Abstract: A nickel-zinc electrochemical cell is disclosed using a polymer matrix separator. The polymer matrix separator includes a polymerization product of one or more monomers selected from the group of water-soluble, ethylenically-unsaturated acids and acid derivatives, and a crosslinking agent, and serves as a primary or supplemental source of electrolyte ionic species for the electrochemistry. Ionic species is contained as a solution phase within the polymer matrix membrane, allowing it to behave as a liquid electrolyte without the disadvantages. In secondary batteries (i.e., rechargeable), polymer matrix membranes are particularly useful as both an electrolyte reservoir and as a dendrite resistant separator between the charging electrode and the zinc electrode. The polymer matrix membrane protects the electrodes from corrosion and prevents zinc oxidation product from the zinc electrode to contaminate the electrolyte.