Graphene-based high specific energy lithium ion capacitor and preparation method thereof

Abstract

The invention discloses a graphene-based high specific energy lithium ion capacitor. The graphene-based high specific energy lithium ion capacitor comprises a positive plate, a negative plate, a diaphragm and an electrolyte solution, wherein the positive plate comprises a positive active material, a positive current collector and a positive conductive agent; the positive active material comprisesa modified ternary material and activated carbon, the mass parts of the modified ternary materials are 0-5 parts, and the mass parts of the activated carbon are 95-100 parts; the negative plate comprises a negative active material, a negative current collector and a negative conductive agent, wherein the negative material is a modified hard carbon material; and the positive electrode conductive agent and the negative electrode conductive agent both comprise grapheme. The invention further discloses a preparation method of the graphene-based high specific energy lithium ion capacitor. The graphene-based high specific energy lithium ion capacitor has the characteristics of high specific energy and high multiplying power, and according to the high-temperature multiplying power, charging and discharging temperature rising is slow, the stability is high, the heat dissipation performance is good, the cost is saved and the service life is prolonged; and a step discharge mode is adopted to perform pre-lithium embedding, so that the lithium embedding efficiency is improved, and a stable SEI film is facilitated to form.

Description

technical field [0001] The invention relates to the technical field of lithium ion capacitors, in particular to a graphene-based high specific energy lithium ion capacitor and a preparation method thereof. Background technique [0002] With the depletion of traditional chemical energy and the deterioration of the environment, countries are forced to vigorously develop and utilize green and sustainable energy and new energy storage devices. Among many energy storage components, lithium-ion batteries and electric double-layer capacitors have received extensive attention due to their outstanding performance advantages, and have been widely used in new energy vehicles, rail transit, heavy machinery, smart grids, and military aerospace. application. [0003] As a new type of asymmetric capacitor with both high energy density of lithium-ion batteries and high power characteristics of electric double-layer capacitors, lithium-ion capacitors not only combine the negative electrode ...

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Problems solved by technology

[0004] At present, the main factor affecting the performance of lithium-ion capacitors is the mismatch of positive and negative electrode kinetics, in which electrode materials play a key role. The electrode materials in the prior art have low specific capacity, poor rate performance, and low cycle stability. Lithium-ion battery containers with high energy density, high rate density and long cycle life