Method for preparing lithium-rich solid solution cathode material through reduction

A positive electrode material and solid solution technology, which is applied in the field of preparation of doped lithium-rich solid solution positive electrode materials, can solve problems such as the inability to eliminate the influence of dissolved oxygen in water, and achieve excellent discharge performance, good cycle performance, and less time-consuming effects.

Active Publication Date: 2013-01-16
FUJIAN NORMAL UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

When ammonia water is used as a precipitant, excess ammonia reacts with cobalt ions to form Co(NH 3 ) 6 2+ Ions can be oxidized by oxygen in the air (Editor-in-Chief of Wuhan University, Analytical Chemistry (2nd Edition), Higher Education Press, October 1982, Beijing: Page 14 to Page 17), therefore, using hydroxide co-precipitation The sintering precursor prepared by the method is a compound of trivalent manganese and divalent manganese, or even a compound of trivalent cobalt and divalent cobalt, although some documents use nitrogen gas when preparing hydroxide precipitation to solve this problem The method of protecting the precipitation, however, the method of protecting the precipitation with nitrogen can only eliminate the influence of oxygen in the air, but cannot exclude the influence of oxygen dissolved in water

Method used

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  • Method for preparing lithium-rich solid solution cathode material through reduction

Examples

Experimental program
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Embodiment 1

[0036] Lithium hydroxide, nickel hydroxide, manganese acetate, cobalt hydroxide, and hydrazine were weighed according to the molar ratio of lithium ion, nickel ion, manganese ion, cobalt ion, and hydrazine being 1.35: 0.195: 0.526: 0.319: 0.27. The total weight of reactants is the total weight of lithium hydroxide, nickel hydroxide, manganese acetate, cobalt hydroxide and hydrazine. The weight ratio of the total weight of reactants to deionized water is 5:50 (equivalent to (2 · (1-x) · y + 4 · (x+z-x · z) + 3 · (1-x) · k-x-3) =0.0998)

[0037] Mix hydrazine with deionized water, then mix with weighed nickel hydroxide, manganese acetate, and cobalt hydroxide, wet mill and mix for 1 hour, add ammonia water to make the solution acidity pH 10, add weighed lithium hydroxide, wet mill and mix A reaction mixture solution containing a precipitate was prepared for 1 hour. The reaction mixture solution containing the precipitate was aged at 40°C for 2 hours to obtain precursor 1; the ...

Embodiment 2

[0040] According to the molar ratio of lithium ion, nickel ion, manganese ion, cobalt ion, vitamin C is 1.15: 0.0425: 0.358: 0.51: 0.01, respectively weigh lithium nitrate, nickel oxalate, manganese sulfate, cobalt chloride and vitamin C (equivalent to ( 2·(1-x)·y + 4·(x+z-x·z) + 3·(1-x)·k-x-3)=-0.10); the total reactants are lithium nitrate, nickel oxalate, manganese sulfate, For the total weight of cobalt chloride and vitamin C, weigh ethanol according to the total weight of reactants and ethanol weight ratio of 5:1.

[0041] Mix vitamin C with ethanol, then mix and weigh nickel oxalate, manganese sulfate and cobalt chloride, wet mill and mix for 15 hours, add ammonia water to make the solution acidity pH 13.5, add weighed lithium nitrate, wet mill and mix for 15 hours to prepare Precipitate in the reaction mixture solution. Precursor 1 was obtained by aging the reaction mixture solution containing the precipitate at 95° C. for 24 hours. Precursor 1 was dried at 110°C with...

Embodiment 3

[0044] According to lithium ion, nickel ion, manganese ion, cobalt ion, reducing agent molar ratio is 1.6: 0.18: 0.77: 0.02: 0.77 respectively weighs lithium iodide, nickel nitrate, manganese oxalate, cobalt oxalate, titanium trichloride; Reactant The total weight is the total weight of lithium iodide, nickel nitrate, manganese oxalate, cobalt oxalate and titanium trichloride, according to the total weight of reactants and methanol weight ratio is 1:1 weighing methanol (equivalent to (2 · (1-x ) y + 4 (x+z-x z) + 3 (1-x) k-x-3)=-0.10).

[0045] Mix titanium trichloride with methanol, then add the weighed nickel nitrate, manganese oxalate and cobalt oxalate, wet mill and mix for 10 hours, add ammonia water to make the solution acidity pH 10, add weighed lithium iodide, wet mill and mix for 11 h, prepare a reaction mixture solution containing the precipitate. Precursor 1 was obtained by aging the reaction mixture solution containing the precipitate at 40° C. for 24 hours. Prec...

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Abstract

The invention relates to a method for preparing a lithium-rich solid solution cathode material through reduction. The method is characterized by comprising the following steps of: weighing a lithium compound, a nickel compound, a manganese compound, a cobalt compound and a reducing agent in a molar ratio of lithium ions to nickel ions to manganese ions to cobalt ions to the reducing agent of (1+x):(1-x).y:(x+z-x.z):(1-x).k:q; and mixing the reducing agent and a wet grinding medium, mixing the weighed nickel compound, manganese compound and cobalt compound in a mixture, performing wet grinding and mixing, adding ammonia water, performing wet grinding again, aging, drying, putting a precursor in air, oxygen-rich gas or pure oxygen atmosphere, and performing two-section or two-time sectional sintering to prepare the lithium-rich solid solution cathode material xLi2MnO3.(1-x)Li[NiyMnzCok]O2. The electrode material prepared by the method has uniform composition, high discharge performance, and high discharge cycle performance particularly under the high-current condition.

Description

technical field [0001] The invention belongs to the technical field of battery electrode material preparation, and in particular relates to a method for preparing a doped lithium-rich solid solution positive electrode material that can be used for lithium batteries, lithium ion batteries, polymer batteries and supercapacitors. technical background [0002] Spinel LiMn 2 o 4 It has the characteristics of high working voltage, low price, and environmental friendliness, but the reversible capacity of the positive electrode material is low, and the discharge point capacity is only 90-100mAh / g when charging and discharging at a rate of 1C; at high temperatures, the discharge capacity of the positive electrode material will change with the Rapid decay with the charge-discharge cycle. [0003] Lithium-rich solid solution cathode material Li 2 MnO 3 ·Li[Ni 1 / 3 co 1 / 3 mn 1 / 3 ]O 2 It shows the advantages of high specific capacity, good thermal stability, and good cycle perform...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/48H01G11/86
CPCY02E60/12Y02E60/10
Inventor 童庆松周惠王浪
Owner FUJIAN NORMAL UNIV
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