Abstract: The present invention discloses an iron-based cathode material for a sodium-ion battery, which comprises a Na3Fe2(SO4)3F material and a carbon-based material embedded into the bulk structure of Na3Fe2(SO4)3F material. The weight percentage of the carbon-based material is ranked between 1% and 10%. The present invention also provides a method for preparing the above-mentioned iron-based cathode material for a sodium-ion battery, and a corresponding sodium-ion full battery using the Na3Fe2(SO4)3F-based cathode material. The Na3Fe2(SO4)3F cathode material ensures desired electrochemical sodium storage performance, involving high specific sodium storage capacity, improved cycle stability and superior rate performance in comparison with that of various pristine NaxFey(SO4)z materials.

Abstract: The present invention discloses an iron-based cathode material for a sodium-ion battery, which comprises a Na3Fe2(SO4)3F material and a carbon-based material embedded into the bulk structure of Na3Fe2(SO4)3F material. The weight percentage of the carbon-based material is ranked between 1% and 10%. The present invention also provides a method for preparing the above-mentioned iron-based cathode material for a sodium-ion battery, and a corresponding sodium-ion full battery using the Na3Fe2(SO4)3F-based cathode material. The Na3Fe2(SO4)3F cathode material ensures desired electrochemical sodium storage performance, involving high specific sodium storage capacity, improved cycle stability and superior rate performance in comparison with that of various pristine NaxFey(SO4)z materials.

Abstract: A fluoride ion (F?) colorimetric sensing polyimide (PI) film, a preparation method therefor and application thereof; the preparation method for a F? colorimetric sensing polyimide film comprises: mixing an aromatic diamine monomer and an aromatic dianhydride monomer in a strong polar aprotic organic solvent, adding a catalyst, vacuumizing at room temperature-introducing argon repeatedly for multiple times, and then reacting same under the protection of argon to obtain a polyimide solution; then preparing a PI fiber; dissolving the PI fiber in the strong polar aprotic organic solvent, thoroughly stirring to dissolve same and then applying same evenly on a clean glass plate, removing the solvent, cooling, then soaking same in hot water for film stripping so as to obtain the F? colorimetric sensing PI film.

Abstract: The present invention discloses an iron-based cathode material for a sodium-ion battery, which comprises a Na3Fe2(SO4)3F material and a carbon-based material embedded into the bulk structure of Na3Fe2(SO4)3F material. The weight percentage of the carbon-based material is ranked between 1% and 10%. The present invention also provides a method for preparing the above-mentioned iron-based cathode material for a sodium-ion battery, and a corresponding sodium-ion full battery using the Na3Fe2(SO4)3F-based cathode material. The Na3Fe2(SO4)3F cathode material ensures desired electrochemical sodium storage performance, involving high specific sodium storage capacity, improved cycle stability and superior rate performance in comparison with that of various pristine NaxFey(SO4)z materials.

Abstract: The invention discloses a preparation method of a polyimide film having a low dielectric constant and high fracture toughness; in the method an aromatic diamine solution is firstly prepared, and then a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane) and aromatic dianhydride are ground, uniformly mixed, added to the aromatic diamine solution, and stirred to obtain a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane)/polyamic acid solution; the solution is uniformly applied on a clean glass sheet, then placed in a vacuum drying oven, cooled to room temperature, and then a film is peeled off in water by ultrasonic and dried under vacuum to obtain the desired product. The dielectric constant of the film obtained by the invention is reduced to 2.

Abstract: The present invention discloses a method for preparing a polyimide film having a low dielectric constant and high fracture toughness. The method comprises: first preparing an aromatic diamine solution, and then grinding and well mixing a carbic anhydride-maleimido heptaisobutyl polysilsesquioxane alternating copolymer and aromatic dianhydride; adding the mixture to the aromatic diamine solution, and then stirring to obtain a carbic anhydride-maleimido heptaisobutyl polysilsesquioxane alternating copolymer/polyamide acid solution; uniformly applying the carbic anhydride-maleimido heptaisobutyl polysilsesquioxane alternating copolymer/polyamide acid solution to a clean glass sheet, and then placing the glass sheet in a vacuum drying cabinet for treatment; cooling the treated glass sheet to room temperature and then putting same in water for ultrasonic peeling of a film, and vacuum drying the film to obtain a target product. The dielectric constant of the film obtained in the present invention is reduced to 2.