synergistic effect, in which each component enhances the overall performance. V2O5 serves as the active species, while MXenes and AuNPs simultaneously improve electronic and ionic conductivity. With improved electron and lithium-ion transport pathways, the kinetics of the intercalation and deintercalation processes are significantly enhanced, leading to faster charge and discharge rates. The structural reinforcement of MXenes, combined with the conductive advantages of AuNPs, leads to improved cycling stability and significantly reduced capacity fade over long-term use. The designed V2O5-Ti2C3 heterostructure is interconnected by the interfacial TiO2 layer, promoting the formation of oxygen vacancies, generating localized stress, and enhancing lithium ion intercalation through synergistic redox and electronic interactions. Titanium atoms further anchor the gold nanoparticles, forming gold-titanium bonds (AuTi3, Au2Ti), further improving interfacial conductivity and structural integrity. The interfacial TiO2 layer formed between V2O5 and Ti2C3 can anchor the oxides, reduce lattice mismatch, introduce oxygen vacancies, and promote electron / ion transport, thereby improving electrochemical performance. 3DP-VTA composites provide ideas for higher-performance energy storage systems.

[0086] The layered stacking structure constructed using direct ink writing (DIW) technology creates interconnected ion transport channels and an electronic conductive network, enhancing ion transport and overall energy density. 3D printing technology enables precise control of electrode thickness, porosity, and geometry, meeting the customized battery volume and performance requirements of different micro-devices and supporting rapid iterative optimization, optimizing material usage and reducing waste. The controllable electrode thickness, combined with the 3D-printed multi-layer stacked battery structure, meets the "small size, long battery life" requirements of wearable devices such as smartwatches and implantable sensors. Structural stability ensures stable performance under complex operating conditions such as bending and vibration, making it suitable for outdoor operation in IoT terminal devices such as wireless sensor nodes.

[0087] The synergistic integration of the two-dimensional conductive layer of MXenes and the catalytic sites of AuNPs into a V2O5 matrix creates a multifunctional "conductivity-catalysis-structural support" composite system. This overcomes the drawback of single carbon-based materials (such as graphene) that only physically enhance conductivity but fail to inhibit structural phase transitions. DIW-based 3D printing technology combines nanoscale material dispersion with macrostructural control. Compared to traditional coating processes, this avoids the problems of active material agglomeration and uneven distribution of conductive additives. It also eliminates the need for high-temperature sintering, reducing energy consumption and making it suitable for large-scale production.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. 3D printed nano-micro battery composite electrode material, characterized in that: The composite electrode material comprises V2O5, Ti3C2MXene material and gold nanoparticles, wherein: V2O5 is the matrix material, acting as an active substance and providing lithium ion storage sites; Ti3C2MXene material acts as a conductive enhancer and structural support, uniformly dispersed in a two-dimensional lamellar structure within a V2O5 matrix material. The two are connected by a defect-rich TiO2 interlayer, which anchors the oxide, reduces lattice mismatch, and introduces oxygen vacancies. Gold nanoparticles act as catalytic active sites and ion transport accelerators, anchored on the Ti sites on the Ti3C2MXene surface, forming conductive interface bonds and uniformly loaded on the V2O5 surface and the gaps between MXene sheets; The composite electrode material is printed and formed by ink direct writing technology to form a layered stacking structure, construct a through-going electronic conductive network and lithium ion transmission channel, accurately control the structure and spatial distribution of the active material, and shorten the ion / electron transmission path.

2. The 3D printed nano-microbattery composite electrode material according to claim 1, characterized in that: The layered stacking structure formed has a single layer thickness of 10-20 μm and a total number of layers of 2-8 layers. The TiO2 intermediate layer and the MXene sheet form a heterojunction interface between the layers, so that the composite electrode material has a layered heterogeneous structure.

3. The 3D printed nano-microbattery composite electrode material according to claim 1, characterized in that: The pore structure of the composite electrode material is regulated by adjusting the solid phase content of the printing ink and the printing parameters.

4. A nano-microbattery prepared based on the 3D printed nano-microbattery composite electrode material according to claim 1, characterized in that: The structure of the nano-micro battery includes: An anode, made of lithium cobalt oxide and manufactured by 3D printing, is disposed on a substrate, and a positive electrode housing is disposed on top of the substrate; A cathode, which is a 3D printed composite material and is disposed on a substrate, with a negative electrode housing disposed at the bottom of the substrate; The diaphragm is a porous polyolefin membrane or a ceramic coating diaphragm, which is arranged between the anode and the cathode; The electrolyte is an organic electrolyte containing lithium ions. The lithium ions are transferred from the anode to the cathode and embedded in the interlayer structure of the cathode material to realize the charging process; the lithium ions are released from the cathode and returned to the anode to realize the discharging process.

5. An application of the nano-microbattery according to claim 4, characterized in that: Applications include wearable devices, medical implants, or IoT sensors.

6. A method for preparing a 3D printed nano-microbattery composite electrode material according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Prepare a precursor ink by mixing V2O5 nanoparticles, Ti3C2MXene material, and gold nanoparticles in a mass ratio of 5:1-3:0.1-1, adding a binder containing a TiO2 precursor and a solvent, and ultrasonically dispersing for 1-3 hours to form a uniform ink. The TiO2 precursor is converted into a defect-rich TiO2 intermediate layer in subsequent processing; S2, 3D printing, using ink direct writing technology, prints the precursor ink layer by layer on the aluminum substrate through a precision nozzle. The thickness of a single layer is 10-20 μm, the interlayer drying time is 5-15 minutes, and a total of 2-8 layers are printed to form a wet electrode blank; S3, post-treatment, vacuum drying the wet electrode blank at 60-80 ° C for 12-24 hours, and then heat treating it at 300-400 ° C in an argon atmosphere for 1-2 hours to remove the binder and strengthen the interface bonding to obtain a 3D printed composite material. During the heat treatment process, the TiO2 precursor is converted into a TiO2 intermediate layer containing oxygen vacancies, and the gold nanoparticles form a conductive interface bond with the Ti sites on the MXene surface.

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