Preparation method of lithium-sulfur battery negative electrode biological carbon material

Abstract

The invention discloses a preparation method of a lithium-sulfur battery negative electrode biological carbon material. The preparation method includes the steps: adding dandelion into water, adding concentrated acid into mixture to perform reaction, diluting the mixture to be neutral, and filtering and drying the mixture to obtain a product C; adding concentrated acid and water into the product C, placing mixture into a hydrothermal reaction kettle to perform reaction of solution D, diluting the solution D to be neutral, and filtering and drying the solution D to obtain a product E; uniformlylaying conductive graphite on the product, and performing heating reaction in a tube furnace to obtain a product F; performing flushing, extraction filtration and drying on the product F top obtain aproduct G; mixing the product G and powdered sulfur to obtain a mixture H; placing the mixture H into the tube furnace to perform heating reaction to obtain the biological carbon negative electrode material. According to the method, the dandelion serves as a biomass raw material, the dandelion is presoaked by mixed acid, a biological carbon precursor is prepared by a hydrothermal method, activation time is controlled in late activation process, the biological carbon material suitable for sulfur storage is acquired in a adjusting and controlling manner, the biological carbon material is applied to a lithium-sulfur battery, and the electrochemical performance of the lithium-sulfur battery is improved.

Description

technical field [0001] The invention relates to a preparation method of a lithium-sulfur battery negative electrode material, in particular to a preparation method of a lithium-sulfur battery negative electrode bio-carbon material. Background technique [0002] With the development of portable electronic devices, the demand for advanced energy storage is becoming more and more urgent. The rapid development of advanced energy systems requires materials to have the advantages of low cost, long life, strong safety, high energy, high power, and environmental friendliness. Lithium-sulfur batteries can better combine the above characteristics, and in the future high-energy (2500Whkg -1 ) has a good application prospect in the storage system. In a lithium-sulfur battery with high energy density, the theoretical capacity of sulfur is 1672mAh g -1 , the theoretical capacity of lithium metal anode is 3860mAh g -1 . During the charge and discharge process, lithium ions are generat...

AI Technical Summary

Problems solved by technology

However, technical barriers of lithium-sulfur batteries limit its application, such as short cycle times and low loading sulfur content

The main reasons are as follows: (1) Due to the formation of polysulfide intermediates in the anode and cathode, complex composition and structural changes occur during the formation of polysulfides, and polysulfides are easily dissolved in the electrolyte to cause capacity loss, poor cycle stability of the electrode; (2) sulfur and discharge product Li 2 S is ionically and electronically insulating, reducing the conductivity of the material

(3) Polysulfides cycle back and forth between the anode and the cathode, resulting in the loss of active materials, low Coulombic efficiency, passivation of the metal electrode surface, and the generation of insulating products Li 2 S / Li 2 S 2

(4) The loss of lithium metal electrodes is mainly due to the passivation of the surface and the formation of an unstable solid-liquid interphase (SEI film), which prevents the long-range cycle stability of lithium-sulfur batteries.

This method can improve the conductivity of the material to a certain extent, but its energy density will also decrease.

Images