In a typical design of an alkaline zinc/air button cell, the caustic solution is immobilized by the addition of a thickening agent (e.g., carboxymethyl cellulose) to prevent electrolyte creep and is retained between a polymerbonded porous carbon for the air electrode and a porous zinc electrode. (Sandia National Laboratories)

Key areas to monitor are signs of excessive electrolyte permeation, delamination of the sealant layer from the metal foil, seam splitting, electrolyte creep at the feed-throughs, and reactions between the laminate and the cell components. (US Department of Energy)

The telegraphers would float a layer of oil on top of the open cell "gravity batteries", also known as crow's foot batteries in order to prevent "electrolyte creep", which is the tendency for the electrolyte salts to climb up over the top of the cell. (eHam.net)