Abstract: A cylindrical electrochemical cell includes a cathode, an anode, a cylindrical separator, coaxial with the cell, for electrically separating the cathode and anode, and a cup seal at an end of the separator for electrically separating the anode and cathode and maintaining an ionic connection therebetween. The cup seal is comprised of one or more first layers of a micro-porous or a non-porous membrane, or a combination thereof, and one or more second layers of a porous membrane and wherein the seal overlaps at least a portion of the separator.

Abstract: The zinc active powder for a mercury-free rechargeable electrochemical cell is coated with a surfactant, and separately with an aqueous solution of indium sulphate. Without any subsequent filtering, washing or drying, the powder is assembled into an electrochemical cell. The cell can include a hydrogen recombination catalyst in contact with the electrochemically active material of the cathode.

Abstract: A rechargeable manganese dioxide/zinc cell is provided, where the cell has high capacity, high volumetric and gravimetric energy densities, high cycle life, and is capable of continued charge-discharge cycles following an overdischarge. The cell has an aqueous electrolyte, with the usual solute of potassium hydroxide, but the solute may also be a mixture of zinc chloride and ammonium chloride. The electrode balance as determined by the ration of the theoretical discharge capacity of the zinc and the theoretical one electron discharge capacity of the manganese dioxide ranges from greater than 65% up to 110%. On the 15th discharge, a cell of the present invention will deliver a discharge capacity of at least 20% of the discharge capacity delivered on the first discharge. A cell according to the present invention is capable of continued charge-discharge cycles after overdischarge or voltage reversal.