CN103367765B - This Multi-layer graphite of the preparation method and application of Multi-layer graphite prepares the method for lithium-air battery cathode - Google Patents
This Multi-layer graphite of the preparation method and application of Multi-layer graphite prepares the method for lithium-air battery cathode Download PDFInfo
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- CN103367765B CN103367765B CN201310317023.0A CN201310317023A CN103367765B CN 103367765 B CN103367765 B CN 103367765B CN 201310317023 A CN201310317023 A CN 201310317023A CN 103367765 B CN103367765 B CN 103367765B
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Abstract
This Multi-layer graphite of the preparation method and application of Multi-layer graphite prepares the method for lithium-air battery cathode, the present invention relates to a kind of preparation method being applied to the graphite material of lithium-air battery cathode.It is low and using graphite material as the problem that the specific discharge capacity of lithium-air battery cathode is low that it will solve the pore volume of existing graphite material.Prepared by Multi-layer graphite: one, take raw material; Two, the concentrated sulfuric acid mixes with acetic acid, adds potassium permanganate and graphite, suction filtration post-drying, is placed in the lower expansion of high temperature inert gas protection, obtains expanded graphite; Three, expanded graphite is scattered in ultrasonic disperse in absolute ethyl alcohol, obtains Multi-layer graphite.The pore volume of Multi-layer graphite of the present invention can reach more than 98%.Prepare cell cathode: Multi-layer graphite and binding agent are stirred into paste, be evenly coated on collector, compressing after drying, obtain lithium-air battery cathode.The specific capacity of the lithium-air battery cathode material prepared is more than 6000mAh/g.
Description
Technical field
The present invention relates to a kind of preparation method being applied to the graphite material of lithium-air battery cathode.
Background technology
Lithium/air cell is that anode made by one lithium metal, using the oxygen in air as the battery of cathode reactant.Because oxygen is not limited as cathode reactant, the capacity of this battery only depends on lithium electrode, therefore its in theory specific energy be 11140W h/kg (not comprising oxygen), or 5210W h/kg (comprising oxygen).But its actual specific energy is lower at present, and cycle performance is poor, its subject matter is that cathode discharge products " oxidate for lithium " can be deposited in the hole of cathode surface or material with carbon element in discharge process, and blocking oxygen therapy passage, causes electric discharge to interrupt.Therefore, cathode material research and development and prepare most important.
The material that current preparation lithium-air battery cathode electrode is selected mostly is material with carbon element, the material with carbon element of different pore size and structure as Super P, mesoporous carbon, Norit carbon black, m-30 carbon, graphite, Graphene etc.The people " Preparation of mesocellular carbon foam and its application for lithium/oxygen battery.Electrochemistry Communications " in 2009 " Electrochemistry Communications " such as Xin-hui Yang describe the specific capacity of existing negative electrode material with carbon element, surface area and aperture contrast, and (discharge current density is 0.1mAcm
-2) as shown in table 1;
Table 1
Be 62m by the known super-P surface area of the data in table 1
2g
-1, aperture is 50nm, and specific capacity reaches 1736mAhg
-1, and activated carbon surface is long-pending up to 2100m
2g
-1, specific capacity is but only 414mAhg
-1, MCF-C surface area is 824m
2g
-1, specific discharge capacity is 2500mAhg
-1, the specific capacity of from then on known electric discharge aperture that is main and material with carbon element presents positive correlation.
To sum up material with carbon element does lithium-air battery cathode, should possess following three features: 1. suitable pore size and particle size can make gaseous oxygen freely pass through, and can hold more discharging product (oxidate for lithium), the carrying out of sustain discharge; 2. good electrical conductance; 3. higher specific area, and the specific area with oxygen reduction activity.
Summary of the invention
The object of the invention is to solve the pore volume of existing graphite material low and using graphite material as the problem that the specific discharge capacity of lithium-air battery cathode is low, and provide this Multi-layer graphite of the preparation method and application of Multi-layer graphite to prepare the method for lithium-air battery cathode.
The preparation method of Multi-layer graphite of the present invention follows these steps to realize:
One, be that ((3.5 ~ 4.5) ︰ (1.0 ~ 2.0) take graphite, potassium permanganate, the concentrated sulfuric acid and acetic acid as raw material to 0.20 ~ 0.30) ︰ to 1.0 ︰ in mass ratio;
Two, the concentrated sulfuric acid in raw material is mixed with acetic acid, add after potassium permanganate dissolves and add graphite again, 20 ~ 40min is reacted under stirring condition, the solid formation be obtained by reacting is through washing, at the temperature of 60 ~ 90 DEG C, 2 ~ 4h is dried after suction filtration, and then the porcelain crucible expansion 5 ~ 20s be placed under 600 ~ 1000 DEG C of high temperature inert gas protections, in expansion process, porcelain crucible constantly overturns, and obtains expanded graphite;
Three, the expanded graphite that step 2 obtains is scattered in anhydrous ethanol solvent, ultrasonic disperse 2 ~ 4h, then dries at 60 ~ 90 DEG C of temperature and obtain Multi-layer graphite.
The expanding volume of the expanded graphite that step 2 of the present invention obtains can reach 700ml/g, the pore volume of the Multi-layer graphite of final preparation can reach more than 98%, and pore structure is based on macropore, pore size distribution range is 1 ~ 103nm, ensure gaseous oxygen by or the accommodation of discharging product.
The method that the present invention's application Multi-layer graphite prepares lithium-air battery cathode follows these steps to realize:
One, binding agent PVDF is joined in organic solvent NMP, wiring solution-forming A, stir into paste after then adding Multi-layer graphite ultrasonic disperse 1 ~ 5h in solution A, obtain paste slurry;
Two, paste slurry step one obtained is evenly coated on collector, is then placed in vacuum drying chamber with the temperature drying 4 ~ 8h of 100 ~ 120 DEG C, uses the circular pole piece of blunderbuss sheet machine blunderbuss after taking out;
Three, by compressing with the pressure of 5MPa for circular pole piece tablet press machine, lithium-air battery cathode is obtained.
The present invention prepares lithium-air battery cathode with Multi-layer graphite, there is specific surface large, pore volume is large, ventilation permeability is good, preparation method is simple, low cost and other advantages, the specific capacity of the lithium-air battery cathode material that application Multi-layer graphite prepares, more than 6000mAh/g, far exceed other material with carbon elements such as Graphene, and cost is far below Graphene.
Accompanying drawing explanation
Fig. 1 is the scanning electron microscope (SEM) photograph that Multi-layer graphite that embodiment one obtains amplifies 2000 times;
Fig. 2 is the scanning electron microscope (SEM) photograph that Multi-layer graphite that embodiment one obtains amplifies 2200 times;
Fig. 3 is the lithium-air battery discharge curve that embodiment two applies that Multi-layer graphite is negative electrode.
Embodiment
Embodiment one: the preparation method of present embodiment Multi-layer graphite follows these steps to implement:
One, be that ((3.5 ~ 4.5) ︰ (1.0 ~ 2.0) take graphite, potassium permanganate, the concentrated sulfuric acid and acetic acid as raw material to 0.20 ~ 0.30) ︰ to 1.0 ︰ in mass ratio;
Two, the concentrated sulfuric acid in raw material is mixed with acetic acid, add after potassium permanganate dissolves and add graphite again, 20 ~ 40min is reacted under stirring condition, the solid formation be obtained by reacting is through washing, at the temperature of 60 ~ 90 DEG C, 2 ~ 4h is dried after suction filtration, and then the porcelain crucible expansion 5 ~ 20s be placed under 600 ~ 1000 DEG C of high temperature inert gas protections, in expansion process, porcelain crucible constantly overturns, and obtains expanded graphite;
Three, the expanded graphite that step 2 obtains is scattered in anhydrous ethanol solvent, ultrasonic disperse 2 ~ 4h, then dries at 60 ~ 90 DEG C of temperature and obtain Multi-layer graphite.
Present embodiment step 2 adds after potassium permanganate dissolves to be needed to add graphite rapidly.In expansion process, by upset porcelain crucible, graphite is heated evenly.
The Multi-layer graphite that present embodiment obtains is the graphite material processed further expanded graphite and obtain, and has suitable pore size and particle size, and gaseous oxygen is freely passed through, and holds more discharging product (oxidate for lithium), the carrying out of sustain discharge.
Embodiment two: present embodiment and embodiment one are 50 orders unlike the graphite described in step one.Other step and parameter identical with embodiment two.
Embodiment three: present embodiment and embodiment one or two unlike step 2 be placed in 900 DEG C of high temperature inert gas protect under porcelain crucible expand.Other step and parameter identical with embodiment one or two.
Inert gas described in present embodiment is nitrogen.
Embodiment four: the method that present embodiment application Multi-layer graphite prepares lithium-air battery cathode follows these steps to realize:
One, binding agent PVDF is joined in organic solvent NMP, wiring solution-forming A, stir into paste after then adding Multi-layer graphite ultrasonic disperse 1 ~ 5h in solution A, obtain paste slurry;
Two, paste slurry step one obtained is evenly coated on collector, is then placed in vacuum drying chamber with the temperature drying 4 ~ 8h of 100 ~ 120 DEG C, uses the circular pole piece of blunderbuss sheet machine blunderbuss after taking out;
Three, by compressing with the pressure of 5MPa for circular pole piece tablet press machine, lithium-air battery cathode is obtained.
Embodiment five: present embodiment and embodiment four are 6% ~ 10% unlike the mass concentration of binding agent PVDF in the solution A described in step one.Other step and parameter identical with embodiment four.
Embodiment six: present embodiment and embodiment four or five are 1.0 ︰ 0.1 ~ 1.0 unlike the mass ratio of the Multi-layer graphite described in step one and binding agent PVDF.Other step and parameter identical with embodiment four or five.
Present embodiment Multi-layer graphite mixes with binding agent PVDF makes it be bonded on collector.
Embodiment seven: present embodiment and embodiment four or five are 1.0 ︰ 0.1 ~ 0.3 unlike the mass ratio of the Multi-layer graphite described in step one and binding agent PVDF.Other step and parameter identical with embodiment four or five.
Embodiment eight: one of present embodiment and embodiment four to seven are nickel foam or carbon paper unlike the collector described in step 2.Other step and parameter identical with one of embodiment four to seven.
Embodiment one: the preparation method of the present embodiment Multi-layer graphite follows these steps to implement:
One, be that 1.0 ︰ 0.26 ︰ 4.0 ︰ 1.3 take graphite, potassium permanganate, the concentrated sulfuric acid and acetic acid as raw material in mass ratio;
Two, the concentrated sulfuric acid in raw material is mixed with acetic acid, add after potassium permanganate dissolves and add graphite again, 40min is reacted under stirring condition, the solid formation be obtained by reacting is through washing, at the temperature of 60 DEG C, 4h is dried after suction filtration, and then the porcelain crucible be placed under the protection of 900 DEG C of high temperature inert gas expands 10s, in expansion process, porcelain crucible constantly overturns, and obtains expanded graphite;
Three, the expanded graphite that step 2 obtains is scattered in anhydrous ethanol solvent, ultrasonic disperse 4h, then dries at 80 DEG C of temperature and obtain Multi-layer graphite.
Wherein the mass concentration of the concentrated sulfuric acid described in step one is 98%, and the purity of acetic acid is that 99.5%(analysis is pure).
The expanding volume of the expanded graphite that the present embodiment step 2 obtains can reach 700ml/g, and the Multi-layer graphite pore volume finally obtained can reach 98%, and pore structure is based on macropore, pore size distribution range 1 ~ 103nm.
Embodiment two: the method that the Multi-layer graphite that Application Example one obtains prepares lithium-air battery cathode follows these steps to implement:
One, the binding agent PVDF of 10g is joined in the organic solvent NMP of 90ml, wiring solution-forming A, get 1g solution A, stir into paste after adding 2g Multi-layer graphite ultrasonic disperse 2h wherein, obtain paste slurry;
Two, paste slurry step one obtained is evenly coated in 50cm
2in nickel foam, be then placed in vacuum drying chamber with the dry 5h of the temperature of 110 DEG C, after taking out, use blunderbuss sheet machine blunderbuss in the nickel foam of drying to go out the circular pole piece that diameter is 14mm;
Three, circular pole piece tablet press machine is shaping with the pressure of 5MPa compacting 5min, obtain lithium-air battery cathode.
The lithium-air battery cathode using the present embodiment to obtain, makes collector with nickel foam, and metal lithium sheet is as anode, and use celgard2400PVDF as diaphragm, electrolyte uses the LiPF of 1mol/L
6/ EC-DEC(1:1) solution, in the glove box being full of argon gas, sealing is assembled into lithium battery.
By lithium battery at 0.1mA/cm
2carry out charge-discharge test under current density, the specific discharge capacity obtaining lithium-air battery reaches 6200mAhg
-1.
Claims (7)
1. the preparation method of Multi-layer graphite, is characterized in that the preparation method of Multi-layer graphite follows these steps to realize:
One, be that ((3.5 ~ 4.5) ︰ (1.0 ~ 2.0) take graphite, potassium permanganate, the concentrated sulfuric acid and acetic acid as raw material to 0.20 ~ 0.30) ︰ to 1.0 ︰ in mass ratio;
Two, the concentrated sulfuric acid in raw material is mixed with acetic acid, add after potassium permanganate dissolves and add graphite again, 20 ~ 40min is reacted under stirring condition, the solid formation be obtained by reacting is through washing, at the temperature of 60 ~ 90 DEG C, 2 ~ 4h is dried after suction filtration, and then the porcelain crucible expansion 5 ~ 20s be placed under 600 ~ 1000 DEG C of high temperature inert gas protections, in expansion process, porcelain crucible constantly overturns, and obtains expanded graphite;
Three, the expanded graphite that step 2 obtains is scattered in anhydrous ethanol solvent, ultrasonic disperse 2 ~ 4h, then dries at 60 ~ 90 DEG C of temperature and obtain Multi-layer graphite;
Wherein the mass concentration of the concentrated sulfuric acid is 98%, and the purity of acetic acid is 99.5%.
2. the preparation method of Multi-layer graphite according to claim 1, is characterized in that the graphite described in step one is 50 orders.
3. the preparation method of Multi-layer graphite according to claim 1, is characterized in that the porcelain crucible that step 2 is placed under the protection of 900 DEG C of high temperature inert gas expands.
4. the Multi-layer graphite that as claimed in claim 1 prepared by method is applied to the method preparing lithium-air battery cathode, it is characterized in that applying the method that Multi-layer graphite prepares lithium-air battery cathode and follows these steps to realize:
One, binding agent PVDF is joined in organic solvent NMP, wiring solution-forming A, stir into paste after then adding Multi-layer graphite ultrasonic disperse 1 ~ 5h in solution A, obtain paste slurry;
Two, paste slurry step one obtained is evenly coated on collector, is then placed in vacuum drying chamber with the temperature drying 4 ~ 8h of 100 ~ 120 DEG C, uses the circular pole piece of blunderbuss sheet machine blunderbuss after taking out;
Three, by compressing with the pressure of 5MPa for circular pole piece tablet press machine, lithium-air battery cathode is obtained.
5. application Multi-layer graphite according to claim 4 prepares the method for lithium-air battery cathode, it is characterized in that the mass concentration of binding agent PVDF in the solution A described in step one is 6% ~ 10%.
6. application Multi-layer graphite according to claim 4 prepares the method for lithium-air battery cathode, it is characterized in that the mass ratio of Multi-layer graphite described in step one and binding agent PVDF is 1.0 ︰ 0.1 ~ 1.0.
7. application Multi-layer graphite according to claim 4 prepares the method for lithium-air battery cathode, it is characterized in that the collector described in step 2 is nickel foam or carbon paper.
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JP6578611B2 (en) * | 2013-11-25 | 2019-09-25 | 独立行政法人国立高等専門学校機構 | Positive electrode for air battery and air battery using the positive electrode |
CN104577145B (en) * | 2014-12-26 | 2017-04-19 | 云南冶金集团创能铝空气电池股份有限公司 | Air electrode catalyst for aluminum-air cell and preparation method of air electrode catalyst |
US10982069B2 (en) * | 2017-04-17 | 2021-04-20 | Baker Hughes, A Ge Company, Llc | Acid resistant carbon composites, methods of manufacture, and articles formed thereof |
CN112840478B (en) * | 2018-11-07 | 2024-06-21 | 株式会社Lg新能源 | Catalyst for positive electrode material for lithium secondary battery and lithium secondary battery comprising same |
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CN1153743A (en) * | 1996-10-18 | 1997-07-09 | 宋克敏 | Prodn process of no-sulphur expansion graphite |
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