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EP-4737616-A1 - COMPOSITE SEPARATOR, AND PREPARATION METHOD THEREFOR AND USE THEREOF

EP4737616A1EP 4737616 A1EP4737616 A1EP 4737616A1EP-4737616-A1

Abstract

A composite separator and a preparation method therefor. The composite separator comprises a main film and an anti-contamination layer, which is arranged on one or both surfaces of the main film, wherein the anti-contamination layer comprises a first polymer a charge agent and/or an anti-fouling agent. The composite separator can be applied to alkaline water electrolysis for hydrogen production and other electrolysis industries, and the anti-contamination layer of the composite separator can effectively prevent impurity species, especially metal ions fallen from a cathode catalyst, from being attached to the surface, which causes the sheet resistance to increase, thereby increasing the electrolytic energy consumption.

Inventors

  • KANG, Peng
  • NIU, Lijuan
  • WANG, XIUPING

Assignees

  • Xi'an Hydrogen Based Carbon Energy Technology Co., Ltd.

Dates

Publication Date
20260506
Application Date
20230912

Claims (10)

  1. A composite separator, comprising a base membrane and an anti-fouling layer disposed on one or both surfaces of the base membrane, wherein the anti-fouling layer comprises a first polymer, a charge agent, and/or an anti-fouling agent.
  2. The composite separator according to claim 1, wherein the anti-fouling agent is one or more of graphene, graphene oxide, and MXene; the charge agent is one or more of aromatic polyamide, polypiperazine amide, polyamide, cellulose acetate, polyimide, polyetherimide, polyaniline, and chitosan.
  3. The composite separator according to claim 1, wherein a thickness of the anti-fouling layer is 2-100 µm; preferably, a mass ratio of the first polymer, the charge agent, and the anti-fouling agent is (5-30):(0-40):(0-30).
  4. The composite separator according to claim 1, wherein the first polymer is one or more of polyarylsulfone, polyethersulfone, polyphenylene sulfone, bisphenol A-type polysulfone, and polyetheretherketone.
  5. The composite separator according to claim 1, wherein the base membrane comprises a hydrophilic inorganic substance, a second polymer, and a pore-forming aid, a mass ratio of the second polymer to the hydrophilic inorganic substance is 1:1-1:8, and a mass ratio of the pore-forming aid to the second polymer is 1:10-2:1; preferably, a thickness of the base membrane is 100-700 µm.
  6. The composite separator according to claim 5, wherein the second polymer is one or more of polyarylsulfone, polyethersulfone, polyphenylene sulfone, bisphenol A-type polysulfone, and polyetheretherketone; the pore-forming aid is one or more of polyvinylpyrrolidone, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, adduct of polypropylene glycol and ethylene oxide, polyethyleneimine, and polyacrylonitrile; the hydrophilic inorganic substance is one or more of titanium dioxide, zirconium dioxide, cerium oxide, barium sulfate, calcium sulfate, barium titanate, and calcium titanate, preferably, a particle size of the hydrophilic inorganic substance is 5 nm-3 µm.
  7. The composite separator according to claim 1, wherein the base membrane further comprises a support mesh or a support cloth, preferably, a thickness of the support mesh or support cloth is 50-500 µm.
  8. A preparation method for the composite separator according to any one of claims 1-7, comprising: S1, forming an anti-fouling layer slurry using a first liquid pore-forming agent, the first polymer, the charge agent, and/or the anti-fouling agent; S2, coating the surface of a substrate with a casting solution for forming the base membrane, coating the surface thereof with the anti-fouling layer slurry, pre-curing in the air, and then placing in a coagulation bath for curing until the liquid pore-forming agent precipitates to obtain the composite separator.
  9. The preparation method according to claim 8, wherein the casting solution comprises a second liquid pore-forming agent, and an addition amount of the second liquid pore-forming agent accounts for 30%-70% of a total mass of the casting solution; an addition amount of the first liquid pore-forming agent accounts for 30%-70% of a total mass of the anti-fouling layer slurry; preferably, in step S2, a pre-curing time in the air is 3-120 s, a temperature of the coagulation bath is 5-80 °C, a curing time in the coagulation bath is 10 min-2 h, and a solvent in the coagulation bath is deionized water or a mixed solvent of deionized water and one of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.
  10. A use of the composite separator according to any one of claims 1-7 in electrolysis, preferably in alkaline water electrolysis for hydrogen production.

Description

TECHNICAL FIELD The present disclosure relates to the technical field of alkaline water electrolysis for hydrogen production, and specifically to a composite separator, a preparation method therefor, and a use thereof. BACKGROUND In the current industrial hydrogen production, alkaline water electrolysis for hydrogen production has the advantages of high technical maturity and low equipment cost, and can be used for large-scale hydrogen production. As a key material of alkaline electrolyzers, the separator serves the dual functions of separating the gases generated in the positive electrode and negative electrode chambers and providing channels for ion migration across the separator in the electrolyte. As a typical representative of current alkaline water electrolysis for hydrogen production separators, composite separators adopt oxide ceramic powders with hydrophilic properties. Meanwhile, the nanoporous structure can be regulated by controlling the film-forming process, both of which can effectively promote electrolyte diffusion. Compared with other hydrogen production separators, they have obvious advantages in gas barrier properties and reducing ion transport resistance, thus becoming a research hotspot. CN110869538A discloses an asymmetric composite separator. By changing the coagulation temperature and humidity conditions, asymmetric pores on both sides of the separator can be obtained to avoid "bubble trapping", prevent gas crossover, and ensure effective transport of OH- ions. Similarly, the literature (Russian Journal of Applied Chemistry, 2016, 89, 618-621) also reports that adding polyvinylpyrrolidone to the casting solution can significantly improve the porosity and hydrophilicity of polysulfone membranes. Consequently, the current research focus is mainly on improving the hydrophilicity and gas barrier properties of separators, with considerable achievements. However, the contamination of separators by impurities is a common problem in the industry that urgently needs to be solved. Impurities can block membrane pores and cover the membrane surface, thereby greatly reducing electrolysis efficiency. These impurities often come from the shedding or corrosion of catalytic electrodes, the corrosion of system process pipelines and tanks, the introduction of impurities in electrolytes or water, and the like. They exist in the electrolyte in the form of particles or metal ions and are difficult to remove by traditional physical filtration methods. With the progress of electrolysis, they gradually accumulate on the membrane surface or in internal pores, increasing the ion migration resistance of the electrolyte, significantly increasing the voltage of the electrolytic cell, and affecting the service life of the separator. Therefore, to solve the above problems encountered in the actual use of separators, it is necessary to develop an efficient electrolytic composite separator with resistance to impurity contamination. In view of this, the present disclosure is proposed. SUMMARY The present disclosure provides an anti-fouling electrolytic composite separator and a preparation method therefor. The present disclosure provides a composite separator, including a base membrane and an anti-fouling layer disposed on one or both surfaces of the base membrane, wherein the anti-fouling layer includes a first polymer, a charge agent, and/or an anti-fouling agent. According to an embodiment of the present disclosure, the anti-fouling agent is one or more of graphene, graphene oxide, and MXene; the charge agent is one or more of aromatic polyamide, polypiperazine amide, polyamide, cellulose acetate, polyetherimide, polyimide, polyaniline, and chitosan. According to another embodiment of the present disclosure, the thickness of the anti-fouling layer is 2-100 µm; preferably, the mass ratio of the first polymer, the charge agent, and the anti-fouling agent is (5-30):(0-40):(0-30). According to another embodiment of the present disclosure, the first polymer is one or more of polyarylsulfone, polyethersulfone, polyphenylene sulfone, bisphenol A-type polysulfone, and polyetheretherketone. According to another embodiment of the present disclosure, the base membrane includes a hydrophilic inorganic substance, a second polymer, and a pore-forming aid. The mass ratio of the second polymer to the hydrophilic inorganic substance is 1:1-1:8, and the mass ratio of the pore-forming aid to the second polymer is 1:10-2:1; preferably, the thickness of the base membrane is 100-700 µm. According to another embodiment of the present disclosure, the second polymer is one or more of polyarylsulfone, polyethersulfone, polyphenylene sulfone, bisphenol A-type polysulfone, and polyetheretherketone; the pore-forming aid is one or more of polyvinylpyrrolidone, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, adduct of polypropylene glycol and ethylene oxide, polyethylene imine, and polyacrylonitrile; the hydrophilic