The electrochemical doping of rare earth polyacetylene (PA) employing aqueous electrolyte and the electrical potentials of the rare earth polyacetylene were studied. The half-plastic batteries consisting of doped polyacetylene as cathode and magnesium as anode aS well as aqueous solution as electrolyte were fabricated. Also, the electrical characteristics of the rechargeable battery with doped PA cathode and lithium anode in organic electrolyte were investigated. The electrochemical doping of rare earth polyacetylene (PA) employing aqueous electrolyte and the electrical potentials of the rare earth polyacetylene were studied. The half-plastic batteries consisting of doped polyacetylene as cathode and magnesium as anode aS well as aqueous solution as electrolyte were fabricated. Also, the electrical characteristics of the rechargeable battery with doped PA cathode and lithium anode in organic electrolyte were investigated.