Porous transport layer, composition for forming same, and method of preparing same

Abstract

Proposed are a porous transport layer (PTL), a composition for forming the same, and a method of forming the same. The porous transport layer contains 30 to 80 wt % of a metallic fiber-type material and 20 to 70 wt % of a metallic particle-type material, with respect to the total weight of the layer. In this case, each metal of the metallic fiber-type material and the metallic particle-type material includes a metal selected from the group consisting of titanium, zirconium, hafnium, nickel, stainless steel, and combinations thereof.

What is claimed is: 
     
         1 . A porous transport layer (PTL) comprising:
 30 to 80 wt % of a metallic fiber-type material; and   20 to 70 wt % of a metallic particle-type material, with respect to a total weight of the layer,   wherein each metal of the metallic fiber-type material and the metallic particle-type material comprises a metal selected from the group consisting of titanium, zirconium, hafnium, nickel, stainless steel, and combinations thereof.   
     
     
         2 . The layer of  claim 1 , wherein the metallic fiber-type material has an average diameter of 10 to 50 μm. 
     
     
         3 . The layer of  claim 2 , wherein the metallic fiber-type material has a length corresponding to 30 to 1,000 times the diameter of the metallic fiber-type material. 
     
     
         4 . The layer of  claim 1 , wherein the metallic particle-type material is derived from a metallic particle-type raw material having an average particle size of 5 to 80 μm. 
     
     
         5 . The layer of  claim 1 , wherein the layer has a surface Ra roughness of 2.5 to 9.5 μm. 
     
     
         6 . The layer of  claim 1 , wherein the porous transport layer has a predetermined pore size in a range of 1 to 70 μm and a pore channel. 
     
     
         7 . The layer of  claim 1 , wherein the layer has a porosity of 30% to 60%. 
     
     
         8 . The layer of  claim 1 , wherein the layer has a gas permeability of 2.8·10 −3  to 8.2·10 −3  cm 4 /gf·s. 
     
     
         9 . The layer of  claim 1 , wherein the layer has a thickness of 100 to 1000 μm. 
     
     
         10 . A composition for forming a porous transport layer (PTL), the composition comprising:
 a metallic fiber-type raw material;   a metallic particle-type raw material; and   a solvent,   wherein the metallic fiber-type raw material and the metallic particle-type raw material have contents of 30 to 80 wt % and 20 to 70 wt %, with respect to a total weight of the metallic fiber-type raw material and the metallic particle-type raw material, respectively, and   wherein each metal of the metallic fiber-type raw material and the metallic particle-type raw material comprises a metal selected from the group consisting of titanium, zirconium, hafnium, nickel, stainless steel, and combinations thereof.   
     
     
         11 . The composition of  claim 10 , further comprising a binder and a dispersant so that the composition comprises:
 21.3 to 56.8 wt % of the metal fiber-type raw material with respect to a total weight of the composition;   14.2 to 49.7 wt % of the metal particle-type raw material with respect to the total weight of the composition;   0.1 to 4 wt % of the binder with respect to the total weight of the composition; and   0.1 to 3 wt % of the dispersant with respect to the total weight of the composition.   
     
     
         12 . The composition of  claim 11 , wherein the dispersant comprises one selected from the group consisting of water, ethanol, methanol, isopropanol, xylene, cyclohexanone, acetone, methyl ethyl ketone, and combinations thereof. 
     
     
         13 . The composition of  claim 11 , wherein the binder includes a material that is thermally degradable at a temperature of 500° C. or lower while allowing binding strength between metallic components to be maintained. 
     
     
         14 . The composition of  claim 13 , wherein the binder comprises one selected from the group consisting of a polyvinyl butyral, a polyvinyl alcohol, a polyvinyl chloride, a polyvinyl acetate, a polyacrylonitrile, and combinations thereof. 
     
     
         15 . A method of forming the porous transport layer (PTL) of  claim 10 , the method comprising:
 (a) removing fat from the composition of  claim 10  through a degreasing process at a predetermined temperature; and   (b) sintering a resulting product obtained in the (a).   
     
     
         16 . The method of  claim 15 , wherein the (a) further comprises a process of shaping the composition. 
     
     
         17 . The method of  claim 15 , wherein the degreasing process in the (a) is performed at the predetermined temperature of 300° C. to 700° C. 
     
     
         18 . The method of  claim 17 , wherein the degreasing process in the (a) is performed by raising a temperature to the predetermined temperature at a heating rate of 1° C./min to 3° C./min and maintaining a same temperature for 1 to 5 hours. 
     
     
         19 . The method of  claim 15 , wherein the sintering in the (b) is performed at a temperature of 900° C. to 1400° C. and a vacuum level of 10 −5  Torr or less.