Method for preparing nanometer ferrous phosphate lithium /carbon composite material

Abstract

The invention belongs to energy materials, particularly relating to a method for preparing nanometer ferrous phosphate lithium / carbon composite material. In the invention, ferrous source, lithium source, phosphorus source are mixed with a small quantity of doped metal salt and organic macromolecular polymer carbon source according to certain ratio followed by the steps of ball milling, parching and calcining. High temperature sintering is carried out on the above mixture in the atmosphere of non-oxidation gas to obtain nanometer lithium iron phosphate LiMxFe(1-x)PO4 / C coated with carbon and LiFe(1-x)NxPO4 / C material, and the particle sizes of which are remarkably reduced and are less than 100nm. When the material is applied to battery assemble, 0.2C multiplying power discharge capacity can reach above 160mAh / g at room temperature, 1C multiplying power discharge capacity can be 140-155mAh / g, and 5C multiplying power discharge capacity is 130-150mAh / g. the initial capacity is 120-140mAh / g under the large multiplying power of 10C, and remains more than 90% through thousands of cycles, demonstrating good multiplying power and cycle properties. The invention features low cost, simple production process and fine safety. The prepared nanometer ferrous phosphate lithium / carbon composite material can be widely applied into manufacturing of convenient and fast equipment, electric vehicles and the like.

Description

technical field [0001] The invention belongs to the technical field of energy materials, in particular to a method for preparing a nanoscale lithium iron phosphate / carbon composite material. Background technique [0002] With the rapid development of society and the continuous advancement of science and technology, people have higher and higher energy requirements for portable electronic products and vehicles, especially for energy security, environmental protection and practicality. These are inseparable from the development of lithium-ion batteries. [0003] Since 1991, Sony Corporation took the lead in introducing the Li x C 6 / Li 1-x CoO 2 Since the commercialization of lithium-ion batteries, lithium-ion batteries have been widely used in portable products such as mobile phones, digital cameras, and notebook computers, and the main factor affecting the development of lithium-ion batteries is the cathode material. Among them, the commercialized cathode material LiCoO...

AI Technical Summary

Problems solved by technology

Among them, the commercialized cathode material LiCoO 2 Due to the lack of cobalt resources, the pollution of the environment, and its unsafe overcharging determines that it cannot be used in large-capacity batteries

For LiNi 0.3 co 0.3 mn 0.3 o 2 Also due to the limitation of cobalt resources and cannot be promoted, LiMnO 4 The structure is less stable, and the discharge capacity is relatively low. Affected by factors such as the dissolution of manganese and the decomposition of the electrolyte, it is prone to capacity decay during the cycle.

LiNiO 2 The synthesis of is relatively difficult, and the cycle performance is poor. Although it has been modified, the possibility of practical application is not large.

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