技术领域Technical Field
本发明属于材料合成技术领域，涉及一种用于锂硫电池的相变隔膜及其制备方法。The invention belongs to the technical field of material synthesis and relates to a phase change diaphragm for a lithium-sulfur battery and a preparation method thereof.
背景技术Background Art
随着新兴市场应用对更高能量密度二次电池的需求，尤其是混合动力交通工具(PHEV)及纯电动交通工具(PEV)等领域需要二次电池的能量密度要达到300Wh kg-1。With the demand for higher energy density secondary batteries in emerging market applications, especially in the fields of hybrid electric vehicles (PHEV) and pure electric vehicles (PEV), the energy density of secondary batteries needs to reach 300Wh kg-1 .
锂硫电池由于理论能量密度达2600Wh kg-1，更接近实用化、资源丰富、价格低廉和环境友好等优点而被广泛研究。Lithium-sulfur batteries have been widely studied due to their theoretical energy density of 2600Wh kg-1 , their proximity to practical application, their abundant resources, their low price, and their environmental friendliness.
然而，阻碍当前锂硫电池发展的主要问题是：单质硫正极在充放电过程中会形成可溶性的多硫化物中间产物，多硫化物在电解液中的持续溶解与扩散，将使其透过隔膜在锂负极表面不断沉积，亦称之为“穿梭效应”，从而造成电池内部阻抗增加，活性物质硫损失以及电化学性能急剧下降，因此抑制多硫化物的“穿梭效应”成为提高当前锂硫电池综合性能的关键所在。同时电池在运行过程存在燃烧爆炸的安全隐患，也使得锂硫电池难以应用于实际生活中。However, the main problem that hinders the development of lithium-sulfur batteries is that the elemental sulfur positive electrode will form soluble polysulfide intermediates during the charge and discharge process. The continuous dissolution and diffusion of polysulfide in the electrolyte will cause it to continuously deposit on the surface of the lithium negative electrode through the diaphragm, also known as the "shuttle effect", which will increase the internal impedance of the battery, cause the loss of active sulfur and a sharp decline in electrochemical performance. Therefore, inhibiting the "shuttle effect" of polysulfide has become the key to improving the comprehensive performance of current lithium-sulfur batteries. At the same time, there are safety hazards of combustion and explosion during the operation of the battery, which also makes it difficult for lithium-sulfur batteries to be used in real life.
发明内容Summary of the invention
目的：为了克服现有技术中的不足，解决现有商用隔膜存在的安全隐患以及无法抑制锂硫电池中“穿梭效应”的问题，本发明提供一种用于锂硫电池的相变隔膜及其制备方法，以提高锂硫电池的安全和性能。Purpose: In order to overcome the deficiencies in the prior art, solve the potential safety hazards of existing commercial diaphragms and the problem of being unable to suppress the "shuttle effect" in lithium-sulfur batteries, the present invention provides a phase change diaphragm for lithium-sulfur batteries and a preparation method thereof, so as to improve the safety and performance of lithium-sulfur batteries.
黑磷(BP)是热力学最稳定磷的同素异形体，电阻率低，介于0.48和0.77Ω·cm之间和超高的室温孔迁移率～1000cm2 V-1s-1。BP也具有低密度2.69g cm-3，良好的体积电导率～3S cm-1，高的锂离子扩散常数以及和硫元素有较高的结合能。这些性质表明BP具有化学结合多硫化锂的能力，同时其高的导电性和高的锂离子扩散常数能有效促进多硫化锂转换为硫化锂的反应动力学。文献也验证了黑磷具有高效吸附并转换多硫化锂的优异性能。然而，黑磷在空气中容易被氧化和分解，限制了它在锂硫电池中的应用。有机金属框架MOF作为一种多孔材料，固定的孔径可以提供锂离子传输的快速通道和均匀沉积，同时可以通过物理屏障的作用来阻隔多硫化锂的穿梭，在锂硫电池中也得到了广泛的应用。然而，大部分MOF导电性较差，而且对于多硫化锂转化动力学的催化能力较弱，不利于提高电池的电化学性能。综上所述，将黑磷和MOF结合起来是一种有效弥补两者不足的办法，黑磷表面的MOF可以起到阻隔氧的作用，提高黑磷的空气稳定性，而且黑磷的高电导率和高催化能力也可以提高MOF在锂硫电池中的应用。Black phosphorus (BP) is the most thermodynamically stable allotrope of phosphorus, with low resistivity between 0.48 and 0.77Ω·cm and ultra-high room temperature pore mobility of ~1000cm2V- 1s-1 . BP also has a low density of 2.69gcm-3 , good volume conductivity of ~3Scm-1 , high lithium ion diffusion constant and high binding energy with sulfur. These properties indicate that BP has the ability to chemically bind lithium polysulfides, and its high conductivity and high lithium ion diffusion constant can effectively promote the reaction kinetics of lithium polysulfides to lithium sulfides. Literature also verifies that black phosphorus has excellent performance in efficiently adsorbing and converting lithium polysulfides. However, black phosphorus is easily oxidized and decomposed in the air, which limits its application in lithium-sulfur batteries. As a porous material, the metal organic framework MOF can provide fast channels and uniform deposition for lithium ion transmission with a fixed pore size, and can also block the shuttling of lithium polysulfides through the role of a physical barrier, and has also been widely used in lithium-sulfur batteries. However, most MOFs have poor electrical conductivity and weak catalytic ability for lithium polysulfide conversion kinetics, which is not conducive to improving the electrochemical performance of batteries. In summary, combining black phosphorus and MOF is an effective way to make up for the shortcomings of both. The MOF on the surface of black phosphorus can block oxygen and improve the air stability of black phosphorus. In addition, the high electrical conductivity and high catalytic ability of black phosphorus can also improve the application of MOF in lithium-sulfur batteries.
本发明制备方法(1)发展了一种在油水界面自组装制备MOF/BP异质结的方法，从而解决BP在空气中容易被氧化的问题。(2)发展了一种以聚丙烯腈PAN为壳，石蜡PW为核的纳米纤维相变隔膜PPW，提高了电池运行的安全性能。(3)最后得到的PPW/MOF/BP相变隔膜，能有效抑制多硫化锂的“穿梭效应”，实现了高安全和高性能的锂硫电池，有广阔的应用前景。The preparation method of the present invention (1) develops a method for preparing a MOF/BP heterojunction by self-assembly at an oil-water interface, thereby solving the problem that BP is easily oxidized in the air. (2) A nanofiber phase change membrane PPW with polyacrylonitrile PAN as a shell and paraffin PW as a core is developed, thereby improving the safety performance of battery operation. (3) The PPW/MOF/BP phase change membrane finally obtained can effectively inhibit the "shuttle effect" of lithium polysulfide, realize a highly safe and high-performance lithium-sulfur battery, and has broad application prospects.
技术方案：本发明采用的优选技术方案为：Technical solution: The preferred technical solution adopted by the present invention is:
根据本发明的第一方面，提供一种相变隔膜的制备方法，包括：According to a first aspect of the present invention, there is provided a method for preparing a phase change membrane, comprising:
步骤(a)MOF/BP异质结的制备：在油水体系中通过界面组装形成金属有机框架/黑磷(MOF/BP)异质结，洗涤、干燥得到MOF/BP异质结粉末；Step (a) Preparation of MOF/BP heterojunction: forming a metal organic framework/black phosphorus (MOF/BP) heterojunction by interfacial assembly in an oil-water system, washing and drying to obtain MOF/BP heterojunction powder;
步骤(b)相变纳米纤维膜PPW的制备：将聚丙烯腈PAN溶液和石蜡PW溶液通过同轴静电纺丝技术制备出核壳结构的纳米纤维膜PPW；Step (b) Preparation of phase change nanofiber membrane PPW: preparing a nanofiber membrane PPW with a core-shell structure by coaxial electrospinning polyacrylonitrile PAN solution and paraffin PW solution;
步骤(c)PPW/MOF/BP相变隔膜的制备：将所述MOF/BP异质结粉末分散于去离子水中形成MOF/BP异质结分散液，将MOF/BP异质结分散液通过真空抽滤的方法沉积在所述纳米纤维膜PPW上，真空干燥即得PPW/MOF/BP相变隔膜。Step (c) Preparation of PPW/MOF/BP phase change membrane: The MOF/BP heterojunction powder is dispersed in deionized water to form a MOF/BP heterojunction dispersion, the MOF/BP heterojunction dispersion is deposited on the nanofiber membrane PPW by vacuum filtration, and the PPW/MOF/BP phase change membrane is obtained by vacuum drying.
在一些实施例中，步骤(a)中，油水体系为己烷/水体系；In some embodiments, in step (a), the oil-water system is a hexane/water system;
金属有机框架MOF为UiO-66，黑磷采用黑磷纳米片。The metal organic framework MOF is UiO-66, and the black phosphorus uses black phosphorus nanosheets.
在一些实施例中，步骤(a)MOF/BP异质结的制备包括：将黑磷纳米片分散于去离子水中，加入氨基对苯二甲酸和醋酸，超声混合后加入正己烷，超声混合，加入氯氧化锆水溶液，将反应体系在油浴中反应，反应结束后，离心、洗涤、干燥得到MOF/BP异质结粉末。In some embodiments, step (a) of preparing a MOF/BP heterojunction includes: dispersing black phosphorus nanosheets in deionized water, adding aminoterephthalic acid and acetic acid, adding n-hexane after ultrasonic mixing, ultrasonic mixing, adding an aqueous zirconium oxychloride solution, reacting the reaction system in an oil bath, and after the reaction is completed, centrifuging, washing, and drying to obtain a MOF/BP heterojunction powder.
在一些实施例中，步骤(b)中，聚丙烯腈PAN溶液的溶剂采用N，N-二甲基甲酰胺(DMF)，优选的聚丙烯腈PAN溶液的浓度为10wt％；石蜡PW溶液的溶剂采用煤油；优选的石蜡溶液的浓度为40％(v/v)。In some embodiments, in step (b), the solvent of the polyacrylonitrile PAN solution is N,N-dimethylformamide (DMF), and the preferred concentration of the polyacrylonitrile PAN solution is 10 wt %; the solvent of the paraffin PW solution is kerosene; and the preferred concentration of the paraffin solution is 40% (v/v).
在一些实施例中，步骤(b)相变纳米纤维膜PPW的制备包括：将聚丙烯腈PAN溶液和石蜡PW溶液分别加入到注射器中，通过同轴静电纺丝技术制备出核壳结构的纳米纤维膜PPW。In some embodiments, the preparation of the phase change nanofiber membrane PPW in step (b) includes: adding polyacrylonitrile PAN solution and paraffin PW solution into syringes respectively, and preparing the nanofiber membrane PPW with a core-shell structure by coaxial electrospinning technology.
进一步地，所述同轴静电纺丝技术中，静电纺丝的参数为电压18.5kV，接收器和针头的距离为17cm，聚丙烯腈PAN溶液和石蜡PW溶液的推进速率为0.5mL/h。Furthermore, in the coaxial electrospinning technology, the electrospinning parameters are: voltage of 18.5 kV, distance between the receiver and the needle of 17 cm, and propulsion rate of polyacrylonitrile PAN solution and paraffin PW solution of 0.5 mL/h.
在一些实施例中，步骤(c)中，MOF/BP异质结分散液的浓度为0.5～5mg/mL，优选为1～2mg/mL。In some embodiments, in step (c), the concentration of the MOF/BP heterojunction dispersion is 0.5 to 5 mg/mL, preferably 1 to 2 mg/mL.
在一些实施例中，步骤(c)中，真空干燥温度为60～80℃，优选为70℃。In some embodiments, in step (c), the vacuum drying temperature is 60-80°C, preferably 70°C.
根据本发明的第二方面，提供一种PPW/MOF/BP相变隔膜，由所述的制备方法制得。According to a second aspect of the present invention, there is provided a PPW/MOF/BP phase change membrane, which is prepared by the preparation method.
根据本发明的第三方面，提供所述的PPW/MOF/BP相变隔膜在锂硫电池中的应用。According to a third aspect of the present invention, there is provided application of the PPW/MOF/BP phase change membrane in a lithium-sulfur battery.
有益效果：本发明一种用于锂硫电池的相变隔膜及其制备方法，过在油水界面处自组装制备MOF/BP异质结，解决黑磷在空气中易氧化分解的问题，同时有效抑制锂硫电池中“穿梭效应”的问题，提高电池的循环性能。并与相变隔膜复合，得到高安全高性能的锂硫隔膜材料。具有以下优点：Beneficial effects: The present invention provides a phase change diaphragm for lithium-sulfur batteries and a preparation method thereof. The MOF/BP heterojunction is prepared by self-assembly at the oil-water interface, which solves the problem of black phosphorus being easily oxidized and decomposed in the air. At the same time, the "shuttle effect" problem in lithium-sulfur batteries is effectively suppressed, and the battery cycle performance is improved. The phase change diaphragm is compounded to obtain a lithium-sulfur diaphragm material with high safety and high performance. It has the following advantages:
(1)在油水界面自组装制备MOF/BP异质结的方法，从而解决BP在空气中容易被氧化的问题。(1) A method for preparing MOF/BP heterojunction by self-assembly at the oil-water interface, thereby solving the problem that BP is easily oxidized in the air.
(2)以聚丙烯腈PAN为壳，石蜡PW为核的纳米纤维相变隔膜PPW，提高了电池运行的安全性能。(2) The nanofiber phase change membrane PPW with polyacrylonitrile PAN as the shell and paraffin PW as the core improves the safety performance of battery operation.
(3)最后得到的PPW/MOF/BP相变隔膜，能有效抑制多硫化锂的“穿梭效应”，实现了高安全和高性能的锂硫电池，有广阔的应用前景。(3) The final PPW/MOF/BP phase change membrane can effectively inhibit the "shuttle effect" of lithium polysulfide, achieving high-safety and high-performance lithium-sulfur batteries and has broad application prospects.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1为实施例1制备的MOF/BP异质结的形貌电镜图；FIG1 is an electron microscope image of the morphology of the MOF/BP heterojunction prepared in Example 1;
图2为实施例1制备的PPW/MOF/BP相变隔膜的电镜图；FIG2 is an electron microscope image of the PPW/MOF/BP phase change membrane prepared in Example 1;
图3为实施例PPW/MOF/BP相变隔膜在加热情况下的温度变化图；FIG3 is a temperature change diagram of the PPW/MOF/BP phase change membrane of the embodiment under heating;
图4为PPW/MOF/BP相变隔膜在锂硫电池中的循环性能图。Figure 4 is a graph showing the cycling performance of the PPW/MOF/BP phase change membrane in a lithium-sulfur battery.
具体实施方式DETAILED DESCRIPTION
下面结合附图和实施例对本发明作更进一步的说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.
出于本说明书和所附权利要求书的目的，除非另有陈述，否则所有表达量、百分数或比例的数字及本说明书和所附权利要求书中所用的其它数值被理解为在所有情况下都由术语“约”修饰。此外，本文公开的所有范围都包括端点在内且可独立组合。For the purpose of this specification and the appended claims, unless otherwise stated, all numbers expressing amounts, percentages or ratios and other numerical values used in this specification and the appended claims are understood to be modified in all cases by the term "about". In addition, all ranges disclosed herein are inclusive and independently combinable.
实施例1Example 1
(1)MOF/BP异质结的制备(1) Preparation of MOF/BP heterojunction
首先，在50mL单口烧瓶中将20mg黑磷纳米片分散于10mL去离子水中，随后加入50mg氨基对苯二甲酸和2mL醋酸，超声5分钟后加入10mL正己烷溶液，继续超声20min后，最后加入1mL八水氯氧化锆(50mg/mL)水溶液，将反应体系在70℃油浴中反应24h。反应结束后，通过离心得到粗产品，然后用DMF和甲醇洗涤除去未反应的单体，50℃真空干燥得到MOF/BP异质结粉末。First, 20 mg of black phosphorus nanosheets were dispersed in 10 mL of deionized water in a 50 mL single-mouth flask, followed by the addition of 50 mg of aminoterephthalic acid and 2 mL of acetic acid, followed by the addition of 10 mL of n-hexane solution after 5 minutes of ultrasonication, followed by the addition of 1 mL of zirconium oxychloride octahydrate (50 mg/mL) aqueous solution after 20 minutes of ultrasonication, and the reaction system was reacted in an oil bath at 70 ° C for 24 hours. After the reaction, the crude product was obtained by centrifugation, and then washed with DMF and methanol to remove the unreacted monomers, and then dried in vacuum at 50 ° C to obtain MOF/BP heterojunction powder.
图1为制备的MOF/BP异质结的形貌电镜图；其中：图1a为纯的黑磷纳米片，图1b为通过常规水热法制备的MOF UiO-66，图1c为实施例中在油水体系中制备的MOF/BP异质结。可以看出，在油水界面体系成功自组装了MOF/BP异质结，同时制备的MOF颗粒较小，这有利保护黑磷，提高黑磷在空气中的稳定性。Figure 1 is an electron microscope image of the prepared MOF/BP heterojunction; wherein: Figure 1a is a pure black phosphorus nanosheet, Figure 1b is a MOF UiO-66 prepared by a conventional hydrothermal method, and Figure 1c is a MOF/BP heterojunction prepared in an oil-water system in the embodiment. It can be seen that the MOF/BP heterojunction is successfully self-assembled in the oil-water interface system, and the prepared MOF particles are small, which is beneficial to protect black phosphorus and improve the stability of black phosphorus in the air.
(2)相变纳米纤维膜PPW的制备(2) Preparation of phase change nanofiber membrane PPW
将1g PAN粉末在50℃加热条件下溶解于10mL DMF中，配置出10wt％浓度的PAN溶液。将固体石蜡加热融化，随后将液体石蜡4mL加入到6mL煤油中配置出40％(v/v)的石蜡溶液。将PAN溶液和石蜡溶液分别加入到注射器中，通过同轴静电纺丝技术制备出核壳结构的相变纳米纤维膜PPW。静电纺丝工艺为：电压18.5kV，接收器和针头的距离为17cm，PAN和PW溶液的推进速率为0.5mL/h。纺丝结束后，将薄膜从接收器中脱离，并70℃真空干燥24h即得到PPW薄膜。Dissolve 1g of PAN powder in 10mL of DMF at 50°C to prepare a 10wt% PAN solution. Heat and melt solid paraffin, then add 4mL of liquid paraffin to 6mL of kerosene to prepare a 40% (v/v) paraffin solution. Add the PAN solution and the paraffin solution into syringes respectively, and prepare the core-shell structured phase change nanofiber membrane PPW by coaxial electrospinning technology. The electrospinning process is: voltage 18.5kV, the distance between the receiver and the needle is 17cm, and the propulsion rate of PAN and PW solution is 0.5mL/h. After spinning, the film is separated from the receiver and vacuum dried at 70°C for 24h to obtain the PPW film.
(3)PPW/MOF/BP复合膜的制备(3) Preparation of PPW/MOF/BP composite membrane
将(2)中的PPW裁剪成4×4cm2的正方形规格，放置于真空抽滤装置上，随后取(1)得到MOF/BP异质结粉末10mg分散于10mL水中，通过真空抽滤的办法沉积到PPW膜表面，随后70℃真空干燥24h得到PPW/MOF/BP相变隔膜，并切成直径为19mm的圆片用于锂硫电池的循环测试。The PPW in (2) was cut into square sizes of 4×4 cm2 and placed on a vacuum filtration device. Then, 10 mg of the MOF/BP heterojunction powder obtained in (1) was dispersed in 10 mL of water and deposited on the surface of the PPW membrane by vacuum filtration. The PPW/MOF/BP phase change membrane was then obtained by vacuum drying at 70°C for 24 h and cut into discs with a diameter of 19 mm for the cycle test of lithium-sulfur batteries.
实施例2Example 2
(1)MOF/BP异质结的制备(1) Preparation of MOF/BP heterojunction
按照实例1进行MOF/BP异质结的制备。The MOF/BP heterojunction was prepared according to Example 1.
(2)相变纳米纤维膜PPW的制备(2) Preparation of phase change nanofiber membrane PPW
按照实例1进行相变纳米纤维膜PPW的制备。The phase change nanofiber membrane PPW was prepared according to Example 1.
(3)PPW/MOF/BP复合膜的制备(3) Preparation of PPW/MOF/BP composite membrane
将(2)中的PPW裁剪成4×4cm2的正方形规格，放置于真空抽滤装置上，随后取(1)得到MOF/BP异质结粉末15mg分散于10mL水中，通过真空抽滤的办法沉积到PPW膜表面，随后70℃真空干燥24h得到PPW/MOF/BP相变隔膜，并切成直径为19mm的圆片用于锂硫电池的循环测试。The PPW in (2) was cut into square sizes of 4×4 cm2 and placed on a vacuum filtration device. Then, 15 mg of the MOF/BP heterojunction powder obtained in (1) was dispersed in 10 mL of water and deposited on the surface of the PPW membrane by vacuum filtration. The PPW/MOF/BP phase change membrane was then obtained by vacuum drying at 70°C for 24 h and cut into discs with a diameter of 19 mm for the cycle test of lithium-sulfur batteries.
图2为实施例2制得的PPW/MOF/BP相变隔膜的电镜图；FIG2 is an electron microscope image of the PPW/MOF/BP phase change membrane prepared in Example 2;
由图2a可以看出，通过静电纺丝技术我们成功制备了纳米纤维膜，交互交织的纳米纤维骨架可以构筑出孔隙丰富的隔膜，有利于电解液的浸润以及锂离子的传输。图2b的透射电镜图核和壳的衬度不同表明成功制备出具有核壳结构的纳米纤维相变隔膜，其中壳为聚丙烯腈PAN，核为石蜡PW，石蜡封装在PAN之中，静电纺丝形成的纳米纤维膜，记为PPW。图2c为PPW/MOF/BP隔膜，表明MOF/BP异质结通过真空抽滤的办法成功沉积在薄膜表面，厚度层约为16微米。As can be seen from Figure 2a, we have successfully prepared a nanofiber membrane through electrospinning technology. The interwoven nanofiber skeleton can construct a porous membrane, which is conducive to the infiltration of electrolytes and the transmission of lithium ions. The different contrasts between the core and the shell in the transmission electron microscope image of Figure 2b indicate that a nanofiber phase change membrane with a core-shell structure has been successfully prepared, in which the shell is polyacrylonitrile PAN and the core is paraffin PW. The paraffin is encapsulated in PAN, and the nanofiber membrane formed by electrospinning is denoted as PPW. Figure 2c is a PPW/MOF/BP membrane, indicating that the MOF/BP heterojunction is successfully deposited on the surface of the film by vacuum filtration, with a thickness of about 16 microns.
图3为PPW/MOF/BP相变隔膜在加热情况下的温度变化图；FIG3 is a temperature change diagram of the PPW/MOF/BP phase change membrane under heating;
将商用隔膜，PPW和PPW/MOF/BP放置于加热板上，通过升温来研究相变隔膜对于热失控的管理。从图3可以看出，加热10min后，PPW/MOF/BP的表面温度远低于商用隔膜的温度，这是由于石蜡在在融化过程中会吸收热量，从而降低体系温度，在电池运行中出现瞬间热失控行为的过程中，石蜡的迅速融化可以降低电池整个体系的温度，从而使得电池运行更加安全。The commercial separator, PPW and PPW/MOF/BP were placed on a heating plate, and the management of thermal runaway by the phase change separator was studied by heating. As can be seen from Figure 3, after heating for 10 minutes, the surface temperature of PPW/MOF/BP is much lower than that of the commercial separator. This is because paraffin absorbs heat during the melting process, thereby reducing the system temperature. In the process of instantaneous thermal runaway behavior during battery operation, the rapid melting of paraffin can reduce the temperature of the entire battery system, making the battery operation safer.
图4为PPW/MOF/BP相变隔膜在锂硫电池中的循环性能图；FIG4 is a graph showing the cycling performance of the PPW/MOF/BP phase change membrane in a lithium-sulfur battery;
从图4可以看出，实施例2制得的PPW/MOF/BP隔膜在0.2C运行100圈后仍有97.5％的容量保持率，而商用隔膜运行100圈后容量迅速衰减到476.8mAh/g，容量保持率仅为51.7％。这个由于多硫化锂的穿梭效应造成，从循环性能也表明PPW/MOF/BP可以有效阻隔多硫化锂的穿梭，从而提高电池的循环性能。As can be seen from Figure 4, the PPW/MOF/BP membrane prepared in Example 2 still has a capacity retention rate of 97.5% after running 100 cycles at 0.2C, while the capacity of the commercial membrane rapidly decays to 476.8 mAh/g after running 100 cycles, and the capacity retention rate is only 51.7%. This is caused by the shuttle effect of lithium polysulfide. The cycle performance also shows that PPW/MOF/BP can effectively block the shuttle of lithium polysulfide, thereby improving the cycle performance of the battery.
实施例3Example 3
(1)MOF/BP异质结的制备(1) Preparation of MOF/BP heterojunction
按照实例1进行MOF/BP异质结的制备。The MOF/BP heterojunction was prepared according to Example 1.
(2)相变纳米纤维膜PPW的制备(2) Preparation of phase change nanofiber membrane PPW
按照实例1进行相变纳米纤维膜PPW的制备。The phase change nanofiber membrane PPW was prepared according to Example 1.
(3)PPW/MOF/BP复合膜的制备(3) Preparation of PPW/MOF/BP composite membrane
将(2)中的PPW裁剪成4×4cm2的正方形规格，放置于真空抽滤装置上，随后取(1)得到MOF/BP异质结粉末20mg分散于10mL水中，通过真空抽滤的办法沉积到PPW膜表面，随后70℃真空干燥24h得到PPW/MOF/BP相变隔膜，并切成直径为19mm的圆片用于锂硫电池的循环测试。The PPW in (2) was cut into square sizes of 4×4 cm2 and placed on a vacuum filtration device. Subsequently, 20 mg of the MOF/BP heterojunction powder obtained in (1) was dispersed in 10 mL of water and deposited on the surface of the PPW membrane by vacuum filtration. The PPW/MOF/BP phase change membrane was then obtained by vacuum drying at 70°C for 24 h and cut into discs with a diameter of 19 mm for the cycle test of lithium-sulfur batteries.
将上述实施例1-3制得的PPW/MOF/BP相变隔膜材料的循环性能见表1，可见相变隔膜的循环性能相比商用隔膜有巨大的提升。The cycle performance of the PPW/MOF/BP phase change membrane materials prepared in the above Examples 1-3 is shown in Table 1. It can be seen that the cycle performance of the phase change membrane is greatly improved compared with the commercial membrane.
表1PPW/MOF/BP相变隔膜材料的循环性能Table 1 Cyclic performance of PPW/MOF/BP phase change membrane materials
本发明在油水体系中成功合成了MOF/BP的异质结，提高了黑磷在空气中的稳定性。同时利用同轴静电纺丝的工艺制备出具有核壳结构的相变纳米纤维膜PPW，能有效解决电池在运行过程中的热失控问题。将MOF/BP和PPW通过简单的抽滤工艺复合在一起，MOF/BP可以有效抑制锂硫电池中多硫化锂的“穿梭效应”，显著提高锂硫电池的循环性能，而PPW相变隔膜，则可以调控电池的热失控问题，提高电池运行的安全。制备的PPW/MOF/BP相变隔膜显著地提高了锂硫电池的循环循环性能，有望在未来应用于实际生活中。The present invention successfully synthesized the MOF/BP heterojunction in the oil-water system, improving the stability of black phosphorus in the air. At the same time, the phase change nanofiber membrane PPW with a core-shell structure was prepared by the coaxial electrospinning process, which can effectively solve the thermal runaway problem of the battery during operation. MOF/BP and PPW are compounded together through a simple filtration process. MOF/BP can effectively inhibit the "shuttle effect" of lithium polysulfide in lithium-sulfur batteries and significantly improve the cycle performance of lithium-sulfur batteries, while the PPW phase change diaphragm can regulate the thermal runaway problem of the battery and improve the safety of battery operation. The prepared PPW/MOF/BP phase change diaphragm significantly improves the cycle performance of lithium-sulfur batteries and is expected to be used in real life in the future.
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明技术原理的前提下，还可以做出若干改进和变形，这些改进和变形也应视为本发明的保护范围。The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
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| CN120202586A (en)* | 2022-11-15 | 2025-06-24 | 三星电子株式会社 | Battery including separator and electronic device including the battery |
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| CN110078034A (en)* | 2019-04-29 | 2019-08-02 | 厦门大学深圳研究院 | A kind of organic metal framework coats the preparation method of two-dimentional black phosphorus nanometer sheet |
| CN112421038A (en)* | 2020-11-06 | 2021-02-26 | 清华大学 | Composite material of black phosphorus nanosheet coated with metal organic framework and preparation method and application thereof |
| CN112928389A (en)* | 2021-03-03 | 2021-06-08 | 华中科技大学 | Phase-change temperature-regulating diaphragm and preparation method and application thereof |
| CN113381124A (en)* | 2021-06-10 | 2021-09-10 | 厦门大学 | Black phosphorus/polyethyleneimine nano composite material as well as preparation method and application thereof |
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| CN109065800A (en)* | 2018-07-03 | 2018-12-21 | 华南师范大学 | A kind of preparation method of metal organic frame carbon nano tube compound material |
| CN110295498B (en)* | 2019-04-15 | 2021-01-26 | 武汉理工大学 | Metal organic framework modified polymer film and preparation method and application thereof |
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| CN109301131A (en)* | 2018-09-28 | 2019-02-01 | 成都新柯力化工科技有限公司 | A kind of the lithium-sulfur cell diaphragm material and preparation method of elemental phosphorous compound polyolefin |
| CN110078034A (en)* | 2019-04-29 | 2019-08-02 | 厦门大学深圳研究院 | A kind of organic metal framework coats the preparation method of two-dimentional black phosphorus nanometer sheet |
| CN112421038A (en)* | 2020-11-06 | 2021-02-26 | 清华大学 | Composite material of black phosphorus nanosheet coated with metal organic framework and preparation method and application thereof |
| CN112928389A (en)* | 2021-03-03 | 2021-06-08 | 华中科技大学 | Phase-change temperature-regulating diaphragm and preparation method and application thereof |
| CN113381124A (en)* | 2021-06-10 | 2021-09-10 | 厦门大学 | Black phosphorus/polyethyleneimine nano composite material as well as preparation method and application thereof |
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