Nanorod-like lithium manganese phosphate anode material and preparation method thereof

Abstract

Belonging to the lithium ion battery material technical field in the field of new energy materials, the invention in particular relate to a nanorod-like lithium manganese phosphate anode material and a preparation method thereof. The method includes: taking ethylene glycol and water as the reaction solvent, synthesizing lithium manganese phosphate by a solvothermal technique, and then mixing the lithium manganese phosphate with sucrose to synthesize a carbon-coated lithium manganese phosphate anode material. The method provided by the invention has the characteristics of simple reaction system, easily controllable process parameters, short process, low preparation cost, and easy mass production, and further expands the research work of the lithium manganese phosphate preparation field. The product obtained in the invention has the advantages of high purity, small size, good particle dispersibility, thus being conducive to effective contact of an electrode material and an electrolyte solution, shortening the lithium ion diffusion distance, and improving the rate performance of the lithium ion battery. The lithium manganese phosphate anode material has a low carbon content, and a small amount of carbon coating can improve the material electronic conductivity and also ensures that the lithium ion battery with the product as the anode material can acquire high energy density.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery materials in the field of new energy materials, and particularly relates to a nano-rod-shaped lithium manganese phosphate positive electrode material and a preparation method thereof. Background technique [0002] Since 1997, Goodenough's group pioneered the report on the application of olivine-type lithium iron phosphate (LiFePO). 4 ) as a cathode material for lithium-ion batteries, this material has been successfully commercialized for its abundant raw materials, low price, and good material safety performance. Although LiFePO 4 It has a high theoretical specific capacity (170mAh / g), but its discharge voltage platform is low, around 3.45V, which limits the energy density of lithium-ion batteries. In recent years, olivine-type lithium manganese phosphate (LiMnPO 4 ) has become one of the research hotspots of cathode materials for lithium-ion batteries, and its discharge voltage is ...

AI Technical Summary

Problems solved by technology

However, the reported one-dimensional nanorod-like LiMnPO 4 Most of the materials are large in size and have unsatisfactory electrochemical properties (J.Power Sources, 2011, 196, 10258-10262; J. Electrochem. Soc., 2011, 158, A227-A230; J.Power Sources, 2014, 248, 655- 659)

At the same time, in order to improve the LiMnPO 4 The electronic conductivity of the material, often the prepared LiMnPO 4 The material is compounded with a large amount of carbon materials. These electrochemically inert carbons cannot provide capacity, which makes it difficult for lithium-ion batteries using lithium manganese phosphate-carbon composites as positive electrodes to provide higher energy density.

In addition, in order to synthesize LiMnPO with high purity and controllable morphology 4 Nanomaterials, the existing preparation technology often introduces polyvinylpyrrolidone (PVP), polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), ascorbic acid, citric acid, etc. in the reaction process Additives, the reaction system is relatively complicated, and it also increases the production cost, which is not conducive to further popularization and application

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