A kind of positive electrode material and its preparation method and application

Abstract

The invention provides a positive electrode material and its preparation method and application, the positive electrode material includes a composite carbon material, nano-titanium oxide and FeF 3 (H 2 O) 0.33 , the composite carbon material and titanium oxide coated in FeF 3 (H 2 O) 0.33 The surface of the composite carbon material is a composite carbon material co-doped with nitrogen, phosphorus, sulfur and chlorine. The method comprises: 1) a composite carbon material co-doped with nitrogen, phosphorus, sulfur and chlorine and FeF 3 (H 2 O) 0.33 Dispersed in nano-titanium oxide sol, ultrasonicated, and then spray-dried to obtain a positive electrode material precursor; 2) microwave treatment to obtain a positive electrode material. The positive electrode material provided by the present invention has good conductivity and discharge specific capacity. After the new positive electrode material is assembled into a lithium ion battery, its discharge specific capacity is greater than 215mAh / g at a rate of 1C, and the capacity remains after 50 cycles. Rate ≥ 95% has broad application prospects.

Description

technical field [0001] The invention belongs to the field of lithium ion battery positive electrode material preparation technology and lithium ion battery, and relates to a positive electrode material and its preparation method and application. Background technique [0002] Since the beginning of the 21st century, energy shortage and environmental pollution have become severe problems faced by all mankind. With the rapid development of the electronic industry and new energy vehicles, people's demand for various batteries is becoming increasingly urgent. Lithium-ion batteries have outstanding advantages such as large discharge specific capacity, high voltage platform, safety, long life, and environmental friendliness. At present, they are widely used in various fields such as small portable batteries, power batteries for new energy vehicles, and energy storage. The competition in the lithium-ion battery industry is becoming more and more fierce. Finding new electrode materia...

AI Technical Summary

Problems solved by technology

[0003] Normally, the specific energy of a lithium-ion battery is determined by the specific capacity and the working voltage of the battery. In the known periodic table, fluorine has the strongest electronegativity, and the bond strength of the formed ionic bond compound is much higher than that of sulfide. And nitride, so when fluoride is used as the positive electrode material of lithium ion battery, its discharge voltage platform is much higher than that of sulfide and nitride, but because fluoride has strong ionic bonds, wide energy band gap and poor conductivity, it is usually an insulator. This leads to the low discharge specific capacity of fluoride as the cathode material of lithium-ion batteries during use

Therefore, although fluoride-based nanocomposites are promising new positive electrode materials, in order to improve their electrical conductivity, various explorations have been carried out, such as the Chinese invention patent, a lithium secondary battery FeF 3 (H 2 O) 0.33 Preparation method of cathode material (authorized notification number CN 100517812C), the patent first mixes ferric salt and alkali evenly, then reacts uniformly with a certain proportion of hydrofluoric acid in a plastic airtight container, filters, washes, dries and pulverizes FeF with orthorhombic crystal structure was obtained 3 (H 2 O) 0.33 positive electrode material, but the conductivity and cycle life of the positive electrode material need to be further improved

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