CN102751486A

CN102751486A - Method for preparing lithium cobalt oxide nanosheets

Info

Publication number: CN102751486A
Application number: CN2012102492872A
Authority: CN
Inventors: 李冬松; 林璋; 王娴; 黄丰
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2012-07-18
Filing date: 2012-07-18
Publication date: 2012-10-24
Anticipated expiration: 2032-07-18
Also published as: CN102751486B

Abstract

The invention discloses a method for preparing lithium cobalt oxide nanosheets. The method includes steps of mixing cobalt salt and strong alkali, heating and centrifuging to obtain dark-blue liquid containing cobalt, and performing heat reaction between the dark-blue liquid containing cobalt and lithium brine so as to obtain the lithium cobalt oxide nanosheets with self-support structures. The method is simple and easy to operate and has a potential industrialization prospect. Products prepared by the method are high in charge and discharge capacity.

Description

A kind of preparation method of cobalt acid lithium nanometer sheet

Technical field

The present invention relates to a kind of preparation method of energy and material, be specifically related to a kind of preparation method with cobalt acid lithium nanometer sheet of self supporting structure.

Background technology

Development along with industrial society; The minimizing day by day of traditional energy such as coal, oil, natural gas; Extensive employing along with the portable electric appts (like mobile phone etc.) that technological progress brought; And to the demand of high-energy battery, people are strong day by day to the pursuit of the battery of high-energy-density, long circulation life, high performance price ratio.Secondary cell mainly contains at present: lead-acid battery, nickel-cadmium cell, Ni-MH battery and lithium ion battery.Lithium ion battery is cobalt acid lithium especially, is just to begin commercial a kind of novel high-energy in 1992 can charge and discharge battery, in fields such as portable electric appts, electric motor car, space technology, national defense industry good prospects for application is arranged all.

Find that through retrieving existing technical literature the technology of preparing of lithium battery is at present domestic and international researcher's a primary study object, technology of preparing commonly used comprises high-temperature solid phase reaction method, sol-gal process, hydro thermal method etc.But these methods need heat treatment at high temperature usually, cause the particle diameter of resulting cobalt acid lithium bigger usually like this, and size are irregular.Bigger particle diameter can cause the embedding of lithium ion and the difficulty of moving out, and the capacity of lithium battery is impacted.Existing hydrothermal technique can be realized the small particle size distribution and the small size of particle to a certain extent, but the particle of nanoscale assembles easily, is difficult for forming stable self supporting structure, has influenced its electric property on the contrary.

Summary of the invention

The objective of the invention is to deficiency, a kind of preparation method with cobalt acid lithium nanometer sheet of self supporting structure is provided to prior art.Method reaction condition of the present invention is gentle simple, with low cost, is a kind of method for preparing high-performance cobalt acid lithium material.

The present invention realizes through following technical scheme, may further comprise the steps: cobalt salt and sodium hydrate aqueous solution are mixed, place under the water heating kettle 150-230 ℃ condition, heated 5-10 hour, obtain navy blue alkaline cobalt-carrying solution.

After above-mentioned water heating kettle is cooled to room temperature, centrifugal black precipitate of removing the solution bottom.

Lithium salts is joined in the above-mentioned navy blue cobalt-carrying solution; This mixed solution is placed under the water heating kettle 150-230 ℃ condition; Heated 5-10 hour; Water heating kettle cooling back obtains having the nano-sheet cobalt acid lithium product of self supporting structure with deionized water and absolute ethyl alcohol cyclic washing lower black deposition.

Description of drawings

Fig. 1 is the sem photograph of product among the embodiment 1

Fig. 2 is the sem photograph of product among the embodiment 2

Fig. 3 is the sem photograph of product among the embodiment 3

Fig. 4 is

embodiment

1,2, the X-ray diffraction spectrogram of product and standard card contrast in 3

Fig. 5 is

embodiment

1,2, the product in 3 discharge and recharge character figure

Embodiment:

Embodiment 1

1) gets Co (Ac) ₂4H ₂The NaOH solution of O 1.4g and 16mL 5M mixes, and places the 20mL water heating kettle, and the baking oven of putting into 170 ℃ after water heating kettle is closed heats 5h.Take out behind the water heating kettle again naturally cool to room temperature in the air after, a navy blue cobalt-carrying solution.

2) with after this dark blue solution taking-up, the centrifugal lower black deposition of removing adds 0.1g LiCl then, and mixed solution is added in the 20mL water heating kettle, and water heating kettle seals 10h in the baking oven that tightly is placed on 150 ℃.In air, naturally cool to room temperature after taking out water heating kettle, at room temperature dry with deionized water and absolute ethyl alcohol cyclic washing black precipitate, obtain sheet LiCoO ₂Nano material.

3) gained cobalt acid lithium being assembled into 2025 type button cells, is under the 2.6-4.4V condition, with 5mA.h.g in charge and discharge platform ^-1Speed test, battery capacity is 113.2 mA.h.g ^-1

Embodiment 2

1) gets CoSO ₄.7H ₂The NaOH solution of O 1.4g and 15mL 10M mixes, and places the 20mL water heating kettle, and the baking oven of putting into 190 ℃ after water heating kettle is closed heats 8h.Take out behind the water heating kettle again naturally cool to room temperature in the air after, a navy blue cobalt-carrying solution.

2) with after this dark blue solution taking-up, the centrifugal lower black deposition of removing adds 0.2g LiCl then, and mixed solution is added in the 20mL water heating kettle, and water heating kettle seals 8h in the baking oven that tightly is placed on 180 ℃.In air, naturally cool to room temperature after taking out water heating kettle, at room temperature dry with deionized water and absolute ethyl alcohol cyclic washing black precipitate, obtain sheet LiCoO ₂Nano material.

3) gained cobalt acid lithium being assembled into 2025 type button cells, is under the 2.6-4.4V condition, with 5mA.g in charge and discharge platform ^-1Speed test, battery capacity is 123.9 mA.h.g ^-1

Embodiment 3

1) gets CoCl ₂.6H ₂The NaOH solution of O 0.5g and 15mL 16M mixes, and places the 20mL water heating kettle, and the baking oven of putting into 200 ℃ after water heating kettle is closed heats 10h.Take out behind the water heating kettle again naturally cool to room temperature in the air after, a navy blue cobalt-carrying solution.

2) with after this dark blue solution taking-up, the centrifugal lower black deposition of removing adds 0.2g Li then ₂SO ₄.H ₂O adds mixed solution in the 20mL water heating kettle, and water heating kettle seals 5h in the baking oven that tightly is placed on 230 ℃.In air, naturally cool to room temperature after taking out water heating kettle, at room temperature dry with deionized water and absolute ethyl alcohol cyclic washing black precipitate, obtain sheet LiCoO ₂Nano material.

3) gained cobalt acid lithium being assembled into 2025 type button cells, is under the 2.6-4.4V condition, with 5mA.h.g in charge and discharge platform ^-1Speed test, battery capacity is 140.1 mA.h.g ^-1

Claims

1. the preparation method of a cobalt acid lithium nanometer sheet comprises the steps:

(1) is raw material with cobalt salt and aqueous slkali, adopts the Hydrothermal Preparation cobalt liquor;

(2) above-mentioned cobalt liquor and lithium salts are reacted under hydrothermal condition, obtain to have the cobalt acid lithium nanometer sheet of self supporting structure.

2. the preparation method of cobalt acid lithium nanometer sheet according to claim 1, it is characterized in that: used highly basic is that concentration is the NaOH solution of 5M-16M.

3. the preparation method of cobalt acid lithium nanometer sheet according to claim 1, it is characterized in that: described cobalt salt is selected CoCl for use ₂.H ₂O, CoSO ₄.7H ₂O or Co (Ac) ₂.4H ₂O.

4. the preparation method of cobalt acid lithium nanometer sheet according to claim 1, it is characterized in that: said lithium salts is selected LiCl, LiSO for use ₄.H ₂O or LiAc.2H ₂O.

5. the preparation method of cobalt acid lithium nanometer sheet according to claim 1, it is characterized in that: hydrothermal temperature is 150-230 ℃ in said step (1) and (2), and the reaction time is 5-10 hour.