Preparation method of lithium ion capacitor (LIC) adopting pre-lithiation hard carbon negative electrode

Abstract

The invention discloses a preparation method of a lithium ion capacitor (LIC) adopting a pre-lithiation hard carbon negative electrode. Commercial activated carbon serves as a positive electrode, hard carbon serves as the negative electrode and 1M LiPF6 / EC+DEC serves as an electrolyte to assemble the LIC. The embedded lithium volume of the LIC is 400 mAh / g, the highest energy density and power density are 76.5 Wh / kg and 5.1 kW / kg respectively, and the energy keeping rate can still be as high as 92.0 percent after 1000 times of circulation. The energy density of the LIC after 15 hours of pre-lithiation can reach 97.2 Wh / kg, and small impedance and good circulation performance are achieved (after 1000 times of circulation at the current density of 1A / g, the energy keeping rate is 91.2 percent). When the mass proportion of the positive electrode and the negative electrode is 2.2, the energy keeping rate is 57.0 percent. Meanwhile, the LIC has quite small charge transfer internal resistance (10.4), and the maximum energy density and the maximum power density are 88.7 Wh / kg and 12 kW / kg.

Description

technical field [0001] The invention relates to a lithium ion capacitor, in particular to a lithium ion capacitor using a pre-lithiated hard carbon negative electrode. Background technique [0002] Lithium-ion capacitor is a new type of power supply element introduced in the new century, whose energy density greatly exceeds that of electric double-layer capacitors, and has great development prospects. Lithium ion capacitor (LIC) can be said to be a hybrid capacitor of lithium ion rechargeable battery (LIB) and electric double layer capacitor (EDLC). The positive electrode uses activated carbon, and the negative electrode uses graphite and other materials. [0003] Since the lithium-ion capacitor uses the electrode materials of the battery and the capacitor, it has some advantages of the battery and some advantages of the capacitor, and is an energy storage element between the lithium-ion battery and the electric double layer capacitor. Its main advantages include better ene...

AI Technical Summary

Problems solved by technology

It can be seen that the positive electrode of the lithium-ion capacitor is ion adsorption and desorption, and the energy storage is limited to the surface of the electrode. The advantage of this energy storage method is that the ion transmission speed is fast, and the energy can be stored very quickly. The disadvantage is that the storage less energy

The negative electrode is just the opposite, energy is stored in the entire electrode material matrix, so more energy is stored but the energy storage speed is slower

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