Method for performing surface coating and gradient doping integrated double-modification on LNMO anode material by using one-step method

Abstract

The invention provides a method for performing surface coating and gradient doping integrated double-modification on a LNMO anode material by using a one-step method. A coating material metal precursor solution is mixed with a lithium ion battery anode material solution, full drying is performed to form gel, the gel is calcined in an inert atmosphere to increase the surface oxygen deficiency sitesof the anode material, metal cations in a coating layer are promoted to diffuse into the surface oxygen deficiency sites of the anode material to form a pinning effect on surface lattices of the anode material while forming a surface coating layer, and then the surface coating and gradient doping integrated double-modification are performed on a lithium ion battery. According to the method provided by the invention, the surface oxygen deficiency sites of the high-voltage anode material LNMO are improved by the calcination in the inert atmosphere, the metal cations in the coating layer are promoted to diffuse into the surface oxygen deficiency sites of the anode material to form the pinning effect in a coating process, thereby realizing the surface coating and gradient doping integrated double-modification of the high-voltage anode material of the lithium ion battery.

Description

technical field

[0001] The invention relates to the field of preparation and modification of positive electrode materials for new energy lithium-ion batteries, in particular to a one-step surface coating and gradient doping integrated double-modified LNMO positive electrode material method. Background technique

[0002] Lithium-ion batteries have been widely used as energy storage devices for portable electronic devices due to their high energy density, long cycle life, good thermal safety performance, and environmental friendliness, and are rapidly expanding into fields such as electric vehicles and large-scale energy storage. At present, the cathode materials of lithium-ion batteries mainly include lithium cobaltate, lithium iron phosphate, layered lithium-rich, layered high-nickel and high-voltage spinel materials. Among them, LiNi 0.5 mn 1.5 o 4 (LNMO) as a representative spinel cathode material due to its high operating voltage (~ 4.7 V), high energy density (~ 690 W...

Examples

Embodiment 1

[0035] "One-step" preparation of Li 3 V 2 (PO 4 ) 3 (LVPO) surface modified LNMO material, the steps are as follows:

[0036] Dissolve a certain amount of lithium acetate, vanadium pentoxide, ammonium dihydrogen phosphate and citric acid in deionized water according to the ratio of 3:2:3:3, mix and stir for 3 hours, fully dissolve the mixed solution and add it dropwise Into the aqueous solution containing 0.2g LNMO cathode material, continue to mix and stir for 8h; stir and evaporate the mixed solution at 80°C for 8h to form a sol, and dry at 120°C for 24h to obtain a xerogel; grind the above xerogel thoroughly and put In a tube furnace, calcined at 400 °C for 6 h in an argon (Ar) atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 3 V 2 (PO 4 ) 3 (LVPO) surface-modified LNMO materials.

[0037] as attached figure 1 Shown are the XRD test and refinement results of the original spinel structure LNMO and the "one-step" LVPO...

Embodiment 2

[0053] "One-step" preparation of Li 3 VO 4 Surface coating and V surface gradient doping double modified LNMO material, the steps are as follows:

[0054] (1) Dissolve a certain amount of lithium acetate, vanadium pentoxide and citric acid in deionized water according to the ratio of 3:1:2, dissolve them and add dropwise to the aqueous solution in which 0.2g of LNMO cathode material is dispersed In, then mixed and stirred for 8h;

[0055](2) The above mixed solution was heated up to 80°C, stirred and evaporated, and then dried at 120°C for 24 hours to obtain a xerogel;

[0056] (3) Put the above dry gel into a crucible after being fully ground, calcined in a tube furnace at 500°C for 6h under an argon atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 3 VO 4 Surface coating and V surface gradient doping double modified LNMO materials.

Embodiment 3

[0058] "One-step" preparation of Li 2 SiO 3 Surface cladding and Si surface gradient doping double modified LNMO material, the steps are as follows:

[0059] (1) Dissolve a certain amount of lithium hydroxide, tetraethyl orthosilicate and citric acid in deionized water according to the ratio of 2:1:1.5, dissolve them and add them dropwise to the dispersed 0.2g LNMO cathode material In the aqueous solution, adjust the pH of the solution to ~7, and then mix and stir for 5h;

[0060] (2) The above mixed solution was heated up to 80°C, stirred and evaporated, and then dried at 120°C for 24 hours to obtain a xerogel;

[0061] (3) Put the above dry gel into a crucible after being fully ground, and calcined in a tube furnace at 500°C for 5 hours under an argon atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 2 SiO 3 Surface coating and Si surface gradient doping double modified LNMO materials.

technical field

[0001] The invention relates to the field of preparation and modification of positive electrode materials for new energy lithium-ion batteries, in particular to a one-step surface coating and gradient doping integrated double-modified LNMO positive electrode material method. Background technique

[0002] Lithium-ion batteries have been widely used as energy storage devices for portable electronic devices due to their high energy density, long cycle life, good thermal safety performance, and environmental friendliness, and are rapidly expanding into fields such as electric vehicles and large-scale energy storage. At present, the cathode materials of lithium-ion batteries mainly include lithium cobaltate, lithium iron phosphate, layered lithium-rich, layered high-nickel and high-voltage spinel materials. Among them, LiNi 0.5 mn 1.5 o 4 (LNMO) as a representative spinel cathode material due to its high operating voltage (~ 4.7 V), high energy density (~ 690 W...

Examples

Embodiment 1

[0035] "One-step" preparation of Li 3 V 2 (PO 4 ) 3 (LVPO) surface modified LNMO material, the steps are as follows:

[0036] Dissolve a certain amount of lithium acetate, vanadium pentoxide, ammonium dihydrogen phosphate and citric acid in deionized water according to the ratio of 3:2:3:3, mix and stir for 3 hours, fully dissolve the mixed solution and add it dropwise Into the aqueous solution containing 0.2g LNMO cathode material, continue to mix and stir for 8h; stir and evaporate the mixed solution at 80°C for 8h to form a sol, and dry at 120°C for 24h to obtain a xerogel; grind the above xerogel thoroughly and put In a tube furnace, calcined at 400 °C for 6 h in an argon (Ar) atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 3 V 2 (PO 4 ) 3 (LVPO) surface-modified LNMO materials.

[0037] as attached figure 1 Shown are the XRD test and refinement results of the original spinel structure LNMO and the "one-step" LVPO...

Embodiment 2

[0053] "One-step" preparation of Li 3 VO 4 Surface coating and V surface gradient doping double modified LNMO material, the steps are as follows:

[0054] (1) Dissolve a certain amount of lithium acetate, vanadium pentoxide and citric acid in deionized water according to the ratio of 3:1:2, dissolve them and add dropwise to the aqueous solution in which 0.2g of LNMO cathode material is dispersed In, then mixed and stirred for 8h;

[0055](2) The above mixed solution was heated up to 80°C, stirred and evaporated, and then dried at 120°C for 24 hours to obtain a xerogel;

[0056] (3) Put the above dry gel into a crucible after being fully ground, calcined in a tube furnace at 500°C for 6h under an argon atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 3 VO 4 Surface coating and V surface gradient doping double modified LNMO materials.

Embodiment 3

[0058] "One-step" preparation of Li 2 SiO 3 Surface cladding and Si surface gradient doping double modified LNMO material, the steps are as follows:

[0059] (1) Dissolve a certain amount of lithium hydroxide, tetraethyl orthosilicate and citric acid in deionized water according to the ratio of 2:1:1.5, dissolve them and add them dropwise to the dispersed 0.2g LNMO cathode material In the aqueous solution, adjust the pH of the solution to ~7, and then mix and stir for 5h;

[0060] (2) The above mixed solution was heated up to 80°C, stirred and evaporated, and then dried at 120°C for 24 hours to obtain a xerogel;

[0061] (3) Put the above dry gel into a crucible after being fully ground, and calcined in a tube furnace at 500°C for 5 hours under an argon atmosphere, then naturally cooled to room temperature, cleaned, filtered, and dried to obtain Li 2 SiO 3 Surface coating and Si surface gradient doping double modified LNMO materials.

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