Lithium ion capacitor and fabrication method thereof

Abstract

The invention relates to a lithium ion capacitor. The lithium ion capacitor comprises a positive pole plate, a negative pole plate, a diaphragm and an electrolyte, wherein the diaphragm is arranged between the positive pole plate and the negative pole plate, the positive pole plate comprises a positive electrode current collector and a positive electrode material coated on the positive electrode current collector, the positive electrode material comprises a positive electrode active substance and a binding agent, the positive electrode active material is formed through in-situ combination of a metal oxide with one or more of porous graphene, porous graphdiyne and a porous carbon fiber material mixture, the negative pole plate comprises a negative electrode current collector and a negative electrode material coated on the negative electrode current collector, the negative electrode material comprises a negative electrode active substance and a binding agent, and the negative electrode active material is one of spherical nature graphite, graphitizing mesocarbon microspheres and graphitizing polyimide microspheres through in-site growth of a carbon nanotube or a nanometer metal nitride after pore forming and nitrogen treatment on the surface. The above lithium ion capacitor has the advantages of high working voltage, good power characteristic and high energy density, and is safe to use. Further, the invention also provides a preparation method of the lithium ion capacitor.

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 increasing energy crisis and environmental problems have accelerated the rapid development of the new energy industry. Under the current situation, the environment-friendly electrochemical energy storage technology that maximizes green energy supply and low-carbon energy conservation and emission reduction has attracted more and more attention. Recently, the state has 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 technologies. In addition, new energy Electrochemical energy storage devices with high energy density and high power density are also requi...

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