| 摘要 |
The present disclosure is directed to an electrode active layer or sheet containing from about 60 to 85 weight % active carbon in intimate admixture with 15 to 40 weight % fibrillated PTFE, a process for making said active layer laminated electrodes containing said active layer, and a process for forming said laminates. This electrode has improved strength and is capable of operation at high current density with resistance to mechanical failure due to blistering of the electrode. The process for making the electrode is characterized by combining a dilute dispersion of smaller polytetrafluoroethylene particles with a suspension of catalyzed or uncatalyzed larger active carbon particles to discontinuously coat active carbon with PTFE; fibrillating same; comminuting said fibrillated PTFE/active carbon mix; and then rolling same into a self-sustaining, coherent sheet form. Alternatively, the sheet form can be provided by deposition of the heat treated, "Teflonated" active carbon on a filter paper or like medium containing a bed of soluble salt. The three-layer laminated electrodes of this invention are suitable for use as oxygen (air) cathodes in chlor-alkali and other electrochemical cells, fuel cells and in other electrochemical applications. These three-layer laminates include an active layer or sheet containing from about 60 to about 85 weight % active carbon, the remainder being unsintered, fibrillated polytetrafluoroethylene in intimate admixture with said active carbon, said active layer being laminated on its working surface to a current distributor and on its opposite surface to a porous, coherent, hydrophobic polytetrafluoroethylene-containing wetproofing layer. |
