Carbon-coating and metallic-element-doped anode material of lithium ion battery

Abstract

The invention relates to a carbon-coating and metallic-element-doped anode material of a lithium ion battery, the composition of the anode material is LixCo025Mn07V0.3Oy / C, wherein the x=1-2, y=2-4, the preparation method comprises the following steps: (1) preparing Co025Mn07V0.3(OH)2 precursor by adopting a hydroxide coprecipitation method: according to a stoichiometric ratio, dissolving cobaltous sulfate, manganese sulfate and vanadic sulfate into deionized water, the concentration is 2.5-3.0 mol / L, stirring uniformly, and then adding to a reaction still, adding ammonium hydroxide and sodium hydroxide solution, so as to adjust the pH value to 10-10.5, evaporating water to sol at water bath of which the temperature is 60-80 DEG C, putting the sol into a muffle furnace and heating with introduced argon after cooling to room temperature, till the sample is completely dry; and (2) preparing the anode material: uniformly mixing the precursor and LiCO3 in proportion, by adopting a third class ablactation technology, preburning for 2-3 hours at temperature of 550-600 DEG C, furnace cooling, grinding after cooling, burning for 8-9 hours at temperature of 850-900 DEG C, furnace cooling, grinding continually after cooling, at last burning for 2-3 hours at temperature of 950-1000 DEG C, naturally cooling, grinding after cooling, sifting, so that the needed anode material is obtained.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery cathode materials, and in particular relates to a carbon-coated lithium-ion battery cathode material doped with metal elements and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, long cycle life, no memory effect, fast charging and discharging, etc., and are widely used. From Sony's release of the first commercial lithium-ion battery in 1991 to the present, its cathode materials mainly include LiCoO 2 , LiNiO 2 , layered LiM-nO 2 , NCM (nickel cobalt lithium manganate ternary material), spinel LiMn 2 o 4 , NVA (lithium nickel cobalt aluminate material), LiMPO 4 (M=Fe, Mn, Ni, Co), lithium-rich material xLi 2 MO 3 ·(1-x)LiM'O 2 , Li 3 V 2 (PO 4 ) 3 and other compounds and their modified compounds. LiCoO 2 It is the most successful cathode material in the market and the mater...

AI Technical Summary

Problems solved by technology

LiCoO 2 It is the most successful cathode material in the market and the material with the highest market share at present, but LiCoO 2 Slight overcharging (4.4V) of the battery will lead to poor thermal stability and cycle performance; LiNiO 2 The problem of poor structural stability cannot be solved fundamentally, which also limits its application; layered LiMnO 2 The cycle stability is poor, and it is difficult to synthesize directly; NCM and NCA materials soaked in the electrolyte will cause lithium dissolution, material structure degradation and capacity loss

In addition, the compatibility of ternary materials and electrolytes is also an important issue that needs to be solved. With the rising price of cobalt, the cost may become an important factor limiting its use in large batteries

There are problems with spinel-type high-temperature cycle performance and storage performance, resulting in loss of battery capacity, and the oxidation and decomposition of the electrolyte produces acidic substances that dissolve Mn and affect battery life; LiFePO 4 Middle Fe 2+ The chemical properties are more active, resulting in poor material consistency, its voltage plateau is lower, and its tap density is lower, resulting in lower volume and weight specific energy