Cathode composition for primary battery

An implantable medical device comprising:

• a housing;
• and
• a primary battery within the housing, the primary battery comprising:
• a cathode comprising at least one active material and at least one of a metal oxide and metal fluoride, wherein the active material exhibits a first discharge capacity and the at least one of metal oxide and metal fluoride exhibits a second discharge capacity at a voltage lower than the first discharge capacity,
• an anode comprising a metal as an electron source, and
• an electrolyte between the cathode and anode,
• wherein the metal reacts with the electrolyte below a third discharge capacity at a voltage lower than the second discharge capacity to form a gas, and
• wherein the metal reacts with the active material at the first discharge capacity, and, following the consumption of the active material of the cathode, the metal reacts with the at least one of metal oxide and metal fluoride of the cathode prior to reacting with the electrolyte below the third discharge capacity.