Internally combined super capacitor

Abstract

The invention provides an internally combined super capacitor which comprises an anode, a cathode, a diaphragm and electrolyte. The internally combined super capacitor is characterized in that the anode and the cathode are composed of active substances and perforated current collectors, the active substance of the anode is a mixture containing built-in lithium metal oxide and active carbon, and the active substance of the cathode is hard carbon. According to the internally combined super capacitor, through the energy storage potential matching technology of the anode and the cathode, the current collectors of the anode and the cathode respectively adopt perforated cathode foil and perforated copper foil, and electrochemical pre-doping of lithium ions is performed on the hard carbon of the cathode through a third electrode, so that the initial charged state of the hard carbon reaches 30% to 80%. According to such a finally obtained super capacitor battery, the characteristics of high specific power, long service life and quick charge of the super capacitor are kept, and the specific energy is greatly increased. Compared with a traditional lithium ion capacitor, the internally combined super capacitor has a great application prospect, and the characteristic of the super long cycle life is reserved. The working voltage of the internally combined super capacitor can reach 4.2 V, the specific energy can reach about 50 Wh/kg, the specific power can reach about 10, 000 W/kg, and the cycle life can reach 50, 000 times.

Description

technical field [0001] The invention relates to the field of chemical power sources, in particular to an internally combined supercapacitor. Background technique [0002] In recent years, lithium-ion secondary batteries have been greatly developed. Carbon materials such as graphite are generally used for the negative electrode of this battery, and lithium-containing metal oxides such as lithium cobalt oxide and lithium manganese oxide are used for the positive electrode. After the battery is assembled, the positive electrode supplies lithium ions to the negative electrode when charging, and the lithium ions from the negative electrode return to the positive electrode when discharging, so it is called a "rocking chair battery". Compared with lithium batteries using metallic lithium, this battery is characterized by high safety and high cycle life. [0003] However, the cycle life of lithium-ion secondary batteries is still limited because the negative electrode material is p...

AI Technical Summary

Problems solved by technology

[0006] The first direction is lithium-ion energy storage at the positive pole and electric double layer energy storage at the negative pole. The advantages of this method are simple combination, fewer electrochemical problems to be solved, the ratio of positive and negative electrodes, the choice of electrolyte and current collector As the research core of this kind of device, this kind of device has also achieved commercial application. The typical representative patent is Xia Yongyao of Fudan University's hybrid water-based lithium-ion battery (application number: 200510025269.6), but the system voltage is generally low. 1.8V, even if the electrolyte chooses an organic electrolyte, the voltage is within 2.7V, which limits the improvement of power and energy

[0007] The second direction is the positive electrode for electric double layer energy storage, and the negative electrode for lithium ion energy storage. This system is characterized by high voltage and high power. At the same time, since the negative electrode active material is lithium storage carbon and the positive electrode has no lithium source, the core of the success of this system is the negative electrode pre-doped lithium ion design

[0010] The third direction is that the positive electrode has both lithium ion energy storage and electric double layer energy storage functions, and the negative electrode also has lithium ion energy storage and electric double layer energy storage at the same time, but due to the voltage limitation of the negative electrode double layer energy storage, the Theoretically, it is difficult for the system to have the same energy storage potential range in an electrolytic cell, and the system is difficult to be practical, and there are few research reports so far

[0011] The fourth direction is that the positive electrode has both lithium ion energy storage and electric double layer energy storage functions, and the negative electrode has lithium ion energy storage. This kind of system has high voltage and can achieve high power. The positive electrode has electric double layer energy storage and lithium ion chemistry Energy storage, so the specific energy can be increased at the same time, is the most ideal system, but because the positive electrode has different energy storage methods, and the potential of energy storage does not completely match, these technical difficulties restrict the development of this system

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