Preparation method of manganese-doped lithium iron phosphate electrode material

Abstract

The invention discloses a preparation method of a manganese-doped lithium iron phosphate electrode material. The method comprises the steps of using a precipitation method to synthesize a lithium ironphosphate precursor under the condition of stirring by respectively taking lithium hydroxide monohydrate, ferrous sulfate heptahydrate and phosphoric acid as a lithium source, an iron source and a phosphorus source, using ascorbic acid as a reducing agent and part of a carbon source and taking ethylene glycol as a stabilizing agent and a reducing agent of a solvothermal method; then, dropwise dripping manganese sulfate monohydrate, used as a doped manganese source, into a precursor solution; after that, dropwise dripping ammonia water into the solution to adjust the pH of the solution to 7-10, carrying out a hydrothermal reaction, then washing, and drying to obtain the nano-rod-shaped uniform manganese-doped lithium iron phosphate electrode material with good dispersibility. The preparation method provided by the invention is simple in process, wide in raw material source and beneficial to large-scale industrial production; the prepared manganese-doped lithium iron phosphate cathode material has excellent rate capability and excellent cycle performance, is stable in charge-discharge voltage platform, and has a higher specific capacity.

Description

technical field [0001] The invention belongs to the technical field of preparation of new energy materials, and relates to a preparation method of a manganese-doped lithium iron phosphate electrode material. Background technique [0002] As the "heart" of electric vehicles, the performance of batteries directly restricts the industrialization of electric vehicles. Lithium iron phosphate (LiFePO 4 ) has attracted extensive attention as a new generation of battery cathode materials. LiFePO 4 The theoretical capacity is 170mAh / g, which has the following advantages: long service life (7-8 years), good safety performance, fast charging speed (it can be fully charged in about 30 minutes at 1.5C), high temperature resistance (350-500°C) , large capacity and no memory effect, green and environmental protection, wide source of raw materials, cheap price. Currently LiFePO 4 It has not yet been applied to power battery materials such as electric vehicles and electric tools on a la...

AI Technical Summary

Problems solved by technology

However, most of the cation doping uses the solid-phase method, which has many disadvantages: such as uneven mixing of solid-phase raw materials, more impurities in the product; generally high temperature is required, and energy consumption is large; low-priced metals are easily oxidized, and the protection The cost of gas is high; the metal doping of the synthesis target product is difficult to control precisely; the morphology is poor, and the agglomeration is serious, and the ideal battery cathode material cannot be obtained

However, its cycle stability is poor, and the structure of the material changes seriously during the charging and discharging process.

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