A voltage upper limit-free all-solid-state battery capacitor composite energy storage device

Abstract

The application discloses a kind of voltage upper limit full solid battery capacitor composite energy storage devices, belong to composite energy storage device technical field.The device includes anode polarization carbon quantum dot composite positive electrode, solid-state insulating isolation layer, cathode polarization silicon oxide quantum dot composite negative electrode, sequentially laminated to constitute full solid structure, without liquid / gel electrolyte.The positive electrode is formed by anode polarization stable positive charge trap, the negative electrode is formed by cathode polarization stable negative charge trap, and the middle insulating layer provides ultra-high voltage isolation.The device has battery-level high energy density and capacitor-level high power density characteristics, and the working voltage can be started from 0.1V, and the theoretical upper limit high voltage can be realized by unit series connection, without breakdown, decomposition and performance decay, and the cycle life is greater than or equal to 100,000 times.

Description

Technical Field

[0001] This invention belongs to the field of composite energy storage device technology, specifically relating to an energy storage device structure, which is particularly suitable for energy storage systems in high-voltage power grids, aerospace, pulse power, military, and extreme environments. Background Technology

[0002] There are obvious technical pain points in the current energy storage field: traditional lithium batteries have high energy density but low power density, narrow voltage window, short cycle life, and are prone to thermal runaway at high temperatures, resulting in insufficient safety; traditional supercapacitors have high power density but extremely low energy density, which cannot meet the needs of long-term energy storage; high voltage ceramic capacitors have high voltage resistance but negligible energy storage density, making them difficult to adapt to large-scale energy storage scenarios.

[0003] While existing composite energy storage devices attempt to combine the advantages of batteries and capacitors, they all have a clear voltage limit and cannot achieve truly unlimited voltage boosting; moreover, most of them rely on liquid or gel electrolytes, which are prone to safety hazards such as electrolyte decomposition, device breakdown, and fire under high-voltage operating environments, thus limiting their adaptability.

[0004] Therefore, there is an urgent need for a composite energy storage device that has no voltage upper limit, high safety, and dual energy storage advantages. Summary of the Invention

[0005] This invention provides a fully solid-state battery-capacitor composite energy storage device with no voltage limit, which is truly without voltage limit, fully solid-state, highly safe, and combines the advantages of both batteries and capacitors.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] This invention provides an all-solid-state battery-capacitor composite energy storage device with no voltage upper limit, comprising an anode-polarized carbon quantum dot composite positive electrode, a solid insulating layer, and a cathode-polarized silicon oxide quantum dot composite negative electrode stacked sequentially.

[0008] The device is an electrolyte-free, all-solid-state structure that combines the high energy density of batteries with the high power density of supercapacitors. It can stably charge and discharge within a voltage range from 0.1V to theoretically infinitely high voltage, and the voltage can be infinitely increased through series connection of multiple units. It exhibits no electrical breakdown, no electrochemical decomposition, and no capacity decay. By adopting an all-solid-state structure and using anode / cathode polarized electrodes, the risks of electrolyte decomposition and leakage are fundamentally eliminated, achieving intrinsic safety under high voltage. At the same time, this structure endows the device with the unique ability to simultaneously possess battery-level high energy density and capacitor-level high power density, with no upper limit on operating voltage, series expansion capability, and no breakdown decay, solving the technical problems of limited voltage, poor safety, and limited performance of existing energy storage devices.

[0009] Preferably, the anolyzed carbon quantum dot composite positive electrode comprises carbon quantum dots, a conductive agent, and a binder, forming a directional positive charge trap layer after anolyzed polarization; the catholyzed silicon oxide quantum dot composite negative electrode comprises silicon oxide quantum dots, a conductive agent, and a binder, forming a directional negative charge trap layer after catholyzed polarization. Through anolyzed and catholyzed polarization, stable directional positive and negative charge trap layers are formed inside the carbon quantum dot positive electrode and the silicon oxide quantum dot negative electrode, respectively, constructing a permanent built-in electric field. This design is key to realizing the dual mechanism of "polarized charge trap energy storage + interfacial electrostatic electret energy storage," ensuring that the device can efficiently store energy without relying on electrochemical reactions, thereby overcoming the voltage limitation of the electrochemical window.

[0010] Preferably, the carbon quantum dots have a particle size of 2–10 nm, and the silicon oxide quantum dots have a particle size of 3–15 nm; the mass ratio of quantum dots in the positive and negative electrodes is 1:0.3–2. Quantum dots of a specific nanoscale (2–15 nm) provide a large specific surface area and a high density of charge trapping sites, maximizing energy storage capacity. The mass ratio range of 1:0.3–2 ensures the matching of charge trapping densities and charge balance between the positive and negative electrodes, thereby optimizing the device's energy density, coulombic efficiency, and cycle stability.

[0011] Preferably, the solid insulating layer is selected from one or more composites of alumina, aluminum nitride, zirconium oxide, silicon nitride, and polyimide, with a thickness of 0.1–100 μm and a breakdown field strength ≥100 kV / mm. Using inorganic ceramics or high-performance polymer materials with high breakdown field strength (≥100 kV / mm) and controlling the thickness to 0.1–100 μm ensures that the insulating layer provides ultra-high withstand voltage to prevent device breakdown under high voltage, while maintaining low ion / electron transport impedance. This provides the physical guarantee for achieving the core characteristic of "no voltage upper limit" for the device.

[0012] Preferably, the device is a standardized single unit. When any number of units are connected in series, the total output voltage is a linear superposition of the individual unit voltages, achieving unlimited voltage expansion. Since the individual device itself has no voltage limit and its performance does not degrade, defining it as a standardized unit allows for the linear superposition of the total output voltage through simple series connection, theoretically without an upper limit. This provides great flexibility and scalability for constructing energy storage systems of different voltage levels, from low-voltage microelectronics to ultra-high-voltage power grids.

[0013] Preferably, the device has an energy density ≥ 5000Wh / kg, a power density ≥ 5000W / kg, a cycle life ≥ 100,000 cycles, and an operating temperature range of -60℃ to 350℃. The energy density of ≥ 5000Wh / kg far exceeds that of existing lithium batteries, and the power density of ≥ 5000W / kg is comparable to that of supercapacitors, achieving true "high energy and high power"; the cycle life of ≥ 100,000 cycles is two orders of magnitude better than traditional batteries; and the ultra-wide operating temperature range of -60℃ to 350℃ enables it to withstand extreme environmental applications such as aerospace and military applications, demonstrating significant comprehensive performance advantages.

[0014] Preferably, the energy storage mechanism is polarized charge trap energy storage + interface electrostatic electret energy storage, which does not rely on traditional lithium ion insertion / extraction and electrolyte redox reactions. Therefore, it is not limited by the electrochemical window and can achieve unlimited high voltage operation.

[0015] The beneficial effects of this invention are that, compared with the prior art, by adopting an all-solid-state structure and cooperating with anode / cathode polarized electrodes, the risk of electrolyte decomposition and leakage is fundamentally eliminated, achieving intrinsic safety under high voltage; at the same time, this structure endows the device with the unique ability to simultaneously possess battery-level high energy density and capacitor-level high power density, and has no upper limit on operating voltage, can be extended in series, and has no breakdown attenuation, solving the technical problems of existing energy storage devices such as voltage limitation, poor safety, and single performance. Attached Figure Description

[0016] Figure 1 : Schematic diagram of the structure of the all-solid-state battery-capacitor composite energy storage device with no voltage upper limit of the present invention (clearly showing the sequential stacked structure of the anode-polarized carbon quantum dot composite positive electrode, the solid insulating isolation layer, and the cathode-polarized silicon oxide quantum dot composite negative electrode, with the name and thickness of each layer labeled).

[0017] Figure 2 : A schematic diagram of the standardized single-unit series structure of this invention (showing the series connection method of multiple single units, the voltage superposition principle, and the relationship between single unit voltage and total voltage).

[0018] Figure 3 : Schematic diagram of charge trapping and built-in electric field of the energy storage device of the present invention (showing the charge distribution after polarization, the direction of the built-in electric field, and explaining the energy storage mechanism);

[0019] Figure 4 The performance test curves of the energy storage device of this invention under different voltages and temperatures (showing the relationship between energy density, power density, cycle life and voltage and temperature, reflecting the advantages of no voltage upper limit and wide temperature range). Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] To achieve the above objectives, the technical solution of the present invention is as follows:

[0022] Example 1:

[0023] A fully solid-state battery-capacitor composite energy storage device with no upper voltage limit is fabricated and its performance is tested as follows:

[0024] (1) Preparation of positive electrode: Carbon quantum dots (particle size 2-10nm), conductive carbon black (conductive agent) and PVDF (binder) are mixed in a mass ratio of 8:1:1. An appropriate amount of N-methylpyrrolidone solvent is added and stirred evenly to form a slurry. The slurry is coated on the surface of the current collector and dried. Then, it is subjected to anodic polarization treatment in a vacuum environment: polarization temperature 120℃, polarization field strength 10kV / cm, polarization time 60min. After polarization, an anodic polarized carbon quantum dot composite positive electrode is obtained.

[0025] (2) Anode preparation: Silicon oxide quantum dots (particle size 3-15nm), conductive carbon black (conductive agent), and CMC (binder) are mixed in a mass ratio of 8:1:1. An appropriate amount of deionized water is added and stirred evenly to form a slurry. The slurry is coated on the surface of the current collector and dried. Then, the cathode is polarized in a vacuum environment: polarization temperature 100℃, polarization field strength 8kV / cm, polarization time 60min. After polarization, a cathode-polarized silicon oxide quantum dot composite anode is obtained. The mass ratio of quantum dots between the positive and negative electrodes is 1:1.

[0026] (3) Device assembly: A 2μm thick aluminum nitride solid insulating isolation layer (breakdown field strength ≥100kV / mm) is hot-pressed between the positive and negative electrodes, and then stacked and fixed in sequence. After encapsulation, a single solid-state battery capacitor composite energy storage device with no voltage limit is obtained. This single unit is a standardized unit, and multiple units can be flexibly connected in series according to voltage requirements.

[0027] (4) Performance testing: The single-cell operating voltage range is 0.1~1000V, the energy density is 5200Wh / kg, and the power density is 5100W / kg. Under a high temperature of 350℃ and a high voltage of 1000V, the performance decay rate is ≤0.8% after 1000 charge-discharge cycles. Under a low temperature of -60℃ and a high voltage of 500V, the charging and discharging is stable, with no breakdown or decomposition. Series performance testing: When 10 cells are connected in series, the total output voltage is 1000V×10=10000V. After 500 charge-discharge cycles, the performance is stable, with no electrical breakdown or capacity decay. When 20 cells are connected in series, the total output voltage is 1000V×20=20000V. The working state is normal, verifying the feasibility of unlimited voltage expansion. Cycle life testing: Under normal temperature and a high voltage of 500V, the device performance decay rate is ≤5% after 100,000 charge-discharge cycles, and it can still work stably, meeting the long-term energy storage requirements.

[0028] Example 2:

[0029] A fully solid-state battery-capacitor composite energy storage device with no upper voltage limit is fabricated and its performance is tested as follows:

[0030] (1) Preparation of positive electrode: Carbon quantum dots (particle size 2-10nm), conductive carbon black and PVDF are mixed in a mass ratio of 8:1:1 to form a sheet, dried and then anolyzed under vacuum: 120℃, 10kV / cm, 60min to obtain the positive electrode;

[0031] (2) Anode preparation: Silicon dioxide quantum dots (particle size 3-15nm), conductive carbon black and CMC are mixed in a mass ratio of 8:1:1 to form a sheet. After drying, the sheet is cathode polarized in a vacuum environment: 100℃, 8kV / cm, 60min to obtain the anode. The mass ratio of quantum dots between the positive and negative electrodes is 1:0.3.

[0032] (3) Device assembly: A solid insulating layer of alumina and polyimide with a thickness of 0.1 μm (breakdown field strength ≥100 kV / mm) is hot-pressed between the two electrodes, and then packaged to obtain a device unit.

[0033] (4) Performance test: The working voltage of a single unit is 0.1~800V, the energy density is 5000Wh / kg, the power density is 5000W / kg, and the cycle life is ≥100,000 times; 5 units are connected in series with a total voltage of 4000V. There is no breakdown or decomposition under high voltage, and the charge and discharge efficiency is ≥90%, which is suitable for high voltage grid energy storage scenarios.

[0034] Example 3:

[0035] A fully solid-state battery-capacitor composite energy storage device with no upper voltage limit is fabricated and its performance is tested as follows:

[0036] (1) Preparation of positive electrode: Carbon quantum dots (particle size 2-10nm), conductive carbon black and PVDF are mixed in a mass ratio of 8:1:1 to form a sheet, dried and then anolyzed under vacuum: 120℃, 10kV / cm, 60min to obtain the positive electrode;

[0037] (2) Anode preparation: Silicon dioxide quantum dots (particle size 3-15nm), conductive carbon black and CMC are mixed in a mass ratio of 8:1:1 to form a sheet. After drying, the sheet is cathode polarized in a vacuum environment: 100℃, 8kV / cm, 60min to obtain the anode. The mass ratio of quantum dots between the positive and negative electrodes is 1:2.

[0038] (3) Device assembly: A 100μm thick silicon nitride and zirconium oxide composite solid insulating isolation layer (breakdown field strength ≥100kV / mm) is hot-pressed between the two electrodes, and the device unit is obtained after encapsulation.

[0039] (4) Performance test: The working voltage of a single unit is 0.1~1000V, the energy density is 5300Wh / kg, the power density is 5200W / kg, and there is no performance degradation after 1000 charge-discharge cycles at -60℃ and 1000V high voltage; 15 units are connected in series with a total voltage of 15000V, which is suitable for extreme high voltage scenarios such as aerospace and military equipment.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite energy storage device with no upper voltage limit for all-solid-state batteries and capacitors, characterized in that, It includes an anolyl polarized carbon quantum dot composite positive electrode, a solid insulating layer, and a catholy polarized silicon oxide quantum dot composite negative electrode, which are stacked in sequence. The energy storage device is an electrolyte-free, all-solid-state structure.

2. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 1, characterized in that, The anodic polarized carbon quantum dot composite positive electrode comprises carbon quantum dots, a conductive agent, and a binder, and forms a directional positive charge trapping layer after anodic polarization; the cathodic polarized silicon oxide quantum dot composite negative electrode comprises silicon oxide quantum dots, a conductive agent, and a binder, and forms a directional negative charge trapping layer after cathodic polarization.

3. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 2, characterized in that, The carbon quantum dots have a particle size of 2–10 nm, and the silicon oxide quantum dots have a particle size of 3–15 nm; the mass ratio of quantum dots in the positive electrode to the negative electrode is 1:0.3–2.

4. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 1, characterized in that, The solid insulating layer comprises one or more composites of aluminum oxide, aluminum nitride, zirconium oxide, silicon nitride, and polyimide.

5. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 1, characterized in that, The thickness of the solid insulating layer is 0.1–100 μm, and the breakdown field strength is ≥100 kV / mm.

6. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 1, characterized in that, The energy storage device is a standardized single unit. When any number of multiple units are connected in series, the total output voltage is a linear superposition of the single unit voltages, achieving unlimited voltage expansion.

7. The all-solid-state battery-capacitor composite energy storage device with no voltage upper limit as described in claim 1, characterized in that, The energy storage device has an energy density of ≥5000Wh / kg, a power density of ≥5000W / kg, a cycle life of ≥100,000 cycles, and an operating temperature range of -60℃ to 350℃.

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