Modified electrode and preparation method and application thereof

Abstract

The invention relates to a modified electrode as well as a preparation method and application thereof. The modified electrode comprises a current collector loaded with a carbon-based active substance as an electrode and a polymer film coated on the surface of the electrode, where the polymer film is formed by performing in-situ polymerization on a small molecular organic matter monomer through an electrochemical method; the micromolecular organic matter monomer at least comprises a carbon-carbon double bond and a heteroatom-containing group, and the heteroatom-containing group is selected from at least one of carboxyl, hydroxyl, carbonyl, aldehyde group, sulfonic acid group, phosphate group, nitryl, amino, sulfydryl, amide group, ester group, halogenated group and cyanamide group.

Description

technical field [0001] The invention relates to a method for modifying electrochemical energy storage materials, in particular to a modified electrode and its preparation method and application, in particular to a method for electrochemical in-situ deposition of small molecular organic substances containing carbon-carbon double bonds on the electrode surface The invention relates to a method for improving the voltage window of a water-based supercapacitor by polymerizing a monomer and its alkali metal salt and alkaline earth metal salt, and belongs to the field of materials. Background technique [0002] Electrochemical energy storage technology is an important technology that affects human production and life, and has received extensive attention from industry and academia. Lithium-ion batteries and supercapacitors are two representative types of energy storage devices in the field of electrochemical energy storage. Compared with traditional secondary batteries, lithium-io...

AI Technical Summary

Problems solved by technology

However, these high-voltage non-aqueous supercapacitors have problems such as expensive electrolytes, poor safety, and unfriendly environment, and the specific capacity of carbon materials in these electrolytes is generally less than half of that in aqueous electrolytes, which weakens high The increase in energy density brought about by voltage, the ionic conductivity of this type of electrolyte is generally only ~10mS cm -1 , much lower than the aqueous electrolyte>100mS cm -1 , so that the rate performance of the device is not good. In addition, there is an oxidation problem in the carbon material under high voltage, which leads to a decrease in the cycle stability of the device.

[0005] Therefore, the development of high-voltage supercapacitors based on aqueous electrolytes is the optimal path to simultaneously achieve high energy density, high power density, high safety, and low cost. The thin film can isolate the direct contact between the electrode and water to inhibit the decomposition of water, but there are still several problems in how to realize the water-based high-voltage supercapacitor: (1) How to break through the limitations of thermodynamics and kinetics and inhibit the electrolysis of water under high voltage, Increase the voltage window to above 2V; (2) How to solve the oxidation problem of active material carbon materials under high voltage; (3) How to controlly prepare a uniform water-repelling and ion-conducting layer on the electrode surface; (4) How to realize the polymer The stability of the film during cycling; (5) How to ensure that the specific capacity and rate performance of the material will not be lost when the device voltage is increased

Images