Method for preparing spheroidal LiFePO4 microlites

Abstract

The invention discloses a method for preparing spheroidal LiFePO4 microlites, which comprises the steps as follows: nitrogen gas is pumped in distilled water, and Li2CO3, NH4H2PO4 and FeC2O4 2H2O are added in distilled water so as to prepare solution B; citric acid is added in solution B so as to obtain solution C; the pH value of solution C is adjusted to range from 3.0 to 12.0 so as to obtain liquid reactant D; liquid reactant D is poured into a microwave hydrothermal kettle, the microwave hydrothermal kettle is sealed up and then put in a temperature and pressure-controlled microwave hydrothermal reaction instrument for reaction, the reaction is carried out by choosing a temperature controlling mode or a pressure controlling mode, and liquid reactant D is cooled down to reach room temperature naturally after the reaction is finished; in addition, the microwave hydrothermal kettle is opened, and obtained liquid reactant is processed through centrifugal separation and then dried in vacuum drying box after being respectively washed through deionized water and anhydrous ethyl alcohol so as to obtain the spheroidal LiFePO4 microlites. The method combines the double advantages of a microwave method and a hydrothermal method; the reaction can be finished in a liquid phase for one time without post processing; in addition, processing equipment is simple, the reaction period is short, and the repeatability is high. Different reaction temperatures are controlled during the preparation process so as to prepare the torispherical LiFePO4 microlites.

Description

technical field [0001] The present invention relates to a LiFePO 4 Preparation method of battery powder, in particular to a spherical LiFePO 4 Method for the preparation of microcrystals. technical background [0002] Lithium-ion batteries refer to the use of carbon materials that can absorb or desorb lithium ions as the negative electrode active material; use metal oxides that can absorb or desorb lithium ions and contain lithium ions as the positive electrode active material, based on the above chemical reaction principle. A rechargeable battery using an organic solvent as the electrolyte. [0003] LiFePO 4 It has an olivine structure and can reversibly intercalate and deintercalate lithium ions. At the same time, it has the advantages of high energy density, stable performance, high safety, environmental friendliness and cheaper price. The theoretical specific capacity of this material is 170mAh / g -1 , has a flat and moderate discharge platform (about 3.4V) relative...

AI Technical Summary

Problems solved by technology

But pure LiFePO 4 There is a disadvantage determined by the crystal structure: the electrical conductivity is small (about 10 -9 S / cm), low ion diffusion coefficient (about 10 -11 ~10 -10 S / cm), leading to a sharp drop in its discharge capacity at high current densities, and poor cycle performance, limiting LiFePO 4 Applications

These methods either require high equipment and are relatively expensive; or the utilization rate of raw materials is very small; or the process is complicated, the preparation cycle is long, and the repeatability is poor.

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