A Li-ion Capacitor with High Energy Density

Abstract

The invention relates to a lithium ion capacitor with high energy density, and especially relates to a lithium ion capacitor with a negative electrode using a silicon carbon composite electrode. The lithium ion capacitor comprises a shell, a battery core arranged inside the shell, and electrolyte; the battery core is composed of a positive electrode slice, a negative electrode slice and a diaphragm arranged between the positive electrode slice and the negative electrode slice by means of winding or laminating; the positive electrode slice comprises a positive current collector and a positive coating layer coated on the positive current collector; and the negative electrode slice comprises a negative current collector and a negative coating layer coated on the negative current collector. Positive electrode active materials are carbon materials with a high specific surface area and negative electrode active materials are silicon carbon composite materials. The lithium ion capacitor takes a metal lithium electrode as a counter electrode, and the negative electrode slice is pre-embedded with lithium. The invention adopts the silicon carbon composite material with high capacity, and the prepared lithium ion capacitor has a higher energy density.

Description

technical field [0001] The invention relates to a lithium-ion capacitor with high energy density, in particular to a lithium-ion capacitor whose negative electrode adopts a silicon-carbon composite electrode. Background technique [0002] With the continuous development of the world economy, the depletion of chemical energy and the increasingly serious environmental pollution, the development and utilization of new energy has become an extremely important development direction. At the same time, more and more stringent performance requirements are put forward for the development of energy storage devices. As a new type of energy storage device, lithium-ion capacitors have higher power density and longer cycle life than lithium-ion batteries, and higher energy density than electric double-layer supercapacitors. They are expected to be used in electric vehicles, rail transit, New energy power generation and other fields have been widely used. However, the energy density of li...

AI Technical Summary

Problems solved by technology

However, the specific capacity of the negative electrode material is low. For example, the theoretical specific capacity of graphite is only 372mAh / g, which will affect the energy density of the entire lithium ion capacitor. The disclosed energy density is 75Wh / kg

Chinese Patent Publication No. CN105047418A discloses a lithium titanate-based lithium ion capacitor. The negative electrode active material is a composite material of lithium titanate and carbon material, but the charging and discharging platform voltage of lithium titanate is relatively high, and the voltage window of the lithium ion capacitor is narrow (from 1 to 2.5V), resulting in lower energy density of Li-ion capacitors

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