Coke powder-based cathode material of lithium ion power battery and preparation method thereof

Abstract

The invention discloses a coke powder-based cathode material of a lithium ion power battery and a preparation method thereof. The cathode material has a D50 of 10-30 [mu]m, a minimum granularity of 5 [mu]m, a maximum granularity of 30 [mu]m, and a tap density of 1.1-1.5 g/cm<3>. The cathode material has a core-shell structure, wherein a core is graphitized coke powder, and a shell is composed of coal pitch pyrolytic carbon and metal particles. The cathode material contains 95.00-99.00 % of solid carbon and 1-5 % of metal or metal oxide particles by mass percent. The preparation method comprises crushing, grading and purifying the coke powder, cladding coal pitch on the coke powder particles, graphitizing under a high temperature, attaching metal or metal oxide on the particles, etc. The cathode material is excellent in rate performance, good in high-temperature and low-temperature performances, low in manufacture cost and suitable for large-scale industrialization.

Description

technical field [0001] The invention relates to a negative electrode material for a lithium-ion power battery and a preparation method thereof, in particular to a rate-type negative electrode material with high capacity, long life and low cost, using coal-based coke powder as a raw material, and a preparation method thereof. The invention belongs to the technical field of lithium ion battery material preparation. Background technique [0002] Lithium-ion batteries are an ideal energy source for development in recent years due to their excellent performance in terms of high energy density, high working voltage, small size, light weight, and no pollution. With the popularization of new energy vehicles, its application range has expanded from portable electronic products to electric vehicles and other fields, and cost control has become one of the key issues in the development of lithium-ion batteries. Negative electrode materials directly affect the performance of lithium-ion...

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Problems solved by technology

For example, in order to improve the rate performance, the patent CN102424376A discloses an artificial graphite negative electrode made of coal tar processed heavy products or petroleum processed heavy products as raw materials, through low-temperature thermochemical reforming, medium-temperature carbonization, and high-temperature graphitization. The rate performance of the material has been greatly improved, but the reversible capacity is slightly lower, and the synthesis cycle is longer and the cost is higher

In order to increase the reversible capacity, the patent CN100589264C proposes that the structure and powder characteristics of the negative electrode material can be improved by delaying coking-crushing-carbonization-catalytic graphitization-sieving of coal-based or petroleum-based heavy oil, so that the larger The reversible capacity is increased to the greatest extent, but its preparation process is lengthy and requires multiple heating treatments and sieving treatments, which will inevitably result in a substantial increase in cost

[0004] In order to reduce the preparation cost of negative electrode materials, the patent CN102522561A uses anthracite as a raw material. After the anthracite is graphitized at high temperature, carbon precursor coating and carbonization treatment are carried out, which improves the first-time efficiency and cycle performance, but the preparation process is still long, and the product It belongs to the nature of microcrystalline graphite, and the rate performance is not good

Patent CN102351163A proposes to prepare nano-carbon microspheres negative electrode material from pitch-based or petroleum coke-based amphiphilic carbon materials through the steps of preparing solution, stirring and rectifying separation. The negative electrode material has the advantages of high capacity and good rate performance, and The preparation process is simple and the process is short, but because the raw materials have only been carbonized at medium temperature, the degree of graphitization of the obtained product is not high, the particle size is too small and the specific surface area is too large, which makes the initial efficiency low

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