Gas diffusion substrate

• Main Authors: SHARMAN JONATHAN DAVID BRERETON, ROWE JULIA MARGARET, SIODLAK JULIAN ANDREW, WALKER NIGEL JULIAN, QUAYLE GEORGE THOMAS, FLETCHER ANDREW JAMES
• Format: Patent
• Language: English
• Published: 13.03.2012
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SEPARATION; TRANSPORTING

A gas diffusion substrate includes a non-woven network of carbon fibres, the carbon fibres are graphitised but the non-woven network has not been subjected to a graphitisation process. A mixture of graphitic particles and hydrophobic polymer is disposed within the network. The longest dimension of at least 90% of the graphitic particles is less than 100 μm. A process for manufacturing gas diffusion substrates includes depositing a slurry of graphitised carbon fibres onto a porous bed forming a wet fibre network, preparing a suspension of graphitic particles and hydrophobic polymer, applying onto, and pulling the suspension into, the network, and drying and firing the network. Another process includes mixing a first slurry of graphitic particles and hydrophobic polymer with a second slurry of graphitised carbon fibres and liquid forming a third slurry, depositing the third slurry onto a porous bed forming a fibre-containing layer, and drying and firing the layer.