CN101020690A

CN101020690A - Microwave process of synthesizing lithium dioxalate borate

Info

Publication number: CN101020690A
Application number: CN 200710064613
Authority: CN
Inventors: 仇卫华; 王赛; 刘伟; 黄佳原
Original assignee: University of Science and Technology Beijing USTB
Current assignee: SHANDONG HIRONG POWER SUPPLY MATERIAL Co Ltd
Priority date: 2007-03-21
Filing date: 2007-03-21
Publication date: 2007-08-22
Anticipated expiration: 2027-03-21
Also published as: CN100509822C

Abstract

The present invention is microwave process of synthesizing LiB(C2O4)2 material, and belongs to the field of lithium borate material technology. The process includes mixing oxalic acid and LiOH.H2O in ratio of (2.5-1.8) to 1 or oxalic acid and Li2CO3 in ratio of (4.1-3.8) to 1 mechanically in a stirrer of 12000 rpm; adding H3BO3 in the ratio to LiOH.H2O of (0.8-1) to 1 and the ratio to Li2CO3 of (1.9-2) to 1 before further stirring for 1-10 min; and setting mixture into beaker and setting the beaker in a microwave oven of 2.45 GHz frequency and 700 W maximum power for two stage synthesis of power of 100-400 W and 200-600 W separately. Compared with common solid phase synthesis process, the present invention has the advantages of fast heating, short synthesis process, low power consumption, and high product yield and purity.

Description

A kind of method that adopts the microwave method synthesizing lithium bis (oxalate) borate

Technical field

The invention belongs to the lithium borate technical field, a kind of employing microwave method synthesizing lithium bis (oxalate) borate LiB (C particularly is provided ₂O ₄) ₂Method, be applied to lithium ion battery electrolyte salt.

Background technology

Lithium ion battery is as a kind of novel power supply, since proposing and realize commercially producing the nineties in 20th century, be subjected to people's extensive attention always, have specific energy height, memory-less effect, pollution-free, advantage such as self-discharge is little, operating voltage is high, have extended cycle life.As the important component part of lithium ion battery, electrolyte solution is most important to the lithium ion battery Effect on Performance.That commercial is maximum at present is LiPF ₆Though contain LiPF ₆The electrolytic solution of salt has higher specific conductivity and electrochemical stability window, but thermostability is bad.In organic solvent, LiPF ₆There is following balance:

LiPF ₆(sol.)＝LiF(s)+PF ₅(sol.)

PF ₅Be a kind of very strong lewis acid, easy and organic solvent reaction moves to right balance.And P-F key instability is even exist trace water also can make LiPF in the solvent ₆Decompose and produce HF.The temperature rising can aggravate the carrying out of above-mentioned reaction, accelerates the deterioration of battery performance.In addition, LiPF ₆Electrolytic solution need be used with NSC 11801 (EC) usually, could be in the effective film forming of negative pole.Yet the fusing point of EC higher (37 ℃), this has also limited its application at low temperatures.

Can substitute LiPF in order to seek ₆Novel electrolytes salt, people constantly attempt all the time, the emphasis of research mainly concentrates on the title complex of some lithium tetraborates and Trilithium phosphate, wherein receiving publicity maximum is dioxalate group lithium borate (LiBOB) electrolytic salt.This electrolyte lithium salt also has the advantage of many uniquenesses except the Essential Performance Requirements that satisfies the lithium ion battery electrolyte lithium salts: A) have unique molecular structure, and can corroding electrode and aluminium collector; B) can in pure PC, stablize graphite cathode, for the low temperature use problem that solves battery provides possibility; C) LiB (C ₂O ₄) ₂Electrolyte has good heat endurance for Ni-based and the positive electrode manganese base; At present at LiB (C ₂O ₄) ₂Synthetic aspect mainly contain following work.

Lischka in Deutsche Bundespatent 19829030C1 with lithium hydroxide (or lithium carbonate), oxalic acid, boric acid (or boron oxide) as raw material, realized LiB (C with water, toluene or oxolane etc. as reaction medium ₂O ₄) ₂Synthetic.

(2001,4 (1): E1～E4) the middle organic liquid phase method that adopts has been synthesized LiB (C to Wu etc. at Electrochemical and Solid-State Letters ₂O ₄) ₂

Enemy Wei Hua research group LiBOB synthetic aspect application the patent of solid phase synthesis LiBOB, and obtained the authorization, the patent No. (2005100115557) is compared with this patent, this project adopts the synthetic LiBOB of microwave method, the time is shorter and purity is higher.

At present in the article of delivering and patent, not yet see the report that the method identical with employing and the present invention synthesized LiBOB.

Summary of the invention:

The object of the present invention is to provide a kind of employing microwave method synthesizing lithium bis (oxalate) borate LiB (C ₂O ₄) ₂Method, the environmental issue that solves in the building-up process also cuts down the consumption of energy.

The present invention adopts microwave-assisted synthesis, can finish LiB (C at 3-60 minute ₂O ₄) ₂Synthesizing of material, compare the energy consumption that greatly reduces in the building-up process with liquid phase method with general solid phase is synthetic, saved synthetic cost, reduced the pollution to environment.Concrete technology is: with oxalic acid (H ₂C ₂O ₄2H ₂O) and LiOHH ₂O presses (2.5～1.8): 1, or oxalic acid (H ₂C ₂O ₄2H ₂O) and Li ₂CO ₃In (4.1～3.8): 1 ratio is packed in 12000 rev/mins of mixers, with the Quick mechanical stirring means the two is mixed 1～10 minute after, with boric acid (H ₃BO ₃) add in the mixer H ₃BO ₃With LiOHH ₂The proportion control of O is at (0.8～1): 1, H ₃BO ₃With Li ₂CO ₃Ratio be (1.9～2): 1, the three continued to mix 1～10 minute.The material that mixes is put into beaker, then beaker is placed household microwave oven, frequency 2.45GHz, peak power 700W.The synthetic two-stage method that adopts, first section is regulated power is 100W～400W, generated time was controlled at 3～30 minutes, was incubated 0～20 minute; Second section is regulated power is 150W～600W, and generated time was controlled at 3～30 minutes, was incubated 0～20 minute.

The invention has the advantages that: compare with liquid-phase synthesis process, technology is simple, and generated time is short, and is environment friendly and pollution-free; Compare with general solid phase synthesis process, heating is rapid, and generated time is short and energy consumption is low.The most outstanding advantage is synthetic product productive rate height, and impurity is few, is fit to industrial mass production.In lithium ion battery, has good application prospects.

Description of drawings

Fig. 1 is the synthetic LiB (C of microwave of the present invention ₂O ₄) ₂XRD figure.Synthesis condition adopts LiOHH ₂O adopts 160W as the lithium source, and first paragraph 5 minutes is incubated 10 minutes, and second segment 9 minutes is incubated 0 minute.Abscissa is 2 θ angles among the figure, and ordinate is intensity.

Fig. 2 is synthetic material LiB (C in the inventive example 1 ₂O ₄) ₂XRD figure after purifying.X-coordinate is 2 θ angles, and ordinate zou is an intensity.

Fig. 3 is the synthetic LiB (C of microwave of the present invention ₂O ₄) ₂XRD figure, the raw material proportioning is H ₂C ₂O ₄2H ₂O: LiOHH ₂O: H ₃BO ₃=2.2: 1: 1, the same Fig. 1 of synthesis condition.X-coordinate is 2 θ angles, and ordinate zou is an intensity.

Fig. 4 is the synthetic LiB (C of microwave of the present invention ₂O ₄) ₂XRD figure, first paragraph 210W, 5 minutes, be incubated 10 minutes, stirrings once in the middle of two sections.Second section 330W 30 minutes is incubated 10 minutes.X-coordinate is 2 θ angles, and ordinate zou is an intensity.

Fig. 5 is the nucleus magnetic resonance boron spectrum before and after embodiment 3 purification of products.

Fig. 6 is 120 ℃ of solid-phase synthesis 3 hours, and 240 ℃ were synthesized into material LiB (C in 6 hours ₂O ₄) ₂XRD figure after 3 purifications, abscissa is 2 θ angles, ordinate is intensity.

Embodiment

To analyze pure oxalic acid (H ₂C ₂O ₄2H ₂O) and LiOHH ₂O packs in 12000 rev/mins the mixer by a certain percentage, with the Quick mechanical stirring means the two is mixed, and will analyze then pure boric acid (H ₃BO ₃) add in the mixer H ₃BO ₃With LiOHH ₂The proportion control of O is in certain limit, and the three continues mixed number minute.

Embodiment 1

Press H ₂C ₂O ₄2H ₂O: LiOHH ₂O: H ₃BO ₃=2.1: 1: 1 ratio takes by weighing H ₂C ₂O ₄2H ₂O 13.23 grams, LiOHH ₂O 2.1 grams, mechanical mixture added H after 2 minutes ₃BO ₃3.09 gram continues to mix 3 minutes.Batch mixing is put into beaker, then beaker is put in the micro-wave oven, adopt 160W, first paragraph 5 minutes is incubated 10 minutes, and second segment synthesized LiB (C in 9 minutes ₂O ₄) ₂, by XRD figure as seen, synthetic product is LiB (C substantially ₂O ₄) ₂, but contain a small amount of impurity.Have no impurity peaks among the product XRD figure after primary purification.The results are shown in Figure 2.

Embodiment 2

Press H ₂C ₂O ₄2H ₂O: LiOHH ₂O: H ₃BO ₃=2.2: 1: 1 ratio takes by weighing H ₂C ₂O ₄2H ₂O 27.87 grams, LiOHH ₂O 4.2 grams, mechanical mixture added H after 3 minutes ₃BO ₃6.214 gram continues to mix 4 minutes.Batch mixing is put into beaker, then beaker is put into microwave oven, first section 160W 5 minutes, is incubated 10 minutes.Second section 160W 25 minutes is incubated 10 minutes.The XRD figure of synthetic product is seen Fig. 3.As seen comparison diagram 1 and Fig. 3 improve the oxalic acid ratio and increase the middle content that link is conducive to impurity reduction that stirs.

Embodiment 3

Press H ₂C ₂O ₄2H ₂O: LiOHH ₂O: H ₃BO ₃=2.1: 1: 1 ratio takes by weighing H ₂C ₂O ₄2H ₂O 27.87 grams, LiOHH ₂O 4.2 grams, mechanical mixture added H after 3 minutes ₃BO ₃6.214 gram continues to mix 4 minutes.Batch mixing is put into beaker, then beaker is put into microwave oven, first section 210W 5 minutes, is incubated 10 minutes, two sections middle stirrings once.Second section 330W 30 minutes is incubated 10 minutes.The XRD figure of synthetic product is seen Fig. 4.As seen comparison diagram 3 and Fig. 4 improve the content that microwave power is conducive to impurity reduction.

Fig. 5 is the nucleus magnetic resonance boron spectrum before and after embodiment 3 purification of products, can see, the product before purifying without any impurity peaks, illustrate at this moment not boron-containing impurities of product except B main peak of LiBOB, and it is few to show as insoluble impurities content in purification process.And the product after purifying has the minute impurities peak except that B main peak of LiBOB, and this may cause in purification process in the product decomposition.

Comparative Examples:

Press H ₂C ₂O ₄2H ₂O: LiOHH ₂O: H ₃BO ₃=2.1: 1: 1 ratio takes by weighing H ₂C ₂O ₄2H ₂O 132.3 grams, LiOHH ₂O 21.0 grams, H ₃BO ₃30.9 gram is synthetic in baking oven, synthesis condition be 120 ℃ 3 hours, 240 ℃ 6 hours.The XRD collection of illustrative plates of sintetics after 3 purifications seen Fig. 6.

Claims

1, a kind of employing microwave method synthesizing lithium bis (oxalate) borate LiB (C ₂O ₄) ₂Method, it is characterized in that: with oxalic acid H ₂C ₂O ₄2H ₂O and LiOHH ₂O presses (2.5～1.8): 1, or oxalic acid H ₂C ₂O ₄2H ₂O and Li ₂CO ₃In (4.1～3.8): 1 the ratio rotating speed of packing into is in 12000 rev/mins of mixers, with the mechanical agitation method the two is mixed 1～10 minute after, add boric acid H ₃BO ₃, H ₃BO ₃With LiOHH ₂The proportion control of O is at (0.8～1): 1, H ₃BO ₃With Li ₂CO ₃Ratio be (1.9～2): 1, the three continued to mix 1～10 minute; The material that mixes is put into beaker, then beaker is placed household microwave oven, frequency 2.45GHz, peak power 700W; The synthetic two-stage method that adopts, the first paragraph regulating power is 100W～400W, generated time is controlled at 3～30 minutes, is incubated 1～20 minute; The second segment regulating power is 150W～600W, and generated time is controlled at 3～30 minutes, is incubated 0～20 minute; Two sections intermediate demands stir once.