Flexible transparent battery device based on composite electrode

Abstract

The invention discloses a flexible transparent battery device based on a composite electrode, and relates to the technical field of flexible energy storage devices, and the flexible transparent battery device comprises a substrate, a gradient alloy electrode layer, an MXene-Si-C gel active layer, a PEDOT: PSS buffer layer, a solid electrolyte layer, a positive electrode layer and a packaging layer which are sequentially arranged from bottom to top; the gradient alloy electrode layer is an Ag-X alloy film, X is one or more of Cu, Zn and Ti, and Ag accounts for 90-99 wt%; the addition of trace Cu, Zn or Ti is used for inhibiting the oxidation of Ag and improving the adhesive force of the film; according to the alloy film-MXene mixed conductive network, an ultrathin silver film is deposited on a substrate through magnetron sputtering, the ultrathin silver film and an MXene gel layer form an interpenetrating structure, and high light transmittance (gt, 75% under the wavelength of 550 nm) and low surface resistance (lt, 9 omega / sq) are achieved.

Description

Technical Field

[0001] This invention belongs to the field of flexible energy storage devices, specifically relating to a flexible transparent battery device based on composite electrodes. Background Technology

[0002] Traditional flexible batteries are limited by the volume expansion effect of silicon anodes, resulting in short cycle life (<200 cycles). Transparent electrodes (such as ITO) have poor mechanical flexibility and are expensive; A single conductive network (such as carbon materials) cannot simultaneously achieve high transparency and high conductivity.

[0003] Pure silver films are easily oxidized to form Ag₂O, which leads to a decrease in conductivity; It is difficult to achieve both high light transmittance and mechanical flexibility in alloy films with high Ag content (>90%). The poor interfacial compatibility between the alloy film and MXene gel affects the charge transport efficiency.

[0004] Comparison of related technologies: CN113488658A: Discloses an MXene / silicon composite electrode, but does not solve the problems of transparency and interface stability; US20220109021A1: Uses silver nanowire transparent electrodes, but silver is easily oxidized and has poor compatibility with silicon.

[0005] CN114597241A: Discloses a transparent Ag nanowire electrode, but does not solve the Ag oxidation problem. Therefore, a flexible transparent battery device suitable for wearable devices, foldable screen phones, and other applications requiring high flexibility and optical performance is designed. Summary of the Invention

[0006] The purpose of this invention is to provide a flexible transparent battery device based on composite electrodes, thereby solving the above-mentioned technical problems.

[0007] The objective of this invention can be achieved through the following technical solutions: A flexible transparent battery device based on composite electrodes includes, from bottom to top, a substrate, a gradient alloy electrode layer, an MXene-Si@C gel active layer, a PEDOT:PSS buffer layer, a solid electrolyte layer, a positive electrode layer, and an encapsulation layer; The gradient alloy electrode layer is an Ag-X alloy film, where X is one or more of Cu, Zn, and Ti, and Ag accounts for 90-99 wt%. The addition of trace amounts of Cu, Zn, or Ti is used to inhibit Ag oxidation and improve film adhesion. The gradient alloy electrode layer and the MXene layer in the MXene-Si@C gel active layer form an interpenetrating structure; The thickness of the gradient alloy electrode layer is 5-20 nm; The gradient alloy electrode layer, from the substrate interface z=0 to the electrode surface z=d, where z is the thickness direction coordinate and d is the total film thickness, has an Ag mass percentage that linearly increases from an initial value of 90%-98% to 98.1%-99.9%, corresponding to a X element content that decreases from 10%-2% to 1.9%-0.1%. The MXene-Si@C gel active layer is a porous MXene-Si@C structure with a thickness of 100-300 nm; wherein, the carbon shell thickness is 10-20 nm, the particle size distribution is 50-100 nm, and the dry film thickness is 100-300 nm. Microcavity encapsulation of Si@C particles is constructed in the MXene gel within the MXene-Si@C gel active layer to form a biomimetic pomegranate structure encapsulation structure.

[0008] As a further aspect of the present invention, the substrate may be any one of polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polydimethylsiloxane (PDMS).

[0009] As a further aspect of the present invention, the thickness of the PEDOT:PSS buffer layer is 150-400nm.

[0010] As a further aspect of the present invention: the solid electrolyte layer is a 10-60 μm PEO-based polymer solid electrolyte with added inorganic fillers.

[0011] As a further aspect of the present invention: the inorganic filler is one or more of TiO2, ZnO, In2O3, Al2O3 and Ga2O3.

[0012] As a further aspect of the present invention: the positive electrode layer is a LiFePO4@MXene core-shell structure, the diameter of the LiFePO4 core is 30-500nm; the thickness of the MXene shell is 1-60nm, and the dry film thickness is 80-600nm.

[0013] As a further aspect of the present invention: the encapsulation layer is a PET / Al composite film with a thickness of 50±5μm.

[0014] The beneficial effects of this invention are: 1. Alloy film composition optimization: By doping with trace amounts of Cu, Zn or Ti (1-10wt%), Ag oxidation is suppressed and film adhesion is improved (the oxidation resistance of CuAg alloy is improved by 40%). 2. Gradient Alloy Design: The Ag content of the thin film increases from the substrate side towards the active layer, balancing average transmittance (>71%) and conductivity (sheet resistance <9Ω / sq); Conductivity Optimization: Moderate X doping near the substrate improves the ohmic contact characteristics between the electrode and the substrate; a high Ag content surface layer provides a low-resistance interface. Mechanical Property Regulation: The gradient structure can alleviate interfacial delamination caused by thermal expansion coefficient mismatch; the strengthening effect of X element can inhibit electromigration and extend electrode life. Enhanced Corrosion Resistance: When the passivation ability of the Ag-rich surface region is weak, the internal X element gradient can form a sacrificial protective layer (such as the Ag-Cu system), achieving selective enhancement of transmittance and electrical properties; 3. Alloy-MXene interface bonding: The doped metal (such as Ti) in the alloy forms Ti-O-Ti or Ti-F bonds with the functional groups (-O, -F) on the MXene surface, reducing the interfacial contact resistance.

[0015] 4. Alloy Thin Film-MXene Hybrid Conductive Network: An ultrathin silver film is deposited on the substrate by magnetron sputtering and forms an interpenetrating structure with the MXene gel layer, achieving high transmittance (>75% at 550nm wavelength) and low surface resistivity (<9Ω / sq). 5. Biomimetic pomegranate structure encapsulation: Microcavity encapsulation of Si@C particles is constructed in MXene gel, and an alloy film serves as an external conductive framework to suppress volume expansion; 6. Gradient Porosity Design: The electrode transitions from a dense alloy layer on the substrate side to a porous MXene-Si@C active layer, balancing ion / electron transport with active material loading (>2mAh / cm³). 2 ); 7. The core-shell structure (LiFePO4@MXene) combines the high safety and stability of lithium iron phosphate (LiFePO4) with that of MXene (such as Ti3C2T). X High conductivity and adjustable structure; 8. Core-shell structures (LiFePO4@MXene) exist in lithium-ion batteries as nano- to micron-sized composite particles, with lithium iron phosphate (LiFePO4) at the core and uniformly coated with MXene sheets on the outside. This structure significantly improves electrode performance through a synergistic effect of physical and chemical processes. This invention improves conversion efficiency and stability, and has high practical value and broad application prospects. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is the transmittance spectrum of the composite electrode in Embodiment 1 of this application; Figure 3 This is the transmittance spectrum of the composite electrode in Embodiment 2 of this application; Figure 4 This is the transmittance spectrum of the composite electrode in Example 3 of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 As shown, the present invention is a flexible transparent battery device based on a composite electrode, comprising, from bottom to top, a substrate 1, a gradient alloy electrode layer 2, an MXene-Si@C gel active layer 3, a PEDOT:PSS buffer layer 4, a solid electrolyte layer 5, a positive electrode layer 6, and an encapsulation layer 7.

[0020] Ag-based alloy thin films (target material is Ag-X alloy, X=Cu / Zn / Ti) are deposited on substrate 1 by magnetron sputtering to form gradient alloy electrode layer 2; MXene colloid and Si@C powder were added to 3-aminopropyltriethoxysilane and ethanol / deionized water at a mass ratio of 3:1 to obtain MXene-Si@C gel, which was then coated on the surface of alloy electrode layer 2 and dried to form MXene-Si@C gel active layer 3. The flexible substrate was impregnated in the diluted PEDOT:PSS solution and dried to obtain PEDOT:PSS buffer layer 4. PEO and LiTFSI were mixed in a molar ratio of 15:1 and added to acetonitrile to obtain an electrolyte, which was then coated on the surface of PEDOT:PSS buffer layer 4 and dried to form a solid electrolyte layer 5. Ti3C2T x The dispersion was added to the LiFePO4 precursor solution and mixed. The resulting dispersion was subjected to hydrothermal reaction, cooling and centrifugation, washing, drying and annealing to obtain the positive electrode layer. A battery device is obtained by hot-pressing a PET / Al composite film to encapsulate the positive electrode and a flexible substrate containing a solid electrolyte layer to form an encapsulation layer 7.

[0021] Example 1: like Figure 2 As shown, a flexible transparent battery device based on a composite electrode includes polyimide (PI) as a flexible substrate 1.

[0022] The gradient alloy electrode layer is an Ag-Cu alloy thin film with a thickness of 10 nm. From the substrate interface (z=0) to the electrode surface (z=10), the mass percentage of Ag increases linearly from the initial value of 96% to 99.5%, and the corresponding Cu element decreases linearly from 4% to 0.5%.

[0023] The MXene-Si@C gel active layer is a porous MXene-Si@C structure with a thickness of 200 nm; wherein, the carbon shell has a thickness of 10 nm and a particle size distribution of 60 nm. The PEDOT:PSS buffer layer has a thickness of 200nm; The solid electrolyte layer is a 20μm PEO-based polymer solid electrolyte with 1% In2O3 filler. The cathode layer has a core-shell structure (LiFePO4@MXene), with a core (LiFePO4) diameter of 200 nm and a shell (MXene) thickness of 10 nm, resulting in a dry film thickness of 300 nm. The encapsulation layer is a PET / Al composite film with a thickness of 48μm.

[0024] Performance testing of the obtained flexible transparent battery: Light transmittance: 75.4% (380nm-760nm wavelength). Surface resistivity: 8.2 Ω / sq; Ionic conductivity: 1.6 × 10⁻⁶ -4 S / cm; Antioxidant properties (85% humidity, 72 hours): Resistance increased by only 8% (pure Ag film increased by 25%). Electrochemical performance: Areometric capacity: 2.3 mAh / cm³ 2 (0.1C, voltage window 0.01-1.5V vs. Li / Li) + ); Cyclic stability: 84% capacity retention after 1000 cycles (1C charge / discharge); Bending test: Capacity decay <3% after 2000 cycles (1mm radius); Scratch adhesion: Critical load 15N (ASTM C1624 standard).

[0025] Example 2: like Figure 3 As shown, a flexible transparent battery device based on a composite electrode includes a polyethylene terephthalate (PET) substrate 1.

[0026] The alloy electrode layer is an Ag-Ti alloy thin film with a thickness of 8 nm. From the substrate interface (z=0) to the electrode surface (z=8), the mass percentage of Ag increases linearly from the initial value of 97.9% to 99.9%, and the corresponding Ti element decreases linearly from 2.1% to 0.1%.

[0027] The MXene-Si@C gel active layer is a porous MXene-Si@C structure with a thickness of 100 nm; wherein, the carbon shell has a thickness of 15 nm and a particle size distribution of 50 nm. The PEDOT:PSS buffer layer has a thickness of 150nm; The solid electrolyte layer is a 20μm PEO-based polymer solid electrolyte with 0.5% d Ga2O3 filler. The cathode layer has a core-shell structure (LiFePO4@MXene), with a core (LiFePO4) diameter of 300 nm and a shell (MXene) thickness of 30 nm, resulting in a dry film thickness of 450 nm. The encapsulation layer is a PET / Al composite film with a thickness of 50μm.

[0028] Performance testing of the obtained flexible transparent battery: Light transmittance: 75.8%, surface resistivity: 9 Ω / sq; ionic conductivity: 1.6 × 10⁻⁶ -4 S / cm; Antioxidant properties (85% humidity, 72 hours): Resistance increased by only 6% (pure Ag film increased by 25%). Electrochemical performance: Areometric capacity: 2.4 mAh / cm³ 2 (0.1C, voltage window 0.01-1.5V vs. Li / Li) + ); Cyclic stability: 86% capacity retention after 1000 cycles (1C charge / discharge); Bending test: Capacity decay <3% after 2000 cycles (1mm radius); Interfacial bonding strength (scratch test): critical load 18N (better than CuAg's 15N, pure Ag film is 9N).

[0029] Example 3: like Figure 4 As shown, a flexible transparent battery device based on a composite electrode includes a polyethylene terephthalate (PET) substrate 1.

[0030] The alloy electrode layer is an Ag-Zn alloy thin film with a thickness of 13 nm. From the substrate interface (z=0) to the electrode surface (z=13), the mass percentage of Ag increases linearly from the initial value of 97.5% to 99.2%, and the corresponding Ti element decreases linearly from 2.5% to 0.8%.

[0031] The MXene-Si@C gel active layer is a porous MXene-Si@C structure with a thickness of 270 nm; wherein, the carbon shell has a thickness of 20 nm and a particle size distribution of 80 nm. The PEDOT:PSS buffer layer has a thickness of 240nm; The solid electrolyte layer is a 20μm PEO-based polymer solid electrolyte with 0.7% d Al2O3 filler. The positive electrode layer has a core-shell structure (LiFePO4@MXene), with a core (LiFePO4) diameter of 280 nm and a shell (MXene) thickness of 40 nm, resulting in a dry film thickness of 400 nm. The encapsulation layer is a PET / Al composite film with a thickness of 45μm.

[0032] Performance testing of the obtained flexible transparent battery: Light transmittance: 73.9%, surface resistivity: 7.1 Ω / sq; ionic conductivity: 1.7 × 10⁻⁶ -4 S / cm; Antioxidant properties (85% humidity, 72 hours): Resistance increased by only 6% (pure Ag film increased by 25%). Electrochemical performance: Areometric capacity: 2.4 mAh / cm³ 2 (0.1C, voltage window 0.01-1.5V vs. Li / Li) + ); Cyclic stability: 86% capacity retention after 1000 cycles (1C charge / discharge); Bending test: Capacity decay <3.2% after 2000 cycles (1mm radius); Interfacial bonding strength (scratch test): critical load 16N (better than CuAg's 15N, pure Ag film is 9N).

[0033] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A flexible transparent battery device based on a composite electrode, characterized in that, The structure includes, from bottom to top, a substrate (1), a gradient alloy electrode layer (2), an MXene-Si@C gel active layer (3), a PEDOT:PSS buffer layer (4), a solid electrolyte layer (5), a positive electrode layer (6), and an encapsulation layer (7). The gradient alloy electrode layer (2) is an Ag-X alloy film, where X is one or more of Cu, Zn and Ti, and Ag accounts for 90-99 wt%; the addition of trace amounts of Cu, Zn or Ti is used to inhibit Ag oxidation and improve film adhesion. The gradient alloy electrode layer (2) and the MXene layer in the MXene-Si@C gel active layer (3) form an interpenetrating structure; The thickness of the gradient alloy electrode layer (2) is 5-20 nm; The gradient alloy electrode layer (2) has a thickness range from z=0 at the interface of the substrate (1) to z=d at the electrode surface, where z is the thickness direction coordinate and d is the total thickness of the film, and the mass percentage of Ag ranges from the initial value of 90% to 98%. The percentage increases linearly to 98.1%-99.9%, corresponding to a decrease in the percentage of element X from 10%-2% to 1.9%-0.1%. The MXene-Si@C gel active layer (3) is a porous MXene-Si@C structure with a thickness of 100-300 nm; wherein, the carbon shell thickness is 10-20 nm, the particle size distribution is 50-100 nm, and the dry film thickness is 100-300 nm. Microcavity encapsulation of Si@C particles is constructed in the MXene gel in the MXene-Si@C gel active layer (3) to form a biomimetic pomegranate structure encapsulation structure.

2. The flexible transparent battery device based on a composite electrode according to claim 1, characterized in that, The substrate (1) is made of any one of the following materials: polyimide, polyethylene terephthalate, polyethylene naphthalate, and polydimethylsiloxane.

3. A flexible transparent battery device based on a composite electrode according to claim 1, characterized in that, The thickness of the PEDOT:PSS buffer layer (4) is 150-400 nm.

4. A flexible transparent battery device based on a composite electrode according to claim 1, characterized in that, The solid electrolyte layer (5) is a 10-60 μm PEO-based polymer solid electrolyte with added inorganic fillers.

5. A flexible transparent battery device based on a composite electrode according to claim 4, characterized in that, The inorganic filler is one or more of TiO2, ZnO, In2O3, Al2O3 and Ga2O3.

6. A flexible transparent battery device based on a composite electrode according to claim 1, characterized in that, The positive electrode layer (6) is a LiFePO4@MXene core-shell structure, with the LiFePO4 core having a diameter of 30-500nm; the MXene shell having a thickness of 1-60nm; and the dry film having a thickness of 80-600nm.

7. A flexible transparent battery device based on a composite electrode according to claim 1, characterized in that, The encapsulation layer (7) is a PET / Al composite film with a thickness of 50±5μm.

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