A primary electrochemical cell having an anode comprising lithium and a cathode comprising iron disulfide (FeS2) and carbon particles. The cell is balanced so that the anode is in theoretical capacity excess (mAmp-hrs) compared to the theoretical capacity of the cathode. The anode and cathode can be spirally wound with separator therebetween and inserted into the cell casing with electrolyte then added. The electrolyte comprises a lithium salt dissolved in organic solvent.