A method for improving the self-discharge of supercapacitors

Abstract

The invention belongs to the technical field of electrochemistry, and in particular relates to a method for improving self discharge of a super capacitor. The method comprises the following steps: 1)putting an activated carbon electrode as a substrate in a vacuum reaction chamber; 2) introducing first precursor gas into the vacuum reaction chamber, wherein the first precursor gas is reacted witha surface functional group of the activated carbon electrode; 3) flushing the electrode with inert gas; and 4) introducing the first precursor gas as a metal source and the second precursor gas as anoxygen source into the vacuum reaction chamber and carrying out atomic layer deposition circulation in an inert gas atmosphere till forming a metal oxide film with a targeted thickness. The metal oxide is deposited to the surface of the activated carbon electrode to form a coating layer by means of the atomic layer deposition technology, so that the surface structure of the carbon electrode is improved, and the stability of the super capacitor in the using process is enhanced; and the purpose of simply and precisely controlling the thickness needed by growth of a film can be achieved by controlling the periodicity of the reaction.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a method for improving the self-discharge of a supercapacitor. Background technique [0002] With the expansion of the field of use of supercapacitors, some of its own shortcomings have also been exposed to the public. The first one is self-discharge, which has a major impact on the energy storage capacity and cycle stability of supercapacitors. When the supercapacitor is independent of the external circuit, the self-discharge is caused by the parasitic current passing through one of the positive and negative electrodes or a pair of independent electrodes, which can be mainly attributed to the following reasons: [0003] 1) When the electrode / electrolyte surface voltage is higher than the electrolyte decomposition voltage, a redox reaction will occur, which will generate a self-discharge caused by a voltage-controlled Faraday impedance, which is proportional ...

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Problems solved by technology

[0020] Self-discharge is a key indicator that determines the performance of supercapacitors. Compared with chemical energy storage, the characteristic of large self-discharge greatly hinders the further promotion of supercapacitor market applications. Therefore, improving the self-discharge of supercapacitors is an urgent need for us to solve Traditional methods for improving supercapacitors mainly start with raw materials and production processes, including pore structure control and surface functional group treatment of activated carbon, control of diaphragm thickness and pore size, and optimization of drying and aging processes; However, these methods for improving supercapacitors are not only complicated, but also have poor stability during use.

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