阅读说明：本技术 一种非对称锂离子电容器的制备方法 (Preparation method of asymmetric lithium ion capacitor ) 是由 武建飞 徐庆君 于 2020-12-14 设计创作，主要内容包括：本发明涉及一种非对称锂离子电容器的制备方法,特别是包括正极粘结剂体系的选择。该锂离子电容器,包括电容器外壳,电容器外壳内的电解液,正极片、隔膜及负极片顺序叠合组装成的电芯。所述正极片包括涂布在正极集流体基体上的由正极活性材料、导电剂、粘结剂、蒸馏水为溶剂制得的混合浆料,所述负极片包括涂布在负极集流体基体上的由负极活性材料,导电剂,粘结剂,嵌入金属锂极流体、蒸馏水为溶剂制得的混合浆料。该方法制备的锂离子电容器工艺简单易于实现工业化生产。(The invention relates to a preparation method of an asymmetric lithium ion capacitor, in particular to selection of a positive electrode binder system. The lithium ion capacitor comprises a capacitor shell, electrolyte in the capacitor shell, and a battery cell assembled by sequentially overlapping a positive plate, a diaphragm and a negative plate. The positive plate comprises mixed slurry which is coated on a positive current collector substrate and prepared by taking a positive active material, a conductive agent, a binder and distilled water as solvents, and the negative plate comprises mixed slurry which is coated on a negative current collector substrate and prepared by taking a negative active material, a conductive agent, a binder, an embedded metal lithium electrode fluid and distilled water as solvents. The lithium ion capacitor prepared by the method has simple process and is easy to realize industrial production.)

1. A method for preparing an asymmetric lithium ion capacitor particularly comprises the selection of a positive electrode binder system.

2. The asymmetric lithium ion capacitor of claim 1 comprises a positive plate, a negative plate, an electrolyte and a separator.

3. The binder system used in the positive electrode of claim 1 is a mixture of a binder system including 2% CMCC and 3% SBR.

4. The positive electrode sheet and the negative electrode sheet according to claim 2, wherein the positive electrode material is usually activated carbon having high conductivity and large specific surface area, the negative electrode material is usually activated carbon having lithium ion intercalation type, and the positive electrode surface of the activated carbon is subjected to ion adsorption and desorption, and lithium ion intercalation and deintercalation occur in the negative electrode bulk phase.

5. SP, KS-6, graphene conductive paste and the like are used as the conductive agent.

6. The electrolyte of claim 2 being LIPF₆、L iCLO₄And (c) a group of (c).

7. The active carbon for the positive electrode active material according to claim 3, wherein the negative electrode material is selected from graphite, hard carbon, soft carbon, etc.

Technical Field

The invention belongs to the technical field of lithium ion capacitors, and particularly relates to a preparation method of an asymmetric lithium ion capacitor, which particularly comprises selection of a positive electrode binder system.

Background

The internal system of the lithium ion capacitor mainly comprises an anode, a cathode, a diaphragm and electrolyte, and combines an electrochemical double electric layer and an energy storage mechanism of the lithium ion battery. Under the general condition, the negative electrode of the lithium ion capacitor adopts a lithium ion battery electrode material embedded with lithium in advance, and energy is stored by reversible oxidation/reduction reaction; the anode adopts an electrode material of a double electric layer capacitor, and energy is stored through rapid and reversible adsorption/desorption reaction.

The lithium ion capacitor pole piece mainly comprises an active substance, a conductive agent and a binder. Usually, the binder is an inactive material and occupies a small proportion in the electrode, but the binder is an essential and important component substance in the preparation of the lithium battery, and plays an important role in maintaining the structural integrity of the electrode and improving the electrochemical performance of the electrode

At the present stage, most of the adhesives used for the lithium ion capacitor pole pieces are PVDF, and NMP must be used as a solvent to dissolve the PVDF, so that the NMP becomes a solvent widely applied to positive and negative electrode slurry of the lithium ion battery. However, the product is irritating to eyes and skin and should be prevented from smoking, and although the toxicity of NMP in China is not specified in detail, it is specified in Europe. On the other hand, domestic large and small lithium ion battery manufacturers have hundreds of families, the dosage of NMP reaches tens of thousands of tons every year, and the value reaches hundreds of millions of yuan. From the perspective of environmental protection and resource saving, the NMP in the tabletting process is recovered and then recycled, which is significant to bring about corresponding pollution problems.

The aqueous adhesive has the advantages of low material cost, no pollution, no need of waste gas treatment relative to NMP, low heating temperature and low energy consumption; the water vapor and the air are mixed without explosion hidden trouble, which is beneficial to the circular heating of the pole piece drying process. Currently, most production enterprises use an aqueous binder system for the negative electrode, but use an oily binder system for the positive electrode, because the stability of the battery made of the aqueous binder system is poor and the cycle performance of the battery is inferior to that of the battery made of the oily system. However, in view of the effect of the used aqueous binder, finding a more suitable binder system to study the better matching performance of the battery material is still a hot research spot.

Disclosure of Invention

In order to overcome and improve the problems of the traditional binder, the selection of the binder system of the positive electrode plate needs to be reasonably selected and the process needs to be designed. The invention achieves ideal effect by selecting a plurality of water-based binders to be mixed according to a certain proportion.

In order to achieve the purpose, the invention adopts the following technical scheme:

preferably, the conductive agent is ks-6, the negative electrode plate is made of carboxymethyl cellulose sodium CMCC as a viscous agent, the active substance is HC, and the positive electrode plate is made of CMCC and SBR which are mixed and used as a binder. The active substance is a superconducting carbon black material, and a certain proportion of metal lithium is embedded into the anode fluid according to the active content of the anode.

As a preferred electrolyteIs LIPF₆、L iCLO₄And (c) a group of (c).

Preferably, the content of the conductive agent is 5% -7%, the content of the binder is 3% -5%, and the content of the slurry is 88% -92%.