Synthesis and surface modification method of lithium excessive laminar oxide anode material

A lithium-rich cathode material and lithium-rich material technology, applied in the field of lithium-ion batteries and electrochemistry, can solve the problems of poor rate performance, low charge-discharge efficiency, and large irreversible capacity loss, so as to improve the charge-discharge efficiency and increase the volume. Energy density, the effect that is conducive to rapid de-embedding

Inactive Publication Date: 2011-10-05
GUANGZHOU HKUST FOK YING TUNG RES INST
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AI Technical Summary

Problems solved by technology

In order to solve the disadvantages of low charge-discharge efficiency, large irreversible capacity loss, and poor rate performance of lithium-rich materials in the first cycle, a method of pretreating the surface of materials with oxidants such as persulfate or sulfate is proposed, which can improve lithium-rich materials. First-time efficiency of the material as well as discharge capacity and cycle stability at high rates

Method used

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  • Synthesis and surface modification method of lithium excessive laminar oxide anode material
  • Synthesis and surface modification method of lithium excessive laminar oxide anode material
  • Synthesis and surface modification method of lithium excessive laminar oxide anode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Step 1. Manganese sulfate, nickel sulfate, and cobalt sulfate are used to prepare a mixed salt solution 1 with a total concentration of 1.0 mol / L, wherein the molar ratio of manganese salt: nickel salt: cobalt salt is 0.54:0.13:0.13.

[0032] Step 2, prepare a 1.0mol / L sodium carbonate solution, add a certain amount of concentrated ammonia water dropwise to the sodium carbonate solution, and record it as solution 2.

[0033] Step 3. Pump solution 1 and solution 2 into the reaction kettle at the same time for co-precipitation reaction, control the reaction temperature to 60°C, control the pH value of the solution by adding ammonia water to 8, and react for 12 hours. -Washing-drying yields carbonate precursor precipitates of two different particle sizes (see figure 1 ). The SEM pattern shows that the carbonate precursor and Li(Li 0.2 mn 0.54 Ni 0.13 co 0.13 )O 2 They are spherical particles with uniform size, the particle sizes are about 4um and 10um respectively, ...

Embodiment 2

[0039] Steps 1-5 are the same as in Example 1.

[0040] Step 6. Dissolve sodium persulfate and potassium persulfate with a mass fraction of 40% and 50% of the lithium-rich material in deionized water, then add the lithium-rich material, and stir at 80°C until the solution is completely volatilized. The obtained powder was calcined at 200°C for 10 h, filtered, washed and dried to obtain Li 1..2-x mn 0.54 Ni 0.13 co 0.13 o 2 .

[0041] Electrochemical tests show that the first charge and discharge efficiency of the material is improved by removing part of the lithium in advance (see image 3 ). In the 2-4.8V interval. At a rate of 0.1C (25mA / g), the lithium-rich materials treated with 40% sodium persulfate and potassium persulfate had an initial discharge capacity of 242 mAh / g and 234 mAh / g, and a charge-discharge efficiency of 82.3% and 78.65 %; 50% mass fraction of sodium persulfate and potassium persulfate treated lithium-rich materials, the first discharge capacity o...

Embodiment 3

[0043] Steps 1-5 are the same as in Example 1.

[0044] Step 6. Dissolve potassium persulfate and ammonium sulfate with a mass fraction of 48% and 23% of the lithium-rich material in deionized water, then add the lithium-rich material, and stir at 80°C until the solution is completely volatilized. The obtained powder was calcined at 300°C for 10 h, filtered, washed and dried to obtain Li 1..2-x mn 0.54 Ni 0.13 co 0.13 o 2 .

[0045] Electrochemical tests showed that (see Figure 4 ), at a discharge rate of 0.1C (25mA / g), the initial discharge capacity of the material pretreated with 48% potassium persulfate in the 2-4.8V range is 250mAh / g, and the initial charge-discharge efficiency is 85.6%. ; while the 23% mass fraction of ammonium sulfate pretreated material is better, the first discharge capacity in the range of 2-4.8V and 2-4.6V is 270mAh / g and 257mAh / g, and the charge and discharge efficiency can reach 88.6% respectively and 92.3%.

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Abstract

The invention relates to a synthesis and surface modification method of a lithium rich anode material Li1+xM1-xO2 (M is one or more of Ni, Co and Mn, and X is more than or equal to 0 and less than or equal to 1/3) for a lithium ion battery. The method comprises the following steps of: synthesizing a precursor by using a carbonate precipitation method, mixing the precursor and a lithium salt, and calcining for 2 to 20 hours at the temperature of between 800 and 1,100 EG C to obtain a lithium rich material, wherein the prepared lithium rich material has controllable particle size and higher reversible capacity; and dissolving persulfate or sulfate in an amount which is 5 to 80 mass percent of the lithium rich material into deionized water, adding the lithium rich material, stirring for 2 to 100 hours at the temperature of between 25 and 80 DEG C, heating the materials to the temperature of between 100 and 500 DEG C in a muffle furnace, calcining the materials for 2 to 20 hours, fully filtering the obtained materials, and washing off impurities to obtain the surface modified anode material Li1+x-yM1-xO2. The synthesized lithium rich material has controllable particle size; the first charge/discharge efficiency of the lithium rich material and the discharge specific capacity and the cyclical stability under high magnification can be improved; and the method is simple, low in cost, convenient for operation and suitable for industrialized production.

Description

technical field [0001] The invention relates to the preparation of a lithium-excessive layered lithium-rich cathode material for a lithium-ion secondary battery and a surface treatment and modification method thereof, belonging to the field of lithium-ion batteries and electrochemistry. Background technique [0002] Lithium-ion batteries have been widely used in various portable electronic devices, and will also have broad application prospects in the fields of electric vehicles and energy storage batteries in the future. This puts forward higher requirements on the performance of lithium-ion battery cathode materials. In recent years, layered lithium-rich transition metal (Ni, Co, Mn, etc.) oxide cathode materials with higher voltage and higher capacity have attracted extensive attention from researchers. The lithium-rich cathode material is mainly Li 2 MnO 3 LMO with layered materials 2 (M is one or more of Ni, Co, Mn) formed solid solution, Li 2 MnO 3 It plays a rol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/139H01M4/1391
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 施志聪郑隽邓胜男陈申陈国华
Owner GUANGZHOU HKUST FOK YING TUNG RES INST
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