Lithium supplement electrode, hybrid supercapacitor and preparation method thereof, and pre-lithiation hybrid supercapacitor
By controlling the N/P ratio and pre-lithiation process of the lithium-supplemented negative and positive electrodes, the problem of low cycle performance of hybrid supercapacitors is solved, and high power and energy density are improved, making it suitable for energy storage systems in multiple fields.
Patent Information
- Application Number
- CN202511032769.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-09-12
AI Technical Summary
The existing hybrid supercapacitors have low cycle performance, especially the problem of capacity attenuation and cycle life reduction of carbon negative electrodes such as hard carbon during charge and discharge.
By controlling the N/P ratio of the surface capacity and the maximum operating voltage of the lithium-replenishing negative electrode and the lithium-replenishing positive electrode, a graded N/P ratio design is achieved. Combined with the pre-lithiation process of the first charge to 100% Vmax~105% Vmax, the adsorption, intercalation and pore-filling lithium storage mechanisms of carbon negative electrodes such as hard carbon are fully utilized to compensate for lithium loss.
It improves the cycle performance of hybrid supercapacitors, combines high power and energy density, and extends the cycle life. It is suitable for electric vehicles, new energy power generation, rail transportation, national defense and military industry, aerospace and other fields.
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Figure CN120637115A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of energy storage devices, and in particular relates to a lithium-supplementing electrode, a hybrid supercapacitor and a preparation method thereof, and a pre-lithiation hybrid supercapacitor. Background Art
[0002] Hybrid supercapacitors, by scientifically combining lithium-ion batteries and electric double-layer capacitors, have overcome the problems of low power of lithium-ion batteries and low energy density of electric double-layer capacitors, becoming a new type of energy storage device that combines high power and energy density. They are widely used in electric vehicles, new energy power generation, rail transportation, national defense and military industry, aerospace and other fields.
[0003] The structure of hybrid supercapacitors is similar to that of lithium-ion batteries, including positive electrode, negative electrode, electrolyte and separator; among them, the negative electrode material used is usually hard carbon, soft carbon, porous carbon and fast-charging graphite or a mixture of the above carbon materials. There is a closed-pore structure inside amorphous carbon negative electrodes such as hard carbon, soft carbon and porous carbon. This part of the structure can increase the lithium storage capacity, compensate for the lithium loss during the cycle, and improve the capacity retention and cycle life; for example, for carbon negative electrodes such as hard carbon, the "adsorption-intercalation-pore filling" lithium storage mechanism is widely recognized, among which adsorption has the highest kinetics, followed by The first is intercalation, and the last is pore filling. In the high-rate and high-power charging and discharging process of the hybrid supercapacitor, the main lithium storage capacity utilized is adsorption and intercalation. However, in the long-term charging and discharging process, the capacity will gradually decay and the cycle life will decrease. At this time, if there is sufficient lithium storage capacity in the closed-pore structure of the carbon negative electrode such as hard carbon, it can effectively alleviate the capacity decay and cycle life of the hybrid supercapacitor. Therefore, lithium supplementation and pore filling of the negative electrode of the hybrid supercapacitor can significantly reduce the negative electrode potential, broaden the voltage window of the hybrid capacitor, and improve capacity retention and cycle life.
[0004] In order to improve performance, pre-lithiation technology is applied in the fields of lithium-ion batteries and hybrid capacitors. Pre-lithiation refers to the technology of introducing additional lithium sources directly into the electrode for lithium replenishment through electrochemical reaction or chemical lithium insertion to achieve lithium resource compensation. On the one hand, pre-lithiation can reduce the negative electrode potential and widen the voltage window of the supercapacitor. On the other hand, it can supplement the consumption of positive electrode lithium by the SEI film. At present, pre-lithiation technical means are mainly focused on providing lithium replenishment positive electrode, lithium replenishment negative electrode or lithium replenishment electrolyte. For example, strategies such as adding positive electrode pre-lithiation additives, negative electrode lithium powder or lithium metal sheet, electrolyte lithium replenishment additives, etc. to the positive and negative electrodes or electrolytes ignore the "adsorption-intercalation-pore filling" lithium storage mechanism and charge and discharge characteristics of carbon negative electrodes such as hard carbon of hybrid capacitors. The additional addition of additives to the positive and negative electrodes or electrolytes increases the cost of hybrid capacitors. It is necessary to develop a new type of lithium replenishment electrode to improve the cycle performance of hybrid supercapacitors. Summary of the Invention
[0005] In view of this, the present application provides a lithium-supplementing electrode, a hybrid supercapacitor and a preparation method thereof, and a pre-lithiation hybrid supercapacitor, which are used to solve the technical problem of low cycle performance of hybrid supercapacitors in the prior art.
[0006] In a first aspect, the present application provides a lithium-supplementing electrode for a hybrid supercapacitor, wherein the N1 / P ratio of the surface capacity of the lithium-supplementing negative electrode in the lithium-supplementing electrode when the lithium insertion potential is not less than 100 mV and the surface capacity of the lithium-supplementing positive electrode at the maximum operating voltage Vmax is controlled to be 0.8 to 1.0;
[0007] The N2 / P ratio of the surface capacity of the lithium-supplementing negative electrode when the lithium insertion potential is not less than 0mV and not greater than 100mV and the surface capacity of the lithium-supplementing positive electrode at the maximum working voltage Vmax is controlled to be 1.3~1.65; the surface capacity of the lithium-supplementing negative electrode when the lithium insertion potential is less than 0mV and the surface capacity of the lithium-supplementing positive electrode at the maximum working voltage V max The N3 / P ratio of the surface capacity is controlled to be 1.65~3.05.
[0008] Preferably, the surface capacity N1 of the lithium supplement negative electrode when the lithium insertion potential is not less than 100mV is y×0.87mAh / cm 2 , when the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is y×1.43mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is y×2.38mAh / cm 2 ;
[0009] The lithium-supplemented positive electrode has a maximum operating voltage V max The surface capacity P is y×1.09mAh / cm 2 ; where y is greater than 0.
[0010] Preferably, the surface capacity N1 of the lithium supplement negative electrode when the lithium insertion potential is not less than 100mV is z×1.06mAh / cm 2 , when the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is z×1.36mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is z×2.08mAh / cm 2 ; The lithium-supplemented positive electrode is at the highest operating voltage V max The surface capacity P is y×1.09mAh / cm 2 ; where y is greater than 0.
[0011] Preferably, the surface capacity N1 of the lithium supplement negative electrode is t×0.96 mAh / cm when the lithium insertion potential is not less than 100 mV. 2 , when the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is t×1.58mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is t×2.63mAh / cm 2 ; The lithium-supplemented positive electrode is at the highest operating voltage V max The surface capacity P is y×1.09mAh / cm 2 ; where z is greater than 0.
[0012] Preferably, the lithium-supplementing negative electrode is an amorphous carbon lithium-supplementing negative electrode.
[0013] Preferably, the amorphous carbon is selected from hard carbon, soft carbon or porous carbon.
[0014] Preferably, the y may be further selected from less than 1000, 100, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1;
[0015] The z may be further selected from less than 1000, 100, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1.
[0016] The t may be further selected from less than 1000, 100, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1.
[0017] A second aspect of the present application provides a method for preparing a lithium-replenishing electrode for a hybrid supercapacitor, which can prepare the lithium-replenishing electrode for the hybrid supercapacitor described in the first aspect, comprising the following steps:
[0018] Steps to obtain lithium-supplemented negative electrode,
[0019] The negative electrode active material is tested and screened in sequence to obtain a negative electrode active material having a preset gram capacity C1 when the lithium insertion potential is not less than 100 mV, a preset gram capacity C2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a preset gram capacity C3 when the lithium insertion potential is less than 0 mV;
[0020] The negative electrode active materials screened in the first screening are tested and screened in sequence to obtain negative electrode active materials screened in the second screening with a preset charge-discharge efficiency CE1;
[0021] The secondary screened negative electrode active material is loaded onto the negative electrode current collector at a preset surface density ρ1 to obtain a lithium-supplemented negative electrode having a surface capacity N1 when the lithium insertion potential is not less than 100 mV, a surface capacity N2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a surface capacity N3 when the lithium insertion potential is less than 0 mV; wherein, the preset gram capacity C1, the preset charge-discharge efficiency CE1, and the preset surface density ρ1 meet the requirement that the product of the three is the surface capacity N1, the preset gram capacity C2, the preset charge-discharge efficiency CE1, and the preset surface density ρ1 meet the requirement that the product of the three is the surface capacity N2, and the preset gram capacity C3, the preset charge-discharge efficiency CE1, and the preset surface density ρ1 meet the requirement that the product of the three is the surface capacity N3;
[0022] Steps to obtain lithium-supplemented positive electrode,
[0023] Test and screen the positive electrode active materials to obtain the highest working voltage V max A primary screened positive electrode active material having a preset gram capacity C4;
[0024] The positive electrode active materials screened in the first screening are tested and screened in sequence to obtain the positive electrode active materials screened in the second screening with a preset charge-discharge efficiency CE2;
[0025] The secondary screened positive electrode active material is loaded onto the positive electrode current collector at a preset surface density ρ2 to obtain the highest operating voltage V max A lithium-supplemented positive electrode having an areal capacity P; wherein, the preset gram capacity C4, the preset charge and discharge efficiency CE2, and the preset areal density ρ2 meet the requirement that the product of the three is the areal capacity P.
[0026] A third aspect of the present application provides a method for preparing a lithium-replenishing electrode for a hybrid supercapacitor, which can also be used to prepare the lithium-replenishing electrode for a hybrid supercapacitor described in the first aspect, comprising the following steps:
[0027] Steps to obtain lithium-supplemented negative electrode,
[0028] Testing and screening the negative electrode active material in sequence to obtain a primary screened negative electrode active material having a preset charge-discharge efficiency CE1;
[0029] The negative electrode active materials screened in the first screening are tested and screened in sequence to obtain a negative electrode active material screened in the second screening, which has a preset gram capacity C1 when the lithium insertion potential is not less than 100 mV, a preset gram capacity C2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a preset gram capacity C3 when the lithium insertion potential is less than 0 mV;
[0030] The secondary screened negative electrode active material is loaded onto the negative electrode current collector at a preset surface density ρ1 to obtain a lithium-supplemented negative electrode having a surface capacity N1 when the lithium insertion potential is not less than 100 mV, a surface capacity N2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a surface capacity N3 when the lithium insertion potential is less than 0 mV;
[0031] Steps to obtain lithium-supplemented positive electrode,
[0032] Testing and screening the positive electrode active material in sequence to obtain a primary screened positive electrode active material having a preset charge-discharge efficiency CE2;
[0033] Test and screen the primary positive electrode active materials to obtain the highest working voltage V max A secondary screened positive electrode active material having a preset gram capacity C4;
[0034] The secondary screened positive electrode active material is loaded onto the positive electrode current collector at a preset surface density ρ2 to obtain the highest operating voltage V max A lithium-supplemented positive electrode with a surface capacity of P.
[0035] Preferably, the process of testing the gram capacity of the negative electrode active material includes: using the negative electrode active material as a working electrode, using a two-electrode system or a three-electrode system to test the gram capacity C1 of the negative electrode active material when the lithium insertion potential is not less than 100 mV, the gram capacity C2 when the potential is not less than 0 mV and not greater than 100 mV, and the gram capacity C3 when the potential is less than 0 mV;
[0036] The process of testing the charge and discharge efficiency of the negative electrode active material includes: making the negative electrode active material into a negative electrode half-cell, discharging it to 0V, and obtaining the negative electrode charge and discharge efficiency CE1.
[0037] Preferably, the process of testing the gram capacity of the positive electrode active material includes: the positive electrode active material is used as a working electrode, and a two-electrode system or a three-electrode system is used to test the positive electrode active material to a maximum working voltage V max hourly capacity C4;
[0038] The process of testing the charge and discharge efficiency of the positive electrode active material includes: making the positive electrode active material into a positive electrode half-cell, charging it to 4.0V, and obtaining the positive electrode charge and discharge efficiency CE2.
[0039] Preferably, the second aspect of the present application provides a method for preparing a lithium-replenishing electrode for a hybrid supercapacitor, in which in the step of obtaining a lithium-replenishing negative electrode, the negative electrode active material obtained by the primary screening has a preset gram capacity C1 of 147 mAh / g at a lithium insertion potential of 100 mV, a preset gram capacity C2 of 242 mAh / g at a lithium insertion potential of 0 mV, and a preset gram capacity C3 of 402 mAh / g at a lithium insertion potential of -50 mV. The negative electrode active material obtained by the secondary screening has a preset charge and discharge efficiency CE1 of 77%, and the preset surface density ρ1 of the negative electrode active material loaded on the negative electrode current collector of the secondary screening is 7.7 mg / cm 2 The surface capacity N1 of the lithium-supplemented negative electrode is 0.87 mAh / cm at a lithium insertion potential of 100 mV. 2 , when the lithium insertion potential is 0mV, the surface capacity N2 is 1.43mAh / cm 2 , when the lithium insertion potential is -50mV, the surface capacity N3 is 2.38mAh / cm 2 ;
[0040] In the step of obtaining the lithium-replenishing positive electrode, the obtained primary screened positive electrode active material has a preset gram capacity C4 of 160 mAh / g at the highest working voltage of 4.0 V, the obtained secondary screened positive electrode active material has a preset charge and discharge efficiency CE2 of 85%, and the preset surface density ρ2 of the secondary screened positive electrode active material loaded on the negative electrode current collector is 8 mg / cm2, so that the surface capacity P of the lithium-replenishing positive electrode is 1.09 mAh / cm at the highest working voltage of 4.0 V. 2 .
[0041] A fourth aspect of the present application provides a hybrid supercapacitor, comprising the lithium-replenishing electrode of the hybrid supercapacitor described in the first aspect.
[0042] The fifth aspect of the present application provides a pre-lithiation method for a hybrid supercapacitor, the method comprising the steps of: charging a hybrid supercapacitor according to the fourth aspect to 100% V during the first charging process; max ~105%V max The pores are filled and lithium is supplemented to obtain a pre-lithiated hybrid supercapacitor.
[0043] In a sixth aspect, the present application provides a pre-lithiated hybrid supercapacitor, which is obtained by pre-lithiating the hybrid supercapacitor described in the fifth aspect.
[0044] The seventh aspect of the present application provides an energy storage system, comprising the pre-lithiation hybrid supercapacitor described in the sixth aspect.
[0045] Compared with the prior art, the lithium-supplementing electrode for a hybrid supercapacitor provided in this application has at least the following beneficial effects:
[0046] 1. The lithium-replenishing electrode of the hybrid supercapacitor provided in the present application tests and screens the gram capacity of the positive and negative active materials and controls the surface density on the positive and negative current collectors, so that the provided lithium-replenishing negative electrode and the lithium-replenishing positive electrode have different N / P ratios in the "adsorption-intercalation-pore filling" stage, realizing graded N / P ratio control, controlling the N / P ratio of the carbon negative electrode such as hard carbon in the adsorption stage, intercalation stage and pore filling stage, and replenishing lithium to provide capacity in the adsorption stage and intercalation stage so that the hybrid supercapacitor provided in the present application has both high power and energy density, and forced lithium replenishment is performed through a large N / P ratio design in the pore filling stage, utilizing the pore filling lithium storage capacity to compensate for lithium loss during the cycle, effectively alleviating the capacity decay of the hybrid supercapacitor, and improving the cycle performance of the hybrid supercapacitor.
[0047] 2. During the pre-lithiation process after the hybrid supercapacitor provided by the present application is composed of the lithium-supplementing electrode and the diaphragm electrolyte to form a hybrid supercapacitor, during the first charging process to 100% V max ~105%V max , preferably 105%V max It can fully release active materials such as lithium ions stored in the positive electrode and fill the pores in the closed-pore structure of the negative electrode, which is beneficial to lithium replenishment in the subsequent cycle process and further improves the cycle performance of the hybrid supercapacitor.
[0048] 3. The negative electrode lithium replenishment method of the pre-lithiation hybrid supercapacitor. The pre-lithiation hybrid supercapacitor after the negative electrode lithium replenishment method has excellent performance and can be used as the core component of the energy storage system. It is widely used in electric vehicles, new energy power generation, rail transportation, national defense and military industry or aerospace and other fields. BRIEF DESCRIPTION OF THE DRAWINGS
[0049] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0050] Figure 1 Schematic diagram of the lithium storage mechanism of hard carbon provided in the examples of this application;
[0051] Figure 2 This is a capacity-potential diagram of the hard carbon provided in the examples of this application under different lithium storage mechanisms and commercially available graphite. The horizontal axis in the figure is capacity and the vertical axis is potential. DETAILED DESCRIPTION
[0052] The present application provides a lithium-supplementing electrode, a hybrid supercapacitor and a preparation method thereof, and a pre-lithiation hybrid supercapacitor, which are used to solve the technical problem of low cycle performance of hybrid supercapacitors in the prior art.
[0053] The following will clearly and completely describe the technical solution of this application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0054] Given that the current pre-lithiation technology mainly focuses on strategies such as positive electrode pre-lithiation additives, negative electrode lithium powder or lithium metal sheets, and electrolyte lithium supplementation additives, the "adsorption-intercalation-pore filling" lithium storage mechanism and charge-discharge characteristics of hard carbon and other carbon negative electrodes of hybrid capacitors are ignored. At present, the existing hybrid capacitors usually set the ratio of the capacity of the negative electrode in the adsorption stage to the capacity contributed by the positive electrode to be greater than 1, while ignoring the capacity of the negative electrode in the intercalation and closed-pore sections. In essence, there is a lack of in-depth understanding of the hard carbon lithium storage mechanism, which makes the cycle performance of the hybrid supercapacitor low; and the lithium storage mechanism of hard carbon and other carbon negative electrodes is as follows. Figure 1 As shown, it can be seen that it has edge adsorption structure, graphite-like intercalation structure and pore structure. The current pre-lithiation method ignores the pore filling lithium storage capacity, while the capacity-potential corresponding to the carbon negative electrode such as hard carbon in the adsorption, embedding (intercalation) and pore filling (filling) stages is as follows: Figure 2 As shown in Figures b and c in the figure, it can be seen that compared with the capacity-potential of the commercially available graphite shown in Figure a, the potential of the carbon negative electrode such as hard carbon gradually decreases and the capacity gradually increases in the adsorption-intercalation-pore filling stage, and it has the highest capacity and the lowest potential under the pore filling lithium storage mechanism; in view of this, the present application provides a hybrid supercapacitor lithium replenishment electrode, in which the lithium replenishment negative electrode in the lithium replenishment electrode has a lithium insertion potential of not less than 100mV, and the surface capacity N when the maximum working voltage Vmax of the lithium replenishment positive electrode is controlled to be 0.8~1.0, and the surface capacity N when the lithium insertion potential of the lithium replenishment negative electrode is not less than 0mV and not more than 100mV and the surface capacity P when the maximum working voltage Vmax of the lithium replenishment positive electrode is controlled to be 0.8~1.0. max When the surface capacity P is controlled to have a N / P ratio of 1.3~1.65, the surface capacity N and the maximum working voltage V of the lithium-supplemented positive electrode are controlled to have a lithium-supplemented negative electrode lithium insertion potential of less than 0mV. maxThe N / P ratio of the surface capacity P is controlled to be 1.65~3.05; the N / P is controlled to be 0.8~1.0 in the adsorption lithium storage stage when the lithium insertion potential of the negative electrode is not less than 100mV, and the capacity is provided in the adsorption stage with the highest kinetics of the carbon negative electrode such as hard carbon, so as to meet the needs of high-rate and high-power charging and discharging of the hybrid capacitor, and the N / P ratio is controlled to be 1.3~1.65 in the intercalation lithium storage stage when the lithium insertion potential of the negative electrode is not less than 0mV and not more than 100mV, so as to provide sufficient capacity to supplement the lithium consumption of the SEI film formed during the first charge and discharge of the carbon negative electrode such as hard carbon. The control of the N / P ratio at 100mV enables the hybrid supercapacitor provided by the present application to have both high power and energy density, and to replenish the lithium consumption in forming the SEI film; and the negative electrode lithium replenishment method of the present application also controls the N / P ratio to 1.65~3.05 when the lithium insertion potential of the negative electrode is less than 0mV, that is, in the lithium filling and storage stage. Such a high N / P ratio forces lithium storage in the closed pores of carbon negative electrodes such as hard carbon, and utilizes the pore filling and lithium storage capacity to compensate for lithium loss during the cycle, effectively alleviating the capacity attenuation and cycle life reduction of the hybrid supercapacitor, so that the cycle performance of the hybrid supercapacitor is significantly improved, overcoming the defect of low cycle performance of the current hybrid supercapacitor.
[0055] As an example, the lithium-supplemented negative electrode, the lithium-supplemented positive electrode sheet, the electrolyte and the diaphragm provided in the present application are assembled into a hybrid supercapacitor; when performing the first formation charge, the hybrid supercapacitor needs to be charged to 100% V max ~105%V max The pores are filled and lithium is supplemented to obtain a pre-lithiated hybrid supercapacitor.
[0056] Preferably, the present application also provides a method for obtaining a lithium-replenishing negative electrode and a lithium-replenishing positive electrode. The method tests commercially available positive and negative electrode active materials and screens out positive and negative electrode active materials whose gram capacity and charge and discharge efficiency meet the preset requirements, and loads them onto the positive and negative electrode current collectors at a preset surface density, respectively, to obtain a lithium-replenishing negative electrode and a lithium-replenishing positive electrode, thereby realizing a graded N / P ratio design.
[0057] As a preferred technical solution, in the negative electrode lithium replenishment method provided by the present application, the surface density of the negative electrode and positive electrode active materials can be controlled during the stirring, coating and rolling process to form electrode sheets; and for the surface capacity of the negative electrode and positive electrode active materials in three potential intervals, namely, the surface capacity N when the lithium insertion potential is not less than 100mV, the surface capacity N when not less than 0mV and not greater than 100mV, and the surface capacity N when less than 0mV, the present application also provides a method for obtaining the surface capacity. The surface capacity of the negative electrode and positive electrode active materials sold on the market is the surface capacity of the entire potential interval, so According to the technical solution, the negative electrode and positive electrode active materials are made into working electrodes, and a two-electrode system is formed with the counter electrode, or a three-electrode system is formed with the counter electrode and the reference electrode to test and obtain the surface capacity of the negative electrode and positive electrode active materials in the potential range; at the same time, for the negative electrode and positive electrode charge and discharge efficiency, the application also provides an acquisition method, and the negative electrode and positive electrode active materials are respectively made into negative electrode and positive electrode half-cells with metal lithium sheets, and the negative electrode half-cell is discharged to 0V to obtain the negative electrode charge and discharge efficiency, and the positive electrode half-cell is charged to 4V to obtain the positive electrode charge and discharge efficiency.
[0058] Correspondingly, the present application also provides a pre-lithiation hybrid supercapacitor obtained after lithium replenishment by the above-mentioned negative electrode lithium replenishment method, and the pre-lithiation hybrid supercapacitor is used to form an energy storage system and applied to electric vehicles, new energy power generation, rail transportation, national defense and military industry or aerospace and other fields; taking electric vehicles as an example, the pre-lithiation hybrid supercapacitor devices, thermal management devices and other devices can be used to form an energy storage system and applied in electric vehicles to provide power.
[0059] The lithium-replenishing electrode for a hybrid supercapacitor provided by the present application will be described in detail below with reference to embodiments and experimental examples.
[0060] Example 1
[0061] This embodiment provides a method for preparing a pre-lithiation hybrid supercapacitor, which includes: a step of obtaining a lithium-supplemented negative electrode, a step of obtaining a lithium-supplemented positive electrode, a battery assembly, and a pre-lithiation step.
[0062] The steps to obtain a lithium-supplemented negative electrode include:
[0063] A batch of commercially available hard carbon negative electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacities of these hard carbon negative electrode active materials at lithium insertion potentials of 100 mV, 0 mV, and -50 mV were obtained. Among these, a hard carbon negative electrode active material with a gram capacity of 147 mAh / g at lithium insertion potential of 100 mV, a gram capacity of 242 mAh / g at lithium insertion potential of 0 mV, and a gram capacity of 402 mAh / g at lithium insertion potential of -50 mV was selected and set aside.
[0064] The hard carbon negative electrode active materials screened above were respectively combined with metal lithium sheets to form negative electrode half-cells, and the negative electrode charge and discharge efficiency was measured by discharging to 0V. The hard carbon negative electrode active material with a negative electrode charge and discharge efficiency of 77% was screened out and set aside;
[0065] The hard carbon negative electrode active material obtained through the secondary screening was made into a negative electrode active slurry and coated on the titanium mesh current collector to make a negative electrode sheet. The surface density of the hard carbon negative electrode active material coated on the negative electrode sheet was controlled to 7.7 mg / cm 2 , and thus the surface capacity is obtained to be 0.87 mAh / cm when the lithium insertion potential is 100 mV, 0 mV and -50 mV respectively. 2 、1.43mAh / cm 2 , 2.38mAh / cm 2 Lithium-supplemented negative electrode sheet (sheet negative electrode);
[0066] The steps to obtain a lithium-supplemented positive electrode include:
[0067] A batch of commercially available NCM622 positive electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacity of the NCM622 positive electrode active materials when charged to a maximum operating voltage of 4.0 V was obtained. From these, an NCM622 positive electrode active material with a gram capacity of 160 mAh / g when charged to 4.0 V was selected and set aside.
[0068] The NCM622 positive electrode active materials obtained by screening were respectively combined with metal lithium sheets to form positive electrode half-cells, and the positive electrode charge and discharge efficiency was tested to 4.0V. The NCM622 positive electrode active material with a charge and discharge efficiency of 85% was screened out and set aside;
[0069] The NCM622 positive electrode active material obtained through the secondary screening was made into a positive electrode active slurry and coated on the titanium mesh current collector to make a positive electrode sheet. The surface density of the hard carbon negative electrode active material coated on the positive electrode sheet was controlled to 8 mg / cm 2 , thus obtaining a surface capacity of 1.09 mAh / cm when the positive electrode has a maximum working voltage of 4.0 V. 2 Lithium-supplemented positive electrode sheet (sheet positive electrode).
[0070] By obtaining the above-mentioned lithium-supplemented negative electrode and lithium-supplemented positive electrode, the N / P ratios at lithium insertion potentials of 100 mV, 0 mV, and -50 mV are controlled to be 0.80 (100 mV), 1.31 (0 mV), and 2.18 (-50 mV), respectively.
[0071] The steps of battery assembly and pre-lithiation include: winding lithium-replenishing negative electrode sheets and lithium-replenishing positive electrode sheets to form a battery cell, and then forming a hybrid supercapacitor through liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charging for pre-lithiation, the battery is charged to 4.2V at a rate of 0.1C, thereby releasing lithium ions stored between 4.0V and 4.2V in the positive electrode sheet and storing them in the closed-pore structure of the negative electrode for pore filling and lithium replenishment, thereby achieving the effect of in-situ lithium replenishment and obtaining a pre-lithiation hybrid supercapacitor.
[0072] Example 2
[0073] This embodiment provides a method for preparing a pre-lithiation hybrid supercapacitor, which includes: a step of obtaining a lithium-supplemented negative electrode, a step of obtaining a lithium-supplemented positive electrode, a battery assembly, and a pre-lithiation step.
[0074] The steps to obtain a lithium-supplemented negative electrode include:
[0075] A batch of commercially available hard carbon negative electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacities of these hard carbon negative electrode active materials at lithium insertion potentials of 100 mV, 0 mV, and -50 mV were obtained. Among these, a hard carbon negative electrode active material with a gram capacity of 178 mAh / g at lithium insertion potential of 100 mV, a gram capacity of 230 mAh / g at lithium insertion potential of 0 mV, and a gram capacity of 350 mAh / g at lithium insertion potential of -50 mV was selected and set aside.
[0076] The hard carbon negative electrode active materials screened above were respectively combined with metal lithium sheets to form negative electrode half-cells, and the negative electrode charge and discharge efficiency was measured by discharging to 0V. The hard carbon negative electrode active material with a negative electrode charge and discharge efficiency of 77% was screened out and set aside;
[0077] The hard carbon negative electrode active material obtained through the secondary screening was made into a negative electrode active slurry and coated on the titanium mesh current collector to make a negative electrode sheet. The surface density of the hard carbon negative electrode active material coated on the negative electrode sheet was controlled to 7.7 mg / cm 2 , and thus the surface capacity is obtained at lithium insertion potentials of 100mV, 0mV and -50mV, respectively, of 1.06mAh / cm 2 、1.36mAh / cm 2 , 2.08mAh / cm 2 Lithium-supplemented negative electrode sheet.
[0078] The steps to obtain a lithium-supplemented positive electrode include:
[0079] A batch of commercially available NCM622 positive electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacity of the NCM622 positive electrode active materials when charged to a maximum operating voltage of 4.0 V was obtained. From these, an NCM622 positive electrode active material with a gram capacity of 160 mAh / g when charged to 4.0 V was selected and set aside.
[0080] The NCM622 positive electrode active materials obtained by screening were respectively combined with metal lithium sheets to form positive electrode half-cells, and the positive electrode charge and discharge efficiency was tested to 4.0V. The NCM622 positive electrode active material with a charge and discharge efficiency of 85% was screened out and set aside;
[0081] The NCM622 positive electrode active material obtained through the secondary screening was made into a positive electrode active slurry and coated on the titanium mesh current collector to make a positive electrode sheet. The surface density of the hard carbon negative electrode active material coated on the positive electrode sheet was controlled to 8 mg / cm 2 , thus obtaining a surface capacity of 1.09 mAh / cm when the positive electrode has a maximum working voltage of 4.0 V. 2 Lithium-supplemented positive electrode sheet (sheet positive electrode).
[0082] By obtaining the above-mentioned lithium-supplemented negative electrode and lithium-supplemented positive electrode, the N / P ratios at lithium insertion potentials of 100 mV, 0 mV, and -50 mV were controlled to be 0.97 (100 mV), 1.25 (0 mV), and 1.91 (-50 mV), respectively.
[0083] The steps of battery assembly and pre-lithiation include: winding lithium-replenishing negative electrode sheets and lithium-replenishing positive electrode sheets to form a battery cell, and then forming a hybrid supercapacitor through liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charging for pre-lithiation, the battery is charged to 4.2V at a rate of 0.1C, thereby releasing lithium ions stored between 4.0V and 4.2V in the positive electrode sheet and storing them in the closed-pore structure of the negative electrode for pore filling and lithium replenishment, thereby achieving the effect of in-situ lithium replenishment and obtaining a pre-lithiation hybrid supercapacitor.
[0084] Example 3
[0085] This embodiment provides a method for preparing a pre-lithiation hybrid supercapacitor, which includes: a step of obtaining a lithium-supplemented negative electrode, a step of obtaining a lithium-supplemented positive electrode, a battery assembly, and a pre-lithiation step.
[0086] The steps to obtain a lithium-supplemented negative electrode include:
[0087] A batch of commercially available hard carbon negative electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacities of these hard carbon negative electrode active materials at lithium insertion potentials of 100 mV, 0 mV, and -50 mV were obtained. Among these, a hard carbon negative electrode active material with a gram capacity of 147 mAh / g at lithium insertion potential of 100 mV, a gram capacity of 242 mAh / g at lithium insertion potential of 0 mV, and a gram capacity of 402 mAh / g at lithium insertion potential of -50 mV was selected and set aside.
[0088] The hard carbon negative electrode active materials obtained by screening were respectively combined with metal lithium sheets to form negative electrode half-cells, and the negative electrode charge and discharge efficiency was obtained by discharging to 0V. The hard carbon negative electrode active material with a negative electrode charge and discharge efficiency of 77% was screened out and set aside;
[0089] The hard carbon negative electrode active material obtained through the secondary screening was made into a negative electrode active slurry and coated on the titanium mesh current collector to make a negative electrode sheet. The surface density of the hard carbon negative electrode active material coated on the negative electrode sheet was controlled to 8.5 mg / cm 2 , and thus the surface capacity is obtained to be 0.96 mAh / cm when the lithium insertion potential is 100 mV, 0 mV and -50 mV respectively. 2 、1.58mAh / cm 2 , 2.63mAh / cm 2 Lithium-supplemented negative electrode sheet.
[0090] The steps to obtain a lithium-supplemented positive electrode include:
[0091] A batch of commercially available NCM622 positive electrode active materials, a graphite counter electrode, and a saturated calomel reference electrode were assembled into a three-electrode system and tested using an electrochemical workstation. The gram capacity of the NCM622 positive electrode active materials when charged to a maximum operating voltage of 4.0 V was obtained. From these, an NCM622 positive electrode active material with a gram capacity of 160 mAh / g when charged to 4.0 V was selected and set aside.
[0092] The NCM622 positive electrode active materials obtained by screening were respectively combined with metal lithium sheets to form positive electrode half-cells, and the positive electrode charge and discharge efficiency was tested to 4.0V. The NCM622 positive electrode active material with a charge and discharge efficiency of 85% was screened out and set aside;
[0093] The NCM622 positive electrode active material obtained through the secondary screening was made into a positive electrode active slurry and coated on the titanium mesh current collector to make a positive electrode sheet. The surface density of the hard carbon negative electrode active material coated on the positive electrode sheet was controlled to 8 mg / cm 2 , thus obtaining a surface capacity of 1.09 mAh / cm when the positive electrode has a maximum working voltage of 4.0 V. 2 Lithium-supplemented positive electrode sheet (sheet positive electrode);
[0094] By obtaining the above-mentioned lithium-supplemented negative electrode and lithium-supplemented positive electrode (P), the N / P ratios at lithium insertion potentials of 100 mV, 0 mV, and -50 mV were controlled to be 0.88 (100 mV), 1.45 (0 mV), and 2.41 (-50 mV), respectively.
[0095] The steps of battery assembly and pre-lithiation include: winding lithium-replenishing negative electrode sheets and lithium-replenishing positive electrode sheets to form a battery cell, and then forming a hybrid supercapacitor through liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charging for pre-lithiation, the battery is charged to 4.2V at a rate of 0.1C, thereby releasing lithium ions stored between 4.0V and 4.2V in the positive electrode sheet and storing them in the closed-pore structure of the negative electrode for pore filling and lithium replenishment, thereby achieving the effect of in-situ lithium replenishment and obtaining a pre-lithiation hybrid supercapacitor.
[0096] Comparative Example 1
[0097] This comparative example 1 provides a method for preparing a hybrid supercapacitor, which includes: a step of obtaining a negative electrode, a step of obtaining a positive electrode, a battery assembly, and a pre-lithiation step.
[0098] The steps of obtaining the negative electrode include: preparing a negative electrode active slurry of a commercially available hard carbon negative electrode active material with a gram capacity of 220 mAh / g at a temperature of 6.5 mg / cm 2 The surface density is coated on the titanium mesh current collector to make the negative electrode sheet.
[0099] The steps of obtaining the positive electrode include: preparing a positive electrode active slurry of a commercially available NCM622 positive electrode active material having a gram capacity of 160 mAh / g when charged to 4.0 V at a temperature of 8 mg / cm 2 The positive electrode is coated on the titanium mesh current collector to make the positive electrode sheet.
[0100] The battery assembly and pre-lithiation steps include: the negative electrode sheet and the positive electrode sheet are wound to form a battery cell, and then a hybrid supercapacitor is formed through liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charge for pre-lithiation, the battery is charged to 4V at a rate of 0.1C to obtain a hybrid supercapacitor.
[0101] Comparative Example 2
[0102] This comparative example 2 provides a method for preparing a hybrid supercapacitor, which includes: a step of obtaining a negative electrode, a step of obtaining a positive electrode, a battery assembly, and a pre-lithiation step.
[0103] The steps of obtaining the negative electrode include: preparing a negative electrode active slurry of a commercially available hard carbon negative electrode active material with a gram capacity of 240 mAh / g at a concentration of 6.65 mg / cm 2 The surface density of the film is coated on the titanium mesh current collector to make the negative electrode sheet.
[0104] The steps of obtaining the positive electrode include: preparing a positive electrode active slurry of a commercially available NCM622 positive electrode active material having a gram capacity of 160 mAh / g when charged to 4.0 V at a temperature of 8 mg / cm 2 The positive electrode is coated on the titanium mesh current collector to make the positive electrode sheet.
[0105] The battery assembly and pre-lithiation steps include: the negative electrode sheet and the positive electrode sheet are wound to form a battery cell, and then a hybrid supercapacitor is formed through liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charge for pre-lithiation, the battery is charged to 4V at a rate of 0.1C to obtain a hybrid supercapacitor.
[0106] Comparative Example 3
[0107] This comparative example 3 provides a method for preparing a hybrid supercapacitor, which includes: a step of obtaining a negative electrode, a step of obtaining a positive electrode, a battery assembly, and a pre-lithiation step.
[0108] The steps of obtaining the negative electrode include: preparing a negative electrode active slurry of a commercially available hard carbon negative electrode active material with a gram capacity of 240 mAh / g at a temperature of 7.3 mg / cm 2 The surface density of the film is coated on the titanium mesh current collector to make the negative electrode sheet.
[0109] The steps of obtaining the positive electrode include: preparing a positive electrode active slurry of a commercially available NCM622 positive electrode active material having a gram capacity of 160 mAh / g when charged to 4.0 V at a temperature of 8 mg / cm 2 The positive electrode is coated on the titanium mesh current collector to make the positive electrode sheet.
[0110] The steps of battery assembly and pre-lithiation include: the negative electrode sheet and the positive electrode sheet are wound to form a battery cell, and then the hybrid supercapacitor is formed through the processes of liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charging and pre-lithiation process, the battery is charged to 4.2V at a rate of 0.1C to obtain a hybrid supercapacitor.
[0111] Comparative Example 4
[0112] This comparative example 4 provides a method for preparing a hybrid supercapacitor, which includes: a step of obtaining a negative electrode, a step of obtaining a positive electrode, a battery assembly, and a pre-lithiation step.
[0113] The steps of obtaining the negative electrode include: preparing a negative electrode active slurry of a commercially available hard carbon negative electrode active material with a gram capacity of 240 mAh / g at a concentration of 7.8 mg / cm 2 The surface density of the film is coated on the titanium mesh current collector to make the negative electrode sheet.
[0114] The steps of obtaining the positive electrode include: preparing a positive electrode active slurry of a commercially available NCM622 positive electrode active material having a gram capacity of 160 mAh / g when charged to 4.0 V at a temperature of 8 mg / cm 2 The positive electrode is coated on the titanium mesh current collector to make the positive electrode sheet.
[0115] The steps of battery assembly and pre-lithiation include: the negative electrode sheet and the positive electrode sheet are wound to form a battery cell, and then the hybrid supercapacitor is formed through the processes of liquid injection packaging, formation process, secondary sealing and capacity division. During the first formation charging and pre-lithiation process, the battery is charged to 4.2V at a rate of 0.1C to obtain a hybrid supercapacitor.
[0116] Experimental Example 1
[0117] In this experimental example 1, the performance of the pre-lithiation hybrid supercapacitors provided in Examples 1-3 was tested, and hybrid supercapacitor comparative examples 1-4 were also provided. For hybrid supercapacitor comparative examples 1-4, commercially available hard carbon negative electrode active materials were not tested and the positive and negative electrode active materials whose gram capacity and charge and discharge efficiency met the preset requirements were screened out, and the surface density of the positive and negative electrode active materials was controlled. The hybrid supercapacitors provided in Examples 1-3 and Comparative Examples 1-4 were subjected to cycle performance tests, and the test results are shown in Table 1.
[0118] Table 1: Cyclic performance test results
[0119]
[0120] As can be seen from Table 1, the cycle performance of the hybrid supercapacitors provided in Comparative Examples 1-4 is relatively low, and the capacity retention rate after 500 cycles does not exceed 95%, while the capacity retention rate of the hybrid supercapacitors provided in Examples 1-3 of the present application can reach 98% after 500 cycles. This shows that the hybrid supercapacitors provided in the present application are based on a full understanding of the "adsorption-intercalation-pore filling" lithium storage mechanism and charge-discharge characteristics of the hard carbon or other carbon negative electrode of the hybrid capacitor. By testing commercially available hard carbon negative electrode active materials and screening out positive and negative electrode active materials with gram capacity and charge-discharge efficiency that meet the requirements, and controlling the surface density, a lithium-replenishing negative electrode and a lithium-replenishing positive electrode are obtained, thereby realizing a technical solution of graded N / P ratio, controlling the N / P ratio of the hard carbon or other carbon negative electrode in the adsorption stage, intercalation stage and pore-filling stage, forcing lithium replenishment in the pore-filling stage, and utilizing the pore-filling lithium storage capacity to compensate for lithium loss during the cycle, effectively alleviating the capacity decay of the hybrid supercapacitor, and improving the cycle performance of the hybrid supercapacitor.
[0121] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A lithium-supplementing electrode for a hybrid supercapacitor, characterized in that: The surface capacity of the lithium-supplemented negative electrode when the lithium insertion potential is not less than 100mV and the surface capacity of the lithium-supplemented positive electrode at the highest working voltage V max The N1 / P ratio of the surface capacity is controlled to be 0.8~1.0; The surface capacity of the lithium-supplemented negative electrode when the lithium insertion potential is not less than 0mV and not greater than 100mV and the surface capacity of the lithium-supplemented positive electrode at the highest working voltage V max The N2 / P ratio of the surface capacity is controlled to be 1.3~1.65; The surface capacity of the lithium-supplemented negative electrode when the lithium insertion potential is less than 0mV and the surface capacity of the lithium-supplemented positive electrode at the highest working voltage V max The N3 / P ratio of the surface capacity is controlled to be 1.65~3.
05.
2. The lithium-supplementing electrode for a hybrid supercapacitor according to claim 1, characterized in that: The surface capacity N1 of the lithium supplement negative electrode is y×0.87 mAh / cm when the lithium insertion potential is not less than 100 mV. 2 When the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is y×1.43mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is y×2.38mAh / cm 2 ; The lithium-supplemented positive electrode has a maximum operating voltage V max The surface capacity P is y×1.09mAh / cm 2 ; where y is greater than 0.
3. The lithium-supplementing electrode for a hybrid supercapacitor according to claim 1, characterized in that: The surface capacity N1 of the lithium supplement negative electrode is z×1.06 mAh / cm when the lithium insertion potential is not less than 100 mV. 2 When the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is z×1.36mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is z×2.08mAh / cm 2 ; The lithium-supplemented positive electrode is at the highest operating voltage V max The surface capacity P is z×1.09 mAh / cm 2 ; Where z is greater than 0.
4. The lithium-supplementing electrode for a hybrid supercapacitor according to claim 2, characterized in that: The surface capacity N1 of the lithium supplement negative electrode is t×0.96 mAh / cm when the lithium insertion potential is not less than 100 mV. 2 When the lithium insertion potential is not less than 0mV and not greater than 100mV, the surface capacity N2 is t×1.58mAh / cm 2 When the lithium insertion potential is less than 0mV, the surface capacity N3 is t×2.63mAh / cm 2 ; The lithium-supplemented positive electrode is at the highest operating voltage V max The surface capacity P is t×1.09mAh / cm 2 ; Wherein, t is greater than 0.
5. A method for preparing a lithium-supplementing electrode for a hybrid supercapacitor, characterized in that: A lithium-supplementing electrode for a hybrid supercapacitor according to any one of claims 1 to 4 can be prepared, comprising the following steps: Steps to obtain lithium-supplemented negative electrode, The negative electrode active material is tested and screened in sequence to obtain a negative electrode active material having a preset gram capacity C1 when the lithium insertion potential is not less than 100 mV, a preset gram capacity C2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a preset gram capacity C3 when the lithium insertion potential is less than 0 mV; The negative electrode active materials screened in the first screening are tested and screened in sequence to obtain negative electrode active materials screened in the second screening with a preset charge-discharge efficiency CE1; The secondary screened negative electrode active material is loaded onto the negative electrode current collector at a preset surface density ρ1 to obtain a lithium-supplemented negative electrode having a surface capacity N1 when the lithium insertion potential is not less than 100 mV, a surface capacity N2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a surface capacity N3 when the lithium insertion potential is less than 0 mV; Steps to obtain lithium-supplemented positive electrode, Test and screen the positive electrode active materials to obtain the highest working voltage V max A primary screened positive electrode active material having a preset gram capacity C4; The positive electrode active materials screened in the first screening are tested and screened in sequence to obtain the positive electrode active materials screened in the second screening with a preset charge-discharge efficiency CE2; The secondary screened positive electrode active material is loaded onto the positive electrode current collector at a preset surface density ρ2 to obtain the highest operating voltage V max A lithium-supplemented positive electrode with a surface capacity of P.
6. A method for preparing a lithium-supplementing electrode for a hybrid supercapacitor, characterized in that: A lithium-supplementing electrode for a hybrid supercapacitor according to any one of claims 1 to 4 can be prepared, comprising the following steps: Steps to obtain lithium-supplemented negative electrode, Testing and screening the negative electrode active material in sequence to obtain a primary screened negative electrode active material having a preset charge-discharge efficiency CE1; The negative electrode active materials screened in the first screening are tested and screened in sequence to obtain a negative electrode active material screened in the second screening, which has a preset gram capacity C1 when the lithium insertion potential is not less than 100 mV, a preset gram capacity C2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a preset gram capacity C3 when the lithium insertion potential is less than 0 mV; The secondary screened negative electrode active material is loaded onto the negative electrode current collector at a preset surface density ρ1 to obtain a lithium-supplemented negative electrode having a surface capacity N1 when the lithium insertion potential is not less than 100 mV, a surface capacity N2 when the lithium insertion potential is not less than 0 mV and not greater than 100 mV, and a surface capacity N3 when the lithium insertion potential is less than 0 mV; Steps to obtain lithium-supplemented positive electrode, Testing and screening the positive electrode active material in sequence to obtain a primary screened positive electrode active material having a preset charge-discharge efficiency CE2; Test and screen the primary positive electrode active materials to obtain the highest working voltage V max A secondary screened positive electrode active material having a preset gram capacity C4; The secondary screened positive electrode active material is loaded onto the positive electrode current collector at a preset surface density ρ2 to obtain the highest operating voltage V max A lithium-supplemented positive electrode with a surface capacity of P.
7. A hybrid supercapacitor, characterized in that: A lithium-replenishing electrode for a hybrid supercapacitor comprising the method according to any one of claims 1 to 4.
8. A pre-lithiation method for a hybrid supercapacitor, characterized in that: include: The hybrid supercapacitor according to claim 7 is charged to 100% V during the first charging process. max ~105%V max The pores are filled and lithium is supplemented to obtain a pre-lithiated hybrid supercapacitor.
9. A pre-lithiation hybrid supercapacitor, characterized in that: It is obtained by pre-lithiation of the hybrid supercapacitor according to claim 8.
10. An energy storage system, characterized in that: Including the pre-lithiation hybrid supercapacitor as described in claim 9.