Preparation method and application of porous molybdenum phosphide/carbon fiber composite material

Abstract

The invention belongs to the technical field of transition metal phosphide composite materials. The invention provides a preparation method and application of a porous molybdenum phosphide / carbon fiber composite material. The preparation method comprises the steps of dissolving a phosphorus source and a molybdenum source into a solution, adding a pore forming agent and a carbon source to prepare aspinning solution, carrying out electrostatic spinning, and carrying out high-temperature carbonization. A dispersed and uniform pore channel structure is generated on the surface of the fiber through shrinkage during pyrolysis of the pore forming agent, and the volume effect caused by ion intercalation and deintercalation in the cyclic process can be effectively relieved, so that the cyclic stability of the material is improved. According to the preparation method, an etching agent and a template agent do not need to be used, a large number of centrifuging and washing processes are avoided,the operation is easy, the morphology is stable and controllable, and continuous preparation is facilitated. The porous molybdenum phosphide / carbon fiber composite material prepared by the invention is used as a negative electrode of a sodium-ion battery, still keeps the specific capacity of 100mAh / g or above after being circulated for 1200 times under the current density of 1A / g, and has good rate capability.

Description

technical field [0001] The application belongs to the technical field of transition metal phosphide composite materials, and in particular relates to a preparation method and application of a porous molybdenum phosphide / carbon fiber composite material. Background technique [0002] Compared with lithium-ion batteries, the performance of sodium-ion batteries is slightly worse when discharged at a high rate, but because of its low manufacturing cost, relatively stable material structure and performance, and safe use, sodium-ion batteries have unique advantages in large-scale energy storage for power grids and other energy storage fields. own advantages. [0003] Transition metal phosphides based on conversion reaction energy storage mechanism, higher theoretical capacity and lower sodium storage voltage are known as ideal candidates for anode materials for sodium ion batteries, but phosphides have poor rate performance and large volume in cycles Bloat hinders its commercializ...

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Problems solved by technology

[0004] The traditional pore-making method usually adopts the route of using a hard template in the synthesis and then removing it by reagents. For example, in the patent (CN110479332A), phosphorus source / molybdenum source / carbon source are used as raw materials, and sodium chloride is used as a pore-forming agent. After freeze-drying, calcining , washed with water to obtain porous molybdenum phosphide nanosheets, the process is cumbersome and consumes a large amount of template agent

Or use a large number of surfactant self-assembly methods to construct the pore structure. For example, in the patent (CN110350181A), hydrofluoric acid is used to etch nano-silicon particles to form holes to prepare nano-porous silicon negative electrode materials, which requires strict pre-treatment of raw materials. processing, and the use of hydrofluoric acid consumes active components and produces corrosive spent acid

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