High-specific-energy low-temperature-resistant carbon-niobium-based hybrid capacitor

Abstract

The utility model discloses a high-specific-energy low-temperature-resistant carbon-niobium-based hybrid capacitor, and belongs to the technical field of electrochemical energy storage. A diaphragm, a positive current collector, a negative current collector, a positive pole piece, a negative pole piece and electrolyte are arranged in the shell, the tail end of the diaphragm is arranged in the shell in a surrounding manner, the head end of the diaphragm is circuitously arranged in a space surrounded by the tail end of the diaphragm, the positive pole piece is fixed on one side of the head end of the diaphragm, and the negative pole piece is fixed on the other side of the head end of the diaphragm; after the diaphragms are roundabout, two adjacent positive pole pieces share one positive current collector, and two adjacent negative pole pieces share one negative current collector. According to the utility model, the anode adopts a carbon material to improve the graphitization degree, and the conductivity and the energy storage capability are improved. The negative electrode is made of a niobium-based material, the energy storage performance is effectively enhanced by an intercalation pseudocapacitance mechanism, and good electrochemical performance is still kept at low temperature. In addition, different capacity requirements can be met by flexibly adjusting the number of circuitous lamination layers of the electrodes.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of high specific energy low temperature resistant carbon-niobium-based hybrid capacitor, belong to electrochemical energy storage technical field. BACKGROUND

[0002] Although the existing hybrid capacitor (HSC) technology provides a good balance between power density and energy density, there are still many technical problems, which limit its wide application, as follows:

[0003] Firstly, the capacity matching problem between positive and negative electrode materials has always been the main obstacle to the development of hybrid capacitor technology. Due to the significant differences in performance of different types of electrochemical materials, especially in the process of energy storage, the mismatch of specific capacity and electrical conductivity of positive and negative electrode materials affects the efficiency and stability of the overall energy storage system. Currently, the combination of activated carbon and titanate, transition metal oxide and other materials has improved the performance of hybrid capacitors to some extent, but the mismatch between energy density and power density is still prominent, affecting the overall performance of the energy storage system.

[0004] Secondly, with the increasing demand for large-capacity energy storage systems in the market, the development of hybrid capacitor technology in this field is particularly urgent. However, the improvement of traditional hybrid capacitors in capacity and energy density has reached its limit, especially under the limitation of the capacity difference between positive and negative electrode materials, the further improvement of overall energy density faces great challenges. How to balance power density, capacity matching and material stability in the design of high-capacity and high-energy density capacitors has become a technical problem that needs to be solved urgently.

[0005] In addition, the low-temperature performance problem is also a bottleneck for the development of hybrid capacitor technology. In low-temperature environment, the electrochemical performance of most capacitors decreases significantly, especially the energy attenuation of activated carbon materials at low temperature is particularly significant, which seriously limits the application of hybrid capacitors in low-temperature conditions. Especially in electric vehicles and renewable energy storage systems, low-temperature starting performance and stability are important indicators for evaluating capacitor performance, so it is particularly important to improve the low-temperature performance of hybrid capacitors.

[0006] In summary, the current hybrid capacitor technology still faces many technical problems such as difficulty in matching positive and negative electrode materials, insufficient design of large-capacity capacitors and poor low-temperature performance, which limits its wide application in high-energy density, large-capacity and low-temperature environment. UTILITY MODEL CONTENT

[0007] To solve the problems in the background art, the utility model provides a kind of high specific energy low temperature resistant carbon-niobium-based hybrid capacitor.

[0008] To achieve the above object, the utility model takes the following technical scheme: A kind of high specific energy low temperature resistant carbon-niobium base hybrid capacitor, including diaphragm, positive current collector, negative current collector, positive pole piece, negative pole piece, shell and electrolyte;The shell is equipped with diaphragm, positive current collector, negative current collector, positive pole piece, negative pole piece and electrolyte, the tail end of the diaphragm is arranged in the inside of shell, the head end of diaphragm is arranged in the space of diaphragm tail end encircles, the one side of diaphragm head end is fixed with positive pole piece, the other side of diaphragm head end is fixed with negative pole piece, after diaphragm detours, two adjacent positive pole pieces share one positive current collector, two adjacent negative pole pieces share one negative current collector.

[0009] The positive current collector is carbon-coated aluminum foil.

[0010] The negative current collector is copper foil.

[0011] The material of the positive pole piece is carbon material.

[0012] The material of the negative pole piece is niobium-based material.

[0013] The electrolyte is a mixture of lithium hexafluorophosphate, ethylene carbonate, diethyl carbonate and dimethyl carbonate organic solution.

[0014] The diaphragm is glass fiber diaphragm.

[0015] Compared with the prior art, the utility model has the advantages that:

[0016] The positive electrode of the utility model uses carbon material to improve graphitization degree, which improves electrical conductivity and energy storage capacity. The negative electrode uses niobium-based material, which effectively enhances the energy storage performance through intercalation pseudo-capacitance mechanism. The energy density, rate performance, low temperature performance and cycle stability of the capacitor are improved, and it still maintains good electrochemical performance at low temperature. In addition, by flexibly adjusting the number of electrode detour laminated layers, different capacity requirements can be met, which is convenient for large-scale production and meets the high requirement application scenarios such as electric vehicles and renewable energy storage. The utility model not only has excellent performance, but also has low manufacturing cost, high application prospect and market value. The hybrid capacitor constructed by using carbon material and niobium-based negative electrode material after high-temperature pre-carbonization and activation significantly improves the energy density, cycle performance and low temperature performance of the hybrid capacitor. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the structure diagram of the utility model. DETAILED DESCRIPTION

[0018] Clearly and completely describe the technical scheme in the utility model in combination with the drawings in the embodiments of the utility model, obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments, on the basis of the embodiments in the utility model, all other embodiments obtained by the ordinary skilled in the art without making creative labor belong to the range of protection of the utility model.

[0019] A high specific energy low temperature resistant carbon-niobium based hybrid capacitor, comprising a separator 1, a positive current collector 2, a negative current collector 3, a positive electrode sheet 4, a negative electrode sheet 5, a shell and an electrolyte; the shell is provided with the separator 1, the positive current collector 2, the negative current collector 3, the positive electrode sheet 4, the negative electrode sheet 5 and the electrolyte, the tail end of the separator 1 is arranged around the inside of the shell, the head end of the separator 1 is arranged in the space around the tail end of the separator 1, and the number of layers of the winding can be arranged according to the capacity requirement of the hybrid capacitor. One side of the head end of the separator 1 is fixed with the positive electrode sheet 4, the other side of the head end of the separator 1 is fixed with the negative electrode sheet 5, and the adjacent two positive electrode sheets 4 share one positive current collector 2 after winding of the separator 1, and the adjacent two negative electrode sheets 5 share one negative current collector 3. The positive and negative current collectors are connected with tabs, and can be connected with an external circuit through wires.

[0020] The positive current collector 2 is a carbon-coated aluminum foil.

[0021] The negative current collector 3 is a copper foil.

[0022] The material of the positive electrode sheet 4 is a carbon material, such as activated carbon, template carbon, graphene or biomass carbon.

[0023] The material of the negative electrode sheet 5 is a niobium-based material, such as TiNb2O7, TiNbO4 or Ti2Nb 10 O 29 .

[0024] The electrolyte is a mixed organic solution of lithium hexafluorophosphate, ethylene carbonate, diethyl carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate, diethyl carbonate and dimethyl carbonate is 1:1:1. The concentration of the electrolyte is 0.5-5 mol / L.

[0025] The separator 1 is a glass fiber separator.

[0026] The binder of the electrode sheet is polyvinylidene fluoride or polytetrafluoroethylene or sodium carboxymethyl cellulose.

[0027] The conductive agent of the electrode sheet is conductive carbon black or acetylene black or carbon nanotube.

[0028] The preparation method of the positive electrode material of the high specific energy low temperature resistant carbon-niobium based hybrid capacitor, the method comprises the following steps:

[0029] S1: pre-carbonization: pre-carbonize the biomass material or coal precursor material at a temperature below 700°C, the pre-carbonization rate is 0.1°C / min-20°C / min, the pre-carbonization time is 1 hour, and obtain carbon powder;

[0030] S2: activation: mix the carbon powder with the salt in a mass ratio of 1:2-4, the salt is potassium hydroxide or potassium carbonate, and heat to the target activation temperature (600°C to 1000°C) in an inert atmosphere furnace, and after constant temperature for a certain time (0.5h-10h), cool to room temperature in the cooling chamber, and obtain porous graphite carbon material;

[0031] S3: after repeatedly washing the obtained porous graphite carbon material with acid washing solution (HF or dilute hydrochloric acid or dilute nitric acid or dilute acetic acid) to remove impurities, wash with deionized water until the solution is neutral, and then dry to obtain the positive electrode material.

[0032] The inert atmosphere is high-purity nitrogen or high-purity argon, and the volume flow rate is 50mL / min-500mL / min.

[0033] The temperature rising rate of the atmosphere furnace is 0.1°C / min-20°C / min.

[0034] The concentration of the acid washing solution is 0.01mol / L-10mol / L.

[0035] The water washing method is solid-liquid separation by vacuum filtration or by centrifuge.

[0036] The drying method is vacuum drying or hot air drying or natural evaporation.

[0037] After drying, the obtained positive electrode material is mixed with conductive agent acetylene black, binder sodium carboxymethyl cellulose, and butadiene rubber in a ratio of 90:5:3:2, and then coated on carbon-coated aluminum foil, vacuum dried, and cut into electrode pieces.

[0038] The negative electrode piece is prepared according to the following steps: mix niobium-based material, conductive agent acetylene black, and binder polyvinylidene fluoride in a ratio of 90:5:5, and then coat on copper foil, vacuum dry, and cut into electrode pieces.

[0039] It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but that it can be implemented in other forms without deviating from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than that of the above description, and it is therefore intended that all changes falling within the meaning and range of equivalents of the claims be embraced therein. Any reference signs in the claims should not be construed as limiting the claims concerned.

[0040] Furthermore, it should be understood that although the present specification is described in terms of embodiments, not every embodiment according to the present specification needs to exhibit each and every characteristic specified in the present specification. The specification can also be described in terms of a single preferred embodiment, it being understood that this single preferred embodiment can exhibit not every aspect or feature of the present specification. The specification can also be described in terms of a generic statement that the disclosure can include one, some, or all embodiments, it being understood that this generic statement can encompass not every aspect or feature of the present specification.

Claims

1. A high specific energy low temperature tolerant carbon-niobium based hybrid capacitor characterized by: The application relates to a battery, which comprises a diaphragm, a positive current collector, a negative current collector, a positive pole piece, a negative pole piece, a shell and an electrolyte; the diaphragm, the positive current collector, the negative current collector, the positive pole piece, the negative pole piece and the electrolyte are arranged in the shell; the tail end of the diaphragm is arranged around the inside of the shell; the head end of the diaphragm is arranged in the space around the tail end of the diaphragm; one side of the head end of the diaphragm is fixed with the positive pole piece; the other side of the head end of the diaphragm is fixed with the negative pole piece; two adjacent positive pole pieces share one positive current collector; two adjacent negative pole pieces share one negative current collector.

2. The high specific energy, low temperature tolerant carbon-niobium based hybrid capacitor of claim 1, wherein: The positive current collector is a carbon-coated aluminum foil.

3. The high specific energy, low temperature tolerant carbon-niobium based hybrid capacitor of claim 1, wherein: The negative current collector is a copper foil.

4. The high specific energy, low temperature tolerant carbon-niobium based hybrid capacitor of claim 1, wherein: The material of the positive pole piece is a carbon material.

5. The high specific energy, low temperature tolerant carbon-niobium based hybrid capacitor of claim 1, wherein: The material of the negative pole piece is a niobium-based material.

6. The high specific energy, low temperature tolerant carbon-niobium based hybrid capacitor of claim 1, wherein: The diaphragm is a glass fiber diaphragm.

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