Preparation method for carbon- and silicon-coated lithium sulfur positive electrode material

Abstract

The invention discloses a preparation method for a carbon- and silicon-coated lithium sulfur positive electrode material. According to the method, zirconium phosphate titanium is used as a carrier, the self-discharge process of a battery can be effectively prevented by a layer effect of the zirconium phosphate titanium, sulfur particles are loaded in the zirconium phosphate titanium, the sulfur particles are tightly wrapped by the special layer structure of the zirconium phosphate titanium, thus, a discharge intermediate product polysulfide can be effectively prevented from being dissolved, and the cycle property of a lithium sulfur battery is improved. The porous characteristic possessed by a carbon- and silicon-coated material is beneficial for electrolyte absorption and storage, a space is provided for volume expansion of the silicon material during the charge-discharge process, the effect of relieving silicon particle volume effect is also achieved by porous silicon size nanoscale, and thus, the carbon- and silicon-coated lithium sulfur positive electrode material has the advantages of high reversible capacity, good cycle property and excellent rate performance.

Description

technical field [0001] The invention relates to the field of battery materials, in particular to a method for preparing a carbon-silicon-coated sulfur-lithium cathode material. Background technique [0002] Compared with traditional lead-acid, nickel-cadmium, nickel-metal hydride and other secondary batteries, lithium-ion secondary batteries have high working voltage, small size, light weight, high capacity density, no memory effect, no pollution, small self-discharge and good cycle life. Long life and other advantages. Since a Japanese company successfully commercialized lithium-ion batteries in 1991, lithium-ion batteries have become the dominant power source for mobile phones, notebook computers and digital products, and their applications in electric vehicles and energy storage have become more and more extensive. [0003] The theoretical specific energy of a lithium-sulfur battery with metallic lithium as the negative electrode and elemental sulfur as the positive elec...

AI Technical Summary

Problems solved by technology

Using the above method 1) due to the use of nano-silicon materials, its cost is high, and it is difficult to disperse uniformly due to the agglomeration of nano-materials; method 2 uses high-energy ball milling, which has a long preparation cycle and high cost; method 3) uses chemical vapor deposition It is difficult to coat silicon material uniformly on the surface of graphite particles

In addition, it is difficult for the above methods to overcome the problem of taking into account both capacity play and first-time efficiency.