Electrolyte Migration Mitigation - The Direct Carbonate Fuel Cell Experience

摘要

Electrolyte movement under the influence of a voltage gradient (called migration) is a common technical consideration among all liquid-electrolyte electrochemical devices (batteries and fuel cells). In these devices during on-load electrochemical operation, ionic species are generated or consumed at electrodes and transported through the electrolyte as well as under the influence of the cell voltage gradient. Ionic species need to migrate to maintain electro-neutrality. The generation, depletion, and movements of charged ions may result in a change of electrolyte volume as well as composition within a cell. Bulk viscous flow via capillary pressure also occurs to try to redistribute and equalize the variation caused by migration. Kunz has reviewed electrolyte migration mechanisms and models in various liquid-electrolyte fuel cells (1), all-influenced by fundamental migration mechanisms.