Nickel lithium ion battery positive electrode material having concentration gradient, and preparation method therefor

Patent metadata

Field	Value
Publication number	US-2017317344-A1
Application number	US-201415522800-A
Country	US
Kind code	A1
Filing date	Dec 15, 2014
Priority date	Oct 30, 2014
Publication date	Nov 2, 2017
Grant date	—

Abstract

A nickel lithium ion battery positive electrode material having a concentration gradient, and a preparation method therefor. The material is a core-shell material having a concentration gradient, the core material is a material having a high content of nickel, and the shell material is a ternary material having a low content of nickel. The method comprises: synthesizing a material precursor having a high content of nickel by means of co-precipitation, co-precipitating a ternary material solution having a low content of nickel outside the material precursor having a high content of nickel, aging, washing, and drying to form a composite precursor in which the low nickel material coats the high nickel material, adding a lithium source, grinding, mixing, calcining, and cooling to prepare a high nickel lithium ion battery positive electrode material. The obtained material has regular morphology, uniform coating, narrow particle size distribution range, gradient distribution of the concentration of the nickel element, high content of the nickel element in the core, and low content of the nickel element in the shell; the nickel element in the core guarantees the specific capacity of the material, and the shell coating material maintains the stability of the structure of the material, so as to improve the safety of the material in the charge and discharge process, and improve the cycle and rate performance of the material.

First claim

1 . A cathode material for nickel lithium ion battery with a concentration gradient, characterized in that the material is a core-shell material with a concentration gradient, wherein the core material has the structural formula of LiNi x M y O 2 , wherein 0.5≦x≦1, 0≦y≦0.5, x+y=1, M=Co α Mn β , 0≦α≦1, 0≦β≦1, α+β=y, and/or the structural formula of LiNi x M y O 2 , wherein 0.5≦x≦1, 0≦y≦0.5, x+y=1, M=Co α Al β , 0≦α≦1, 0≦β≦1, α+β=y; the shell material is a nickel-containing ternary material having the structural formula of LiNi x Co y Mn z O 2 , wherein 0<x≦0.5, 0<y≦1, 0<z≦1, x+y+z=1, and/or the structural formula of LiNi x Co y Al z O 2 , wherein 0<x≦0.5, 0<y≦1, 0<z≦1, x+y+z=1.

2 . The cathode material for nickel lithium ion battery according to claim 1 , characterized in that the core material has an average particle size of 5-15 μm;
the shell material has an average thickness of 1-5 μm.

3 . A process for preparing the cathode material for nickel lithium ion battery according to claim 1 , characterized in that the process comprises the steps of:
(1) synthesizing a precursor of the core material by co-precipitation, then co-precipitating a shell material solution outside the core material precursor, aging, washing and drying to obtain a composite precursor in which the core material is coated with the shell material; and (2) adding a lithium source into the composite precursor, grinding and mixing, calcining and cooling to prepare a cathode material for nickel lithium ion battery.

4 . The process according to claim 3 , characterized in that the co-precipitation of the core material precursor comprises the following steps:
(1) weighing in turn nickel salt, cobalt salt and manganese salt to formulate a solution after mixing; (2) weighing a precipitator to formulate of a precipitator solution having a concentration of 1-3 mol/L, adding an ammonia as a complexing agent to formulate a mixed solution; (3) pumping into a reaction still the solution in step (1) and the mixed solution in step (2) via a constant flow pump; (4) controlling the flow of the two solutions in step (3) and adjusting the pH, stirring under constant temperature conditions till the completion of adding dropwise the solution; or the co-precipitation of the core material precursor comprises the following steps: (1′) weighing in turn nickel salt, cobalt salt and aluminium salt to formulate a solution after mixing; (2) weighing a precipitator to formulate a precipitator solution having a concentration of 1-3 mol/L, adding an ammonia as a complexing agent to formulate a mixed solution; (3) pumping into a reaction still the solution in step (1′) and the mixed solution in step (2) via a constant flow pump; (4) controlling the flow of the two solutions in step (3) and adjusting the pH, stirring under constant temperature conditions till the completion of adding dropwise the solution.

5 . The process according to claim 4 , characterized in that, the nickel salt in the co-precipitation of the core material precursor is anyone selected from the group consisting of nickel chloride, nickel sulfate, nickel nitrate, nickel carbonate, nickel acetate, nickel phosphate and nickel oxalate, or a combination of at least two selected therefrom;
the cobalt salt in the co-precipitation of the core material precursor is anyone selected from the group consisting of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt phosphate and cobalt oxalate, or a combination of at least two selected therefrom; the manganese salt in the co-precipitation of the core material precursor is anyone selected from the group consisting of manganese chloride, manganese sulfate, manganese acetate, manganese nitrate, manganese carbonate and manganese oxalate, or a combination of at least two selected therefrom; the aluminium salt in the co-precipitation of the core material precursor is anyone selected from the group consisting of aluminum chloride, aluminum sulfate, aluminum acetate, aluminum nitrate, aluminum carbonate and aluminum oxalate, or a combination of at least two selected therefrom;

6 . The process according to claim 4 , characterized in that, the nickel salt, cobalt salt and manganese salt in step (1) of the co-precipitation of the core material precursor have a metal element molar ratio of 6-9:0-2.5:0-2.5, including 0;
the nickel salt, cobalt salt and aluminium salt in step (1′) of the co-precipitation of the core material precursor have a metal element molar ratio of 6-9:0-2.5:0-2.5, including 0; each component of the solution(s) formulated in step (1) and/or step (1′) of the co-precipitation of the core material precursor has a concentration of 1-3 mol/L.

7 . The process according to claim 4 , characterized in that, the precipitator in step (2) of the co-precipitation of the core material precursor is anyone selected from the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate, or a combination of at least two selected therefrom;
the ammonia in step (2) of the co-precipitation of the core material precursor is added in an amount of making the ammonia concentration in the mixed solution be 0.2-0.5 mol/L.

8 . The process according to claim 4 , characterized in that, the solution is pumped into the reaction still in step (3) of the co-precipitation of the core material precursor using a hydroxide precipitator at a flow rate which makes the pH of the solution in step (4) be 9-11;
the solution is pumped into the reaction still in step (3) of the co-precipitation of the core material precursor using a carbonate precipitator at a flow rate which makes the pH of the solution in step (4) be 7.5-8.5; the constant temperature in step (4) of the co-precipitation of the core material precursor ranges from 45-55° C.; the stirring rate in step (4) of the co-precipitation of the core material precursor ranges from 800-1000 r/min.

9 . The process according to claim 3 , characterized in that the co-precipitation of the shell material solution outside the core material precursor comprises the following steps:
(1) weighing in turn nickel salt, cobalt salt and manganese salt to formulate a solution; (2) weighing a precipitator to formulate a precipitator solution having a concentration of 1-3 mol/L, adding an ammonia as a complexing agent to formulate a mixed solution; (3) pumping into a reaction still the solution in step (1) and the mixed solution in step (2) via a constant flow pump at the same time after the completion of adding dropwise the solution during the synthesis of the core material precursor by co-precipitation; (4) controlling the flow of the two solutions in step (3) and adjusting the pH till the completion of adding dropwise the solution; or the co-precipitation of the shell material solution outside the core material precursor comprises the following steps: (1′) weighing in turn nickel salt, cobalt salt and aluminium salt to formulate a solution; (2) weighing a precipitator to formulate a precipitator solution having a concentration of 1-3 mol/L, adding an ammonia as a complexing agent to formulate a mixed solution; (3) pumping into a reaction still the solution in step (1′) and the mixed solution in step (2) via a constant flow pump after the completion of adding dropwise the solution during the synthesis of the core material precursor by co-precipitation; (4) controlling the flow of the two solutions in step (3) and adjusting the pH till the completion of adding dropwise the solution.

10 . The process according to claim 9 , characterized in that, the nickel salt in the co-precipitation of the shell material solution is anyone selected from the gr

Assignees

• Inst Process Eng Cas

Inventors

• Tan Qiangqiang
• Kan Guangwei
• Xu Yuxing

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C01P2004/84

  one phase coated with the other · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title