Proton Exchange Membrane Fuel Cell Gas Diffusion Layer

Example 22

A method for preparing a gas diffusion layer for proton exchange membrane fuel cell, includes steps as follows:

• • (1) preparing the carbon fiber suspension;
  • mixing the carbon fiber dispersion with the fibrous binder dispersion, then adding the ceramic fiber of 1 mm length (zirconia fiber), and then shearing and dispersing at a high-speed rate of 1500 r/min to obtain the carbon fiber suspension;
  • wherein the carbon fiber dispersion consists of the carbon fiber, the dispersant and water;
  • wherein the fibrous binder dispersion consists of the fibrous binder, the dispersant and water;
  • wherein the viscosity of dispersion composed of the dispersant and water is 2000 Pa·s in the carbon fiber suspension;
  • wherein the dispersant is Tween 60; wherein the amount of the dispersant in the carbon fiber suspension is 1.5 wt % of the amount of water;
  • wherein the fibrous binder is the composite filament numbered F-4 in Table 1;
  • wherein the length of the carbon fiber is 10-20 mm, the aspect ratio of the carbon fiber is 100-3000, and the mass of carbon fibers with the aspect ratio in the interval [100, 500) accounts for 10 wt % of the total mass of carbon fibers, the mass of carbon fibers with the aspect ratio in the interval [500, 1000) accounts for 60 wt % of the total mass of carbon fibers, the mass of carbon fibers with the aspect ratio in the interval [1000, 2000) accounts for 25 wt % of the total mass of carbon fibers, and the mass of carbon fibers with the aspect ratio in the interval [2000, 3000] accounts for 5 wt % of the total mass of carbon fibers; wherein the amount of the carbon fiber in the carbon fiber suspension is 5 wt % of the amount of water;
  • wherein the amount of the ceramic fiber is 5 wt % of the amount of the carbon fiber;
  • (2) papermaking and drying the carbon fiber suspension to obtain the carbon fiber base paper;
  • wherein the drying temperature is 140° C. and the drying time is 5 min;
  • in the prepared carbon fiber base paper, wherein the content of the fibrous binder is 30 wt %;
  • (3) cross-linking and curing of the carbon fiber base paper (hot-pressing cross-linking);
  • wherein the temperature of hot-pressing cross-linking is 300° C., the time of hot-pressing cross-linking is 5 min, and the pressure applied to the carbon fiber base paper is 5 MPa;
  • (4) carbonizing and graphitizing the cross-linked carbon fiber base paper under the protection of argon to obtain a gas diffusion layer for proton exchange membrane fuel cell;
  • wherein the carbonization temperature is 1250° C. and the carbonization time is 15 min; wherein the graphitization temperature is 2000° C. and the graphitization time is 5 min.

The prepared gas diffusion layer for proton exchange membrane fuel cell has hydrophilic channels composed of the ceramic fiber, and the pore gradient (that is, the pore size increases or decreases along the thickness direction), and the layer with the smallest pore size is the intrinsic microporous layer; wherein the gas diffusion layer for proton exchange membrane fuel cell has a thickness of 100 μm, a porosity of 70%, a contact angle with water of 145°, a tensile strength of 30 Ma, a normal resistivity of 70 mΩ·cm, an in-plane resistivity of 7 mΩ·cm, and a permeability of 2060 (mL·mm)/(cm2·h·mmAq).