Manganese dioxide electrode doped with Bi or Pb compounds and containing a conductive component can be reversibly cycled with exploitation of 50-90% of the theoretical two-electron capacity; however, after 10 or more cycles there is a negative effect of structural changes consisting in dissolution of Mn oxides, blocking of pores, and impairment of the pore electrolyte conductance. The electrode porosity can be increased by adding a powdered, little soluble compound as pore former, which is gradually leached out, leaving pores.