A lithium ion capacitor based on charge injection regulation of zero voltage potential and a preparation method thereof
By using the electrochemical charge injection method to control the zero-voltage potential of the anode and cathode of lithium-ion capacitors, the problem of uncoordinated voltage and capacitance between the anode and cathode was solved, resulting in a significant increase in energy density and enhanced electrochemical stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TONGJI UNIV
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-19
Smart Images
Figure CN122245976A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to a lithium-ion capacitor based on charge injection to control zero voltage potential and its preparation method. Background Technology
[0002] In current commercial energy storage systems, lithium-ion batteries and electric double-layer capacitors (EDL capacitors) dominate. Lithium-ion batteries, limited by the slow kinetics of insertion / deinsertion, struggle to meet current demands for fast charging and long cycle life. In contrast, EDL capacitors, with their rapid ion adsorption / desorption behavior, exhibit excellent high power density and cycle stability, but their lower energy density limits their wider application. Lithium-ion capacitors combine the energy storage mechanisms of both types of devices, offering both high energy and power densities, and are considered a promising energy storage device. It is worth noting that although the energy density of lithium-ion capacitors is superior to that of EDL capacitors, it is still lower than that of lithium-ion batteries. Therefore, further improving their energy density while maintaining high power density is of great significance.
[0003] During charging / discharging, the total number of ions within the device remains constant, and its maximum storable energy density depends on the weakest link among the cathode, anode, and electrolyte. Therefore, increasing the capacitance of a single electrode does not directly translate into an increase in the overall energy density of the device; focusing solely on improving the performance of a single electrode has limited significance. A more effective strategy is to comprehensively optimize the performance of both electrodes by matching the capacitance of the anode and cathode and widening their stable operating voltage window, thereby synergistically improving the energy density of the device. In practical lithium-ion capacitors, there is often a significant capacitance difference between the anode and cathode, which can easily cause one electrode to reach its potential limit prematurely during charging, leading to side reactions. This not only reduces material utilization but also exacerbates the kinetic imbalance between the electrodes, thus limiting the effective utilization of energy density.
[0004] To address the aforementioned issues, existing technologies offer some improvement ideas. Patent publication number CN117936277A discloses an electrode matching method for a lithium-ion hybrid supercapacitor, employing a high-capacity carbon aerogel-lithium manganese iron phosphate composite positive electrode matched with a high-rate phosphorus-carbon composite negative electrode to improve device performance. However, this method focuses on increasing the capacity of the electrode materials themselves, failing to adequately coordinate the voltage and capacity balance between the two electrodes; the overall energy density of the device remains limited by the lower-performing electrode. Patent publication number CN117133552A proposes using nitrogen-phosphorus co-doped graphene as the negative electrode material to improve capacity, but its operating voltage range remains limited to 2.2–3.8 V. Since energy density is proportional to the square of the operating voltage, relying solely on capacity improvement contributes limitedly to energy density; broadening the stable voltage window is more crucial.
[0005] In summary, existing lithium-ion capacitor technologies often focus on improving the capacity of a single electrode, without adequately addressing the need to suppress side reactions and extend the stable operating range through synergistic optimization of voltage and capacity between the anode and cathode. This results in significant room for improvement in energy density. Therefore, there is an urgent need for a technical solution that can effectively couple the performance of the anode and cathode, fully utilize the potential of each electrode's voltage window, and thus achieve a significant improvement in energy density. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a lithium-ion capacitor based on charge injection-controlled zero-voltage potential and its fabrication method. By actively controlling the zero-voltage potential of the positive and negative electrodes through electrochemical charge injection, the potential matching and capacitance balance between the anode and cathode are optimized. This method can effectively broaden the operating voltage range of the device, suppress side reactions during charging and discharging, and promote kinetic coordination between the anode and cathode, thereby significantly improving the energy density of the lithium-ion capacitor while maintaining high power density.
[0007] The objective of this invention can be achieved through the following technical solutions: In one aspect, the present invention provides a method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential, comprising the following steps: S1. Prepare the cathode and anode plates; S2. Perform electrochemical charge injection pretreatment on the cathode and anode plates to adjust the zero voltage potential of the lithium-ion capacitor to the target zero voltage potential. S3. Assemble the diaphragm, electrolyte, and the cathode and anode plates to obtain a lithium-ion capacitor.
[0008] Further, in step S1, the preparation process of the cathode electrode is as follows: mixing cathode material, conductive agent, binder and solvent to obtain positive electrode slurry, and coating the positive electrode slurry onto the current collector to obtain the cathode electrode; The anode electrode is prepared by mixing anode material, conductive agent, binder and solvent to obtain negative electrode slurry, and coating the negative electrode slurry onto current collector to obtain anode electrode.
[0009] Furthermore, the cathode material is one or more of activated carbon, lithium iron phosphate, or lithium cobalt oxide; The anode material is one or more of graphite, hard carbon, or soft carbon.
[0010] Further, in step S2, the specific steps of the electrochemical charge injection pretreatment are as follows: The anode and cathode are assembled separately into a half-cell, with lithium metal as the counter electrode; Using an electrochemical workstation or potentiostat, a constant pretreatment potential is applied to and maintained on the half-cell. The anode half-cell is held at the pretreatment potential for 12 to 48 hours; The cathode half-cell was held at the pretreatment potential for 12 to 48 minutes. After pretreatment, the electrodes are removed from the half-cell for subsequent device assembly.
[0011] Furthermore, the pretreatment potential for the anode electrode is 0.01~1 V (vs. Li). + / Li), for the cathode electrode is 1~4 V (vs. Li) + / Li).
[0012] Here, vs. is an abbreviation of "versus," meaning "relative to" or "comparative to"; Li + / Li refers to a standard "lithium metal reference electrode" on which the reversible reaction Li+ + e- ⇌ Li occurs, and its potential is defined as zero (0 V).
[0013] Taking "pre-charging the potential of the anode plate to 0.01 V" as an example, 0.01 V (vs. Li + / Li) indicates that, with the potential of the lithium metal electrode as a reference (defined as 0 V), the potential of the anode electrode is precisely tuned to +0.01 V. In the electrochemical context of lithium-ion battery systems, this potential value indicates that the hard carbon electrode is in an extremely low potential state, meaning that the degree of lithium-ion intercalation within it is very high, approaching the thermodynamic potential critical point at which lithium ions begin to be reduced on its surface and may form a lithium metal plating layer (lithium plating). This state is crucial for achieving the target control of zero voltage potential through the stabilization pretreatment of the electrode surface.
[0014] Furthermore, in step S2, the electrochemical charge injection pretreatment is regulated by a dual-electrode system.
[0015] Further, in step S2, the method for determining the target zero voltage potential is as follows: The capacitance of the cathode and anode plates was measured separately within their respective stable voltage windows. Based on the capacitance curves of the cathode and anode plates as a function of voltage, the potential value that matches the capacitance of the two plates is calculated and determined, and this potential value is set as the target zero voltage potential.
[0016] Furthermore, the step of measuring the capacitance of the cathode and anode electrodes includes: The anode and cathode are assembled separately into a half-cell, with lithium metal as the counter electrode; The cathode electrode was tested at 1~4V (vs. Li) using constant current charge-discharge testing and / or cyclic voltammetry. + Within a voltage range of 1~2V (preferably Li), the anode electrode is at 0.01~1V (vs. Li) + Capacitance characteristics within a voltage range of / Li (preferably 0.05~0.2V).
[0017] Furthermore, the lower limit of the stable voltage window of the cathode electrode is determined by cyclic voltammetry within the range of 1–50 mV / s. -1 The values were determined by testing at various scan rates, with typical values including but not limited to 1, 3, 5, 8, 10, 20, 30, or 50 mV / s. -1 One of them.
[0018] Furthermore, the constant current charge-discharge test uses a current density range of 0.1~20 A g. -1 (Based on the mass of electrode active material), typical values include, but are not limited to, 0.1, 0.3, 0.5, 1, 3, 5, 10, 15, or 20 Ag. -1 One of them.
[0019] Further, in step S2, the current density at the zero voltage potential is 0.1~20 A g. -1 .
[0020] Furthermore, in step S3, the mass ratio of the cathode electrode to the anode electrode is 1:0.5~2; The electrolyte is an organic electrolyte containing lithium salt, and the diaphragm is a glass fiber diaphragm.
[0021] In another aspect, the present invention also provides a lithium-ion capacitor based on charge injection to control zero voltage potential, which is prepared by the aforementioned preparation method.
[0022] Compared with the prior art, the beneficial effects achieved by the present invention include: (1) This invention successfully applies the zero-voltage potential dynamic control method to lithium-ion capacitor systems. By using the electrochemical charge injection pretreatment method, the surface chemical state and bulk lithium storage degree of the electrode (especially the negative electrode) are actively and controllably adjusted, thereby achieving precise control of the key parameter of zero voltage potential of the device, overcoming the defects of fixed zero voltage potential and inability to optimize matching in traditional devices.
[0023] (2) This invention significantly improves the energy density of the device. Through the above-mentioned regulation, the potential window distribution between the cathode and anode is optimized, which on the one hand broadens the effective working potential range of the cathode, allowing its capacity to be fully utilized; on the other hand, it makes reasonable use of the anode's capacity. This optimization fundamentally alleviates the problem of incomplete window utilization caused by the mismatch between the anode and cathode capacity and kinetics in traditional lithium-ion capacitors, thereby achieving a breakthrough improvement in energy density.
[0024] (3) The present invention effectively suppresses side reactions and improves the electrochemical stability of the device. The pretreated electrode interface is more stable, and the regulated zero voltage potential allows the anode and cathode potentials to enter their respective stable electrochemical windows earlier during the charging and discharging process, avoiding irreversible side reactions such as electrolyte decomposition caused by a single electrode reaching its potential limit too early, thereby enhancing the cycle life and reliability of the device. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the zero-voltage potential control method of the present invention, wherein P 0V P 0V’ P 0V” All are zero voltage potential values, representing the process of gradually adjusting the zero voltage potential; Figure 2 This is a comparison chart of the energy density of Embodiment 1 and Comparative Example 1 of the present invention.
[0026] Figure 3 This is a comparison chart of energy density in Comparative Example 2 of Embodiment 2 of the present invention. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without creative effort are within the scope of protection of this application.
[0028] Unless otherwise specified, the reagents, methods, instruments and equipment used in this invention are conventional reagents, methods, instruments and equipment in the art.
[0029] Example 1 A method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential includes the following steps: (1) Prepare the cathode and anode plates.
[0031] The cathode electrode is prepared as follows: activated carbon, conductive agent, and binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 8:1:1, and an appropriate amount of solvent n-methylpyrrolidone (NMP) is added to mix them to obtain a positive electrode slurry. The positive electrode slurry is coated on the copper foil of the current collector, dried, and then cut into a disc with a diameter of 12 mm, which is the activated carbon cathode electrode.
[0032] The anode electrode preparation process is as follows: hard carbon anode material, conductive agent Super P, and binder polyvinylidene fluoride are mixed in a mass ratio of 8:1:1, and an appropriate amount of solvent NMP is added to mix them to obtain a negative electrode slurry. The negative electrode slurry is coated on the copper foil of the current collector, and after drying, it is cut into a disc with a diameter of 12 mm, which is the hard carbon anode electrode.
[0033] The active material surface loading of both the activated carbon cathode and hard carbon anode is approximately 5 mg cm⁻¹. -2 All electrodes were vacuum dried at 80°C for 12 hours before assembly and stored in an argon atmosphere to avoid contact with air and moisture.
[0034] (2) Perform electrochemical charge injection pretreatment on the cathode and / or anode plates to adjust the zero voltage potential of the lithium-ion capacitor to the target zero voltage potential.
[0035] To determine the target parameters for pretreatment, the intrinsic properties of the electrodes were first evaluated. The cathode and anode electrodes were assembled into half-cells with lithium metal counter electrodes, respectively. The electrolyte was a 1 M LiPF6 EC / DMC (volume ratio 1:1) solution, and the separator was glass fiber (Whatman GF / C).
[0036] Cathode stability window test: Cyclic voltammetry was performed on the activated carbon cathode half-cell at a scan rate of 10 mVs. -1 Test results showed that a significant reduction current peak ("voltage pit") appeared when the potential was below 0.8 V (vs. Li+ / Li), indicating electrolyte decomposition. Therefore, to ensure electrochemical stability, the minimum safe operating potential of the activated carbon cathode was determined to be 0.8 V, while its complete stable voltage window is 0.8–4.0 V. In practical device design, to further ensure reliability, the minimum operating potential of the cathode was conservatively limited to 1.5 V. Capacity testing: For the cathode half-cell, the voltage range is 1.0~4.0 V (vs. Li). + / Li) voltage range, anode half-cell in 0.01~1.0 V (vs. Li) + Constant current charge-discharge tests were performed within the / Li voltage range (current density: 0.5 A g). -1 ), and obtain their respective capacitance-voltage curves.
[0037] Based on the above curves, calculations show that when the anode and cathode capacitances are equal, the theoretical zero-voltage potential of the device is approximately 0.4-1.4V (vs. Li). + / Li). Set this value as the target zero voltage potential for charge injection pretreatment in this embodiment.
[0038] To regulate the zero-voltage potential of the device to the aforementioned target value, a co-regulation mode for pretreatment was employed. The cathode and anode electrodes to be treated were reassembled with the lithium metal counter electrode to form a half-cell (electrolyte and separator as before). Using an electrochemical workstation, the potential of the cathode half-cell was kept constant at 1.5V (vs. Li). + / Li), for 24 minutes. This operation aims to bring the activated carbon cathode to a deep, stable deionized state and form a stable interface. The potential of the anode half-cell is kept constant at 0.1 V (vs. Li). + The process involves pre-treating the hard carbon anode with lithium for 24 hours. This step aims to achieve deep lithium intercalation in the anode and introduce an active lithium source. After pretreatment, the electrode is removed, lightly rinsed with dimethyl carbonate (DMC) solvent, and then allowed to dry at room temperature in a glove box for 30 minutes before use.
[0039] Through the aforementioned synergistic regulation, the cathode side is maintained at a relatively high potential of 1.5 V, effectively avoiding electrolyte reduction and decomposition caused by excessively low potential, thus forming a more stable electrode / electrolyte interface. The anode side is deeply lithium-intercalated to an extremely low potential of 0.01 V. This state not only pre-treats the anode surface but, more importantly, stores a large amount of active lithium within it.
[0040] The above process actively modulates the zero-voltage potential of the device to a lower target value (0.4~1.4 V vs. Li+ / Li). Lowering the zero-voltage potential is equivalent to widening the potential range available to the cathode while narrowing the potential range required by the anode, alleviating the capacity mismatch problem by allowing the typically lower-capacity cathode to contribute more capacity. The additional active lithium (300-800 mAh g) introduced by the anode and cathode pretreatment... -1 This can compensate for irreversible capacity loss in subsequent cycles, thereby achieving increased energy density without sacrificing device cycle life.
[0041] Figure 1 This is a schematic diagram of the zero-voltage potential control method of the present invention, wherein P 0V P 0V’ P 0V” All values are zero voltage potential values, representing the process of gradually adjusting the zero voltage potential.
[0042] (3) Assemble the diaphragm, electrolyte and the cathode and anode plates to obtain a lithium-ion capacitor.
[0043] The cathode and anode plates, which have undergone electrochemical charge injection pretreatment, are paired at a mass ratio of activated carbon to hard carbon of 1:1 and separated by a glass fiber diaphragm (Whatman GF / C). 100 μL of 1 M LiPF6 / EC:DMC (1:1, v / v) electrolyte is injected, and the plates are encapsulated in an argon atmosphere glove box (H2O < 1.0 ppm, O2 < 1.0 ppm) to form a standard CR2032 lithium-ion capacitor.
[0044] The assembled lithium-ion capacitor was tested for its full-cell electrochemical performance using the Neware battery testing system. The results show that the device exhibits excellent energy storage performance (performance curves are shown in Figure 1). Figure 2 (As shown). Specifically, at 146.9 Wkg -1 At a power density of [value missing], its energy density reaches as high as 151.0 Wh kg. -1 In contrast, under the same test conditions, the maximum energy density of the control device (Comparative Example 1) without the aforementioned charge injection pretreatment was only 67.9 Wh kg. -1 The maximum power density is 70.1 W kg. -1 The lithium-ion capacitor prepared in this embodiment achieves a significant improvement in energy density.
[0045] Example 2 Compared with Example 1, the only difference is that the anode material is changed from hard carbon to soft carbon.
[0046] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results show that the device exhibits excellent energy storage performance (performance curves are shown in Figure 1). Figure 3 (As shown). Specifically, at 141.1 W kg -1 At its power density, its energy density reaches 138.9 Wh kg. -1 In contrast, under the same test conditions, the maximum energy density of the control device (Comparative Example 2) without the aforementioned charge injection pretreatment was only 65.0 Wh kg. -1 The maximum power density is 80.6 W / kg. -1 The lithium-ion capacitor prepared in this embodiment achieves a significant improvement in energy density.
[0047] Example 3 Compared with Example 1, except that in step (1) the cathode material was changed from activated carbon to a mixture of activated carbon and lithium iron phosphate (mass ratio 4:1) and in step (2) the potential of the anode half cell was kept constant at 0.2 V (vs. Li+ / Li) for 24 hours, everything else was the same.
[0048] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results show that the device exhibits excellent energy storage performance. Specifically, at 140.0 W kg... -1 At its power density, its energy density reaches as high as 209.6 Wh kg. -1 .
[0049] Example 4 Compared with Example 1, except that in step (1) the cathode material was changed from activated carbon to a mixture of activated carbon and lithium cobalt oxide (mass ratio 4:1), everything else was the same.
[0050] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results show that the device exhibits excellent energy storage performance. Specifically, at 138.9 W kg⁻¹, the energy storage capacity is [not specified in the original text]. -1 At its power density, its energy density reaches as high as 250.4 Wh kg. -1 .
[0051] Example 5 Compared with Example 4, except that in step (2) the potential of the anode half-cell was kept constant at 0.8 V (vs. Li+ / Li) for 24 hours, everything else was the same.
[0052] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results show that the device exhibits excellent energy storage performance. Specifically, at 131.2 W kg⁻¹, the energy storage capacity is [not specified in the original text]. -1 At its power density, its energy density reaches as high as 200.1 Wh kg. -1 .
[0053] Comparative Example 1 Compared with Example 1, everything is the same except that step (2) is not performed.
[0054] The electrochemical performance of the prepared lithium-ion capacitor was tested using the Neware battery testing system. The maximum energy density of the comparative example was measured to be 67.9 Wh kg. -1 The maximum power density is 70.1 W kg. -1 .
[0055] Comparative Example 2 Compared with Example 2, everything is the same except that step (2) is not performed.
[0056] The electrochemical performance of the prepared lithium-ion capacitor was tested using the Neware battery testing system. The maximum energy density of the comparative example was measured to be 65.0 Wh kg. -1 The maximum power density is 80.6 W kg. -1 .
[0057] Comparative Example 3 Compared to Example 1, except for the pretreatment using a single-electrode adjustment mode in step (2), the anode electrode to be treated was reassembled with the lithium metal counter electrode into a half-cell (electrolyte and separator as before). Using an electrochemical workstation, the potential of the anode half-cell was kept constant at 0.1 V (vs. Li+ / Li) for 24 hours, and all other parameters were the same.
[0058] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results showed that at 123.6 W / kg... -1 At its power density, its energy density is 87.5 Wh kg. -1 .
[0059] Comparative Example 4 Compared to Example 1, except for the pretreatment using a single-electrode adjustment mode in step (2), the cathode electrode to be treated and the lithium metal counter electrode were reassembled into a half-cell (electrolyte and separator as before). Using an electrochemical workstation, the potential of the anode half-cell was kept constant at 1.5 V (vs. Li+ / Li) for 24 hours, and all other parameters were the same.
[0060] The electrochemical performance of the assembled lithium-ion capacitor was tested using the Neware battery testing system. The test results showed that at 71.2 W kg... -1 At its power density, its energy density is 75.7 Wh kg. -1 .
[0061] Table 1 below shows the performance data of lithium-ion capacitors in Examples 1-5 and Comparative Examples 1-4.
[0062] Table 1 Performance of Lithium-ion Capacitors As can be seen from Examples 1-5 and Comparative Examples 1-4, the pretreatment using a cathode-anode synergistic regulation mode allows for full utilization of the electrochemical stability voltage window of the electrodes, promotes the coupling between the cathode and anode, reduces the occurrence of side reactions, and increases energy density. This invention utilizes the coupling between the cathode and anode, fully utilizing the electrode stability voltage windows of both electrodes, thus significantly improving the energy density of lithium-ion capacitors. This technical solution has high energy density, excellent performance, and is suitable for large-scale production. Although the invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which are obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the invention fall within the scope of protection claimed by this invention.
Claims
1. A method for preparing a lithium ion capacitor based on charge injection regulated zero voltage potential, characterized by, Includes the following steps: S1. Prepare the cathode and anode plates; S2. Perform electrochemical charge injection pretreatment on the cathode and anode plates to adjust the zero voltage potential of the lithium-ion capacitor to the target zero voltage potential. S3. Assemble the diaphragm, electrolyte, and the cathode and anode plates to obtain a lithium-ion capacitor.
2. The method of claim 1, wherein the method is performed at a temperature of 20- 30 °C. In step S1, the cathode electrode is prepared by mixing cathode material, conductive agent, binder and solvent to obtain positive electrode slurry, and coating the positive electrode slurry onto current collector to obtain cathode electrode. The anode electrode is prepared by mixing anode material, conductive agent, binder and solvent to obtain negative electrode slurry, and coating the negative electrode slurry onto current collector to obtain anode electrode.
3. The method of claim 2, wherein the method further comprises the step of: The cathode material is one or more of activated carbon, lithium iron phosphate, or lithium cobalt oxide. The anode material is one or more of graphite, hard carbon, or soft carbon.
4. The method of claim 1, wherein the method is characterized by: In step S2, the specific steps of the electrochemical charge injection pretreatment are as follows: The anode and cathode are assembled separately into a half-cell, with lithium metal as the counter electrode; Using an electrochemical workstation or potentiostat, a constant pretreatment potential is applied to and maintained on the half-cell. The anode half-cell is held at the pretreatment potential for 12 to 48 hours; The cathode half-cell was held at the pretreatment potential for 12 to 48 minutes. After pretreatment, the electrodes are removed from the half-cell for subsequent device assembly.
5. The method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential according to claim 4, characterized in that, The pre-treatment potential is 0.01 to 1 V (vs. Li + / Li) for the anode electrode sheet and 1 to 4 V (vs. Li + / Li) for the cathode electrode sheet.
6. The method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential according to claim 1, characterized in that, In step S2, the method for determining the target zero voltage potential is as follows: The capacitance of the cathode and anode plates was measured separately within their respective stable voltage windows. Based on the capacitance curves of the cathode and anode plates as a function of voltage, the potential value that matches the capacitance of the two plates is calculated and determined, and this potential value is set as the target zero voltage potential.
7. The method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential according to claim 6, characterized in that, The steps for determining the capacitance of the cathode and anode electrodes include: The anode and cathode are assembled separately into a half-cell, with lithium metal as the counter electrode; The capacitance characteristics of the cathode electrode in the voltage range of 1~4V (vs. Li+ / Li) and the anode electrode in the voltage range of 0.01~1V (vs. Li+ / Li) are obtained by constant current charge-discharge test and / or cyclic voltammetry test.
8. The method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential according to claim 1, characterized in that, In step S2, the current density of the zero-voltage potential is 0.1-20 A g -1 .
9. The method for fabricating a lithium-ion capacitor based on charge injection to control zero voltage potential according to claim 1, characterized in that, In step S3, the mass ratio of the cathode electrode to the anode electrode is 1:0.5~2; The electrolyte is an organic electrolyte containing lithium salt, and the diaphragm is a glass fiber diaphragm.
10. A lithium-ion capacitor based on charge injection to regulate zero voltage potential, which is prepared by any one of the preparation methods described in claims 1 to 9.