Sulfur-containing composite anode material, anode plate and Li-S (lithium-sulfur) secondary battery and preparation method thereof

Abstract

The invention discloses a sulfur-containing composite anode material which is of a core-shell structure, wherein a core is a C / S (carbon / sulfur) composite composited by utilizing elemental sulfur and nano conductive carbon black; and a shell is an organic polymer clad film layer containing a plasticizer. The preparation method comprises the following steps: mixing the sulfur and carbon and heating to obtain the C / S composite; adding an organic polymer solution; emulsifying and shearing the mixture; and finally filtering and drying. The invention further discloses an anode plate which comprises an aluminum current collector and the sulfur-containing composite anode material coated on the aluminum current collector. The anode plate is prepared by ball milling and blending the sulfur-containing composite anode material with adhesives, a solvent and process additives, and printing or coating on the aluminum current collector. The invention also discloses a Li-S (lithium-sulfur) secondary battery which is formed by packaging a battery core and an electrolyte, wherein the battery core mainly comprises a cathode component, a polymer porous diaphragm and the anode plate. The cathode component comprises a lithium foil, and the electrolyte comprises an organic solvent and lithium electrolyte salts. The secondary battery disclosed by the invention has the advantages of high specific energy and good cycle performance.

Description

technical field [0001] The invention relates to a secondary battery and its positive electrode sheet, positive electrode material and respective preparation methods, in particular to a secondary battery with elemental sulfur as the positive electrode, its positive electrode sheet, positive electrode material and their respective preparation methods. Background technique [0002] The Li-S secondary battery system based on lithium metal anode and sulfur element cathode is one of the combinations with the highest energy density among known chemically reversible systems. The theoretical energy density of the Li-S battery system is 2600Wh / kg and 2800Wh / L, and the average voltage is 2.1V. Compared with the theoretical energy density of lithium-ion batteries of 580Wh / kg and TNT equivalent of 1280Wh / kg, the Li-S battery system has a rather high energy density. Assuming that 25% of the theoretical value can be realized on the actual battery, the energy density of the Li-S battery sy...

AI Technical Summary

Problems solved by technology

For the problem of rapid decline in discharge capacity caused by the dissolution of sulfide in the electrolyte, the cycle efficiency of Li-S batteries using colloidal polymer electrolytes is higher than that of liquid electrolyte batteries, and the average decay rate is about 5. %, but the positive electrode active material utilization rate of the formula using the colloidal polymer electrolyte is not high, which is estimated to be related to the adsorption of the intermediate product of the electrochemical reaction by the gel state material, and the colloidal polymer electrolyte separator has a certain Difficulty in crafting

[0004] Judging from the published literature, in the research of improving the dispersion of sulfur and improving the conductivity of the positive electrode active material of Li-S batteries, the sublimation process of sulfur and the high-strength ball milling of sulfur and conductive carbon have been used to prepare C The preparation process of the / S composite is reported, but the utilization rate of cathode sulfur in the existing process is extremely limited, and the capacity decays greatly during the cycle process, which needs further improvement.

Images