Preparation method and application of in-situ carbon-compounded prussian blue type compound thin film

Abstract

The invention discloses a preparation method and application of an in-situ carbon-compounded prussian blue type compound thin film. The preparation method comprises the following steps: (1) carrying out ultrasonic dispersion on carbon materials in a NaCl solution; (2) weighing transition metal cyano complexes, a reducing agent and inorganic acid in a ratio and adding into the solution; (3) electrolyzing for 3-5 minutes in water to clean the surface of an ITO conducting substrate; and (4) generating the in-situ carbon-compounded prussian blue type compound thin film on the ITO conducting substrate under a constant-voltage condition relative to voltage from -2.0V to 2.0V of a standard Ag/AgCl electrode. According to the preparation method and the application, the film is formed in one step, the preparation method is rapid and simple and low in cost and the electrical conductivity of the obtained compound material is greatly improved; and the content of sodium is high, and vacancy and the water content are low. As a sodium-ion battery positive electrode material, the material has the characteristics of high specific capacity, high cycling stability, excellent rate performance and the like, and has a bright prospect in large-scale development and application of sodium-ion batteries.

Description

technical field [0001] The invention relates to a preparation method and application of a Prussian blue compound thin film of in-situ composite carbon, belonging to the fields of energy material preparation and electrochemistry. Background technique [0002] Lithium-ion batteries have shown broad application prospects in portable electronic devices and electric vehicles due to their advantages such as high specific capacity, high power density, stable discharge, and environmental friendliness. However, the reserves of lithium resources in the earth's crust are limited, and the price of lithium raw materials continues to rise, hindering the sustainable development of lithium-ion batteries. In addition to having a similar working principle to lithium-ion batteries, sodium-ion batteries also have the advantages of abundant resources and low cost, and are considered to be an ideal choice for next-generation energy storage power sources. In the current reports on sodium-ion batt...

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Problems solved by technology

[0004] However, in practical application, the Prussian blue complexes still have the following two deficiencies: first, the sodium ion content in the complexes prepared by the general method is too low, and the internal vacancies and water content are high, which makes the charge and discharge capacity far lower. Lower than the theoretical value, and the cycle performance is poor; second, the electronic conductivity of the material itself is poor, resulting in poor rate performance

The above two reasons restrict the full play of its electrochemical performance.

In addition, from the perspective of the electrode preparation process, firstly, the active material and the conductive agent in the electrode prepared by the traditional coating method are difficult to mix uniformly, resulting in insufficient contact with each other, resulting in poor conductivity of the electrode; secondly, the coating film Active substances in the method are easily interfered by foreign substances such as conductive agents and binders, which will greatly affect the full play of their intrinsic properties.

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