Preparation method of lithium ion battery anode material lithium vanadate with negative attenuation coefficient

Abstract

The invention relates to a method for preparing lithium ion battery Li1+xV308 anode material lithium vanadate with negative attenuation coefficient by using bi-component complex agent collosol gel. The preparation method is characterized in that: the complex agent consists of two components A and B, wherein the component A has lithium ion complex agent and carboxyl protected by amide; the component B has vanadium ion complex radical and hydroxyl; the complex agents A and B are in complexation with the lithium ion and the vanadium ion; the complex agent A-lithium-containing system and the complex agent B-ammonium metavanadate are mixed after carboxyl protection is removed through hydrolysis; the pH value of the water system is regulated to be 6.8-7.5 with ammonia water; the temperature of the system rises to 80-90 DEG C and is kept for 0.5-1h to obtain foam-like puffy product; the output is dried for 10-20h in a vacuum oven at 110-130 DEG C and is then burnt for 3-5h in a box-type resistor furnace at 450-550 DEG C to obtain the Li1+xV308 anode material after natural cooling. In the method, complete chemistry dose ratio mixture on the molecule level and the Li1+xV308 anode material with complete pure phase are formed, the irreversible transition is reduced in the process of transforming LiV308 into Li4V308 and the discharge capacity in 50 charge-discharge circulations is progressively increased along with increasing of the circulation number.

Description

technical field [0001] The invention relates to the technical field of lithium vanadate, an anode material of a lithium ion battery. Background technique [0002] Since the beginning of the 20th century, the demand for lithium-ion batteries has grown rapidly, and the search for lithium-ion battery materials with better performance has become a research focus and focus. The current commercial lithium-ion batteries basically use layered LiCoO 2 As a positive electrode material, its main advantages are: high working voltage, stable charge and discharge voltage, suitable for high current charge and discharge, high specific energy, high conductivity, simple production process, easy preparation, etc., but cobalt salt is expensive and pollutes the environment seriously , the resistance to overcharge is poor, and the cycle performance needs to be further improved. LiNiO with layered structure 2 Low self-discharge rate, no pollution, good compatibility with various electrolytes, c...

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Problems solved by technology

The current commercial lithium-ion batteries basically use layered LiCoO 2 As a positive electrode material, its main advantages are: high working voltage, stable charge and discharge voltage, suitable for high current charge and discharge, high specific energy, high conductivity, simple production process, easy preparation, etc., but cobalt salt is expensive and pollutes the environment seriously , the overcharge resistance is poor, and the cycle performance needs to be further improved

LiNiO with layered structure 2 Low self-discharge rate, no pollution, good compatibility with various electrolytes, cheap, but LiNiO 2 Has a fatal disadvantage: the preparation conditions are very harsh, which gives LiNiO 2 The commercial production of LiMnO has brought considerable difficulties; the thermal stability is poor, and the heat release is large, which brings great safety hazards to the battery; LiMnO 2 Rich resources, cheap price, high safety, relatively easy to prepare, the disadvantage is that the theoretical capacity is not high; the John-Teller lattice deformation causes the battery capacity to decay rapidly

However, conventional one-component complexing agents all have complexing groups and polymeric groups at the same time, and complexing agents are also undergoing polycondensation between each other while complexing metal ions, that is, citric acid molecules, complexing metal ions The citric acid molecules are in a state of disordered polycondensation. Although the stoichiometric ratio is reached in a certain small area, it still does not reach the complete stoichiometric ratio at the molecular level.

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