Lithium manganese nickel oxide cathode material having nickel manganese concentration gradient and preparation method thereof

Abstract

The invention discloses a lithium manganese nickel oxide cathode material having nickel manganese concentration gradient and a preparation method thereof. The average chemical composition of the lithium manganese nickel oxide cathode material can be shown as a molecular formula of LiNi<0.5-x>Mn<1.5+x>O<4>, wherein x is more than or equal to 0.1 and less than or equal to 0.35, the concentration of Ni is gradually reduced in a gradient distribution manner from the particle center to the particle surface of the lithium manganese nickel oxide cathode material, and the concentration of Mn is gradually reduced in a gradient distribution manner from the particle center to the particle surface of the lithium manganese nickel oxide cathode material. The preparation method comprises the following steps of firstly, synthesizing a spherical-like particle having a core-shell structure by a co-precipitation process; and finally, preparing the lithium manganese nickel oxide cathode material with change on the nickel and manganese concentration by element diffusion during the high-temperature roasting process. The cathode material disclosed by the invention has excellent high-temperature cycle stability and rate performance, high reversible capacity, high chemical stability, long cycle life, and excellent comprehensive electrochemical performance.

Description

technical field

[0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and in particular relates to a lithium-nickel-manganese oxide cathode material with a nickel-manganese concentration gradient and a preparation method thereof. Background technique

[0002] The large-scale application of lithium-ion batteries in electric vehicles and large-scale energy storage devices has put forward higher requirements for their energy density, power, service life and safety. Compared with other cathode materials, the cathode material LiNi with spinel structure 0.5 mn 1.5 o 4 The discharge platform is as high as 4.7V, which is comparable to the current commercial cathode material LiCoO 2 Compared with the energy density increased by 20%, so LiNi 0.5 mn 1.5 o 4 It has become a candidate cathode material for high energy density lithium-ion batteries. However, the high voltage cathode material LiNi 0.5 mn 1.5 o 4 The poor cycle stability, e...

Examples

Embodiment 1

[0039] MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in pure water according to the molar ratio of 1.65:0.35, and the total concentration is 1.33mol / L mixed solution I, the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in pure water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.67mol / L; NaOH and NH 3 ·H 2 O was dissolved in pure water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0040] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 0.7ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution I into the kettle, and control the pH value of the solution in the reaction kettle by adjus...

Embodiment 2

[0050] MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in deionized water according to the molar ratio of 1.8:0.2, and the total concentration is 1.5mol / L mixed solution I, and the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O was dissolved in deionized water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.7mol / L; NaOH and NH 3 ·H 2 O was dissolved in deionized water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0051] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 9.5ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution Ⅰ into the kettle, and control the pH value of the solution in the reaction...

Embodiment 3

[0056] MnSO 4 ·H 2 O was dissolved in deionized water to prepare a solution I with a concentration of 1.4mol / L, and the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O was dissolved in deionized water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.6mol / L; NaOH and NH 3 ·H 2 O was dissolved in deionized water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0057] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 2ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution Ⅰ in the middle, and control the pH value of the solution in the reaction kettle by adjusting the pumping speed of solution Ⅰ to keep it a...

technical field

[0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and in particular relates to a lithium-nickel-manganese oxide cathode material with a nickel-manganese concentration gradient and a preparation method thereof. Background technique

[0002] The large-scale application of lithium-ion batteries in electric vehicles and large-scale energy storage devices has put forward higher requirements for their energy density, power, service life and safety. Compared with other cathode materials, the cathode material LiNi with spinel structure 0.5 mn 1.5 o 4 The discharge platform is as high as 4.7V, which is comparable to the current commercial cathode material LiCoO 2 Compared with the energy density increased by 20%, so LiNi 0.5 mn 1.5 o 4 It has become a candidate cathode material for high energy density lithium-ion batteries. However, the high voltage cathode material LiNi 0.5 mn 1.5 o 4 The poor cycle stability, e...

Examples

Embodiment 1

[0039] MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in pure water according to the molar ratio of 1.65:0.35, and the total concentration is 1.33mol / L mixed solution I, the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in pure water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.67mol / L; NaOH and NH 3 ·H 2 O was dissolved in pure water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0040] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 0.7ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution I into the kettle, and control the pH value of the solution in the reaction kettle by adjus...

Embodiment 2

[0050] MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O is dissolved in deionized water according to the molar ratio of 1.8:0.2, and the total concentration is 1.5mol / L mixed solution I, and the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O was dissolved in deionized water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.7mol / L; NaOH and NH 3 ·H 2 O was dissolved in deionized water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0051] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 9.5ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution Ⅰ into the kettle, and control the pH value of the solution in the reaction...

Embodiment 3

[0056] MnSO 4 ·H 2 O was dissolved in deionized water to prepare a solution I with a concentration of 1.4mol / L, and the MnSO 4 ·H 2 O and NiSO 4 ·6H 2 O was dissolved in deionized water at a molar ratio of 3:1 to form a mixed solution II with a total concentration of 0.6mol / L; NaOH and NH 3 ·H 2 O was dissolved in deionized water respectively to form a mixed solution of sodium hydroxide-ammonia water, in which NaOH and NH 3 ·H 2 The concentration of O in the mixed solution is 2mol / L and 0.24mol / L respectively;

[0057] Take solution Ⅰ, solution Ⅱ and sodium hydroxide-ammonia water mixed solution with a volume ratio of 1:1:2, respectively. Pump the mixed solution of sodium hydroxide-ammonia water into the reactor at a constant speed of 2ml / min. The temperature of the reactor is 60°C and the stirring speed is 1000r / min. Pump solution Ⅰ in the middle, and control the pH value of the solution in the reaction kettle by adjusting the pumping speed of solution Ⅰ to keep it a...

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