37results about How to "Reduced mass transfer polarization" patented technology

The invention discloses a carbon nanofiber, a diffusion layer, a membrane electrode, a fuel cell, a preparation method and an application thereof. The preparation method of the carbon nanofiber comprises the following steps: S1, drying the spinning solution after electrospinning; wherein, the spinning solution includes a polymer and a solvent, and the mass of the polymer in the spinning solution Fraction is 6~10%, described polymer comprises nitrogen-containing polymer, and described nitrogen-containing polymer is one or more in polyacrylonitrile, polyvinylpyrrolidone, polyethylimide and polyaniline; The temperature of the carbonization is 60-80°C; S2, high-temperature carbonization, the temperature of the carbonization is 750-950°C. The diffusion layer prepared by the carbon nanofiber has large pore volume, small material diffusion free path and strong material transmission capacity.

The invention describes an ordered catalytic layer of a membrane electrode, including the construction of an ordered structure, the formation of a metal / alloy that can absorb hydrogen / CO, and the in-situ reduction preparation of a thin-layer catalyst. Some metals or alloys have adsorbed H 2 and the role of CO, the adsorbed H 2 and CO have reducing properties for the preparation of thin-layer catalysts, and the loading of the catalyst is determined by the adsorbed H 2 / CO volume control. The membrane electrode structure prepared by the invention has the advantages of low catalyst loading, high catalyst utilization rate, excellent mass transfer, high stability and the like, while avoiding the use of ion polymers in the catalytic layer as proton conductors.

The invention discloses a flow field plate and an iron-chromium flow battery, comprising an electrolyte solution inlet, an electrolyte solution outlet, an inflow-limiting channel, an outflow-limiting channel, a divided inflow channel, and a divided outflow channel; the electrolyte solution outlet and The outflow-limiting channel is connected, the electrolyte solution inlet is connected to the inflow-limiting channel, the outflow-limiting channel diverges at least two outflow channels, the inflow-limiting channel diverges at least two inflow channels, the outflow channel and the The end of the inflow channel is a blind end; the outflow channel and the inflow channel form a serpentine cross structure or a parallel cross structure. The present invention improves fluid resistance distribution, reduces fluid resistance, and reduces internal bypass current loss, so that internal bypass current loss is controlled within 1%, thereby improving the mass transfer effect of the electrolyte solution in the carbon paper electrode, thus possibly reducing the electrode The mass transfer polarization on .

The invention relates to a carbon-sulfur composite for positive electrodes of lithium-sulfur batteries and its preparation and application. The composite includes carbon materials and elemental sulfur, wherein the carbon materials have a gradient ordered tertiary pore structure, and the pore diameter of the tertiary channels is The distribution range is that micropores less than 2nm are used as primary pores, small mesopores around 3-10nm are used as secondary pores, and large mesopores of 10-30nm are used as tertiary pores. The secondary pores are located on the pore wall of the tertiary pores. The primary pores are located on the pore wall of the secondary pores; the elemental sulfur is filled in the pores of the carbon material, and the elemental sulfur accounts for 10-80wt% of the total amount of the compound. The carbon-sulfur composite is used in lithium-sulfur secondary batteries, exhibits high sulfur utilization rate and good cycle stability, and has the advantages of simple preparation process, good repeatability, low cost and microscopic controllability.

The invention relates to a fuel cell technology and aims to provide a direct methanol fuel cell with homogeneous assisted catalysis and porous carbon-supported platinum catalysis. According to preparation of methanol fuel in the battery, 1 liter of sulfuric acid with a mass concentration of 5 to 10 wt% is taken and heated to 50 to 70 DEG C; 0.1 to 1 mol of V2O5 is added, reacting under stirring for 5 h is carried out, and after filtering, a (VO2)2SO4 sulfuric acid solution is obtained; after cooling to room temperature, 1 to 4 liters of methanol aqueous solution with a mass concentration of 50to 60 wt% are added, (VO2)2SO4 changes to (VO)SO4 through uniform mixing, and modified methanol fuel containing a cocatalyst (VO)SO4 is obtained. Oxidation and carbon monoxide poisoning on the surface of a platinum catalyst in the electrochemical oxidation process of methanol are avoided through the assisted catalytic effect of VO<2+> ions; and the performance of direct methanol fuel cell is improved through the synergy of the high activity of carbon-loaded platinum and the assisted catalytic effect of liquid phase VO<2+> ions. (VO)SO4 can be recycled, the cost can be effectively reduced, andthe application and the popularization of methanol fuel cells are facilitated.

The invention discloses an electrode for electrochemical reduction of carbon dioxide and its preparation and application. It includes a base layer and a Sn catalyst nano-layer attached to the base layer. cm-2, the Sn in the electrode is composed of one or more of 1nm-500nm nanowires, nanorods, and nanofibers. The invention significantly increases the specific surface area and active area of ​​the electrode by in-situ growing Sn nanorods with abundant edge active sites on the substrate, and improves the Faradaic efficiency of the electrode for electrochemically reducing carbon dioxide to formic acid.

The invention discloses a porous conductive additive and a preparation method thereof. The porous conductive additive consists of graphene-based particles, having flaky particle shapes, the size distribution of 0.01-5 microns in a planar direction, the size distribution of 0.1-50 nanometers in a thickness direction, and through holes with the diameters of 1-1000 nanometers inside, with the porosity of 20-70%. The preparation method comprises the following steps of: dispersing a graphene-based material into a solvent to obtain a dispersion solution, adding a pore forming agent in a mass ratio of the pore forming agent to the graphene-based material of 0.1-1000, and performing ultrasonic treatment or mixing to obtain a uniform mixed solution; heating the mixed solution, removing the solvent, drying an obtained solid, and heating the solid in an oxygen-free protective atmosphere to obtain the porous conductive additive. The porous conductive additive has very high conductivity efficiency and can optimize a pore structure in an electrode and reduce ion conducting paths.