Superlattice structure all-solid-state thin-film battery cathode materials, their preparation methods and applications

Abstract

This invention discloses a superlattice structure all-solid-state thin-film battery cathode material, its preparation method, and its applications. The cathode material consists of a substrate and a stacked structure deposited on the substrate surface. The stacked structure is formed by alternating deposition of a first transition metal oxide layer and a second transition metal oxide layer from bottom to top. The first and second transition metal oxides of this invention have different work functions and lithium-ion intercalation potentials. An integrated electric field is induced through interface bandgap engineering, synergistically enhancing electron / ion transport dynamics. Simultaneously, lattice pinning and lattice pre-strain are used to suppress structural degradation during cycling. The cathode material provided by this invention exhibits high specific capacity, excellent rate performance, long cycle life, and low preparation temperature, is compatible with semiconductor processes, and is suitable for microelectronic integrated systems.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage materials and devices, specifically to a superlattice structure all-solid-state thin-film battery cathode material, its preparation method, and its application. Background Technology

[0002] All-solid-state thin-film batteries are miniaturized and integrable on-chip energy storage devices, primarily used in embedded power supplies within the integrated circuit field. Unlike traditional power supply solutions that rely on external coin cells or supercapacitors, thin-film batteries can be co-integrated with chips at the wafer, packaging substrate, or system-in-package level, providing long-term, stable local power support for ultra-low-power electronic systems.

[0003] However, due to the slow electron / ion conduction kinetics, the actual capacity of traditional thin-film cathode materials is far lower than the theoretical value, making it difficult to meet the requirements for high energy density and most application scenarios, thus greatly limiting their large-scale application. Furthermore, commercial cathode materials (such as LiCoO2 and LiMn2O4) generally require high-temperature annealing and crystallization (>500℃), making them incompatible with semiconductor fabrication processes, which significantly limits the potential application of all-solid-state thin-film batteries in the microelectronics field.

[0004] In recent years, research on improving electrode performance by constructing multilayer composite structures has received widespread attention. However, these techniques mostly use physical methods such as magnetron sputtering to prepare ordinary multilayer films with a layer thickness of usually more than 10 nm. The interfaces are rough, the improvement of electron / ion transport is limited, and the synergistic effect is mostly due to the simple superposition of material functions, failing to give full play to the quantum effect of heterogeneous interfaces.

[0005] Therefore, there is an urgent need to develop a new type of cathode material that can precisely control the interface structure at the atomic scale and achieve synergistic enhancement of electron / ion transport. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a superlattice structured all-solid-state thin-film battery cathode material, its preparation method, and its applications. This invention utilizes two transition metal oxides with complementary electrochemical properties, alternatingly epitaxially growing them at the atomic scale to form a periodic superlattice. This structure leverages interface band engineering to induce a built-in electric field, significantly enhancing electron / ion transport dynamics, while simultaneously using lattice strain to suppress volume expansion and structural degradation during cycling.

[0007] To achieve the above objectives, the technical solution designed by the present invention is as follows:

[0008] This invention provides a superlattice structure all-solid-state thin-film battery cathode material, wherein the cathode material consists of a substrate and a stacked structure deposited on the substrate surface, the stacked structure being formed by alternating deposition of a first transition metal oxide layer and a second transition metal oxide layer from bottom to top.

[0009] The number of alternating depositional stacking cycles is 40-80;

[0010] The work function of the first transition metal oxide in the first transition metal oxide layer is 4.0~6.9 eV, and the lithium ion intercalation potential is 1.0~4.0 V;

[0011] The work function of the second transition metal oxide in the second transition metal oxide layer is 4.8~6.5 eV, and the lithium ion intercalation potential is 1.0~3.5 V;

[0012] The first transition metal oxide is any one of V2O5, MoO3, WO3 and TiO2; the second transition metal oxide is any one of V3O7, NiO, Mn3O4 and Fe2O3.

[0013] Furthermore, the substrate is any one of silicon wafer, sapphire, polyimide film and quartz, the single-layer thickness of the first transition metal oxide layer is 0.5~2 nm; the single-layer thickness of the second transition metal oxide layer is 1~3 nm; and the interface roughness of the positive electrode material is less than 0.3 nm.

[0014] Furthermore, the substrate is a silicon wafer, the thickness of the first transition metal oxide layer is 2 nm, and the first transition metal oxide is V2O5; the thickness of the second transition metal oxide layer is 2 nm, and the second transition metal oxide is V3O7.

[0015] The number of alternating depositional stacking cycles is 50.

[0016] The present invention also provides a method for preparing the aforementioned cathode material, comprising the following steps:

[0017] (1) The substrate is ultrasonically cleaned and dried sequentially;

[0018] (2) A first transition metal oxide layer is deposited on the dried substrate surface using molecular beam epitaxy or high-power pulsed magnetron sputtering.

[0019] (3) A second transition metal oxide layer is deposited on the surface of the first transition metal oxide layer using molecular beam epitaxy or high-power pulsed magnetron sputtering.

[0020] (4) Repeat steps (2) and (3) for a total of 40 to 80 alternating deposition cycles to obtain a superlattice thin film;

[0021] (5) After deposition, the sample is subjected to flash Joule heat treatment or annealing, and after cooling, the superlattice structure all-solid-state thin film battery cathode material is obtained.

[0022] Furthermore, in step (1), the substrate is any one of silicon wafer, sapphire, polyimide film and quartz.

[0023] Furthermore, in steps (2) and (3), the conditions for the molecular beam epitaxy method are: the temperature of the beam source furnace is 1000~1300℃, and the oxygen partial pressure is 2×10⁻⁶. -4 ~1×10 -3 Pa, deposition rate of 0.01~0.02 nm / s, substrate temperature maintained at 250~400℃;

[0024] The conditions for the high-power pulsed magnetron sputtering method are as follows: magnetron sputtering power of 50~100 W, oxygen to argon volume ratio of 1:6~10 in the oxygen-argon mixed atmosphere, magnetron sputtering pressure of 0.5~2 Pa, and substrate temperature maintained at 100~300℃.

[0025] Furthermore, in step (5), the atmosphere of the flash Joule heat treatment is oxygen, the temperature of the flash Joule heat treatment is 100~300℃, and the time of the flash Joule heat treatment is 30~300s.

[0026] The annealing atmosphere is oxygen or argon, the annealing temperature is 150~300℃, and the annealing time is 5~60 min.

[0027] The present invention also provides an application of the aforementioned cathode material in the preparation of all-solid-state thin-film batteries.

[0028] The present invention also provides an all-solid-state thin-film battery, wherein the all-solid-state thin-film battery uses the aforementioned positive electrode material as the positive electrode, lithium metal or lithium alloy as the negative electrode, and LiPON or LATP as the solid electrolyte.

[0029] The principle of this invention:

[0030] In this atomically scaled, periodically stacked superlattice thin-film cathode material, a first transition metal oxide layer and a second transition metal oxide layer are alternately epitaxially arranged to form a superlattice structure with a clear heterojunction. This structure enables lattice continuity and band coupling between the two materials at the atomic scale. The difference in work function at the interface induces a built-in electric field, significantly reducing the diffusion barrier for lithium ions across the interface. Simultaneously, the band folding effect enhances electronic conductivity. The first transition oxide layer provides a rapid lithium-ion insertion channel and structural framework, while the second transition oxide layer contributes additional active sites and an electronic conductivity network. The two layers synergistically enhance each other through interface quantum confinement and coherent strain, effectively buffering volume expansion and suppressing stress accumulation during charge and discharge, thereby significantly improving cycle life.

[0031] This invention utilizes a combination of molecular beam epitaxy and high-power pulsed magnetron sputtering to precisely control the alternating growth of two oxides at the atomic level. Combined with in-situ monitoring using high-energy electron diffraction, it ensures atomically flat interfaces and lattice continuity. The method eliminates the need for high-temperature annealing (≤300℃) and is compatible with flexible substrates and semiconductor back-end processes. During fabrication, the thickness and number of cycles of each layer are precisely controlled by adjusting the pulse deposition sequence time or beam switching, achieving controllable fabrication of the material's structure and properties.

[0032] The beneficial effects of this invention are:

[0033] 1. The superlattice structure all-solid-state thin-film battery cathode material provided by the present invention has high specific capacity and excellent rate performance, thanks to the acceleration effect of the built-in electric field of the superlattice interface on ion transport and the improvement of electronic conductivity by band engineering.

[0034] 2. The periodic coherent strain of the superlattice structure of the present invention effectively suppresses volume expansion and structural degradation during cycling, enabling the battery to have an ultra-long cycle life.

[0035] 3. The preparation temperature of this invention is below 300°C, which is fully compatible with CMOS processes and flexible substrates, and can be directly integrated into microelectronic chips or flexible devices. Attached Figure Description

[0036] Figure 1 SEM image of the surface of cathode material 1 for a superlattice structure all-solid-state thin-film battery;

[0037] Figure 2 A high-resolution transmission electron microscope image of the cross-section of cathode material 1 for a superlattice structure all-solid-state thin-film battery;

[0038] Figure 3 Here is a surface SEM image of the thin-film cathode material D1;

[0039] Figure 4Cycle performance test results for superlattice structure all-solid-state thin-film battery cathode material 1 and thin-film cathode material D1;

[0040] Figure 5 Photographs of an all-solid-state thin-film battery assembled using superlattice structure all-solid-state thin-film battery cathode material 2, and an application demonstration diagram of driving an infrared sensor device. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can understand it.

[0042] Example 1

[0043] Superlattice structure all-solid-state thin-film battery cathode material 1 is formed by alternating deposition of V2O5 and V3O7. The work function of V2O5 is 5.5~6.7 eV, and the lithium-ion intercalation potential of V2O5 is 2.0~4.0 V. The work function of V3O7 is 5.3~6.0 eV, and the lithium-ion intercalation potential of V3O7 is 2.0~3.5 V. The preparation method is as follows:

[0044] 1. Clean the silicon wafer substrate sequentially with acetone, anhydrous ethanol, and deionized water using ultrasonic cleaning for 15 minutes, dry it with nitrogen, and then place it in a vacuum oven at 80°C for 2 hours.

[0045] 2. Fix the dried silicon wafer substrate onto the sample stage of the molecular beam epitaxy and high-power pulsed magnetron sputtering system, and evacuate to a background pressure of 10. -6 ~10 -8 Pa;

[0046] 3. Growth of V₂O₅ layer using molecular beam epitaxy: Heating the pure V metal beam source furnace to 1100℃, with an oxygen partial pressure of 5×10⁻⁶. - 4 Deposition was carried out under Pa conditions at a deposition rate of 0.02 nm / s to form a V2O5 layer. The thickness of the V2O5 layer was precisely controlled to 2 nm (corresponding to the number of RHEED intensity oscillations) by reflection high-energy electron diffraction (RHEED) oscillation, while the substrate temperature was maintained at 250 °C.

[0047] 4. High-power pulsed magnetron sputtering was used to grow a V3O7 layer: First, 100 W of power was applied to a V target (99.99% purity) under a mixed atmosphere of oxygen and argon (oxygen to argon volume ratio 1:10) at a sputtering pressure of 0.5 Pa. The substrate temperature was maintained at 300℃ during the deposition process. By controlling the pulsed sputtering time to 5 min, a V3O7 layer with a thickness of 2 nm was obtained. RHEED monitoring showed layered growth and clear diffraction fringes.

[0048] 5. Repeat steps 3 and 4 forty-nine times, for a total of fifty deposition cycles, to obtain a superlattice film with a total thickness of 200 nm.

[0049] 6. After deposition, the material is subjected to flash Joule heat treatment at 100~300℃ in an oxygen atmosphere for 30~300 s to eliminate interface defects and achieve an interface roughness of less than 0.3 nm. After natural cooling to room temperature, the superlattice structure all-solid-state thin-film battery cathode material 1 is obtained.

[0050] SEM analysis was performed on the surface of cathode material 1 of the superlattice structure all-solid-state thin-film battery, and the results are as follows: Figure 1 As shown, the surface of the deposited film is relatively uniform, exhibiting a densely stacked morphology of small particles with few pores.

[0051] High-resolution transmission electron microscopy analysis was performed on the cross-section of cathode material 1 of the superlattice structure all-solid-state thin-film battery. The results are as follows: Figure 2 As shown, V2O5 and V3O7 layers are arranged alternately to form a periodic superlattice structure. This structure allows the two materials to be uniformly mixed at the nanoscale while maintaining their respective crystalline characteristics, and the interface is clear and continuous. By controlling the thickness and period number of each layer, the electron / ion conduction path of the material can be optimized, thereby improving the charge transport efficiency.

[0052] Example 2

[0053] Superlattice structure all-solid-state thin-film battery cathode material 2 is formed by alternating deposition of MoO3 and NiO. The work function of MoO3 is 5.3~6.9 eV, and the lithium-ion intercalation potential of MoO3 is 1.0~3.5 V. The work function of NiO is 4.9~5.2 eV, and the lithium-ion intercalation potential of NiO is 1.0~3.0 V. The preparation method is as follows:

[0054] 1. The sapphire (0001) substrate was ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 minutes in sequence, dried with nitrogen and then placed in a vacuum oven at 150°C for 1 hour.

[0055] 2. Fix the dried sapphire (0001) substrate onto the sample stage of the molecular beam epitaxy and high-power pulsed magnetron sputtering system, and evacuate to a background pressure of 10. -6 ~10 -8 Pa;

[0056] 3. MoO3 layer growth by molecular beam epitaxy: The pure Mo metal beam source furnace is heated to 1100℃, with an oxygen partial pressure of 5×10⁻⁶. -4Deposition was carried out under Pa conditions at a deposition rate of 0.02 nm / s to form a MoO3 layer. The thickness of the MoO3 layer was precisely controlled to be 2 nm (corresponding to the number of RHEED intensity oscillations) by reflection high-energy electron diffraction (RHEED). The substrate temperature was maintained at 300℃ during the deposition process.

[0057] 4. Molecular beam epitaxy is used to grow NiO layers: The pure Ni beam source furnace is heated to 1000℃, and the oxygen partial pressure is 2×10⁻⁶. -4 Deposition was carried out under Pa conditions at a deposition rate of 0.015 nm / s to form a NiO layer. The layer thickness was precisely controlled to be 1.5 nm by RHEED oscillation, and the substrate temperature was maintained at 250 °C.

[0058] 5. Repeat steps 3 and 4 fifty-nine times, for a total of sixty deposition cycles, to obtain a superlattice film with a total thickness of 210 nm.

[0059] 6. After deposition, the superlattice structure was rapidly thermally annealed at 300°C for 5 minutes in an argon atmosphere to stabilize the superlattice structure. After cooling to room temperature, the superlattice structure all-solid-state thin-film battery cathode material 2 was obtained with an interface roughness of less than 0.3 nm.

[0060] Example 3

[0061] Superlattice structure all-solid-state thin-film battery cathode material 3 is formed by alternating deposition of WO3 and Mn3O4. The work function of WO3 is 4.0~6.2 eV, and the lithium-ion intercalation potential of WO3 is 1.0~3.0 V. The work function of Mn3O4 is 4.8~6.5 eV, and the lithium-ion intercalation potential of Mn3O4 is 2.0~3.5 V. The preparation method is as follows:

[0062] 1. Clean the polyimide (PI) film (5 μm thick) sequentially with isopropanol and deionized water using ultrasonic cleaning, dry it with nitrogen, and then place it in a vacuum oven at 80°C for 12 hours.

[0063] 2. Attach the PI film onto a stainless steel foil or quartz glass plate, fix it on the sample stage of the molecular beam epitaxy and high-power pulsed magnetron sputtering system, and evacuate to a background pressure of 5 × 10⁻⁶. -6 ~1×10 -8 Pa.

[0064] 3. High-power pulsed magnetron sputtering was used to grow a WO3 layer: First, 80 W of power was applied to a W target (99.99% purity) under a mixed atmosphere of oxygen and argon (oxygen to argon volume ratio 1:10) at a sputtering pressure of 2 Pa. The substrate temperature was maintained at 100℃ during the deposition process. By controlling the pulsed sputtering time to 180 s, a WO3 layer with a thickness of 2 nm was obtained. RHEED monitoring showed a nanocrystalline structure, but the interface remained continuous.

[0065] 4. High-power pulsed magnetron sputtering was used to grow a Mn3O4 layer: First, a power of 50 W was applied to a Mn target (99.99% purity) under a mixed atmosphere of oxygen and argon (volume ratio 1:6), with a sputtering pressure of 0.5 Pa. The substrate temperature was maintained at 200℃ during the deposition process. By controlling the pulsed sputtering time to 150 s, a 3 nm thick Mn3O4 layer was obtained. RHEED monitoring showed layered growth.

[0066] 5. Repeat steps 3 and 4 for 39 cycles, for a total of 40 deposition cycles, to obtain a superlattice film with a total thickness of 200 nm.

[0067] 6) After deposition, the superlattice film is rapidly annealed at 200°C for 30 minutes in an argon atmosphere to improve crystallinity. After natural cooling to room temperature, the superlattice film is peeled off from the surface of the stainless steel foil or quartz glass sheet to obtain the superlattice structure all-solid-state thin-film battery cathode material 3 with an interface roughness of less than 0.3 nm.

[0068] The superlattice structure all-solid-state thin-film battery cathode material 3 of this embodiment showed no surface cracks after being repeatedly bent 1000 times at a bending radius of 5 mm; the superlattice structure all-solid-state thin-film battery cathode material 3 has a periodic layered structure with clear interfaces.

[0069] Example 4

[0070] Superlattice structure all-solid-state thin-film battery cathode material 2 is formed by alternating deposition of TiO2 and Fe2O3. The work function of TiO2 is 4.0~6.0 eV, and the lithium-ion intercalation potential of TiO2 is 1.0~3.5 V. The work function of Fe2O3 is 5.3~6.4 eV, and the lithium-ion intercalation potential of Fe2O3 is 2.0~3.5 V. The preparation method is as follows:

[0071] 1. Clean the quartz substrate sequentially with acetone, anhydrous ethanol, and deionized water using ultrasonic cleaning for 15 minutes, dry it with nitrogen, and then place it in a vacuum oven at 200°C for 1 hour.

[0072] 2. Fix the substrate on the sample stage of the molecular beam epitaxy and high-power pulsed magnetron sputtering system, and evacuate to a background pressure of 10. -6 ~10 -8 Pa.

[0073] 3. Molecular beam epitaxy is used to grow TiO2 layers: The pure Ti metal beam source furnace is heated to 1300℃, and the oxygen partial pressure is 1×10⁻⁶. -3 Deposition was carried out at Pa at a deposition rate of 0.01 nm / s to form a TiO2 layer. The layer thickness was precisely controlled to 1 nm by RHEED oscillation, and the substrate temperature was maintained at 400℃ during the deposition process.

[0074] 4. Molecular beam epitaxy is used to grow Fe2O3 layers: The pure Fe metal beam source furnace is heated to 1050℃, and the oxygen partial pressure is 5×10⁻⁶. -4 Fe2O3 layer was deposited at Pa at a deposition rate of 0.02 nm / s, and the layer thickness was precisely controlled to 1 nm by RHEED oscillation at a substrate temperature of 300℃.

[0075] 5. Repeat steps 3 and 4 for seventy-nine cycles, for a total of eighty deposition cycles, to obtain a superlattice film with a total thickness of 160 nm.

[0076] 6. After deposition, the material is rapidly thermally annealed at 150°C for 1 hour in an oxygen atmosphere to improve crystallization quality. After cooling to room temperature, a superlattice structure all-solid-state thin-film battery cathode material 4 is obtained with an interface roughness of less than 0.3 nm.

[0077] In this embodiment, the RHEED pattern of the superlattice structure all-solid-state thin-film battery cathode material 4 consistently appears as stripes, indicating a two-dimensional growth mode. High-resolution transmission electron microscopy reveals clear superlattice stripes, indicating good lattice matching (mismatch <3%). X-ray photoelectron spectroscopy confirms that Ti is in the +4 valence state and Fe is in the +3 valence state.

[0078] Comparative Example 1

[0079] The preparation method of thin-film cathode material D1 is as follows:

[0080] 1. Clean the silicon wafer substrate sequentially with acetone, anhydrous ethanol, and deionized water using ultrasonic cleaning for 15 minutes, dry it with nitrogen, and then place it in a vacuum oven at 80°C for 2 hours.

[0081] 2. Fix the cleaned substrate onto the substrate stage of the magnetron sputtering equipment, with a target-substrate distance of 7 cm and a substrate rotation speed of 10 rpm. Evacuate the sputtering chamber until the background pressure is below 3 × 10⁻⁶. -4 Pa;

[0082] 3. Introduce argon and oxygen. The argon flow rate is 50 sccm and the oxygen flow rate is 5 sccm. The volume ratio of oxygen to argon is 1:10. Adjust the gate valve to stabilize the working pressure at 0.5 Pa.

[0083] 4. Using radio frequency magnetron sputtering, 100 W of power was applied to a V2O5 target (purity 99.99%) and continuous deposition was carried out for 2 hours to form a pure V2O5 thin film.

[0084] 5. After deposition, the sample was annealed in air at 350°C for 2 hours and then naturally cooled to room temperature to obtain thin film cathode material D1 with a thickness of 300 nm.

[0085] SEM analysis of the thin-film cathode material D1 yielded the following results: Figure 3 As shown, the deposited film has a cracked and rough surface, and does not form a smooth film, which is not conducive to its subsequent application in batteries.

[0086] Comparative Example 2

[0087] The preparation method of thin-film cathode material D2 is as follows:

[0088] 1. Clean the silicon wafer substrate sequentially with acetone, anhydrous ethanol, and deionized water using ultrasonic cleaning for 15 minutes, dry it with nitrogen, and then place it in a vacuum oven at 150°C for 1 hour.

[0089] 2. Fix the cleaned substrate onto the substrate stage of the magnetron sputtering equipment, with a target-substrate distance of 7 cm and a substrate rotation speed of 10 rpm. Evacuate the sputtering chamber until the background pressure is below 3 × 10⁻⁶. -4 Pa.

[0090] 3. Introduce argon and oxygen. The argon flow rate is 50 sccm, the oxygen flow rate is 5 sccm, and the volume ratio of oxygen to argon is 1:10. Adjust the gate valve to stabilize the working pressure at 0.5 Pa.

[0091] 4. Using radio frequency magnetron sputtering, a power of 100 W was first applied to a V2O5 ceramic target (99.99% purity). The deposition rate was 0.2 nm / s, and a V2O5 layer with a thickness of 20 nm was obtained after 100 seconds of deposition.

[0092] 5. Keeping the working gas constant, switch to a Co3O4 ceramic target (99.99% purity) and apply 100 W power. The deposition rate is 0.15 nm / s, and a 20 nm thick Co3O4 layer is obtained after 133 seconds of deposition.

[0093] 6. Repeat steps 4 and 5 for nine cycles, for a total of ten deposition cycles, to obtain a V2O5 / Co3O4 multilayer composite film with a total thickness of 400 nm.

[0094] 7. After deposition, the sample was annealed in air at 350°C for 2 hours and then naturally cooled to room temperature to obtain thin film cathode material D2.

[0095] In this comparative example, the thin-film cathode material D2 was not monitored in situ, and interface formation was mainly controlled by deposition time. The film surface was relatively rough, and a layered structure was visible in the cross-section, but the interface was blurred, and the layer thickness uniformity was poor. V2O5 and Co3O4 crystallized independently, without a clear epitaxial relationship.

[0096] Example 5

[0097] Fabrication of all-solid-state thin-film battery 1

[0098] Using the superlattice structure all-solid-state thin-film battery cathode material 1 of Example 1 as the cathode material, lithium metal as the anode material, and LATP (lithium titanium aluminum phosphate) or LiPON (lithium phosphorus oxygen nitrogen) as the solid electrolyte, the all-solid-state thin-film battery 1 is encapsulated to form the battery 1.

[0099] Meanwhile, the thin-film cathode material D1 of Comparative Example 1 was assembled into an all-solid-state thin-film battery D1 according to the above steps.

[0100] The electrochemical performance of the two batteries was tested at a rate of 0.1C using a Blue Battery Tester. The results are as follows: Figure 4 As shown, the all-solid-state thin-film battery 1 retains 84% ​​of its capacity after 100 cycles, and its average coulombic efficiency is close to 100%, which is much better than that of the all-solid-state thin-film battery D1. This indicates that the all-solid-state thin-film battery 1 assembled using the superlattice structure all-solid-state thin-film battery cathode material 1 of the present invention has good cycle stability and capacity utilization.

[0101] Example 6

[0102] Fabrication of all-solid-state thin-film battery 2

[0103] Using the superlattice structure all-solid-state thin-film battery cathode material 2 of Example 2 as the cathode material, lithium metal as the anode material, and LATP (lithium titanium aluminum phosphate) or LiPON (lithium phosphorus oxygen nitrogen) as the solid electrolyte, the all-solid-state thin-film battery 2 is encapsulated to form the battery 2.

[0104] Figure 5 The photograph shows the assembled all-solid-state thin-film battery driving an infrared sensor, visually demonstrating its reliable power supply capability and application potential in microelectronic systems.

[0105] All other parts not described in detail are existing technologies. Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A superlattice structure all-solid-state thin-film battery cathode material, characterized in that: The positive electrode material consists of a substrate and a stacked structure deposited on the substrate surface. The stacked structure is formed by alternating deposition of a first transition metal oxide layer and a second transition metal oxide layer from bottom to top. The number of alternating depositional stacking cycles is 40-80; The work function of the first transition metal oxide in the first transition metal oxide layer is 4.0~6.9 eV, and the lithium ion intercalation potential is 1.0~4.0 V; The work function of the second transition metal oxide in the second transition metal oxide layer is 4.8~6.5 eV, and the lithium ion intercalation potential is 1.0~3.5 V; The first transition metal oxide is any one of V2O5, MoO3, WO3 and TiO2; the second transition metal oxide is any one of V3O7, NiO, Mn3O4 and Fe2O3.

2. The cathode material according to claim 1, characterized in that: The substrate is any one of silicon wafer, sapphire, polyimide film and quartz, the single-layer thickness of the first transition metal oxide layer is 0.5~2 nm; the single-layer thickness of the second transition metal oxide layer is 1~3 nm; the interface roughness of the positive electrode material is less than 0.3 nm.

3. The cathode material according to claim 2, characterized in that: The substrate is a silicon wafer, the thickness of the first transition metal oxide layer is 2 nm, and the first transition metal oxide is V2O5; the thickness of the second transition metal oxide layer is 2 nm, and the second transition metal oxide is V3O7. The number of alternating depositional stacking cycles is 50.

4. A method for preparing the cathode material according to any one of claims 1 to 3, characterized in that: Includes the following steps: (1) The substrate is ultrasonically cleaned and dried sequentially; (2) A first transition metal oxide layer is deposited on the dried substrate surface using molecular beam epitaxy or high-power pulsed magnetron sputtering. (3) A second transition metal oxide layer is deposited on the surface of the first transition metal oxide layer using molecular beam epitaxy or high-power pulsed magnetron sputtering. (4) Repeat steps (2) and (3) for a total of 40 to 80 alternating deposition cycles to obtain a superlattice thin film; (5) After deposition, the sample is subjected to flash Joule heat treatment or annealing, and after cooling, the superlattice structure all-solid-state thin film battery cathode material is obtained.

5. The preparation method according to claim 4, characterized in that: In step (1), the substrate is any one of silicon wafer, sapphire, polyimide film and quartz.

6. The preparation method according to claim 4, characterized in that: In steps (2) and (3), the conditions for molecular beam epitaxy are: the temperature of the beam source furnace is 1000~1300℃, and the oxygen partial pressure is 2×10⁻⁶. -4 ~1×10 -3 Pa, deposition rate of 0.01~0.02 nm / s, substrate temperature maintained at 250~400℃; The conditions for the high-power pulsed magnetron sputtering method are as follows: magnetron sputtering power of 50~100 W, oxygen to argon volume ratio of 1:6~10 in the oxygen-argon mixed atmosphere, magnetron sputtering pressure of 0.5~2 Pa, and substrate temperature maintained at 100~300℃.

7. The preparation method according to claim 4, characterized in that: In step (5), the atmosphere of the flash Joule heat treatment is oxygen, the temperature of the flash Joule heat treatment is 100~300℃, and the time of the flash Joule heat treatment is 30~300s. The annealing atmosphere is oxygen or argon, the annealing temperature is 150~300℃, and the annealing time is 5~60 min.

8. The application of the cathode material according to any one of claims 1 to 3 in the preparation of all-solid-state thin-film batteries.

9. A fully solid-state thin-film battery, characterized in that: The all-solid-state thin-film battery uses the positive electrode material described in any one of claims 1 to 3 as the positive electrode, lithium metal or lithium alloy as the negative electrode, and LiPON or LATP as the solid electrolyte.

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