▎ 摘　　要

NOVELTY - Microporous layer comprises silica sol, polyvinyl alcohol, crosslinking agent and graphene. USE - Microporous layer used for gas diffusion layer, and for proton exchange membrane fuel cell which is further used as a power battery in automobiles (all claimed). ADVANTAGE - The microporous layer is formed by the combination of polyvinyl alcohol, silica sol and graphene, with good hydrophobic properties, and gas permeability and effective diffusivity of oxygen, and can reduce the resistance of water and increase the transmission rate of liquid water, hence effectively alleviating flooding. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing a microporous layer, which involves adding graphene to the mixture of silica sol, polyvinyl alcohol and crosslinking agent, and mixing to obtain a composite gel, and then curing the obtained composite gel to obtain the microporous layer; (2) a gas diffusion layer comprises a base layer and a microporous layer on one surface of the base layer, and the base layer is a carbon fiber paper layer; (3) a method for preparing a gas diffusion layer, which involves adding graphene to the mixture of silica sol, polyvinyl alcohol and cross-linking agent, and mixing to obtain a composite gel, and then coating the obtained composite gel on the surface of the base layer and drying, and curing to obtain the gas diffusion layer, and performing the drying in a supercritical device, and the curing temperature is 510-710 degrees C, and the curing time is 5-9 hours; and (4) a proton exchange membrane fuel cell includes a proton membrane exchange layer, a catalytic layer, and a gas diffusion layer stacked together.