CN116799432A - Lithium-sulfur battery diaphragm and preparation method and application thereof - Google Patents
Lithium-sulfur battery diaphragm and preparation method and application thereof Download PDFInfo
- Publication number
- CN116799432A CN116799432A CN202310590439.3A CN202310590439A CN116799432A CN 116799432 A CN116799432 A CN 116799432A CN 202310590439 A CN202310590439 A CN 202310590439A CN 116799432 A CN116799432 A CN 116799432A
- Authority
- CN
- China
- Prior art keywords
- sulfur battery
- lithium
- pan
- sio
- electrostatic spinning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- JDZCKJOXGCMJGS-UHFFFAOYSA-N [Li].[S] Chemical compound [Li].[S] JDZCKJOXGCMJGS-UHFFFAOYSA-N 0.000 title claims abstract description 51
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 229920002239 polyacrylonitrile Polymers 0.000 claims abstract description 132
- 239000002048 multi walled nanotube Substances 0.000 claims abstract description 69
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 66
- 238000010041 electrostatic spinning Methods 0.000 claims abstract description 31
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 27
- 239000005543 nano-size silicon particle Substances 0.000 claims abstract description 18
- 239000011159 matrix material Substances 0.000 claims abstract description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 20
- 239000000377 silicon dioxide Substances 0.000 claims description 15
- 239000003960 organic solvent Substances 0.000 claims description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 238000001523 electrospinning Methods 0.000 claims description 8
- 229910021389 graphene Inorganic materials 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 5
- 238000011068 loading method Methods 0.000 claims description 4
- 238000000967 suction filtration Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims 1
- 229920001021 polysulfide Polymers 0.000 abstract description 17
- 239000005077 polysulfide Substances 0.000 abstract description 17
- 150000008117 polysulfides Polymers 0.000 abstract description 17
- 238000009792 diffusion process Methods 0.000 abstract description 15
- 239000003792 electrolyte Substances 0.000 abstract description 6
- 239000011885 synergistic combination Substances 0.000 abstract description 2
- 229910003003 Li-S Inorganic materials 0.000 abstract 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 93
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 25
- 229910001416 lithium ion Inorganic materials 0.000 description 9
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 8
- 238000002484 cyclic voltammetry Methods 0.000 description 8
- 238000002604 ultrasonography Methods 0.000 description 8
- 238000001000 micrograph Methods 0.000 description 6
- 239000002121 nanofiber Substances 0.000 description 6
- 239000004743 Polypropylene Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 229920001155 polypropylene Polymers 0.000 description 5
- 238000003828 vacuum filtration Methods 0.000 description 5
- 229910018091 Li 2 S Inorganic materials 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000004626 scanning electron microscopy Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 230000002441 reversible effect Effects 0.000 description 3
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000011244 liquid electrolyte Substances 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- -1 polypropylene Polymers 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 238000001157 Fourier transform infrared spectrum Methods 0.000 description 1
- 229910013553 LiNO Inorganic materials 0.000 description 1
- 229910002808 Si–O–Si Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 125000004093 cyano group Chemical group *C#N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000010294 electrolyte impregnation Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 239000005486 organic electrolyte Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention relates to the technical field of batteries, in particular to a lithium-sulfur battery diaphragm and a preparation method and application thereof. The lithium-sulfur battery diaphragm comprises an electrostatic spinning base film and multi-wall carbon nanotubes loaded on the electrostatic spinning base film; the electrostatic spinning base film takes polyacrylonitrile as a matrix, and the matrix contains nano silicon dioxide. According to the invention, through the synergistic combination of the components, the diffusion of polysulfide in the Li-S battery can be effectively inhibited, the diaphragm has excellent porosity and electrolyte wettability, and the prepared battery has excellent cycle stability and rate capability.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a lithium-sulfur battery diaphragm and a preparation method and application thereof.
Background
Lithium Ion Batteries (LIBs) are widely used as power supplies for portable electronic devices due to their long cycle life, high power density, high energy density, and the like. However, lithium ion batteries are always limited in large-scale applications, such as electric vehicles, stationary energy storage, and the like, which also motivates numerous researchers to further develop new batteries to solve the limitation problem in the above-mentioned fields. Lithium-sulfur (Li-S) batteries are a promising candidate because of the advantages of rich sulfur (S) content, relatively low cost, non-toxicity, high theoretical capacity (1675 mAh g-1), high energy density (2600 Wh kg-1), and the like.
Despite the advantages, lithium-sulfur batteries currently have the disadvantages of long cycle life, short self-discharge, low coulombic efficiency, etc., which severely limit their practical applications. These disadvantages are mainly due to the fact that lithium polysulfide (Li 2 S) into the organic electrolyte, resulting in loss of positive electrode active material and shuttling of polysulfide. In order to obtain a high performance Li-S battery, it is extremely important to suppress shuttle diffusion of polysulfides.
In order to solve the challenges faced by Li-S batteries, many efforts have been made, with a focus mainly on the simple substance of S and conductive materials (such as porous carbon, graphene, carbon nanotubes, conductive polymers and oxides with polysulfide absorption capacity, such as TiO 2 ，Al 2 O 3 Etc.) are combined to form a composite material. However, these approaches can lead to complex positive electrode structural designs, which undoubtedly hamper the utility of Li-S batteries.
As is well known, the separator is an essential component in all liquid electrolyte batteries. The separator of an ideal Li-S cell not only has good ionic conductivity after absorbing the liquid electrolyte, but also slows down polysulfide diffusion during cycling. At present, a commonly used separator material for a lithium battery is microporous polypropylene (PP), but the defects of low porosity and poor electrolyte wettability seriously prevent the electrochemical performance of the Li-S battery from being exerted, in particular the rate performance and the long-term cycle stability performance.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide a lithium sulfur battery diaphragm, which aims to solve the technical problem that the diaphragm in the prior art cannot well inhibit shuttle diffusion of polysulfide, so that the electrochemical performance of a lithium sulfur battery is poor.
The invention also aims to provide a preparation method of the lithium-sulfur battery diaphragm, which is simple and easy to implement.
Another object of the present invention is to provide a lithium sulfur battery as described, which has excellent electrochemical properties.
In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
the lithium-sulfur battery diaphragm comprises an electrostatic spinning base film and multi-wall carbon nanotubes loaded on the electrostatic spinning base film; the electrostatic spinning base film takes polyacrylonitrile as a matrix, and the matrix contains nano silicon dioxide.
In one embodiment, the mass ratio of the nano silicon dioxide to the polyacrylonitrile to the multi-wall carbon nano tube is (200-1000): (2500-3500): (1.5-2.5).
In one embodiment, the nanosilica has a particle size of from 10 to 20nm.
In one embodiment, the multiwall carbon nanotubes have an outer diameter of 8 to 15nm and a length of 40 to 60 μm.
In one embodiment, the polyacrylonitrile has a weight average molecular weight of 120000 ～ 160000g/mol.
In one embodiment, the lithium sulfur battery separator has an effective area density of 0.19 to 0.26mg/cm 2 。
In one embodiment, the lithium sulfur battery separator has a thickness of 2.8 to 3.2 μm.
In one embodiment, the porosity of the lithium sulfur battery separator is 72% to 77%.
In one embodiment, part or all of the silica is replaced with alumina and/or graphene.
In one embodiment, some or all of the multiwall carbon nanotubes are replaced with graphene and/or activated carbon.
The preparation method of the lithium sulfur battery diaphragm comprises the following steps:
(a) Carrying out electrostatic spinning treatment on a mixed system formed by nano silicon dioxide, polyacrylonitrile and an organic solvent to obtain an electrostatic spinning base film;
(b) Dispersing the multi-wall carbon nano tube in an alcohol solvent, and loading the multi-wall carbon nano tube onto the electrostatic spinning base film by adopting a vacuum suction filtration mode to obtain the lithium-sulfur battery diaphragm.
In one embodiment, the preparation method of the mixed system specifically comprises the following steps: dispersing nano silicon dioxide in an organic solvent, and uniformly mixing with the polyacrylonitrile.
In one embodiment, the ratio of the amount of nanosilica to the amount of organic solvent is (0.2 to 1) g (40 to 60) mL.
In one embodiment, the voltage of the electrospinning treatment is 13-16 kV, and the feeding rate of the electrospinning treatment is 0.7-0.8 mL/min.
In one embodiment, the ratio of the multi-walled carbon nanotubes to the alcohol solvent is (1.5-2.5) mg (350-450) mL.
A lithium sulfur battery comprising a lithium sulfur battery separator as described above.
Compared with the prior art, the invention has the beneficial effects that:
(1) The lithium sulfur battery diaphragm provided by the invention has a porous structure and good electrolyte wettability, and the electrostatic spinning base film contains-C (identical to N) and nano SiO in polyacrylonitrile 2 The diffusion of polysulfide can be relieved by matching; in addition, the existence of the multi-wall carbon nano tube can further improve the electrochemical performance of the Li-S battery, not only can increase the contact area with the surface of the cathode, but also can provide high utilization rate of active materials, and can inhibit the migration of polysulfides, so that the shuttle reaction of the multi-wall carbon nano tube can be avoided; by each group ofThe synergistic combination of the components can promote the exertion of the electrochemical performance of the lithium-sulfur battery.
(2) The method is simple and efficient. The electrostatic spinning base film is prepared by an electrostatic spinning technology, and the multi-wall carbon nano tube is loaded on the electrostatic spinning base film by adopting a simple suction filtration mode.
(3) The lithium sulfur battery has excellent cycle performance and rate performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is PAN/SiO 2 -scanning electron microscopy of 10 nanofibers;
FIG. 2 is PAN/SiO 2 -scanning electron microscopy of 30 nanofibers;
FIG. 3 is a scanning electron microscope image of MWCNTs;
FIG. 4 is a transmission electron microscope image of MWCNTs;
FIG. 5 is a high resolution transmission electron microscope image of MWCNTs;
FIG. 6 is PAN, PAN/SiO 2 -10 and PAN/SiO 2 -FT-IR spectrum of 30 nanofiber membrane;
FIG. 7 is PAN/SiO 2 -10 scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery;
FIG. 8 is PAN/SiO 2 -30 scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery;
FIG. 9 is PAN/SiO 2 -30-MWCNT scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery;
FIG. 10 is PAN/SiO 2 -10 charge-discharge curve of the cell prepared at a current density of 0.2C;
FIG. 11 is PAN/SiO 2 -30 battery prepared atA charge-discharge curve graph at a current density of 0.2C;
FIG. 12 is PAN/SiO 2 -30-MWCNT produced cell charge-discharge curve at current density of 0.2C;
FIG. 13 is PAN/SiO 2 -10，PAN/SiO 2 -30,PAN/SiO 2 -cycle performance plot for cells prepared with 30-MWCN, current density of 0.2C;
FIG. 14 is PAN/SiO 2 -cycle performance plot of a cell prepared from 30-MWCNT at high current density of 2C;
FIG. 15 is PAN/SiO 2 -10，PAN/SiO 2 -30,PAN/SiO 2 -a rate performance plot of a battery prepared from 30-MWCN;
FIG. 16 is PAN/SiO 2 -10 discharge/charge curves of Li-S cells at different rates;
FIG. 17 is PAN/SiO 2 -30 discharge/charge curves of Li-S cells at different rates;
FIG. 18 is PAN/SiO 2 -discharge/charge profile of Li-S cells at different rates for 30-MWCNT;
FIG. 19 is PAN/SiO 2 -10 different voltage sweep rate CV plots of the battery;
FIG. 20 is PAN/SiO 2 -a CV plot of different voltage sweep rates for 30 cells;
FIG. 21 is PAN/SiO 2 -different voltage sweep rate CV curves for Li-S cells of 30-MWCNT;
FIG. 22 is PAN/SiO 2 -10 linear fit of the Li-S cell peak current;
FIG. 23 is PAN/SiO 2 -a linear fit of Li-S cell peak current of 30;
FIG. 24 is PAN/SiO 2 -a linear fit of the Li-S cell peak current of a 30-MWCNT.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
According to one aspect, the present invention relates to a lithium sulfur battery separator comprising an electrospun base film and multi-walled carbon nanotubes supported on the electrospun base film; the electrostatic spinning base film takes polyacrylonitrile as a matrix, and the matrix contains nano silicon dioxide.
The battery diaphragm adopts an electrostatic spinning Polyacrylonitrile (PAN) nanofiber membrane and-CH in the polypropylene diaphragm 3 In contrast, cyano (-C.ident.N) groups are compared with Li 2 The binding energy of S or polysulfide is higher and it has higher porosity and more excellent electrolyte wettability, which results in better electrolyte impregnation and high ionic conductivity, facilitating rapid transport of ions. The invention is to blend nano silicon dioxide (SiO) into polyacrylonitrile 2 ) The porous membrane can be used as an adsorbent of polysulfide, and can be combined with polyacrylonitrile to prepare an electrostatic spinning base membrane, so that the diffusion of the polysulfide in a Li-S battery can be effectively inhibited; further, the multi-wall carbon nano tube (MWCNT) is loaded on the electrostatic spinning base film, so that obviously improved cycle stability and rate capability can be provided for the Li-S battery, a complex positive electrode structure is not required to be introduced, and the practicability of the Li-S battery is further enhanced.
In one embodiment, the mass ratio of the nano silicon dioxide to the polyacrylonitrile to the multi-wall carbon nano tube is (200-1000): (2500-3500): (1.5-2.5). In one embodiment, the mass ratio of nanosilica, polyacrylonitrile, and multi-walled carbon nanotubes includes, but is not limited to, 200:2500:1.5, 300:3000:1.8, 500:3100:2, 800:3200:2.2, or 1000:3500:2.5. According to the invention, the nano silicon dioxide, polyacrylonitrile and multi-wall carbon nanotubes with proper mass ratio are adopted, and the prepared lithium sulfur battery diaphragm can better inhibit the diffusion of polysulfide in a Li-S battery, and improve the cycle stability and the rate capability.
In one embodiment, the nanosilica has a particle size of from 10 to 20nm. In one embodiment, the nanosilica has a particle size of 10nm, 12nm, 15nm, 17nm, 19nm, or 20nm. The silicon dioxide disclosed by the invention adopts proper particle size, has large specific surface area, high surface energy and large chemical reaction activity, and is more beneficial to inhibiting the diffusion of polysulfide in a Li-S battery.
In one embodiment, the multiwall carbon nanotubes have an outer diameter of 8 to 15nm, such as 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, or 15nm, and a length of 40 to 60 μm, such as 40 μm, 42 μm, 45 μm, 48 μm, 50 μm, 52 μm, 55 μm, 60 μm, or the like. In one embodiment, the multiwall carbon nanotubes of the present invention are derived from Shanghai Ala Biotechnology, inc.
In one embodiment, the polyacrylonitrile has a weight average molecular weight of 120000 ～ 160000g/mol. In one embodiment, the polyacrylonitrile has a weight average molecular weight of 120000g/mol, 125000g/mol, 130000g/mol, 140000g/mol, 150000g/mol, 160000g/mol, and the like.
In one embodiment, the lithium sulfur battery separator has an effective area density of 0.19 to 0.26mg/cm 2 . In one embodiment, the lithium sulfur battery separator has a thickness of 2.8 to 3.2 μm. In one embodiment, the porosity of the lithium sulfur battery separator is 72% to 77%.
In one embodiment, part or all of the silica is replaced with alumina and/or graphene.
In one embodiment, some or all of the multiwall carbon nanotubes are replaced with graphene and/or activated carbon.
According to another aspect of the invention, the invention also relates to a preparation method of the lithium sulfur battery diaphragm, which comprises the following steps:
(a) Carrying out electrostatic spinning treatment on a mixed system formed by nano silicon dioxide, polyacrylonitrile and an organic solvent to obtain an electrostatic spinning base film;
(b) Dispersing the multi-wall carbon nano tube in an alcohol solvent, and loading the multi-wall carbon nano tube onto the electrostatic spinning base film by adopting a vacuum suction filtration mode to obtain the lithium-sulfur battery diaphragm.
The preparation method of the lithium-sulfur battery diaphragm is simple and efficient. The electrostatic spinning base film is obtained by carrying out electrostatic spinning technology through a mixed system formed by nano silicon dioxide, polyacrylonitrile and an organic solvent. And loading the multi-wall carbon nano tube onto the electrostatic spinning base film in a vacuum filtration mode.
In one embodiment, the preparation method of the mixed system specifically comprises the following steps: dispersing nano silicon dioxide in an organic solvent, and uniformly mixing with the polyacrylonitrile.
In one embodiment, the organic solvent comprises dimethylformamide (DMF, >99.5%, sigma-Aldrich). In one embodiment, the nanosilica is homogeneously dispersed in the organic solvent using sonication.
In one embodiment, the ratio of the amount of nanosilica to the amount of organic solvent is (0.2 to 1) g (40 to 60) mL. In one embodiment, the nanosilica and the organic solvent are used in a ratio of 0.2g:40ml, 0.3g:45ml, 0.5g:50ml, 1g:60ml.
In one embodiment, the voltage of the electrospinning process is 13 to 16kV, for example 13V, 14V, 15V, 16V, etc. The feed rate of the electrospinning treatment is 0.7-0.8 mL/min, for example 0.7mL/min, 0.71mL/min, 0.72mL/min, 0.73mL/min, 0.74mL/min, 0.75mL/min, 0.76mL/min, 0.77mL/min, 0.78mL/min, 0.79mL/min or 0.8mL/min.
In one embodiment, the multi-walled carbon nanotubes are used in an amount of (1.5 to 2.5) mg (350 to 450) mL, such as 1.5mg:350mL, 1.8mg:370mL, 2mg:400mL, 2.5mg:450mL, etc. In one embodiment, the alcohol solvent comprises an ethanol solvent.
According to another aspect of the invention, the invention also relates to a lithium sulfur battery comprising a lithium sulfur battery separator as described above.
The battery of the invention has excellent cycle stability and rate capability.
The following is a further explanation in connection with specific examples.
Example 1
The preparation method of the lithium-sulfur battery diaphragm comprises the following steps:
(a) 0.3g of silica (nanoscale powder, 10-20 nm, sigma-Aldrich) was dispersed in 50mL of dimethylformamide (DMF,>99.5%, sigma-Aldrich) was well dispersed with the aid of ultrasound, after which 3g of polyacrylonitrile PAN (mw=150000, sigma-Aldrich) was added to prepare PAN/SiO 2 A solution; PAN/SiO to be mixed uniformly 2 The solution was electrospun (at a high pressure of 15kV, feed rate of 0.75 mL/min) to form PAN/SiO 2 Electrospinning a base film according to SiO 2 The ratio to PAN is named PAN/SiO 2 -10；
(b) 2mg of commercially available multi-wall carbon nanotubes (outer diameter: 8 to 15nm, length: 50 μm, shanghai Ala Biochemical technologies Co., ltd.) were first dispersed in 400mL of absolute ethanol (5 mg/L), sufficiently dispersed with the aid of ultrasound, and then loaded onto the above-mentioned electrospun base film by means of vacuum filtration.
Example 2
The preparation method of the lithium-sulfur battery diaphragm comprises the following steps:
(a) 0.9g of silica (nanoscale powder, 10-20 nm, sigma-Aldrich) was dispersed in 50mL of dimethylformamide (DMF,>99.5%, sigma-Aldrich) was well dispersed with the aid of ultrasound, after which 3g of polyacrylonitrile PAN (mw=150000, sigma-Aldrich) was added to prepare PAN/SiO 2 A solution; PAN/SiO to be mixed uniformly 2 The solution was electrospun (at a high pressure of 15kV, feed rate of 0.75 mL/min) to form PAN/SiO 2 Electrospinning a base film according to SiO 2 The ratio to PAN is named PAN/SiO 2 -30；
(b) 2mg of commercially available multi-wall carbon nanotubes (outer diameter: 8 to 15nm, length: 50 μm, shanghai Ala Biochemical technologies Co., ltd.) were first dispersed in 400mL of absolute ethanol (5 mg/L), sufficiently dispersed with the aid of ultrasound, and then loaded onto the above-mentioned electrospun base film by means of vacuum filtration.
Example 3
The preparation method of the lithium-sulfur battery diaphragm comprises the following steps:
(a) 0.2g of silica (nanoscale powder, 10-20 nm, sigma-Aldrich) was dispersed in 50mL dimethylformamide (DMF as a solution of the compound,>99.5%, sigma-Aldrich) was well dispersed with the aid of ultrasound, after which 3g of polyacrylonitrile PAN (mw=150000, sigma-Aldrich) was added to prepare PAN/SiO 2 A solution; PAN/SiO to be mixed uniformly 2 The solution was electrospun (at a high pressure of 13kV, feed rate of 0.7 mL/min) to form PAN/SiO 2 Electrostatic spinning of the base film;
(b) 1.5mg of commercially available multi-wall carbon nanotubes (outer diameter: 8 to 15nm, length: 50 μm, shanghai Ala Biochemical technologies Co., ltd.) were first dispersed in 350mL of absolute ethanol (5 mg/L), sufficiently dispersed with the aid of ultrasound, and then loaded onto the above-mentioned electrospun base film by means of vacuum filtration.
Example 4
The preparation method of the lithium-sulfur battery diaphragm comprises the following steps:
(a) 0.5g of silica (nanoscale powder, 10-20 nm, sigma-Aldrich) was dispersed in 50mL of dimethylformamide (DMF,>99.5%, sigma-Aldrich) was well dispersed with the aid of ultrasound, after which 3g of polyacrylonitrile PAN (mw=150000, sigma-Aldrich) was added to prepare PAN/SiO 2 A solution; PAN/SiO to be mixed uniformly 2 The solution was electrospun (at a high pressure of 13kV, feed rate of 0.7 mL/min) to form PAN/SiO 2 Electrostatic spinning of the base film;
(b) 2.5mg of commercially available multi-wall carbon nanotubes (outer diameter: 8 to 15nm, length: 50 μm, shanghai Ala Biochemical technologies Co., ltd.) were first dispersed in 450mL of absolute ethanol (5 mg/L), sufficiently dispersed with the aid of ultrasound, and then loaded onto the above-mentioned electrospun base film by means of vacuum filtration.
Experimental example
1. Atlas analysis
FIG. 1 is PAN/SiO 2 -scanning electron microscopy of 10 nanofibers; FIG. 2 is PAN/SiO 2 -scanning electron microscopy of 30 nanofibers; FIG. 3 is a scanning electron microscope image of MWCNTs; FIG. 4 is a transmission electron microscope image of MWCNTs; fig. 5 is a high resolution transmission electron microscope image of MWCNT.
Referring to FIGS. 1 and 2, scanning Electron Microscope (SEM) images show PAN/SiO 2 -10 and PAN/SiO 2 -30, which is different from the slit-like porous structure of the microporous PP separator. Both of these separators consisted of randomly arranged fibers with average diameters of 625nm and 600nm, respectively. PAN/SiO 2 -10 and PAN/SiO 2 -30 has a porosity of 72% and 75%, respectively, both significantly higher than the 41% porosity of the PP separator. PAN/SiO 2 The porosity of the-30-MWCNT is 76%, and each of the multi-walled carbon nanotubes has a diameter of about 50nm and a good crystalline structure, as shown in fig. 4, and the multi-walled carbon nanotubes in direct contact with S can provide good conductivity, thus facilitating electrochemical performance of the battery.
FIG. 6 is a PAN film, PAN/SiO 2 -10 film and PAN/SiO 2 -30 film infrared spectrum at 1452cm -1 、2243cm -1 And 2937cm -1 The peaks at the-CH of PAN respectively 2 Characteristic peaks of-C.ident.N and-CH. PAN/SiO 2 -10 and PAN/SiO 2 -30 at 1084cm -1 The peak of the catalyst is obviously SiO 2 The stretching vibration peak of Si-O-Si.
2. Electrochemical performance test
Sulfur (S, 99.5-100.5%, sigma-Aldrich), conductive carbon black (C-65,TIMCAL Graphite)&Carbon ltd.) and polyvinylidene fluoride (PVDF) in a weight ratio of 7:2:1 in N-methyl-2-p Luo Wantong (NMP, 99%, sigma-Aldrich) to a uniform slurry, then pasting the slurry onto Carbon coated aluminum foil, drying and standing at 60 ℃ under vacuum for 12 hours; lithium metal foil as anode, 1MLiTFSI and 0.1M LiNO 3 A mixture (volume ratio of 1:1) of 1, 3-dioxolane and 1, 2-dimethoxyethane was used as an electrolyte; after the batteries were assembled with the separators of the various embodiments of the present invention, the test was performed in a voltage window of 1.7V to 2.8V. Lithium ion diffusion coefficient D Li + (cm 2 S -1 ) CV measurements at different scan rates were calculated according to the Randes-Sevick equation:
I p ＝2.69×10 5 n 1.5 A D Li +0.5 C Li + ν 0.5
wherein I is p Is the peak current, n is the number of electrons in the reaction (Li-S cell is2) A is the electrode area in cm 2 ，C Li + And v represents the concentration of lithium ions in the electrolyte in mol mL -1 CV scan rate unit is V s -1 。
FIG. 7 is PAN/SiO 2 -10 scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery; FIG. 8 is PAN/SiO 2 -30 scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery; FIG. 9 is PAN/SiO 2 -30-MWCNT scan rate of 0.1mV s -1 A cyclic voltammogram of the Li-S battery; FIG. 10 is PAN/SiO 2 -10 a battery prepared with a charge-discharge curve at a current density of 0.2C; FIG. 11 is PAN/SiO 2 -30 charge-discharge curve of the prepared cell at a current density of 0.2C; FIG. 12 is PAN/SiO 2 -30-MWCNT produced cells with a charge-discharge curve at a current density of 0.2C.
Referring to FIGS. 7, 8 and 9, FIG. 7 shows the PAN/SiO 2 The peaks at the cathodes of the cells with-10 separator were about 2.25V and 2.00V, corresponding to the conversion of S to long chain polysulfides (Li 2 S x Conversion of 4.ltoreq.x.ltoreq.8) (region 1) and long-chain polysulfides to lower-order Li 2 S 2 Even Li 2 S (region 2). PAN/SiO 2 -30 and PAN/SiO 2 -30-MWCNT also showed similar redox reactions. FIGS. 10, 11 and 12 show PAN/SiO 2 -10、PAN/SiO 2 -30 and PAN/SiO 2 -30-MWCNT initial charge-discharge current of Li-S cell at 0.2C constant current density, respectively. Three cells each exhibited two discharge plateaus and two closely spaced charge plateaus, consistent with their CV diagrams. As can be seen from FIG. 12, the cell was PAN/SiO in three samples 2 The capacity of the-30-MWCNT is highest because the conductive MWCNT provides sufficient contact with the cathode surface, providing a very high active material utilization. In addition, such MWCNT sheets inhibit migration of polysulfide intermediates, avoiding the shuttle effect.
FIG. 13 is PAN/SiO 2 -10，PAN/SiO 2 -30,PAN/SiO 2 -cycle performance plot for cells prepared with 30-MWCN, current density of 0.2C; FIG. 14 is PAN/SiO 2 -30-MWCNT (carbon nano tube) preparationCycling performance plot of the prepared cell at high current density of 2C; FIG. 15 is PAN/SiO 2 -10，PAN/SiO 2 -30,PAN/SiO 2 -rate performance plot of cells prepared with 30-MWCN. As can be seen from FIG. 13, PAN/SiO 2 -30 and PAN/SiO 2 The initial discharge capacity was slightly increased compared to-10 (from 930mAh g -1 To 946mAh g -1 ). In contrast, PAN/SiO 2 The MWCN (metal wrap-through carbon) can be increased to 1182mAh g -1 . In PAN/SiO 2 The battery with the separator of 30-MWCNT can still provide 741mAh g after 100 times of circulation under the condition of 0.2C current density -1 Is a high capacity of (a). To further investigate PAN/SiO 2 Electrochemical performance of the 30-MWCNT cell, long-term cycling test was performed at a current density of 2C, as shown in FIG. 14, at such high current densities, containing PAN/SiO 2 The cell of-30-MWCNT still provides up to 816mAh g -1 More importantly, 426mAh g can be maintained even after 300 cycles -1 Is 96.3%, which further indicates its excellent electrochemical performance. It is well known that rate capability is one of the important indicators of batteries, particularly for high power applications and the ability to charge quickly. The performance of three different separator assembled lithium sulfur batteries was thus investigated, as shown in fig. 15, with the current density increasing stepwise from 0.1C to 1C, every ten consecutive cycles, and then returning to 0.1C. PAN/SiO 2 -10 and PAN/SiO 2 The stable reversible capacity of the Li-S battery of the-30 system is respectively from 613mAh g -1 And 671mAh g -1 Down to 317mAh g -1 And 357mAh g -1 . While PAN/SiO 2 The battery capacity of the-30-MWCNT is 960mAh g when the reversible capacity is 0.1C -1 Start to slowly drop to 845 (0.2C), 726 (0.5C), 627 (1C) mAh g -1 . Importantly, 842mAh g can be achieved when the current density is reduced to 0.1C -1 Indicating the use of PAN/SiO 2 The 30-MWCNT can realize a Li-S battery with high reversibility and high efficiency.
FIG. 16 is PAN/SiO 2 -10 discharge/charge curves of Li-S cells at different rates; FIG. 17 is PAN/SiO 2 -30 discharge/charge curves of Li-S cells at different ratesThe method comprises the steps of carrying out a first treatment on the surface of the FIG. 18 is PAN/SiO 2 -discharge/charge profile of Li-S cells at different rates for 30-MWCNT. At low current rates, all discharge curves have the dual plateau characteristic of a typical S-cathode, while charge curves show two plateaus, respectively, which is consistent with their CV diagrams. PAN/SiO 2 The 30-MWCNT cell shows two longer discharge plateau, indicating its high reversible capacity and low polarization characteristics.
FIG. 19 is PAN/SiO 2 -10 different voltage sweep rate CV plots of the battery; FIG. 20 is PAN/SiO 2 -a CV plot of different voltage sweep rates for 30 cells; FIG. 21 is PAN/SiO 2 -different voltage sweep rate CV curves for Li-S cells of 30-MWCNT. FIG. 22 is PAN/SiO 2 -10 is a linear fit of the Li-S cell peak current of the separator; FIG. 23 is PAN/SiO 2 -30 is a linear fit of the Li-S cell peak current of the separator; FIG. 24 is PAN/SiO 2 -30-MWCNT is a linear fit of the Li-S cell peak current of the separator.
Investigation of SiO 2 And the effect of MWCNT on lithium ion diffusion is important because the rate capability is closely related to the diffusion of lithium ions in the battery. The lithium ion diffusion coefficient was estimated by a series of CV measurements at different scan rates and calculated by Randes-Sevcik equation. Here, the cathode peak at 2.2V and 1.95V and the anode peak at 2.45V are defined as A, B and C peaks, respectively. The peak current I is reduced according to Randles-Sevcik equation p A straight line should be obtained with the square root of the scan rate as shown in fig. 22 to 24. From the slope of the linear fit, calculate PAN/SiO 2 -10 Li-S cell having a lithium ion diffusion coefficient D Li + (A)＝6.17×10 -9 cm 2 s -1 ，D Li + (B)＝9.56×10 -9 cm 2 s -1 ，D Li + (C)＝2.33×10 -8 cm 2 s -1 。PAN/SiO 2 -30 increase of Li-ion diffusion coefficient of Li-S cell as separator to D Li + (A)＝1.05×10 -8 cm 2 s -1 ，D Li + ＝2.05×10 -8 cm 2 s -1 ，D Li + (C)＝3.66×10 -8 cm 2 s -1 。PAN/SiO 2 The diffusion coefficient of the Li-S cell with the separator of 30-MWCNT is further increased to D Li + (A)＝1.12×10 -8 cm 2 s -1 ，D Li + (B)＝2.09×10 -8 cm 2 s -1 ，D Li + (C)＝4.55×10 -8 cm 2 s -1 。
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. The lithium-sulfur battery diaphragm is characterized by comprising an electrostatic spinning base film and multi-wall carbon nanotubes loaded on the electrostatic spinning base film; the electrostatic spinning base film takes polyacrylonitrile as a matrix, and the matrix contains nano silicon dioxide.
2. The lithium sulfur battery separator according to claim 1, wherein the mass ratio of the nano silicon dioxide, the polyacrylonitrile and the multi-wall carbon nano tube is (200-1000): (2500-3500): (1.5-2.5).
3. The lithium sulfur battery separator according to claim 1, comprising at least one of the following features (1) to (3):
(1) The particle size of the nano silicon dioxide is 10-20 nm;
(2) The outer diameter of the multi-wall carbon nano tube is 8-15 nm, and the length is 40-60 mu m;
(3) The weight average molecular weight of the polyacrylonitrile was 120000 ～ 160000g/mol.
4. The lithium sulfur battery separator according to claim 1, comprising at least one of the following features (1) to (3):
(1) The effective area density of the lithium sulfur battery diaphragm is 0.19-0.26 mg/cm 2 ；
(2) The thickness of the lithium sulfur battery diaphragm is 2.8-3.2 mu m;
(3) The porosity of the lithium sulfur battery diaphragm is 72% -77%.
5. The lithium sulfur battery separator according to claim 1, comprising at least one of the following features (1) to (2):
(1) Replacing part or all of the silicon dioxide with aluminum oxide and/or graphene;
(2) And replacing part or all of the multi-wall carbon nanotubes with graphene and/or activated carbon.
6. The method for preparing a lithium sulfur battery separator according to any one of claims 1 to 5, comprising the steps of:
(a) Carrying out electrostatic spinning treatment on a mixed system formed by nano silicon dioxide, polyacrylonitrile and an organic solvent to obtain an electrostatic spinning base film;
(b) Dispersing the multi-wall carbon nano tube in an alcohol solvent, and loading the multi-wall carbon nano tube onto the electrostatic spinning base film by adopting a vacuum suction filtration mode to obtain the lithium-sulfur battery diaphragm.
7. The method of producing a lithium sulfur battery separator according to claim 6, characterized by comprising at least one of the following features (1) to (2):
(1) The preparation method of the mixed system specifically comprises the following steps: dispersing nano silicon dioxide in an organic solvent, and uniformly mixing with the polyacrylonitrile;
(2) The dosage ratio of the nano silicon dioxide to the organic solvent is (0.2-1) g (40-60) mL.
8. The method for preparing a lithium sulfur battery separator according to claim 6, wherein the voltage of the electrospinning treatment is 13-16 kV, and the feeding rate of the electrospinning treatment is 0.7-0.8 mL/min.
9. The method according to claim 6, wherein the ratio of the multi-walled carbon nanotubes to the alcohol solvent is (1.5-2.5) mg (350-450) mL.
10. A lithium-sulfur battery comprising the lithium-sulfur battery separator according to any one of claims 1 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310590439.3A CN116799432A (en) | 2023-05-23 | 2023-05-23 | Lithium-sulfur battery diaphragm and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310590439.3A CN116799432A (en) | 2023-05-23 | 2023-05-23 | Lithium-sulfur battery diaphragm and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116799432A true CN116799432A (en) | 2023-09-22 |
Family
ID=88046085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310590439.3A Pending CN116799432A (en) | 2023-05-23 | 2023-05-23 | Lithium-sulfur battery diaphragm and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116799432A (en) |
-
2023
- 2023-05-23 CN CN202310590439.3A patent/CN116799432A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sun et al. | 3D printing nanocomposite gel-based thick electrode enabling both high areal capacity and rate performance for lithium-ion battery | |
| US10450674B2 (en) | Process for preparing a silicon-carbon nanocomposite nanofiber | |
| US11387445B2 (en) | Positive electrode for lithium-ion rechargeable battery, lithium-ion rechargeable battery, and method for producing positive electrode for lithium-ion rechargeable battery | |
| US10418630B2 (en) | Lithium-sulfur battery cell electrode | |
| US11749831B2 (en) | Li—S battery with carbon coated separator | |
| US20180331352A1 (en) | Carbon composites | |
| CN111213262A (en) | Negative electrode and secondary battery comprising same | |
| Wang et al. | Mesoporous Li4Ti5O12/carbon nanofibers for high-rate lithium-ion batteries | |
| CN1588679A (en) | Lithium ion secondary cell positive pole material and its preparing method | |
| US10224565B2 (en) | High energy density secondary lithium batteries | |
| Li et al. | Highly stable GeO x@ C core–shell fibrous anodes for improved capacity in lithium-ion batteries | |
| CN110391398B (en) | Black phosphorus/reduced graphene oxide composite electrode, preparation method thereof and flexible lithium ion battery comprising composite electrode | |
| CN111969164A (en) | Composite modified diaphragm for lithium-sulfur battery and preparation method thereof | |
| Zou et al. | Sodium Titanate/Carbon (Na2Ti3O7/C) Nanofibers via Electrospinning Technique as the Anode of Sodium‐ion Batteries | |
| Wang et al. | Electrochemical properties of carbon nanocoils and hollow graphite fibers as anodes for rechargeable lithium ion batteries | |
| US20230183524A1 (en) | Polyamine composite material and preparation method therefor, slurry, separator, electrode sheet, and lithium-sulfur battery containing the same | |
| KR20190101724A (en) | Secondary battery | |
| KR20200129519A (en) | Electrode for lithium sulfur battery and lithium sulfur battery comprising the same | |
| JP2005209498A6 (en) | Non-aqueous electrolyte secondary battery | |
| US20240266533A1 (en) | Sodium-Chromium-Titanium-Manganese Phosphate Self-Supporting Electrode Material, and Preparation Method Therefor and Use Thereof | |
| CN108666533B (en) | Preparation method and application of sulfur electrode of lithium-sulfur battery | |
| CN113571841A (en) | Lithium-sulfur battery composite diaphragm and preparation method thereof | |
| JP2023520194A (en) | Negative electrode and secondary battery containing the same | |
| CN116799432A (en) | Lithium-sulfur battery diaphragm and preparation method and application thereof | |
| US20230216030A1 (en) | Si-containing composite anode for energy storage devices |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |