A kind of lithium ion capacitor and preparation method thereof

Abstract

The invention relates to a lithium ion capacitor, which comprises a positive pole piece, a negative pole piece, a diaphragm interposed between the positive and negative pole pieces, and an electrolytic solution. The positive electrode includes a positive electrode current collector and a positive electrode material coated on the positive electrode current collector. The positive electrode material is composed of a positive electrode active material and a binder, wherein the positive electrode active material is made of metal oxide and porous graphene, porous graphyne or porous carbon fiber One or more of the material mixtures are formed by in-situ compounding; the negative electrode sheet includes a negative electrode current collector and a negative electrode material coated on the negative electrode current collector, and the negative electrode material is composed of a negative electrode active material and a binder, wherein the negative electrode active material It is one of spherical natural graphite, graphitized mesophase carbon microspheres, and graphitized polyimide carbon microspheres with in-situ growth of carbon nanotubes or nano-metal nitrides on the surface after pore-forming and nitriding treatment; the above-mentioned lithium Ion capacitors have the advantages of high working voltage, good power characteristics, high energy density, and safe use. In addition, a preparation method of the lithium ion capacitor is also provided.

Description

Technical field [0001] The invention relates to an electrochemical energy storage device, in particular to a lithium ion capacitor and a preparation method thereof. Background technique [0002] The energy crisis and the increasing environmental problems have accelerated the rapid development of the new energy industry. Under the current situation, environmentally friendly electrochemical energy storage technology that maximizes green energy supply and low-carbon energy saving and emission reduction has received increasing attention. Recently, the state proposed to establish a near-zero carbon emission project based on the Energy Internet, the core content of which includes renewable energy power generation, distributed energy storage technology, etc., which puts forward higher requirements for new and efficient energy storage technology. In addition, new energy Electric vehicles, low-temperature starting power supplies, high-speed rail / urban rail transit braking energy recovery...

AI Technical Summary

Problems solved by technology

[0004] Patent 201110320933.5 discloses a supercapacitor battery. The anode active material of the capacitor battery is a mixture of activated carbon, carbon aerogel, carbon nanotubes or pyrolytic carbon and the anode material of the lithium ion battery. Although the specific surface area of ​​activated carbon and carbon aerogel High, but the conductivity is still unsatisfactory. Carbon nanotubes are one-dimensional conductive materials with a relatively low specific surface area, while pyrolytic carbon is relatively poor in terms of specific surface area and conductivity, and cannot greatly improve power performance. The negative electrode active material is a mixture of silicon nanowires, carbon nanotubes and graphene. Silicon materials have a huge volume expansion and contraction effect when used as lithium intercalation materials, which is not conducive to long-term cycle performance. The specific surface area of ​​graphene disclosed is only 200~600m 2 / g

Patent 201010114612.5 discloses a supercapacitor battery. The negative electrode active material of the capacitor battery is hard carbon material, but the discharge voltage of hard carbon material varies greatly with capacity, and the first charge and discharge efficiency is low, and the discharge voltage hysteresis is obvious. The positive electrode active material is lithium A mixture of ion intercalation compounds and porous carbon materials (activated carbon, carbon cloth, carbon fiber, carbon felt, carbon aerogel, carbon nanotubes), the problem is the same as that of patent 201110320933.5

Patent 201510130056.3 discloses a lithium supercapacitor battery negative electrode. The method is to sprinkle lithium powder on the surface of negative graphite or hard carbon material, and then roll to obtain the negative electrode. The disadvantage of this method is that the amount of lithium powder spread is harsh. Seriously, the use of metallic lithium has potential safety hazards in the long-term charging and discharging process. Lithium dendrites are likely to be caused by a little carelessness, which will break through the diaphragm and cause a short circuit.

In addition, there are two common problems in the three patents disclosed above. One is that the power performance cannot be maximized due to the limitation of the structure of the negative electrode active material. Conductive, which increases the difficulty of the positive and negative electrode slurry mixing process