Low mercury content electrochemical cell

摘要

Alkaline electrochemical cells are disclosed having high drain capacities, especially cells having high drain rate capabilities at voltages of at least 1.1 volts for use in small appliances such as hearing aids. Such a cell (10) has an anode (22) with an anode can (24) which contains anode material (26) including potassium hydroxide, zinc powder, 0.02% to 0.5% indium as indium compound separate from the zinc powder, optionally a low level of mercury, and preferably a surfactant comprising hydroxyethylcellulose. The cell (10) has a cathode (40) which provides sufficient oxidative capability to oxidize the zinc at a sufficient rate to support the electrical drain demands on the cell. The cathode (40), preferred zinc air cell for a hearing aid, has a cathode can (44) which includes at least 5 air ports (54), evenly distributed over the surface of the bottom of the cathode can. Such a cell can exhibit prolonged operation at relatively constant voltage over 1.1 volts, and relatively constant power output at a power density of at least about 210 milliwatts per square inch of the reaction surface area of the cathode assembly, for prolonged periods.