Stereo braiding-based carbon sulfur composite electrode for sodium sulfur battery

Abstract

The invention relates to a stereo braiding-based carbon sulfur composite electrode for a sodium sulfur battery. The carbon sulfur composite electrode is characterized by consisting of a graphite felt and high-purity sulfur, namely the carbon sulfur composite electrode consists of the porous graphite felt with adjustable carbon fiber crossing angles and combined fiber layers and the sulfur, wherein the sulfur in the composite electrode enters pores of the graphite felt after being melted with a penetration method. The graphite felt prepared by a stereo crossing braiding mode has the characteristics of high tensile strength and low elastic modulus; and by adjusting the crossing angles among the fibers, optimization of the sulfur on the wetting performance of the carbon felt is realized, theelectric conductivity of a sodium sulfur battery anode is improved, the contact performance of the sulfur electrode and ceramic electrolyte is enhanced, polarization is reduced, the working property of the anode in the battery is improved, and the performance (see embodiments) of the sodium sulfur battery is improved. The carbon sulfur composite electrode is particularly suitable for the sulfur pole of the high-power sodium sulfur battery.

Description

technical field [0001] The invention relates to a sulfur positive electrode of a sodium-sulfur battery, more precisely, the invention relates to a carbon-sulfur composite electrode based on three-dimensional weaving for a sodium-sulfur battery, which belongs to the field of chemical power sources. Background technique [0002] Sodium-sulfur batteries are based on β(β”)-Al 2 o 3 Ceramics are the electrolyte and diaphragm, sulfur and metal sodium are the positive and negative electrodes, and it is an all-solid secondary battery at room temperature. Since sulfur is an insulator, in order to improve the conductivity of the positive electrode, carbon felt or graphite felt with good conductivity is generally used as an auxiliary electrode to ensure that the secondary battery can work normally when sodium and sulfur are in a molten state between 300 and 350 ° C. Its theoretical specific energy is as high as 760Wh / kg, and there is no self-discharge phenomenon, and the Coulombic ef...

AI Technical Summary

Problems solved by technology

If the capillary action of liquid sulfur or sodium polysulfide in the micropores of graphite felt is not strong, the diffusion speed of liquid sulfur or sodium polysulfide will be very slow and it will be difficult to change the potential distribution of the sulfur electrode to form a gradient distribution, and the electrode reaction will produce very serious diffusion. Polarization, greatly reducing the power density, energy density and cycle life of sodium-sulfur batteries

If the purity of graphite felt or carbon felt and the active material sulfur is not high, impurities such as potassium, calcium, and iron mixed in it will also deposit on the surface of the electrolyte, blocking the transmission of sodium ions, greatly reducing the power density of the battery, and causing damage to the electrolyte

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