Chemical method for preparing nano iron phosphate lithium as anode material of lithium ion battery

Abstract

The invention relates to a chemical method for preparing nano iron phosphate lithium as anode material of lithium ion battery, which belongs to the technical field of new energy materials. The chemical method comprises the following technological steps: preparing the solutions of a lithium compound, an iron compound and a phosphorous compound, mixing the three solutions in the mol ratio of Fe:Li:P=(0.8-1.5):1:1, dropwise adding a prepared ammonia solution into the mixed solution, and stirring the solution continuously to form a suspension; pouring the suspension into a reactor, heating to 70-100 DGE C, reacting for 5-10 h, taking out the products to filter and wash, and drying to obtain a precursor product; putting the precursor product into a high temperature furnace, heating to 500-800 DEG C under the protection of inert gas or reducing gas, and maintaining the temperature for 12-24 h; cooling to room temperature, and taking out the product to obtain the nano iron phosphate lithium powder. The preparation method has the advantages of simple synthesis technology and low cost, the particle diameter of the prepared iron phosphate lithium powder is controlled at nano level, and the electric conductivity and the electrochemical performance of the power are improved.

Description

technical field

[0001] The invention relates to a chemical method for preparing lithium iron phosphate, a cathode material of a nanoscale lithium ion battery, and belongs to the technical field of new energy materials. Background technique

[0002] In recent years, lithium-ion batteries have developed rapidly, and cathode materials are an important part of lithium-ion batteries. The research on new cathode materials and that have become the key to the development of lithium-ion batteries. At present, the cathode material commercialized on a large scale is LiCoO2, but it is toxic, cobalt is expensive, and there are certain safety problems. LiNiO2 has low cost and high capacity, but its preparation process is complicated and its thermal stability is poor. Spinel LiMn2O4 has low cost and good safety performance, but low capacity and poor high temperature cycle performance. The new lithium ion battery cathode material LiFePO4 has the advantages of low price, high capacity, goo...

Examples

Embodiment 1

[0020] Configure 0.5mol / l lithium chloride, 0.5mol / l ferrous chloride, 0.5mol / l diamine hydrogen phosphate, mix the three solutions, add 5mol / l ammonia solution dropwise to the mixed solution, and keep stirring, A suspension was formed. The suspension was poured into the reactor, the temperature was raised to 80°C, and the reaction time was 5 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass nitrogen protection, set parameters, raise the temperature to 500°C at a heating rate of 10°C / min, and keep it for 12 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to make electrodes uniformly. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mixed so...

Embodiment 2

[0021] Configure 0.8 mol / l lithium acetate, 1.0 mol / l iron acetate, 1.0 mol / l diamine hydrogen phosphate, mix the three solutions, add 6 mol / l ammonia solution dropwise to the mixture, keep stirring to form a suspension liquid. The suspension was poured into the reactor, the temperature was raised to 90°C, and the reaction time was 8 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass through argon protection, set parameters, raise the temperature to 600°C at a heating rate of 10°C / min, and keep it warm for 12 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to make electrodes uniformly. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mixed s...

Embodiment 3

[0023] Configure 0.55 mol / l lithium carbonate, 1.0 mol / l ferrous chloride, 1.0 mol / l ammonium dihydrogen phosphate, mix the three solutions, add 8 mol / l ammonia solution dropwise to the mixed solution, and keep stirring to form Suspension. The suspension was poured into the reactor, the temperature was raised to 100°C, and the reaction time was 10 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass nitrogen protection, set parameters, raise the temperature to 800°C at a heating rate of 10°C / min, and keep it for 24 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to uniformly make electrodes. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mix...

technical field

[0001] The invention relates to a chemical method for preparing lithium iron phosphate, a cathode material of a nanoscale lithium ion battery, and belongs to the technical field of new energy materials. Background technique

[0002] In recent years, lithium-ion batteries have developed rapidly, and cathode materials are an important part of lithium-ion batteries. The research on new cathode materials and that have become the key to the development of lithium-ion batteries. At present, the cathode material commercialized on a large scale is LiCoO2, but it is toxic, cobalt is expensive, and there are certain safety problems. LiNiO2 has low cost and high capacity, but its preparation process is complicated and its thermal stability is poor. Spinel LiMn2O4 has low cost and good safety performance, but low capacity and poor high temperature cycle performance. The new lithium ion battery cathode material LiFePO4 has the advantages of low price, high capacity, goo...

Examples

Embodiment 1

[0020] Configure 0.5mol / l lithium chloride, 0.5mol / l ferrous chloride, 0.5mol / l diamine hydrogen phosphate, mix the three solutions, add 5mol / l ammonia solution dropwise to the mixed solution, and keep stirring, A suspension was formed. The suspension was poured into the reactor, the temperature was raised to 80°C, and the reaction time was 5 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass nitrogen protection, set parameters, raise the temperature to 500°C at a heating rate of 10°C / min, and keep it for 12 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to make electrodes uniformly. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mixed so...

Embodiment 2

[0021] Configure 0.8 mol / l lithium acetate, 1.0 mol / l iron acetate, 1.0 mol / l diamine hydrogen phosphate, mix the three solutions, add 6 mol / l ammonia solution dropwise to the mixture, keep stirring to form a suspension liquid. The suspension was poured into the reactor, the temperature was raised to 90°C, and the reaction time was 8 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass through argon protection, set parameters, raise the temperature to 600°C at a heating rate of 10°C / min, and keep it warm for 12 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to make electrodes uniformly. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mixed s...

Embodiment 3

[0023] Configure 0.55 mol / l lithium carbonate, 1.0 mol / l ferrous chloride, 1.0 mol / l ammonium dihydrogen phosphate, mix the three solutions, add 8 mol / l ammonia solution dropwise to the mixed solution, and keep stirring to form Suspension. The suspension was poured into the reactor, the temperature was raised to 100°C, and the reaction time was 10 hours. Take out, filter, wash, and dry to obtain the precursor product. Put the precursor product into a high-temperature furnace, pass nitrogen protection, set parameters, raise the temperature to 800°C at a heating rate of 10°C / min, and keep it for 24 hours. Cool down to room temperature, take out the product, and obtain nanoscale lithium iron phosphate powder. Weigh lithium iron phosphate powder, acetylene black, and PVDF at a mass ratio of 82:8:10, and grind them to uniformly make electrodes. Use metal lithium sheets as negative electrodes, and the electrolyte is dissolved in ethyl carbonate and diethyl carbonate. LiPF6 in mix...